The Echinoderm Fauna of Ascension Island, South Atlantic Ocean MARINE SCIENCES NUMBER SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTION Emphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the Institution, Joseph Henry outlined a program that included the following statement: " I t is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This theme of basic research has been adhered to through the years by thousands of titles issued in series publications under the Smithsonian imprint, commencing with Smithsonian Contributions to Knowledge in 1848 and continuing with the following active series: Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in Air and Space Smithsonian Studies in History and Technology In these series, the Institution publishes small papers and full-scale monographs that report the research and collections of its various museums and bureaux or of professional colleagues in the world of science and scholarship. The publications are distributed by mailing lists to libraries, universities, and similar institutions throughout the world. Papers or monographs submitted for series publication are received by the Smithsonian Institution Press, subject to its own review for format and style, only through departments of the various Smithsonian museums or bureaux, where the manuscripts are given substantive review. Press requirements for manuscript and art preparation are outlined on the inside back cover. S. Dillon Ripley Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES ? NUMBER 2 The Echinoderm Fauna of Ascension Island, South Atlantic Ocean David L. Pawson SMITHSONIAN INSTITUTION PRESS City of Washington 1978 A B S T R A C T Pawson, David L. The Echinoderm Fauna of Ascension Island, South Atlantic Ocean. Smithsonian Contributions to the Marine Sciences, number 2, 31 pages, 11 figures, 1978.?Two recent intertidal collecting expeditions and existing museum collections have added much to knowledge of the Ascension Island echinoderm fauna. Twenty-five species are now known from Ascension; eight are new records. One new species, Holothuria (Halodeima) manningi, and one new subspecies, Echinometra lucunter polypora, are described. Diadema ascensionis Mortensen is regarded as a subspecies of D. antillarum Philippi, and Pseudo- boletia atlantica H. L. Clark is regarded as a subspecies of P. maculata Troschel. The echinoderm fauna of Ascension Island includes 8 amphi-Atlantic species, 3 western Atlantic species, 4 eastern Atlantic species, 5 circumtropical species, 4 species shared only with St. Helena, and 1 endemic species. There are in addi? tion three endemic subspecies. Twelve species are shared with St. Helena, and both islands are closely similar in terms of numbers and relationships of their faunal components. Colonization of both islands by planktonic larval stages is suggested. Dendrochirotid holothurians, which lack such larval stages, are not represented at either St. Helena or Ascension. The structure of the Ascension fauna seems to have been determined by vagaries of ocean surface and sub? surface currents. In contrast, Bermuda, which sits astride the Gulf Stream, has a fauna that is entirely typical of the West Indian region to the south. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESICN: Seascape along the Atlantic coast. Library of Congress Cataloging in Publication Data Pawson, David Leo, 1938- The Echinoderm fauna of Ascension Island, South Atlantic Ocean. (Smithsonian contributions to the marine sciences ; 2) Bibliography: p. 1. Echinodermata?Ascension Island (Atlantic Ocean) I. Title. II. Series. QL383.35.A8P38 593'.9 77-20941 Contents Page Introduction 1 Previous Records of Echinoderms from Ascension 2 Checklist of Ascension Island Echinoderms 4 Composition of the Ascension Echinoderm Fauna 4 Relationships of the Ascension Echinoderm Fauna 4 How "Isolated" Is Ascension? 6 Material Examined 8 Class STELLEROIDEA 9 Subclass ASTEROIDEA 9 Order PAXILLOSIDA 9 Family ASTROPECTINIDAE 9 Tethyaster magnificus (Bell) 9 Order VALVATIDA 9 Family CHAETASTERIDAE 9 Chaetaster longipes (Retzius) 9 Family OPHIDIASTERIDAE 10 Ophidiaster guildingi Gray 10 Linckia guildingi Gray 10 Subclass OPHIUROIDEA 1 Order OPHIURIDA 1 Family OPHIACTIDAE 1 Ophiactis savignyi (Miiller and Troschel) 1 Ophiactis lymani Ljungman 1 Family AMPHIURIDAE 1 Amphiura capensis Lyman 1 Ophiostigma abnorme (Lyman) L Family OPHIOTHRICIDAE 12 Ophiothrix (Ophiothrix) roseocaerulans Grube 12 Class ECHINOIDEA 12 Order CIDAROIDA 12 Family CIDARIDAE 12 Eucidaris clavata Mortensen 12 Tretocidaris spinosa Mortensen 16 Order DIADEMATOIDA 17 Family DIADEMATIDAE 17 Diadema antillarum ascensionis Mortensen 17 Order ARBACIOIDA 17 Family ARBACIIDAE 17 fCoelopleurus floridanus Agassiz 17 Order TEMNOPLEUROIDA 17 Family TOXOPNEUSTIDAE 17 Pseudoboletia maculata atlantica Clark 17 iii SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Page Tripneustes ventricosus (Lamarck) 20 Order ECHINOIDA 20 Family ECHINOMETRIDAE 20 Echinometra lucunter polypora, new subspecies 20 Echinometra Specimens 22 Summary of Echinometra Morphometric Data 22 Order HOLECTYPOIDA 23 Family ECHINONEIDAE 23 Echinoneus cyclostomus Leske 23 Order CLYPEASTEROIDA 23 Family ROTULIDAE 23 Heliophora orbiculus (Linnaeus) 23 Order SPATANGOIDA 24 Family BRISSIDAE 24 Brissus unicolor (Leske) 24 Class HOLOTHUROIDEA 24 Order ASPIDOCHIROTIDA 24 Family HOLOTHURIIDAE 24 Holothuria (Halodeima) grisea Selenka 24 Holothuria (Halodeima) manningi, new species 26 Holothuria (Thymiosycia) arenicola Semper 27 Holothuria (Platyperona) sanctori Delle Chiaje 27 Family STICHOPODIDAE 27 Isostichopus badionotus (Selenka) 27 Order APODIDA 28 Family SYNAPTIDAE 28 Euapta lappa (Muller) 28 Literature Cited 29 The Echinoderm Fauna of Ascension Island, South Atlantic Ocean David L. Pawson Introduction Ascension Island lies in the South Atlantic at 07?57'S, 14?22W, approximately 150 kilometers west of the centerline of the mid-Atlantic Ridge (Wilson, 1963). It is an entirely volcanic island, comprising the uppermost part of a cone which rises from a depth of about 3000 meters below sea level (Atkins et al., 1964). Daly (1925) has noted that the only nonvolcanic material on the island are "some small patches of beach material thrown up by storm waves." Much of this material is calcareous, derived from calcareous algae and mollusk shells. The island is approximately circular, with an area of about 97 square kilometers (Figure 1). In the absence of fossils and other reliable indicators, it is difficult to determine the length of time that Ascen? sion has stood above sea level. Estimates range from approximately 1.5 million years to considerably less than 1 million years (Sullivan, 1974; Daly, 1922; J. D. Bell (in litt.) in Chace and Manning, 1972). The nearest large land masses are a considerable distance away; the coast of Brazil lies 2200 km to the west, West Africa is 1300 km to the northeast (Figure 2). T o the south, 1100 km away, lies St. Helena, another volcanic island, but considerably older (20 million years; Wilson, 1963) than Ascen? sion. David L. Pawson, Department of Invertebrate Zoology, Na? tional Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. Until very recently, no extensive collections of invertebrates have been made at Ascension, and our knowledge of the echinoderm fauna stems from one or two small collections made during the late 1800s, and visits by Antarctic research vessels during the first half of this century. Dr. R. B. Manning, National Museum of Natural History, visited Ascen? sion in 1971 and made extensive collections of in? vertebrates. The interesting material obtained led to the organization of a second Smithsonian expedi? tion in 1976. This paper is based upon material collected during those two expeditions: Asc. = col? lection stations for 1976 expedition; RBM = col? lection stations for 1971 expedition; USNM ? cata? log numbers using abbreviation for former United States National Museum, collections of which are in the National Museum of Natural History, Smith? sonian Institution. ACKNOWLEDGMENTS.?I am grateful to Dr. R. B. Manning for making a fine collection of echino? derms at Ascension in 1971. A second expedition to the island in 1976 by Dr. Manning, Dr. M. L. Jones, Dr. J. Rosewater and myself, of the National Museum of Natural History, and Dr. A. J. Pro- venzano, Jr., of the Old Dominion University, Nor? folk, resulted in the amassing of an extensive series of shallow water marine invertebrates, among them numerous echinoderms. Mr. Ross Simons of the Office of the Assistant Secretary for Science, Smith? sonian Institution, was especially helpful in making necessary arrangements with the U.S. Air Force and SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES ENGLISH BAY NORTH EAST BAY FORT HAYES COLLYER POINT 7 U 5 7 I S ? MCARTHUR POINT TURTLE SHELL BEACH SOUTH WEST BAY SHELLY BEAC l a 52 w FICURE 1.?Outline map of Ascension Island, showing collecting localities. with the Administrator of Ascension Island. The Administrator, Mr. Jeffrey C. Guy, the U.S. base commanders Major Henry Spangler and Lieutenant Colonel Thomas Morris, and the head of the NASA tracking station, Mr. Jefferson Speck, were most helpful to us during our stay at Ascension. Our expenses were met by a grant from the Smithsonian's Fluid Research Fund; we are grateful to Mr. S. Dillon Ripley, Secretary of the Smithsonian Institu? tion, for his support. For the loan of additional study material, I wish to thank Miss Ailsa M. Clark of the British Museum (Natural History), Dr. F. Jensenius Madsen, Uni- versitetets Zoologiske Museum, Copenhagen, and Dr. Lowell P. Thomas, University of Miami. The photographs were made by Mr. V. Krantz, the maps and graphs by Irene Jewett. Miss Tamara A. Vance assisted with measurements of echinoids and col? lation of data. I thank Drs. M. L. Jones and R. B. Manning for reviewing the manuscript. Partial sup? port for preparation of this paper was derived from a grant made by the Smithsonian Research Founda? tion (SRF 71500525). PREVIOUS RECORDS OF ECHINODERMS FROM ASCENSION The first record of an echinoderm from the island was that of Cuninghame (1699:298), who made the following observations: One small warted Barbadoes sea egg. Echinus ovarious Bar- bad, verrucis plur imis minor ibus Mus. Petiver 123. T h e spines of these are purpl ish , especially the tips, the largest I have yet seen, exceed not a crow-quill in thickness, and are scarce an inch long; they end pointed, and are finely striated if strictly viewed. T h e naked shell of this was some? what more than six inches in circumference, and about 5 broadways and 5y2 lengthways. Bell (1881:437) suggested that this "small warted Barbadoes sea egg" was undoubtedly a specimen of Echinometra sub angular is Leske (= E. lucunter (Linnaeus)); Cunninghame's description fits that species admirably. In the same paper Bell listed the following species from Ascension Island: Bell's name Cidaris metularia Lamarck Diadema setosum Gray Tripneustes angulosus Leske Echinometra subangularis Leske Echinoneus cyclostomus Leske Rotula dentata Leske Linckia diplax Miiller and Troschel Current ly accepted name Eucidaris clavata Mortensen Diadema antillarum ascensionis Mortensen Tripneustes ventricosus (Lamarck) Echiyxometra lucunter polypora Pawson Same Heliophora orbiculus (Linnaeus) Linckia guildingi Gray NUMBER 2 FIGURE 2.?Central Atlantic Ocean, showing principal islands. During the early part of this century, several ships paused briefly at Ascension, when they were returning from expeditions in the southern oceans, and made collections, usually by dredging. Koehler (1908) reported the following species from Ascen? sion, collected by the Scotia: Current ly accepted name Tethyaster magniftcus (Bell) Koehler's name Moiraster magniftcus (Bell) Chaetaster longipes (Retzius) Amphiura capensis Lyman Tretocidaris spinosa Mortensen Cidaris minor, new species }Coelopleurus floridanus Agassiz Echinometra subangularis (Leske) Pseudoboletia maculata Troschel Same Same Same Eucidaris clavata Mortensen Same Echinometra lucunter polypora Pawson Pseudoboletia maculata atlantica Clark dema ascensionis Mortensen (now D. antillarum ascensionis) at Ascension, according to Mortensen (1909). As a result of a visit by the Discovery, Fisher (1940) noted the presence of Ophidiaster guildingii at Ascension, and Mortensen (1936) listed the fol? lowing species: The Deutsche Sudpolar-Expedition collected Dia- Mortensen's name Ophiothrix roseocaerulans Grube Ophiactis savignyi (Muller and Troschel) Ophiostigma abnorme (Lyman) Eucidaris tribuloides (Lamarck) Diadema antillarum var. ascensionis Mortensen Echinometra lucunter (Linnaeus) Current ly accepted name Same Same Same Eucidaris clavata Mortensen Diadema antillarum ascensionis Mortensen Echinometra lucunter polypora Pawson SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Thus, at the time of writing of this paper, 17 species of echinoderms were known from Ascension. The following checklist lists all 25 known species in systematic order; new records are marked with an asterisk (*). ful (see p. 11). The single juvenile specimen of Coelopeurus recorded from Ascension was identi? fied by Koehler (1908) as C. floridanus Agassiz; this identification must remain in doubt until adult specimens are found. CHECKLIST OF ASCENSION ISLAND ECHINODERMS CRINOIDEA None ASTEROIDEA Family OPHIOTHRICIDAE Tethyaster magniftcus (Bell) Family CHAETASTERIDAE Chaetaster longipes (Retzius) Family OPHIDIASTERIDAE Ophidiaster guildingi Gray Linckia guildingi Gray OPHIUROIDEA Family OPHIACTIDAE Ophiactis savignyi (Muller and Troschel) * Ophiactis lymani L jungman Family AMPHIURIDAE 7 Amphiura capensis Lyman Ophiostigma abnorme (Lyman) Family OPHIOTHRICIDAE Ophiothrix (Ophiothrix) roseocaerulans Grube ECHINOIDEA Family CIDARIDAE Eucidaris clavata Mortensen Tretocidaris spinosa Mortensen Family DIADEMATIDAE Diadema antillarum ascensionis Mortensen Family ARBACIIDAE ?Coelopleurus floridanus Agassiz Family TOXOPNEUSTIDAE Pseudoboletia maculata atlantica H . L. Clark Tripneustes ventricosus (Lamarck) Family ECHINOMETRIDAE Echinometra lucunter polypora Pawson Family ECHINONEIDAE Echinoneus cyclostomus Leske Family ROTULIDAE Heliophora orbiculus (Linnaeus) Family BRISSIDAE *Brissus unicolor (Leske) HOLOTHUROIDEA Family HOLOTHURIIDAE *Holothuria (Halodeima) grisea Selenka ^Holothuria (Halodeima) manning!, new species ^Holothuria (Thymiosycia) arenicola Semper *Holothuria (Platyperona) sanctori Delle Chiaje Family STICHOPODIDAE *Isostichopus badionotus (Selenka) Family SYNAPTIDAE *Euapta lappa (Muller) The record of Amphiura capensis Lyman is doubt- COMPOSITION OF THE ASCENSION ECHINODERM FAUNA The fauna as it is known today comprises 25 species (Table 1), of which one, Amphiura capensis, is a doubtful record. The identity of Coelopleurus floridanus has yet to be confirmed. Eight species are reported from Ascension for the first time, but only one of these, Holothuria manningi, is new. There are some notable absentees from the fauna. No members of the holothurian Order Dendro- chirotida have yet been found, despite the fact that these "cucumaria-type" holothurians are common on both sides of the Atlantic Ocean (see below for discussion). No crinoids are known from Ascension. It is also surprising that many species that are amphi-Atlantic in distribution and can tolerate a variety of habitats are apparently absent from Ascension. These include such common shallow- water forms as Linckia bouvieri Perrier, Axiognathus squamatus (Delle Chiaje), Ophiocoma pumila Liitken, Ophioderma appressum (Say), and Ophio- lepis paucispina (Say). RELATIONSHIPS OF THE ASCENSION ECHINODERM FAUNA As can be seen from Table 1, the relationships of the echinoderm fauna of Ascension are complex: 8 species (32%) are amphi-Atlantic; 1 species (4%) is restricted to Ascension; 3 species (12%) are also known from the western Atlantic only; 4 species (16%) are also known from the eastern Atlantic only; 5 species (20%) are circumtropical in distribu? tion; 4 species (16%) are also known from St. Helena only; 12 species (48%) are shared by Ascen? sion and St. Helena. These figures are similar to those for the mol- lusks given by Rosewater (1975). The only notable difference lies in the fact that 5 of the 89 Ascension mollusk species (6%) occur at Ascension and St. Helena only, while 4 of the 25 echinoderms (16%) have this distribution pattern. There is some indi? cation here that Ascension-St. Helena are more NUMBER 2 TABLE 1.?Relationships of Ascension echinoderms (+ = present; O = present as species, but not as subspecies listed; ? = doubtful record) Ascension echinoderms A sc en si on A m ph i-A tla nt ic W es te rn A tla nt ic E as te rn A tla nt ic G os m op ol ita n- c ir cu m tr op ic al St . H el en a St . H el en a a n d A sc en si on + + + + + + + + + + + + + + + + + + o ? + + ? o + + + ? 0 + + + + + + + + + + + + + 1 8 3 b 5 12 6 "isolated" for the echinoderms than for the mol- lusks, but little weight can be attached to such slender evidence. The relationships expressed in the above per? centages imply that propagules have reached Ascen? sion from the east and from the west. It seems likely that colonization of Ascension was mediated by surface and subsurface transport of planktonic larval stages. Briggs (1974) has pointed out that Ascension lies on the "northern limb of the South Atlantic gyre where the water movement is relatively rapid and the direction of flow almost due west." He notes that if this pattern of surface water flow were con? stant, then one would expect that for the fishes there would be a strong relationship with West Africa. But this is not so, and Briggs suspects that Ascension comes under the influence of the east- SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES ward-flowing Equatorial Countercurrent for at least part of the year. The equatorial undercurrent, flowing eastward at velocities of around 0.8 to 2.9 knots (Metcalf et al., 1962; Sturm and Voigt, 1966; Voigt, 1975), with a core which may range from the surface to (usually) around 75 meters, has been suggested by Chesher (1966) as a likely route for transportation of larvae of echinoids across the Atlantic from west to east, thereby maintaining genetic continuity between populations of amphi-Atlantic species. Chesher cal? culated that larvae might make the trans-Atlantic trip in a minimum of 43 days and a maximum of 70 days. Scheltema (1968, 1971) suggested that the undercurrent would be a potent dispersal agent for his so-called teleplanic molluscan larvae. The true extent of the equatorial undercurrent is not known. Most authors estimate that it extends southwards to a latitude of around 2?S. Possibly then the current might not directly influence the fauna of Ascension, which lies at latitude 7?57/S, some 600 km away. Some alternative mechanisms for trans-Atlantic transport of pelagic larval stages have been dis? cussed by Scheltema (1968, 1971) for the North Atlantic; similar patterns of current flow exist for the South Atlantic. For successful transport of larvae in the North or South Atlantic gyres, the larvae must be eurythermal and long-lived. Six of the ten mollusk species discussed by Scheltema in 1971 have larval lives of at least three months; two others can reach the settling state in less than two months; these two, plus the remaining two species, can probably delay metamorphosis until conditions are suitable for settlement. Regrettably, very little is known about the actual larval life span of echinoderms. The excellent in? vestigations of Mortensen (1921, 1931, 1938) and others are mostly descriptive. For Ascension Island species, the following in? formation is available. Linckia guildingi: In the related L. multifora the late brachiolaria stage is reached after 27 days (Mortensen, 1938); in L. laevigata metamorphosis can take place after 22 days (Yamaguchi, 1973). Ophiactis savignyi: Late ophiopluteus is reached after 21 days (Mortensen, 1931). Eucidaris clavata: In the closely related E. tribuloides metamorphosis takes place after about 25 days (McPherson, 1968). Tripneustes ventricosus: Fully developed larva after 22 days (Mortensen, 1921). Echinometra lucunter: Metamorphosis takes places after 19 days (Mortensen, 1921). Holothuria species: In H. impatiens metamorphosis can take place after 21 days, and in H. difficilis after 14 days (Mortensen, 1938). Devaney (1973) extracted estimates of average lengths of larval life for tropical echinoderms from Thorson (1946) as follows: Number of days 0-9 10-20 21-30 31-40 41-50 Percentage of species 7 33 26 17 13 While the figures given above provide some use? ful guidelines, it must always be borne in mind that metamorphosis can be delayed for considerable periods of time if proper food and/or proper sub? strate are not available, or if physical factors such as temperature and salinity are not optimal (Thor? son, 1950). The fact that Ascension appears to have received colonists from the east and from the west leads to the suggestion that the important surface and sub? surface currents mentioned above are not exerting a continuous influence on the island's fauna. Lati? tudinal shifts in currents accompanied by extensive midocean eddies (Robinson, 1976) over the past one million years have no doubt had important effects upon composition of the Ascension fauna. How "ISOLATED" IS ASCENSION? Oceanic islands are useful natural laboratories for investigation of effects of isolation upon their resi? dent populations of animals and plants. MacArthur and Wilson (1967) noted that new populations arriving on an island might pass through three overlapping evolutionary phases. During the first phase, genetic divergence from the "mother" popu? lation might take place (founder effect: see Mayr, 1963) because the colonizing population is small, and contains fewer genes than the "mother popula? tion" (the founder principle.) There is some experi? mental evidence in support of the founder prin? ciple (see MacArthur and Wilson, 1967) but some critics have suggested that many colonizations are made by successive waves of propagules, and that large fractions of the genetic variation of the mother population can be inserted into the founder popula- NUMBER 2 tion, thus reducing genetic drift to a low level. During the second phase, adjustments are made to the new environment. The third phase comprises speciation, secondary emigration, and radiation. It is assumed that Ascension has been available for colonization only within the past one million years or so. The Ascension fauna offers some excel? lent possibilities for exploration of the effects of isolation. Many of the Ascension echinoderm species are consistently different in a variety of ways from their conspecifics elsewhere. The reader is referred to the systematic section of this paper for details, but some species are worth mentioning here in this context. Ophiactis lymani: Ventral arm plates with convex distal edges in St. Helena and Ascension forms. Specimens of this species from the eastern and western Atlantic do not have convex distal edges on ventral arm plates. Diadema antillarum ascensionis: Tridentate pedicellariae in Ascension and St. Helena popula? tion (also Fernando de Noronha ?) with curved valves. Valves essentially straight in eastern and western Atlantic populations of this species (Dia? dema antillarum antillarum). Pseudoboletia maculata atlantica: There are usually five pore-pairs to the arc in Ascension and St. Helena populations of this species. In Pseudo? boletia maculata maculata there are typically four pore-pairs. Echinometra lucunter polypora: Ascension and St. Helena populations have seven pore-pairs to the arc, and the test is purplish adapically. In Echino? metra lucunter lucunter there are typically six pore- pairs, and the test is greenish or white adapically. Holothuria (Halodeima) grisea: In comparison with West Indian specimens of this species, Ascen? sion specimens have smaller buttons with more numerous larger perforations, and the ossicles in the tube feet are a different shape. Holothuria (Platyperona) sanctori: In Ascension and St. Helena specimens of this species, the but? tons have numerous small knobs. In contrast, speci? mens from the eastern Atlantic and Mediterranean have buttons with very few knobs or with none. These striking and consistent differences from presumed "mother" populations prompt enquiry as to whether they might be environmentally or genetically induced. In the absence of experimental evidence (rearing of specimens from different At? lantic localities in uniform environments would be most informative), it is almost impossible to answer the question. If the differences are genetic, one must presume that Ascension is genetically isolated from the eastern and western Atlantic, but not from St. Helena, and that recruitment of newly settling juveniles is entirely internal. There is some evidence to indicate that Ascension is genetically isolated to a considerable degree. Amphi-Atlantic populations of many species are virtually identical morphologically, and a genetic continuity across the Atlantic has been postulated for the echinoids by Chesher (1966). But in the case of Ascension, it is notable that (1) several amphi- Atlantic species appear not to have been able to colonize this island, and that (2) many taxa, in? cluding Eucidaris clavata, Diadema antillarum ascensionis, and Echinometra lucunter polypora appear to have originated from populations else? where in the Atlantic, but have not been "swamped" by continuing recolonization, nor have populations of these taxa apparently become established in other parts of the Atlantic (Fernando de Noronha may be the exception; this area of the Atlantic requires further investigation). It also seems evident that colonization by plank- tonic larval stages is the only method by which the Ascension echinoderms have reached the island. The absence of dendrochirotid holothurians is attribu? table to the fact that these animals generally lack planktotrophic larvae. Some dendrochirotids dis? perse by rafting on floating weed. In the tropics, and certainly in the case of Ascension, this method of colonization is not common. The Ascension-St. Helena fauna might be inter? preted as being in the third evolutionary phase in the sense of MacArthur and Wilson (1967). This is the phase of "speciation, secondary emigration, and radiation." The process of speciation is obviously slow, but establishment of subspecies, especially in the echinoids, is proceeding rather rapidly. One might contrast the fauna of Ascension with that of Bermuda, another isolated island, which lies 1075 km away from the nearest land-mass. The known echinoderm fauna of Bermuda now com? prises approximately 50 species (Pawson, in MS); none of these are endemic to Bermuda, and all are common in the West Indian region. Only one species, Lytechinus variegatus (Lamarck), shows slight but consistent differences from its West 8 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Indian conspecifics. Bermuda is a relatively much older island than Ascension (36 million years), and thus might be expected to have developed some endemic species. The single overwhelming factor influencing the Bermuda fauna, however, is the Gulf Stream; this gigantic river must be rapidly transporting endless numbers of larval and early juvenile stages of echinoderms from the West Indies to Bermuda. No equivalent physical factor exists for Ascension. MATERIAL EXAMINED This report is based upon material from several sources. In 1970, Storrs Olson, National Museum of Natural History, took time from his search for fossil birds to make some shore collections; these included species of echinoderms. Stimulated by Dr. Olson's discoveries, R. B. Manning visited the island in May 1971, and made general collections of shallow-water marine invertebrates; these in? cluded an excellent series of echinoderms. Further material was obtained during a second visit in July 1976, to Ascension by a party comprising R. B. Manning, M. L. Jones, J. Rosewater, A. J. Pro- venzano, Jr., and me. A specimen of Ophidiaster guildingii collected at Ascension by Mr. A. Love- ridge, together with ophiuroids and asteroids col? lected by the U.S. Eclipse Expedition to West Africa in 1890 are described in this report. Some echino? derms collected a few years ago by Mrs. K. M. Hutchfield, a former resident of Ascension, and deposited in the British Museum (Natural History) were kindly sent to me for study by Miss Ailsa M. Clark. The small collection in the Ascension His? torical Society Museum at Fort Hayes was examined during July 1976. In the station list below only the 1971 Manning expedition and the 1976 expedition stations are listed. Miscellaneous records are given under the relevant species accounts. The number of specimens is indicated after the author of the species. R. B. MANNING'S 1971 EXPEDITION TO ASCENSION RBM 3: 18 May 1971, T u r t l e Shell Beach, beach and rocky point (MacArthur Point) at no r the rn edge of South West Bay, coarse sand beach and rocky intert idal , 1900-2030, R B M and D. Rogers Holothuria grisea Selenka, 1 RBM 5: 19 May 1971, Nor th East Bay Beach and tidepools on rocky poin t west of main beach, t empera tu re 27?C, salinity 38%o, 0900-1100, RBM, D. Rogers, P. Kashulines Ophidiaster guildingi Gray, 1 Ophiothrix (Ophiothrix) roseocaerulans Grube , 1 Eucidaris clavata Mortensen, 1 (found dry on beach, not represented in collections) Echinoneus cyclostomus Leske, 2 R B M 9: 20 May 1971, T u r t l e Shell Beach (MacArthur Point) , nor thern edge of South West Bay, t idepool wi th sand bot tom in lava flow area, 0800-0930> RBM and P. Kashulines Isostichopus badionotus (Selenka), 1 RBM 10: 20 May 1971, rocky po in t at no r the rn edge of English Bay, in ter t ida l pools a n d subt idal rocky shore, some coarse sand bot tom, t empera tu re 27?C, salinity 39%o, 1430- 1900, RBM and P. Kashulines Eucidaris clavata Mortensen, 1 Holothuria (Halodeima) grisea Selenka, 1 R B M 12: 21 May 1971, T u r t l e Shell Beach, nor thern edge of South West Bay (MacArthur Point) , t idepool wi th sand bot tom in lava flow area, 1200-1630 Ophiothrix (Ophiothrix) roseocaerulans Grube , 7 Echinometra lucunter polypora Pawson, 1 RBM 13: 22 May 1971, rocky poin t off Fort Hayes, George? town, algal mats in inter t idal , 0800-1100, R B M and D. Rogers Holothuria (Thymiosycia) arenicola Semper, 1 RBM 14: 22 May 1971, rocky flat near Collyer Point , rock surface at low tide wi th dense algal mat , area locally known as Cable and Wireless Beach, 1100-1130, R B M and D. Rogers Echinometra lucunter polypora Pawson, 1 RBM 15: 22 May 1971, same locality as sta 10, bu t second tidepool from shore as well as more isolated tidepool, 1330- 1600, RBM, D. Rogers, K. Double Ophiothrix (Ophiothrix) roseocaerulans Grube , 1 Eucidaris clavata Mortensen, 1 Echinoneus cyclostomus Leske, 1 Holothuria (Platyperona) sanctori Delle Chiaje, 2 RBM 16: 22 May 1971, Shelly Beach, flat exposed at low tide on open beach proper , 1830-2330, R B M and D. Rogers Eucidaris clavata Mortensen, 1 Diadema antillarum ascensionis Mortensen, 2 RBM 18: 23 May 1971, Shelly Beach, tidepools in flat exposed at low tide on open beach, t empera tu re 27?C, salinity 40%o, 1000-1200, RBM, D. Rogers, K. Double Ophiothrix (Ophiothrix) roseocaerulans Grube , 8 Schinometra lucunter polypora Pawson, 2 R B M 20: 23 May 1971, same as sta 14, 1900-2030, R B M Eucidaris clavata Mortensen, 1 Echinometra lucunter polypora Pawson, 2 R B M 21: 24 May 1971, rocky point at no r the rn edge of Eng? lish Bay, tidepools on rocky flat, 0800-1200 Ophiothrix (Ophiothrix) roseocaerulans Grube , 4 Ophiactis savignyi Muller and Troschel , 2 Isostichopus badionotus (Selenka), 1 RBM 22: 24 May 1971, T u r t l e Shell Beach, nor the rn edge of South West Bay (MacArthur Point) , t idepool about 20 feet in diameter wi th clear, soft sand bot tom, 1300-1700 Ophiothrix (Ophiothrix) roseocaerulans Grube , 1 Eucidaris clavata Mortensen, 1 NUMBER 2 Diadema antillarum ascensionis Mortensen, 1 Echinometra lucunter polypora Pawson, 3 Holothuria (Thymiosycia) arenicola Semper, 2 RBM 23: 25 May 1971, same as sta 22, 0800-1030, RBM, K. Double Eucidaris clavata Mortensen, 1 Diadema antillarum ascensionis Mortensen, 5 RBM 24: 25 May 1971, same as sta 14, 1030-1230, R B M and K. Double Diadema antillarum ascensionis Mortensen, 7 Echinometra lucunter polypora Pawson, 17 RBM 24: 25 May 1971, same as sta 14, t empera ture high pool 42?C, shore pool 38?C, salinity high pool 32%o, shore pool 28%o, 1300-1530 Ophiothrix (Ophiothrix) roseocaerulans Grube , 1 T H E 1976 EXPEDITION TO ASCENSION Asc. 1-76: 11 Ju l 1976, MacArthur Point , t empera ture 25?C, salinity 34%o IB, associated with rocks Ophiothrix (Ophiothrix) roseocaerulans Grube , 12 Ophiactis savignyi (Muller and Troschel), 2 Eucidaris clavata Mortensen, 7 Echinometra lucunter polypora Pawson, 27 Holothuria (Halodeima) grisea Selenka, 8 1C, in clumps of coralline algae Ophiothrix (Ophiothrix) roseocaerulans Grube, 12 Ophiactis savignyi (Muller and Troschel), 1 Echinometra lucunter polypora Pawson, 3 Asc. 3-76: 12 J u l 1976, English Bay, t empera ture 28?C (inner pool), 25?C (outer pool), salinity 34%o 3A, sand, inner t idepool Isostichopus badionotus (Selenka), 1 3C, associated wi th rocks beyond outer pool Ophiothrix (Ophiothrix) roseocaerulans Grube, 10 Ophiactis savignyi (Muller and Troschel), 2 Eucidaris clavata Mortensen, 1 3D, associated wi th rocks, outer pool Eucidaris clavata Mortensen, 13 Holothuria (Halodeima) grisea Selenka, 6 Holothuria (Platyperona) sanctori Delle Chiaje, 3 3G, collected by snorkeling in 5-10 m beyond outer tide pool, calcareous sand and rock bo t tom Holothuria (Halodeima) manningi Pawson, 3 Asc. 5-76: 13 Ju l 1976, Shelly Beach, t empera tu re 31?C, salin? ity 3496o 5A, isolated tide pools in back of open shore Ophiothrix (Ophiothrix) roseocaerulans Grube , 2 Ophiactis savignyi (Muller and Troschel) , 6 Holothuria (Halodeima) grisea Selenka, 1 Holothuria (Thymiosycia) arenicola Semper, 2 Asc. 6-76: 14 J u l 1976, Collyer Point , t empera ture 26?C, salinity 34%o 6A, isolated tide pools Ophiothrix (Ophiothrix) roseocaerulans Grube , 48 Ophiactis lymani L jungman, 1 Echinometra lucunter polypora Pawson, 2 Echinoneus cyclostomus Leske, 1 6B, associated with exposed rocks Ophiothrix (Ophiothrix) roseocaerulans Grube , 3 Eucidaris clavata Mortensen, 4 Diadema antillarum ascensionis Mortensen, 4 Asc. 7-76: 14 July 1976, off Collyer Point , diving, collected by Mr. K. Jourdan Ophidiaster guildingi Gray, 1 Ophiothrix (Ophiothrix) roseocaerulans Grube , 2 Echinometra lucunter polypora Pawson, 1 Asc. 8-76: 15 Ju l 1976. MacAr thur Point , isolated tide pool Ophiothrix (Ophiothrix) roseocaerulans Grube , 3 Asc. 9-76: 16 J u l 1976, Northeast Bay, t empera tu re 25?C, salinity 34%o 9C, isolated tide pool Ophiothrix (Ophiothrix) roseocaerulans Grube , 7 Ophiactis savignyi (Muller and Troschel) , 1 9D, associated with rocks in the inter t idal Holothuria (Platyperona) sanctori Delle Chiaje, 1 Class STELLEROIDEA Subclass ASTEROIDEA Order PAXILLOSIDA Family ASTROPECTINIDAE Tethyaster magniftcus (Bell) Archaster magniftcus Bell, 1882:440. Monaster magniftcus.?Koehler, 1908:630, pi. 12: figs. 107? 110.?Mortensen, 1933a:422, pi. 21 : figs. 1-2, p i . 22: fig. 1. Tethyaster magniftcus.?A. M. Clark and A. H . Clark, 1954: 16, pis. 9, 10: figs. 2e-g. MATERIAL EXAMINED.?None. DISTRIBUTION.?This species is known only from St. Helena (40 meters) and Ascension Island (72 meters). Order VALVATIDA Family CHAETASTERIDAE Chaetaster longipes (Retzius) Chaetaster longipes.?Koehler, 1908:632.?Mortensen, 1933a: 431. MATERIAL EXAMINED.?USNM 17473, Ascension Island, 77 m, collected by Wil l iam Harvey Brown, 28 Mar 1890, U.S. Eclipse Expedi t ion to West Africa, 4 specimens. 10 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES REMARKS.?The four specimens are typical of the species in all respects. Largest specimen has R = 52 mm. DISTRIBUTION.?Madsen (1950) gives the distri? bution of this species as western Mediterranean, European Atlantic coast as far north as Bretagne, off West Africa, Morocco and Cape Palmas, St. Helena, the Cape Verdes, the Canaries, and the Azores, in 30-1140 meters. HABITAT AT ASCENSION.?Not known. Family OPHIDIASTERIDAE Ophidiaster guildingi Gray FIGURE 3 Ophidiaster guildingii.?Clark, 1921a:79.?Fisher, 1940:269. MATERIAL EXAMINED.?RBM 5, 1 specimen; Asc. 1B-76, 6 specimens; Asc. 3D-76, 1 specimen; Asc. 7-76, 1 specimen. Ascension Island, collected A. Loveridge, 31 Aug 1963, 1 specimen. REMARKS.?The smallest specimen has R = 10 mm (station RBM 5); the largest has R = 52 mm. The ratio R / r = approximately 1:8. When alive, all specimens were mottled light and dark orange- brown, and none were unicolor red. The adambu- FICURE 3.?Left, Ophidiaster guildingi Gray from Ascension. Right , O. ophidianus (Lamarck) from the Azores. Note con? spicuous difference in shape of adambulacra l spines. lacral spines (see Figure 3) conform exactly to the description of H. L. Clark (1921a), and, thus, in all respects the Ascension specimens concur with Clark's concept of this species. Fisher (1940) was of the same opinion concerning a specimen collected at Ascension by the Discovery. Mortensen (1933a) re? corded O. ophidianus (Lamarck) from St. Helena, noting that his specimens were either uniformly red or had mottled coloration; he doubted that the two species could be separated on the basis of color alone. Chapman (1955) records O. ophidianus from the Azores without comment, and this species also occurs at the Cape Verde Islands (see A. M. Clark, 1955). The question of the validity of the two species and their limits of variation can be settled only by a thorough study of several scattered popu? lations. DISTRIBUTION.?Common throughout the West Indies (Clark, 1921a), and recorded from Ascension by Fisher (1940). O. ophidianus is known from the Mediterranean, West Africa, and the islands men? tioned above. HABITAT AT ASCENSION.?On underside of rocks or exposed in intertidal zone. Also present sub- tidally (Asc. 7-76). Linckia guildingi Gray Linckia diplax.?Bell, 1881:437. Linckia guildingii.?Clark, 1921a:67.?Madsen, 1950:216. MATERIAL EXAMINED.?Brit ish Museum (Natural History) Catalogue No. 1972.1.21.3, collected Mrs. K. Hutchfield, 1 specimen; Catalogue No. 81.10.27.15, collected T . Conry, 1 specimen. REMARKS.?Both specimens undoubtedly repre? sent this widespread species. One specimen (Cata? logue No. 81.10.27.15) is that which was identified by Bell (1881) as Linckia diplax. DISTRIBUTION.?As Clark (1921) points out, this seems to be "a truly tropicopolitan species of sea- star, absent only from the western coast of America." It has not been reported from St. Helena; according to Mortensen (1933a) another species which he named Linckia formosa occurs there. L. formosa is apparently most closely related to the amphi- Atlantic species, L. bouvieri Perrier. HABITAT AT ASCENSION.?Not known. Probably same as for preceding species. NUMBER 2 11 Subclass OPHIUROIDEA Order OPHIURIDA Family OPHIACTIDAE Ophiactis savignyi (Muller and Troschel) Ophiactis savignyi.?Mortensen, 1933a:442; 1936:264.?Clark, 1955:36.?Madsen, 1970:207, fig. 33. MATERIAL EXAMINED.?RBM 21, 4 specimens; Asc. 1B-76, 2 specimens; Asc. 1C-76, 1 specimen; Asc. 3C-76, 2 specimens; Asc. 5A-76, 6 specimens; Asc. 9C-76, 1 specimen. REMARKS.?All specimens have six arms and all possess the very large radial shields that render this species readily recognizable. DISTRIBUTION.?According to Madsen 1970) this species has a circumtropical distribution in littoral- sublittoral depths. It has been recorded from Ascen? sion by Mortensen (1936) and also from St. Helena (Mortensen, 1933a). HABITAT AT ASCENSION.?Under rocks in tide pools. Not uncommon in clumps of coralline algae. Ophiactis lymani Ljungman Ophiactis lymani.?Mortensen, 1933a:442, fig. 15 ?Clark, 1955:35, fig. 12.?Madsen, 1970:208, fig. 34. MATERIAL EXAMINED.?Asc. 6A-76, 1 specimen. REMARKS.?This species has been well illustrated by all of the authors cited in the synonymy above. The single specimen from Ascension is typical in most respects. Disc spines are virtually absent, there being only one or two at the base of each arm. Mortensen (1933a) pointed out that in St. Helena specimens the ventral arm plates have convex distal margins, whereas in populations from elsewhere, the distal margins tend to be concave. In the pres? ent specimens the distal margins are convex on all ventral arm plates until approximately the 12th arm joint, where the margins become concave, and then they remain so throughout the length of the arm. In alcohol the disc is light and dark gray mottled, and the arms are light brown and dark gray mottled. DISTRIBUTION.?Madsen (1970) described this species as an amphi-Atlantic sublittoral form, known from several localities off tropical West Africa, from the Cape Verdes to northern Angola in 0-90 meters, from the Virgin Islands in the West Indies, and from St. Helena (10-110 meters). The present record from Ascension is therefore not unexpected. HABITAT AT ASCENSION.?Under rock in isolated tide pool. Family AMPHIURIDAE Amphiura capensis Lyman Amphiura capensis.?-Koehler, 1908:634. MATERIAL EXAMINED.?None. REMARKS.?Koehler recorded this species from Ascension Island, and it has not been collected there since. Mortensen (1933a) seriously doubted the valid? ity of this record, and suggested that there had been a mistake with the locality labels. Further doubt is cast upon the validity of Koehler's identi? fication by Mortensen's (1933b) restudy of Koehler's (1914) presumed Amphiura capensis from Angola and Senegal; Mortensen found that these specimens comprised two genera, neither of which was an Amphiura. Ophiostigma abnorme (Lyman) Ophiostigma abnorme.?Mortensen, 1936:293.?Clark, 1955: 38.?Madsen, 1970:200, fig. 29. MATERIAL EXAMINED.?USNM 17488 Ascension Island, 36- 54 m, collected by William Harvey Brown, 25 Mar 1890, U.S. Eclipse Expedition to West Africa, 1 specimen; USNM 17489, as above, 72 m, 5 specimens. REMARKS.?The six specimens are in fair condi? tion; they are typical examples of this species. None have numerous spines on the upper surface of the disc; at best they are sparsely scattered. DISTRIBUTION.?Madsen (1970) notes that this is an amphi-Atlantic sublittoral species. It is also known from the Cape Verdes. Mortensen (1936) first recorded O. abnorme from Ascension. HABITAT AT ASCENSION.?Not known; has been taken at 16-27 m (Mortensen 1936) and at 36-72 m. 12 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Family OPHIOTHRICIDAE Ophiothrix (Ophiothrix) roseocaerulans Grube Ophiothrix roseocaerulans.?Koehler, 1904:97.?Mortensen, 1933a:440, pi. 22: figs. 5-7; 1936:2262. Ophiothrix (Ophiothrix) roseocaerulans.?A. M. Clark, 1967: 647. MATERIAL EXAMINED.?RBM 5, 1 specimen; RBM 12, 7 specimens; R B M 15, 1 specimen; RBM 18, 9 specimens; RBM 21, 5 specimens; R B M 22, 1 specimen; RBM 25, 1 specimen. Asc. 1B-76, 12 specimens; Asc. 1C-76, 12 specimens; Asc. 3C-76, 10 specimens; Asc. 5A-76, 2 specimens; Asc. 6A-76, 48 specimens; Asc. 6B-76, 3 specimens; Asc. 7-76, 2 specimens; Asc. 8-76, 3 specimens; Asc. 9C-76, 7 specimens. South West Bay (MacArthur Point), sandy bot tom tide pool, collected by Storrs Olson, 12 Ju l 1970, 2 specimens; Ascension Island, from dead Cymatium shell, collected K. Jourdan , Ju l 1976, 1 specimen. REMARKS.?These are typical specimens of this beautiful species. The color is highly variable, as Mortensen (1933a) had noted for his St. Helena material. Most commonly shades of blue to purple are represented, but light blue and even pink speci? mens were collected at Ascension. A. M. Clark (1967) in her revision of the family Ophiotrichidae referred this species to the typical subgenus Ophi- othrix (Ophiothrix). DISTRIBUTION.?The species is known to occur only at St. Helena (see Mortensen, 1933a) and at Ascension. HABITAT AT ASCENSION.?Almost ubiquitous in the intertidal, encountered in clumps of coralline algae, under rocks, and in crevices. It was common at all stations sampled. Class ECHINOIDEA Order CIDAROIDA Family CIDARIDAE Eucidaris clavata Mortensen FICURES 4-7 Cidaris metularia.?Qe\\, 1881:436. Cidaris tribuloides juv.?A. Agassiz, 1881:36, pi. I: figs. 3, 5, 6. Cidaris minor Koehler, 1908:638, pi. 16: figs. 136-138. [Al? though C. minor Koehler, 1908, seems to be the oldest available n a m e for E. clavata, it is not available, as Mor? tensen (1928) has pointed out, because it is preoccupied by at least two earlier homonyms.] Eucidaris tribuloides.?Clark, 1925:21 [in par t ] ?Mortensen, 1936:213, pi. 1: figs. 13-15 [in pa r t ] . Eucidaris clavata Mortensen, 1928:408, pi. 42: figs. 1-4; pi . 67: figs. 10-11, pi . 73: fig. 2, pi. 86: fig. 15; 1932:169, pi . 4: figs. 3-5; 1933a:464. Not Cidaris minor Koehler, 1914:217 [=Eucidaris tribuloides africana~\. REMARKS.?The status of the species E. clavata has been in doubt for some time. On the basis of St. Helena material, Mortensen described his new species E. clavata in 1928, and later (1932, 1933a) reinforced his opinion of the validity of the spe? cies. Clark (1925) called attention to the clavate spines of his St. Helena specimens, but also noted that not all specimens had such spines. Later, Mortensen (1936) described some small specimens from Ascension as E. tribuloides and noted their similarity to specimens from Annobon, West Africa (now Pagalu, Equatorial Guinea), which he re? garded as representing a "var. africana." Compara? tive measurements made upon small numbers of specimens (2 from Annobon, 6 from Ascension, 4 from West Indies) of small size (largest specimen 18 mm h.d.) tended to support his contention. Ex? amination of larger series of mature specimens for the present paper show that Mortensen's conclu? sions were erroneous, that the Ascension Eucidaris is identical to the St. Helena form, and quite dis? tinct from the West African-West Indian species. A complete description of E. clavata is not in? cluded here; details can be found in Mortensen (1928, 1932). However, it is necessary to discuss those characters that are of apparent systematic importance. Relationship between Areole Width and Width of Median Area of Interamb: Mortensen (1936) measured the width of a primary areole at the ambitus, and compared this with the width of the median area of the interamb. He found that in two West African species measured the areole width exceeded slightly the width of the median area; by contrast, in three West Indian specimens of E. tribuloides the areole width was less than the width of the median area. This supposed differ? ence, together with some others of a minor nature, led Mortensen to erect a new variety, E. tribuloides africana, for the West African forms. I have made additional measurements of some "typical" West Indian E. tribuloides, and these are presented graphically herein (Figure 4). It is apparent that NUMBER 2 13 0 0 1 I h h 0 0 i i B. 0 o ?- g a 0.9 ? 0.7? Q.S ? o ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? o o o # ? ? ? ? 1 ? 1 I 3 0 a o 5 0 EO HORIZONTAL D IAMETER OF TEST ( M M ) FIGURE 4.?Comparison of Eucidaris tribuloides (Lamarck) with E. clavata Mortensen (for details, see text). tribuloides ? clavata (Ascension) ? clavata (St. Helena) Q the relationship between dimensions of median area and areole approaches unity (median area width as percentage of areole width: mean 97%) and that, in fact, Mortensen's use of this character to distinguish a new variety africana was not justi? fiable. Chesher (1972) has plotted the same parame? ters to distinguish E. tribuloides from E. thouarsii; his graph shows the same results for the relation? ship between areole and median interamb area in E. tribuloides sensu stricto as does Figure 4 herein. In the case of Ascension and St. Helena Eucidaris, the situation is somewhat different (see Figure 4). Here, the areole is almost twice as wide as the median interamb area (interamb width as per? centage of areole width: mean 51.5%). It is be? lieved that this character is important in distin? guishing E. clavata from E. tribuloides. Relationship between Diameter of Peristome and Diameter of Apical System: As shown in Figure 5, for E. tribuloides from West Africa and from the West Indies area, the peristome and apical sys? tem have approximately the same diameter (apical system diameter as percentage of peristome diame? ter: mean 102%). The West African and West 14 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES 1 . 2 - 1 . 1 - I . O - 0 . 9 - o . a - 0 . 7 - o 1 D ? ? ? ? ? ? ? ? ? ? ? ? o ? o o ? ? ? ? ? ? ? ? ? 1 ? ? ? ? a ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? o o o ? ? o ? 1 1 ? ? ? ? ? ? ? ? ? o ? ? ? ? i ? ? i I D 2Q 3D a O E H O R I Z O N T A L D IAMETER OF TEST ( M M ) FIGURE 5.?Comparison of Eucidaris tribuloides (Lamarck) with E. clavata Mortensen (for details, see text). tribuloides (West Indies) ? (West Africa) ? clavata (Ascension) ? (St. Helena) Q Indian specimens are indistinguishable in respect to this relationship. In contrast, in Ascension and St. Helena Eucidaris, the peristome is considerably larger than the apical system (apical system diame? ter as percentage of peristome diameter: mean 77%). This character also is regarded as important in distinguishing Ascension-St. Helena Eucidaris from its congeners on each side of the Atlantic. Shape of the Spines: Mortensen (1928, 1932) regarded the shape of the spines as a feature of paramount importance in distinguishing E. clavata from E. tribuloides. He noted that while many of his St. Helena specimens had the club-shaped spines (such as those shown in Figure 6a-b herein) others, NUMBER 2 15 b *Sk . &'? f FIGURE 6.?Eucidaris clavata Mortensen: a, St. Helena, 20-30 meters; b, St. Helena, 20-30 meters; c, St. Helena, shore; d, Ascension, shore; e, Ascension, shore; /, St. Helena, 20-30 meters (Specimens a-c, f are in the Zoological Museum, Copenhagen.) 16 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES particularly from the intertidal area, had more slender, almost cylindrical, spines (Figures 6c-e, 7). In Ascension specimens the spines are almost in? variably cylindrical (Figures 6e, 7); on occasional specimens a tendency towards clavate form is ex? hibited (Figure 6d), but in no case were specimens with truly club-shaped spines found. No deeper water specimens have yet been recovered at Ascen? sion (apart from Koehler's (1908) Cidaris minor), so the true range of spine shape for the Ascension Eucidaris is not yet known. Examination of a great variety of specimens of western Atlantic E. tribu? loides from a variety of habitats in the collections of the National Museum of National History re? vealed not one specimen with a tendency to form club-shaped spines similar to those from St. Helena. It is believed that, while presence of club-shaped spines is a useful indicator of the identity of this species, this character is highly variable in its expression, and, consequently, is not completely reliable. Affinities of E. clavata: E. clavata is readily dis? tinguished from E. tribuloides on the basis of rela? tionships between dimensions of peristome and periproct, relationships between width of ambital areoles and width of median interamb areas, and, to a lesser extent on the shape of the spines. McPherson (1968) measured some specimens of Eucidaris from Ascension to complement his study of shape and growth of E. tribuloides, and he re? garded the Ascension forms as conspecific with E. tribuloides sensu stricto. He did not analyze his data, however, in a way which would have indicated the obvious differences that exist, for such an analy? sis was not relevant to his study. E. clavata may be derived from E. tribuloides, as has been suggested by Mortensen (1933a). The eastern Pacific species E. thouarsii closely resembles E. clavata in terms of the relationship between diameter of peristome and apical system, and in relationship between areole width and width of median interamb area. T h e two species are dis? tinctly separated on the basis of color alone. A form from the Galapagos Islands, often referred to as E. galapagensis (Doderlein) resembles E. clavata in having club-shaped spines. The interesting parallel was noted by Mortensen (1928), who commented in some detail upon the status of E. galapagensis. The complex of taxa, tribuloides-clavata-thouarsii- galapagensis, requires a thorough analysis, based upon large series of specimens. The present arrange? ment of the species is even now not completely satisfactory. T h e intriguing question about forma? tion of club-shaped spines at isolated oceanic islands has yet to be investigated; a genetic basis is suggested by the slender evidence available. DISTRIBUTION.?E. clavata is known only from Ascension and St. Helena, in depths of 0-60 meters. HABITAT AT ASCENSION.?All specimens were found either lodged in rock crevices or under rocks, always on hard substrates. Mostly smaller specimens of up to 38 mm h.d. were found intertidally. Sub- tidally, within snorkel diving range, considerably larger specimens were found (50+ mm h.d.), usually wedged inextricably in deep crevices. Off St. Helena, Mortensen (1932) found numerous specimens lodged in holes and cavities of the sponge Chondrosia plebeia Schmidt at depths of 20-30 meters. Tretocidaris spinosa Mortensen Tretocidaris spinosa Mortensen, 1903:17, 28, pi. 10: figs. 10, 11, 16.?Koehler, 1908:636, pi. 16: figs. 163, 164.?Morten? sen, 1928:317, pis. 33: figs. 1-3, pi. 34: figs. 1-2, pi. 67: fig. 9, pi. 71: fig. 15, pi. 82: figs. 32-36; 1932:154, pi. 4: figs. 6-12, 15, pi. 13: fig. 3; 1933a:465. FIGURE 7.?Spines from specimens of Eucidaris clavata Mortensen, Ascension Island. MATERIAL EXAMINED.?None. DISTRIBUTION.?Known from Ascension (72 me? ters) and St. Helena (50-60) meters. NUMBER 2 17 Order DIADEMATOIDA Family DIADEMATIDAE Diadema antillarum ascensionis Mortensen Diadema setosum?Bell, 1881:436. Diadema ascensionis Mortensen, 1909:55, pi. 7: fig. 10, pi. 16 figs. 1, 4, 8, 16-17, 21-23; 1940:279, pi .48: fig. 2, pi. 54 fig. 4, pi. 61: figs. 6-11, pi. 73: figs. 14-16.?Tommasi, 1966 11, figs, 3-5?Lima-Verde, 1969:10.?Brito, 1962:5; 1971 264, fig. 1. Diadema antillarum.?Clark, 1925:42 [in part]. Diadema antillarum var. ascensionis.?Mortensen, 1933a:465; 1936:216. MATERIAL EXAMINED.?RBM 16, 2 specimens; RBM 22, 1 specimen; RBM 23, 5 specimens; RBM 24, 7 specimens; Asc. 6B-76, 4 specimens. Turtle Shell Beach (MacArthur Point), rocky tide pools, collected by Storrs Olson 18 Jun 1970, 1 specimen. REMARKS.?The status of the Ascension-St. Helena populations of Diadema has been the sub? ject of considerable discussion, mainly on the part of Mortensen (1909, 1933a, 1936, 1940). His final conclusion was that these populations should be re? garded as a separate species from D. antillarum Philippi. The main character upon which the separation was based is the shape of the tridentate pedicellariae, the blades of which are distinctly curved in D. ascensionis, while they are more or less straight in typical D. antillarum. This char? acter appears to be reasonably consistent, although a survey of USNM material of D. antillarum revealed that slightly curved tridentate pedicellariae are com? mon. Mortensen (1940) also stated that in D. ascen? sionis the median series of primary tubercles in the interambs are arranged almost in a straight line, whereas in D. antillensis the series remain distinct; thus, in D. ascensionis there appear to be five series of tubercles in each interamb. Again, this character seems to be consistent for Ascension populations, but numerous specimens of D. antillarum in USNM collections show exactly the same type of tubercle arrangement. Mortensen (1940) also notes that the spines of St. Helena specimens are "somewhat coarser" than those of D. antillarum; this is not a reliable character, for the size of the spines can vary considerably within populations. In view of the broad distribution of D. antillarum (see below), and the apparent restriction of D. ascen? sionis to Atlantic islands or island groups, it would seem wisest to regard D. ascensionis merely as a subspecies of D. antillarum. DISTRIBUTION.?D. a. antillarum occurs on both sides of the Atlantic, in the west from Bermuda south to Brazil, perhaps to 23?S (Tommasi, 1966), and in the east from Cape Verde to the Gulf of Guinea (Angola) on the African coast, also the Azores, Canaries, and Madeira Islands. D. a. ascen? sionis is known from Ascension (Mortensen, 1909) and St. Helena (Mortensen, 1933a), Fernando de Noronha (Clark, 1925; Mortensen, 1940), also Isla Trindade (Brito, 1971) and Atol das Rocas (Lima- Verde, 1969). Atol das Rocas is only 200 km from the coast of Brazil, and possibly the Diadema there is antillarum rather than ascensionis. Bathymetric range is 0-360 meters. HABITAT AT ASCENSION.?Common in tide pools, in rock crevices, and partially concealed under rocks. Order ARBACIOIDA Family ARBACIIDAE "iCoelopleurus floridanus Agassiz Coelopleurus floridanus.?Koehler, 1908:640.?Mortensen, 1935:612, pi. 68: figs. 5-7, p. 88: figs. 17-18, 31-34. MATERIAL EXAMINED.?None. REMARKS.?The juvenile specimen, 9 mm in diameter, upon which Koehler (1908) based his identification is the only specimen of this genus so far known from Ascension. As Mortensen (1935) points out, only additional adult material will settle the question of the identity of the species. He also notes that the Ascension form may be C. floridanus, or the African species C. interruptus Doderlein, or perhaps a new species. DISTRIBUTION.-?Ascension Island, 72 meters (Koehler, 1908); western Atlantic from West Indies to Cape Hatteras, U.S.A., in 90-2380 meters (Mor? tensen, 1935). Order TEMNOPLEUROIDA Family TOXOPNEUSTIDAE Pseudoboletia maculata atlantica Clark Pseudoboletia maculata.?Koehler, 1908:641, pi. 15: figs. 139- 142, pi. 16: fig. 165. 18 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Pseudoboletia atlantica.? Clark, 1912:344; 1925:131.?Morten? sen, 1933a:467; 1943:534, pi. 32: figs. 1-5, pi. 39: fig. 6, pi. 40: fig. 6, pi. 42: figs. 1-3, pi. 43: figs. 1-2, pi. 44: fig. 1, pi. 55: figs. 1, 3, 19, 20. MATERIAL EXAMINED.?No specimens in collections being described here. REMARKS.?Koehler (1908) was the first to record this species (as P. maculata) from Ascension, the two specimens being collected at a depth of 40 fathoms off Point Pyramid. Clark (1912) regarded the Ascension specimens as a new species, P. atlan? tica, and Mortensen (1933a) reported the species from St. Helena. Study of the literature of this species and of an? other Atlantic Ocean species, P. occidentalis Clark, together with examination of specimens of both (Table 1), has led to the conclusion that P. atlantica should be regarded as subspecies of P. maculata Troschel and that P. occidentalis is a junior syno? nym of P. maculata. A brief analysis is given here of the features used in the past to distinguish these taxa. Pseudoboletia MATERIAL EXAMINED.?P occiden? talis Clark: holotype (USNM E4531); 4 specimens (USNM E12353) from off Venezuela, 83-186 meters, diameters 63, 69, 78, 79 mm; 3 specimens (USNM El6203, El6204) from off Florida north of Miami, 19-21 meters, diameters 60, 76, 85 mm. P. atlantica Clark: 3 specimens (USNM El6096, diameter 71 mm; USNM El 1732, diameter 82 mm; USNM E5953, diameter 89 mm) from St. Helena. Spicules in Gills: In the gills of both P. atlantica and P occidentalis spicules of the bihamate and C- shaped type are numerous. The C-shaped spicules appear to be more numerous than the bihamate type in P atlantica, and the reverse might appear to be true in P occidentalis, but it was found that the relative proportions of the types of spicules can depend to a great extent upon the area of gill that is being studied. The same is probably true for P. maculata. It is concluded that this character is unreliable. Mortensen (1943:537) referred to the "remarkable differences from [the Indo-Pacific spe? cies] indiana and maculata . . ." in the matter of the spicules of P. atlantica, but apparently did not regard a supposed difference as being important sys? tematically. Number of Plates on the Periproct: Clark (1921b: 116-117) noted that "In maculata the periproct is covered by about 30 plates," and that in P. occi? dentalis there are "about 20 plates." In the four additional specimens of P. occidentalis examined there are more than 30 plates in the periproct, and the same situation applies in specimens of P. at? lantica. Clearly, no reliance can be placed upon this character, as has already been pointed out by Mortensen (1943). Size and Shape of Primary Spines: Clark (1921b) noted that the ambital primary spines of P. occi? dentalis are "about 12 mm long, terete basally, and becoming flattened only slightly near tip"; this sit? uation he contrasted with that in P. maculata, where the spines are "markedly flattened, with bluntly chisel-shaped tips (though with a terminal concavity), and are 14-16 mm long." The primary spines of the additional specimens of P. occidentalis examined are typically 15 mm or more in length, often approaching 20 mm. They are terete basally, and the degree of flattening near the tip is highly variable. Ambital spines of P. atlantica are similiar, but tend to be shorter, averaging approximately 14 mm in length. First Appearance of Inner Primary Tubercle: Clark (1921:117) notes that in P. maculata the inner primary tubercle in the ambs appears first on the seventh, eighth, or ninth plate from the ocular plate in specimens 52-55 mm in diameter, whereas in his specimen of P. occidentalis it occurs first on the tenth-twelfth plate. In the additional specimens of P. occidentalis, the tubercles first ap? pear on the eighth to the 14th plate from the ocular; the number of plates are correlated to some extent with size of the specimen. In a specimen of 63 mm h.d., the first tubercle appears on plates 8-9 from the ocular, while in a specimen of 78 mm h.d. it appears on plates 11-14. In P. atlantica the tubercles appear on plates 8-10 from the ocular. These figures confirm Clark's (1921b) own sugges? tion that this character is "inconstant and unreli? able." Color of Test: The dark brownish or greenish blotches which appear to characterize P. maculata are also present on the holotype of P. occidentalis. They are present and conspicuous in most specimens of the additional material of P. occidentalis. Mor? tensen (1943) notes that in P. atlantica the blotches may be absent, or that there may be some darker spots or bands in the median spaces aborally. It is NUMBER 2 19 evident that in the Atlantic Pseudoboletia the test coloration is somewhat variable. Color of Spines: In all specimens of P occidentalis examined, the color of the spines has faded some? what, but in most cases the spines are greenish basally and pale fawn elsewhere, or almost totally white. In the holotype and most non-type specimens, spines located on the greenish blotches on the test are mostly dark green, light only at the tips, a feature already noted by Clark (1921b) for the holotype. In P. atlantica, according to Mortensen (1943) the spines may be whitish, with green or brown basal areas, or they may be banded with dull green or brown. Clark (1921b) noted that in P. maculata the spines are "green at base and red- purple or reddish at tip . . . quite different from the pale colors of occidentalis." Pedicellariae: In his original description of P. occidentalis, Clark (1921b) did not describe the pedicellariae in detail, and Mortensen (1943) ex? pressed regret that Clark had not illustrated the tridentate pedicellariae he had described as "slender, with valves 1.25 mm long." I could find no such pedicellariae on the holotype or on the additional specimens of P occidentalis. All of the tridentate pedicellariae found were of the broad-bladed type, none of them exceeding 1.1 mm in total length. In all features these pedicellariae closely resembled those of P. maculata, P atlantica, and P. indiana. It is impossible to determine from Mortensen's (1943) figures of tridentate pedicellariae from these three species exactly how they differ from each other, although he mentions (p. 533, 537) that they are essentially the same in P. atlantica and P. indi? ana, and that those of P indiana and P. maculata differ. I do not believe that these differences, what? ever they might be, are significant. The globiferous pedicellariae also present a con? fusing picture. Mortensen (1943:531) notes that the globiferous pedicellariae in P. indiana "are as in P. maculata," but two pages later (p. 533) he states that the smaller globiferous pedicellariae "differ rather conspicuously in the length of the blade, it being distinctly longer than the basal part in maculata, scarcely as long as the basal part in in? diana." His figures show a conspicuous difference in the pedicellariae of these two species. The same type of pedicellariae in P. atlantica are virtually identical to those of P. maculata, and in P. occiden? talis a condition resembling that in P. maculata was found, although the blade appears to be relatively shorter. An extensive study of large series of pedicellariae from many parts of the world might settle the several problems that exist with regard to the pedicellariae in this genus, but on the basis of the admittedly scanty evidence now available, it would seem that they do not afford the best characters for distinction of species in Pseudoboletia. Number of Pore-Pairs to the Pore-Arc: All species in the genus Pseudoboletia have four pore-pairs in each pore-arc, except P. atlantica, which has five. In this respect, P. atlantica forms an interesting parallel to Echinometra from Ascension (see p. 22). The presence of five pore-pairs has been noted by Mortensen (1943) in a large specimen of P. indiana 75 mm in diameter, and, conversely, P. atlantica frequently has arcs of four pore-pairs. Mortensen (1943) states: The pore-pairs are in general arranged in arcs of 5 . . . . But this is by no means constantly so; some specimens have in the main only 4 pore-pairs, or there may be here and there a plate with only 4 pairs, most of the plates having 5 pore- pairs. This has nothing to do with age; thus the specimen of 94 mm h.d. . . has in the main 4-geminate plates, whereas the specimens of 62 and 68 mm have regularly 5-geminate plates. In the present collection, all specimens of P. occi? dentalis have four pore-pairs to the arc, and all specimens of P. atlantica have five. It is concluded that the only reasonably consistent difference between P. atlantica and other species in the genus is the presence of five pore-pairs in each pore-arc. There appears to be no evidence for main? taining P. occidentalis as a species distinct from P. maculata; all of the distinguishing features enu? merated by Clark fall within the range of variation of P. maculata. Further, in view of the fact that some other echinoid species at Ascension Island have undergone some phenetic changes as a result of isolation, environment, or a combination of the influences of these factors, the presence of five pore- pairs would not appear to be sufficient to warrant maintenance of P. atlantica as a separate species, distinct from P. maculata, and it is here recognized as a subspecies of P. maculata. The status of P. maculata in relation to P. indiana cannot be determined here. 20 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES DISTRIBUTION.?P. maculata atlantica is so far known only from Ascension and St. Helena in 20-40 meters. P. maculata maculata is known from Ceylon, the Philippines and the Macclesfield Bank, and the Banda and Timor Sea in 20-70 meters (Mortensen, 1943), also southern Japan (Utinomi, 1954); in the western Atlantic, P. m. maculata is known from off Barbados (holotype of P. occiden? talis), from off Venezuela in 83-186 meters, and from off southeastern Florida in 19-21 meters. Tripneustes ventricosus (Lamarck) Tripneustes angulosus.?Bell, 1881:437. Tripneustes esculentus.?Clark, 1925:124. Tripneustes ventricosus.?Mortensen, 1943:490. MATERIAL EXAMINED.?None. REMARKS.?Bell (1881) first reported this species (as T. angulosus) from Ascension and Clark (1925) referred again to Bell's specimen, confirming its identity as T. esculentus (=T. ventricosus). No fur? ther specimens of the species have been taken at Ascension, in spite of assiduous intertidal and sub? tidal collecting in what would seem to be suitable habitats for the species. Mortensen (1933a) was inclined to believe that the record of this species from St. Helena (Cunning? ham, 1910) was erroneous, for he found no further material in his collecting around that island. In fact, he suggested that the material of this species which was described by Cunningham may have been collected at Ascension. DISTRIBUTION.?Common in the West Indies and the west coast of Africa (Mortensen, 1943). The rec? ords from Ascension and St. Helena must be re? garded as questionable. Order ECHINOIDA Family E C H I N O M E T R I D A E Echinometra lucunter polypora, new subspecies FIGURES 8-10 Echinometra acufera Mellis, 1875:219. Echinometra subangularis.?Bell, 1881:437.?Koehler, 1908: 640.?Cunningham, 1910:125. Echinometra lucunter.?Clark, 1925:143 [in part].?Morten? sen, 1933a:468; 1936:224 [in part]; 1943:357, pi. 41: figs. 1-5, pi. 42: figs. 12-14, pi. 43: figs. 1-13, pi. 44: fig. 9, pi. 64: figs. 17, 20-24 [in part]. MATERIAL EXAMINED.?Holotype: USNM E16206, RBM 24, 25 May 1971, Ascension Island, rocky flat near Collyer Point, rock surface at low tide with dense algal mat, collected by R. B. Manning and K. Double. Paratypes: USNM E16190, RBM 24, 16 specimens (same data as holotype); USNM E16186, RBM 12, 1 specimen; USNM EI6179 (4), USNM E16191 (1), RBM 14, 5 specimens; USNM E16184, RBM 18, 2 specimens; USNM E16185, RBM 20, 2 specimens; USNM E16187, RMB 22, 3 specimens; USNM E16180, Asc. 1B-76, 27 specimens; USNM E16181, Asc. 1C-76, 3 specimens; USNM E16189, Asc. 6A-76, 2 specimens; USNM E16182, Asc. 7, 1 specimen; USNM E16183, Turtle Shell Beach (MacArthur Point), rocky tide pools, collected Storrs Olson 18 Jun 1970, 3 specimens. DIAGNOSIS.?Like E. I. lucunter, except that there are predominantly 7 pore-pairs to the arc, when greatest test diameter of approximately 32 mm is reached. Upper surface of test with conspicuous tinge of purple; no trace of green color adapically. REMARKS.?While I am reluctant to erect sub? species in a group that is poorly known in so many ways, there seem to be excellent grounds for regard? ing the Ascension and St. Helena populations of E. lucunter (Linnaeus) as distinct from the "typi? cal" amphi-Atlantic populations. Mortensen (1933a, 1943) has already called attention to differences that he noted in St. Helena specimens of this species, and my examination of larger samples of speci? mens from Ascension and elsewhere tend to confirm Mortensen's observation (for the St. Helena speci? mens) that they are "about to develop into a sepa? rate variety" (1943:366). Mortensen's observation (1943:366) that the Ascension Echinometra are dif? ferent from St. Helena specimens in some respects are contradicted by my present findings, and I could find no morphological differences between Ascen? sion and St. Helena. DISTRIBUTION.?Ascension and St. Helena, inter? tidal and shallow subtidal. HABITAT AT ASCENSION.?This is by far the most common intertidal species at Ascension. Specimens were found in great numbers in high splash pools, in pools between tidemarks, and in rock faces at and slightly below low tide level. While most were occupying shallow burrows in the volcanic rock, many were lodged in crevices or were exposed on the rock surface (Figure 8). Commonly, specimens were found in association with Diadema antillarum NUMBER 2 21 FIGURE 8.?Two contrasting habitats for Echinometra lucunter polypora at Collyer Point, Ascension Island: upper, specimens on surface of rock; lower, specimens occupying burrows. (Photos: R. B. Manning.) 22 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES ascensionis. J. Rosewater (pers. com.) found small clusters of the gastropod mollusk Hipponyx anti- quatus (Linnaeus) in the bottoms of several of the burrows after removal of Echinometra. This may be merely a fortuitous association, for numerous specimens of the gastropod were also found in other habitats, not associated with Echinometra. Approxi? mately 20 specimens of Echinometra were washed in formaldehyde in search of commensals; none were found. Echinometra Specimens COLOR OF TEST.?In all specimens from Ascen? sion, the upper part of the cleaned test has a dis? tinct purple tinge; the test is white elsewhere. By contrast, all specimens from the western Atlantic examined have the test either more or less white, or more often with a greenish tinge to the upper part of the test. Color of specimens from Annobon, off West Africa (now Pagalu, Equatorial Guinea) is variable; some specimens have greenish tests, some have a very pale purplish tinge, while others are virtually white. According to Koehler (1914), the West African specimens he examined are indistin? guishable from the West Atlantic forms. Mortensen (1943) noted that West African specimens are "darker," but apparently he was referring to color of the spines. Specimens from St. Helena are all purplish adapi- FIGURE 9.?Ambulacrum of Echinometra lucunter polypora, new subspecies, showing arcs of 7 pore-pairs. cally (Mortensen, 1933a) as they are in USNM col? lections. COLOR OF SPINES.?Mortensen (1943) noted that the spines "show all intermediates between wholly black and wholly white. . . . It is very noteworthy however that all the numerous specimens from St. Helena, Ascension, and West Africa that I have seen are black." The living specimens at Ascension appeared quite black upon superficial examination. Preserved and dried specimens have dark green spines with purplish tips. The same coloration can be found in specimens from Annobon, off West Africa (USNM El2263). NUMBER OF PORE-PAIRS.?Mortensen (1943) noted that in West Indian specimens of E. lucunter the number of pore-pairs is "more generally 6 (though often 7) to each arc," while in St. Helena specimens there are "almost constantly 7 (or often 8. . . ." The number of pore-pairs in Ascension specimens were counted and results are given below, together with data gathered from series of E. lucunter from the eastern Atlantic (Annobon) and the western Atlantic (St. Croix, Virgin Islands; Key West, Flor? ida; and Curacao). The pore-pairs counted were those immediately above the ambitus. See Figure 9. Summary of Echinometra Morphometric Data ASCENSION ISLAND.?Number of specimens exam? ined, 56. Greatest length 9-64 mm, width 8-64 mm. Average width as percentage of length 90%. In 12 specimens the product of length X width was less than 900, and 10 (84%) of these specimens have 6 pore-pairs to the arc. In the 44 specimens where length X width exceeded 900, 24 (approximately 55%) have 7 pore-pairs to the arc, 3 (7%) have pre? dominantly 7 pore-pairs and 10 (23%) have 6 and 7 pore-pairs present in approximately equal propor? tions. None of the latter specimens have 6 pore-pairs to the arc throughout. EASTERN ATLANTIC.?Number of specimens exam? ined, 15. Greatest length 10-60 mm, width 9-50 mm. Average width as percentage of length 9 1 % . In 11 specimens the product of length X width ex? ceeded 900, and in all of these (100%) the number of pore-pairs to the arc is 6. No specimens have arcs with 7 pore-pairs. WESTERN ATLANTIC.?St. Croix Population: Num? ber of specimens examined, 110. Greatest length 25-62 mm, width 23-58 mm. Average width as per- NUMBER 2 23 centage of length 88%. In 74 specimens the product of length X width exceeded 900, and in 66 (89%) of these there are 6 pore-pairs to the arc. One speci? men had predominantly but not exclusively 7 pore- pairs, and in only 7 specimens (9%) arcs with 7 pore-pairs were present in equal numbers with arcs with 6. No specimens have 7 pore-pairs to the arc throughout. Key West and Curagao Specimens: Number of specimens examined, 30. Greatest length 19-62 mm, width 17-54 mm. In 23 specimens the product of length X width exceeded 900, and in 15 specimens (65%) there are 6 pore-pairs to the arc. In 4 speci? mens (17%) there are 7 pore-pairs, and in 4 speci? mens (17%) 6 and 7 pore-pairs were present in approximately equal proportions. SUMMARY OF DATA.?The data summarized above and presented graphically in Figure 10 show that the populations of E. lucunter at Ascension are con? sistently different from those examined from the eastern and western Atlantic in terms of number of pore-pairs to the arc. After a length of approxi? mately 32 mm is reached (at which point length X width will approximate 900), the typical configura? tion for Ascension specimens is to have 7 pore-pairs, while eastern and western Atlantic forms typically have 6. The combination of characters here regarded as taxonomically important (number of pore-pairs and color of test) warrant the erection of a new sub? species to accommodate the central Atlantic popula? tions of the species. m M O S T L Y B P O P E - P A I R S 6 = 7 P O P E - P A I R S M O S T L Y 7 P O R E - P A I R ! FIGURE 10.?Numbers of pore-pairs to the arc in three popu? lations of Echinometra lucunter (Linnaeus): a, Western At? lantic (St. Croix); b, Ascension; c, Eastern Atlantic (Anno? bon). (For details, see text.) Order HOLECTYPOIDA Family ECHINONEIDAE Echinoneus cyclostomus Leske Echinoneus cyclostomus.?Bell, 1881:437.?Mortensen, 1948: 75, fig. 60, pi. 1: figs. 14, 26; pi. 12: figs. 21-23. MATERIAL EXAMINED.?RBM 5, 2 specimens; RBM 15, 1 specimen; Asc. 6A-76, 1 specimen. REMARKS.?The four specimens (total lengths 20, 26, 31, 41 mm) are typical of this well-known species, and need no further comment here. DISTRIBUTION.?A truly "tropicopolitan" species, which ranges the Indo-Pacific and the western At? lantic; it has not yet been recorded from West Africa (Mortensen, 1948:79). HABITAT AT ASCENSION.?Under rocks on hard or calcareous sand substrate. Order CLYPEASTEROIDA Family R O T U L I D A E Heliophora orbiculus (Linnaeus) Rotula dentata.?Bell, 1881:436. Rotula orbiculus?Clark, 1925:175.?Mortensen, 1948:459, pi. 57: fig. 1, pi. 72: fig. 4; 1951b:298.?Cherbonnier, 1959: 49, pi. 7: fig. K; 1963:187. 24 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Heliophora orbiculus?Durham, 1955:185; 1966:U491, fig. 377, 4a-c. MATERIAL EXAMINED.?None. REMARKS.?The inclusion of this species in the faunal list for Ascension rests upon the record of Bell (1881) of two bare tests. No further specimens have been collected at Ascension. The species is not known from St. Helena. DISTRIBUTION.?From Senegal to Angola (Mor? tensen, 1940), also Ascension Island (Bell, 1881) and the Cape Verdes (Mortensen, 1951b). Order SPATANGOIDA Family BRISSIDAE Brissus unicolor (Leske) Brissus unicolor.?Mortensen, 1951a:509, pi. 38: fig. 10. MATERIAL EXAMINED.?Ascension Island, collected by divers, Ascension Historical Society, approximately 1972, specimen on display in Ascension Historical Society Museum, Fort Hayes, Ascension Island. REMARK.?The single specimen of Brissus uni? color was apparently collected by diving at Ascen? sion Island, and was initially identified by Ailsa M. Clark of the British Museum (Natural History). No other specimens of the species have been recorded from Ascension. The bare test was photographed, and approximate dimensions (based upon the photo? graph) are as follows: length 115 mm, greatest width 87 mm, greatest height 52 mm, height at level of apical system 42 mm, length of left posterolateral petal 44 mm, length of left anterolateral petal 29 mm. DISTRIBUTION.?Mortensen (1951a) records the species from the "warmer regions of both the Western and Eastern Atlantic." The record from St. Helena (Clark, 1952) is exceedingly doubtful although, in the light of the known occurrence of the species at Ascension, it seems quite likely that it could also occur at St. Helena. Chesher (1972) notes that some specimens of Brissus from the Gulf of California cannot be distinguished from B. uni? color, and he considers that this species ranges into the eastern Pacific, where its relationships with B. obesus Verrill have yet to be determined. Class HOLOTHUROIDEA Order ASPIDOCHIROTIDA Family HOLOTHURIIDAE Holothuria (Halodeima) grisea Selenka FIGURE lla-e Holothuria grisea.?Deichmann, 1930:76, pi. 5: figs. 1-4. Holothuria (Holothuria) grisea.?Panning, 1934a:31, fig. 23. Ludwigothuria grisea.?Deichmann, 1958:311. Holothuria (Halodeima) grisea.?Rowe, 1969:138. MATERIAL EXAMINED.?RBM 3, 1 specimen; RBM 10, 1 specimen. Asc. 1B-76, 8 specimens; Asc. 5A-76, 1 specimen; Asc. 6A-76, 6 specimens. DISTRIBUTION.?In external features, specimens conform with previous descriptions. Color in life generally reddish ground color, with yellowish and brownish patches marking presence of dorsal tube feet. Color in alcohol mottled greyish. Ventral feet form conspicuous sole, light greenish-yellow in life, brownish in alcohol. Ossicles in body wall numerous tables and buttons (rosettes). Tables (Figure 11a) with small disc carry? ing few perforations; generally four large central perforations surrounded by four to twelve smaller peripheral holes. Edge of disc with approximately 12 blunt projections. Spire short, with one crossbar, and terminating in 12 spines, of which four project more or less vertically. Dimensions: average diam? eter of disc 58 /mi (SD 6.75; SE 2.04); average height of spire 51 /mi (SD 4.28, SE 1.29). Buttons (rosettes) apparently derived from basic form with 4-6 larger holes and variable number of smaller holes (Figure lid); edges of buttons indented. Length ranges from about 36 to about 45 jum; average length 39 jam (SD 3.72, SE 1.24). Ventral tube feet contain well developed end plates, together with rods (Figure l ib ) with per? forated ends; some rods develop four large lateral perforations as well. Rods average approximately 115 tun in length. Tentacles contain rods (Figure l ie) with perfo? rated ends and with short spines near perforations. Tentacle rods greatly variable in size, up to maxi? mum length of approximately 250 /xm. REMARKS.?The ossicles of the Ascension repre? sentatives of this species show some consistent dif- NUMBER 2 25 50 urn SQjjm d 5Qjum 50urn 50um 5 0 urn 100 um 50 urn 100 um 5 0 u m 100 um 50 um FIGURE 11.?Holothuria (Halodeima) grisea Selenka: a, tables from body wall; b, rods from ventral tube feet of Ascension specimens; c, rods from ventral tube feet of specimen from the Bahamas (USNM 32489); d, buttons from body wall; e, rods from tentacles. Holothuria (Halo? deima) manningi, new species: /, tables from body wall; g, buttons from body wall; h, rods from tentacles; i, perforated plates from tube feet. Holothuria (Platyperona) sanctori Delle Chiaje: /, buttons from body wall of specimen from Naples (USNM 17025); k, tables from body wall; /, buttons from body wall. Isostichopus badionotus (Selenka): m, tables from body wall of juvenile specimens. 26 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES ferences from those of West Indian specimens. The tables are virtually identical, although those from Ascension may be slightly higher. The buttons or rosettes are smaller in the Ascension form (Deich? mann, 1930:77, notes that they are about 50 /un in diameter in West Indian forms), and appear to have more numerous larger holes. While very few of the ossicles illustrated by Deichmann (1930, pi. 5: fig. 1) can be found in the ventral tube feet, most are the shape shown in Figure 11&. By contrast, tube foot ossicles from USNM 32489, a specimen from Andros Island, Bahamas (Figure l ie) , are quite different, with more irregular shape, and few complete perforations in the ends. It can be seen, however, that both of these ossicles follow the same basic pattern. The tentacle rods are quite variable in both populations, although the Ascension speci? mens tend to have rods with more numerous per? forations. DISTRIBUTION.?Common in the tropical western Atlantic (Deichmann, 1930), and also known from West Africa (Greef, 1882). HABITAT AT ASCENSION.?Fairly common under rocks or on sand under rockly ledges. Despite bright coloration, difficult to see because of covering of particles of sand. Holothuria (Halodeima) manningi, new species FIGURE 11/?g MATERIAL EXAMINED.?Holotype: USNM E16167, total length 90 mm. Asc. 3G-76, 12 Jul 1976, English Bay, Ascen? sion Island, collected by snorkeling from depths of approxi? mately 5 m in broad surge channel; substrate rock or coarse coralline "sand." Water temperature 25?C, salinity 34%o. Paratypes: USNM E16168, total length 95 and 80 mm. Same locality data as holotype. ETYMOLOGY.?The species is named for Dr. Ray? mond B. Manning, Department of Invertebrate Zoology, National Museum of Natural History, who has contributed so much to our knowledge of Ascension Island invertebrates by his assiduous col? lecting and who was the first to discover the speci? mens described herein. DIAGNOSIS.?Deposits include tables of average height 54 /mi with completely reduced disk and with spire surmounted by 12 projections, and minute circular buttons of average diameter 22 /un, typically with 2 large and 2 small perforations, but nature and disposition of perforations highly vari? able. DESCRIPTION.?Body cylindrical, lacking con? spicuous tubercles dorsally. In life, dark brown dorsally, darker along mid-dorsal interradius, fading to lighter brown on flanks; ventral surface light brown. In alcohol, color similar. Tentacles olive green in life, yellowish green in alcohol. Skin slightly rough to touch due to presence of numer? ous ossicles. Dorsal and ventral tube feet identical. Dorsally, feet sparsely scattered; ventrally, feet much more numerous, but not forming conspicuous sole. Largest specimen with conspicuous naked band along mid-ventral radius, but naked area not obvi? ous in smaller specimens. Ossicles in dorsal and ventral body wall identical, consisting of tables and buttons. Tables with com? pletely reduced disc; basal portion rounded (Figure 11/). T o p of spire with "maltese cross" comprising 12 projections, none of which appear to point ver? tically. Spire with one crossbar. Average height of tables 54 /xm (SD 3.63). Buttons minute, tending to be circular. Typical form (Figure 1 lg) has four per? forations, two larger and two smaller, but nature and disposition of perforations highly variable. Most buttons with only two perforations. Average diameter 22 /xm (SD 2.28). Tube feet contain end plates, tables, buttons, and flat perforated plates (Figure Hi), usually with two larger perforations and numerous small perforations at ends. Developmental stages of these plates com? mon. Tentacles contain scattered minute straight or curved spinous rods (Figure llh), averaging approxi? mately 50 tun in length. REMARKS.?This species falls within the subgenus Halodeima of the genus Holothuria as defined by Rowe (1969). It is immediately distinguished from all species listed by Rowe, except Holothuria (Halodeima) edulis Lesson, in having tables with a completely reduced disc. This Indo-Pacific species has tables that closely resemble those of Holothuria (Halodeima) manningi, but the buttons in both species are very different, for in H (H.) edulis the buttons tend to be elongate, have generally larger holes, and are frequently reduced to form X-shaped granules. Further, this latter species has distinctive coloration, being brown dorsally and rose red ven? trally when alive (Clark, 1946); this color is quite consistent and distinctive. NUMBER 2 27 While relationship with H. (H.) edulis might be postulated, H. (H.) manningi appears to bear no close relationship to any species of Holothuria in the Atlantic Ocean. The species was found only at English Bay, and only in minimum depths of 3-4 meters. Further searching in the English Bay area revealed that the species is relatively common and conspicuous, lying exposed on rocks and calcareous sand. Holothuria (Thymiosycia) arenicola Semper Holothuria arenicola.?Deichmann, 1930:66, pi . 4: figs. 1-9. Holothuria (Holothuria) arenicola.?Panning, 1935:88 fig. 73. Bradtothuria arenicola.?Deichmann, 1958:290. Holothuria (Thymiosycia) arenicola.?Rowe, 1969:145. MATERIAL EXAMINED.?RBM 13, 1 specimen; RBM 22, 2 specimens; Asc. 5A-76, 2 specimens. DESCRIPTION.?Specimens typical of species. Speci? men from RBM 13 is juvenile, with tables only in body wall; buttons absent. In adult specimens tables average 61.5 pm in diameter (SD 2.70, SE 0.85) and buttons average 48.8 jnm in length (SD 1.69, SE 0.56). REMARKS.?In all characters examined, specimens from Ascension conform well with descriptions of the species. Dimensions of ossicles fall within the range of variation for H. arenicola. Deichmann (1930) noted that there was surprisingly little vari? ation in ossicle size throughout the geographic range of the species. DISTRIBUTION.?This species is cosmopolitan in the tropics, generally living under rocks or burrow? ing into sandy substrates. HABITAT AT ASCENSION.?R. B. Manning noted that the specimens collected at RBM 22 were found "burrowing deep in bottom of pool." The speci? mens from Asc. 5A-76 were found under rocks, burrowing into coarse calcareous rubble. Holothuria (Platyperona) sanctori Delle Chiaje FIGURE 11 / - / Holothuria farcimen.?Mortensen, 1933a:471, fig. 29. Holothuria sanctori.?Panning, 1934b:74, fig. 55.?Tortonese, 1965:61, figs. 21A, 22. Microthele sanctori.?Deichmann, 1958:287. Holothuria (Platyperona) sanctori.?Rowe, 1969:145. MATERIAL EXAMINED.?RBM 15, 2 specimens; Asc. 30-76, 3 specimens; Asc. 90-76, 1 specimen. DESCRIPTION.?Specimens typical of species in most respects, although ossicles show some differ? ences. Tables apparently normal (Figure 11 A), but buttons consistently possess several small knobs (Figure III). REMARKS.?Most typical specimens of H. sanctori have smooth buttons, with no trace of knobs on their surface. A single specimen from Naples (USNM 17025) possesses buttons with few knobs (Figure 11/); approximately six knobs per button was the largest density observed. The presence of numerous knobs on the buttons was also observed by Mortensen (1933a) in the St. Helena specimens he described as Holothuria farcimen Selenka. DISTRIBUTION.?Mediterranean Sea, Azores (Se? lenka, 1867; Chapman, 1955), St. Helena (Morten? sen, 1933a). According to Tortonese (1965), the bathymetric range is 5-30 meters. At St. Helena the species was collected intertidally, and at a depth of 40 meters (Mortensen, 1933a). The Ascension rec? ords are all intertidal. HABITAT AT ASCENSION.?Under rocks on rocky substrate. Family STICHOPODIDAE Isostichopus badionotus (Selenka) FIGURE 11m Stichopus badionotus.?Deichmann, 1930:80, pi. 5: figs. 30-36. ?Cherbonnier , 1976:631, pi. 1 A - C : fig. 1A-G, fig. 2 H - O . Isostochopus badionotus.?Deichmann, 1958:280. MATERIAL EXAMINED.?RBM 9, 1 specimen; R B M 21, 1 specimen; Asc. 3A-76, 1 specimen (juvenile). DESCRIPTION.?Specimens from station RBM 9 and RBM 21 are typical of the species. Juvenile specimen from Asc. 3A-76, white alive and in alco? hol, total length 10 mm. Body wall soft, with scat? tered tube feet. Ossicles exclusively tables (Figure 11m) with four central perforations, surrounded by eight or more marginal perforations. Spire tall, with four or more crossbars. Diameter of tables variable, usually 50-60 /mi; spire with same dimensions. REMARKS.?Clark (1922) described the ossicles of a juvenile 20 mm in length, and in that specimen the tables were 75 /mi across and the spire 50 ju.ni high, with two crossbars and with teeth on the top. 28 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Differences from the ossicles of the Ascension speci? men are obvious. However, Clark's specimen was approximately twice as long as the present one, and he noted (Clark, 1922:57) that growth changes in the ossicles can be quite dramatic. It does not seem likely that two species of Isostichopus occur at Ascension Island; thus the juvenile specimen is assigned to I. badionotus. DISTRIBUTION.?Deichmann (1930) notes that this species is distributed over "most of the West Indian Seas, from Bermuda to Panama." Greef (1882) re? ported the species (as Stichopus maculata) from West Africa, as did Bell (1883) (as S. assimilis), and Cherbonnier (1975) confirmed that I. badionotus occurs in West African waters. No stichopodids are known from St. Helena. HABITAT AT ASCENSION.?Exposed on sand or rock. Not common intertidally. Order APODIDA Family SYNAPTIDAE Euapta lappa (Muller) Euapta lappa?Clark, 1924:464, pi. 1: figs. 5-7.?Heding, 1928:136, figs 8.2, 9.4, 10.5, 10.6.?Mortensen, 1933a:471. MATERIAL EXAMINED.?British Museum, unregistered holo- thurian, English Bay, Ascension Island; Ascension Island Historical Society, Fort Hayes Museum, Dec 1972, one frag? ment, anterior end of body. DESCRIPTION.?Specimen comprises anterior end of body approximately 220 mm in length. Tentacles 14. Color mottled brown. Ossicles comprise anchors and anchor plates, all of approximately the same size. Anchors average 368 /xm in length and 210 p.m in width, and plates average 233 /mi in length and 166 ju.m in width. REMARKS.?This is a typical specimen of E. lappa. The dimensions of the anchors and plates conform well with those given by Clark (1924) and Heding (1928). The label with the specimen notes: "white sea- slug apparently is never observed during daylight hours. This specimen was recovered during dark? ness." In spite of searching in a variety of habitats during the 1976 expedition, no further specimens were found. Apparently the species is not common in shallow water. DISTRIBUTION.?E. lappa is common in the West Indies and the Caribbean area generally. Theel (1886) records the species or a close relative, from off Teneriffe in the Canary Islands, and Mortensen (1933a) described what was probably this species from St. Helena. Literature Cited Agassiz, A. 1881. Report on the Echinoidea Dredged by H.M.S. Challenger during the Years 1873-76. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology, 3(9): 321 pages, 45 plates. Atkins, F. B., P. E. Baker, J. D. Bell, and D.G.W. Smith 1964. Oxford Expedition to Ascension Island. Nature, 204:722-724. Bell, F. J. 1881. Report of a Collection Made by Mr. T. Conry in Ascension Island: Echinodermata. Annals and Maga? zine of Natural History, series 5, 44:436-438. 1882. Description of a New Species of the Genus Archaster from St. Helena. Annals and Magazine of Natural History, series 5, 48:440-441. 1883. Studies on the Holothuroidea, II: Descriptions of New Species. Proceedings of the Zoological Society of London lS83:5S-62, plate XV. Briggs, J. C. 1974. Marine Zoogeography, x + 475 pages. New York: McGraw-Hill Book Company. Brito, I. M. 1962. Ensaio de catalogo dos Equinodermas do Brasil. Universidade do Brasil Faculdade Nacional de Filosofta, Centro de Estudos Zoologicos, 13:1-10, 3 plates. 1971. Contribuicao ao conhecimento dos Equinodermas de Ilha la Trinidade, Brasil. Archivos do Museu Nacional, 54:261-265. Chace, F. A., Jr., and R. B. Manning 1972. Two New Caridean Shrimps, One Representing a New Family, from Marine Pools on Ascension Island (Crustacea: Decapoda: Natantia). Smithso? nian Contributions to Zoology, 131:1-18, 11 figures. Chapman, G. 1955. Aspects of the Fauna and Flora of the Azores, IV: Echinodermata. Annals and Magazine of Natu? ral History, series 12, 8:398-400. Cherbonnier, G. 1959. Echinides. Expedition Oceanographique Beige dans les Eaux Coutieres Africaines de 1'Atlantique Sud (1948-1949), 3(6): 35-59, plates I-X. 1963. Echinodermes des cotes du Cameroun recoltes par A. Crosnier en Decembre 1962-Janvier 1963. Bul? letin du Museum National d'Histoire Naturelle, 35(2): 179-193, 3 figures. 1975. Note sur la presence dans la Golfe de Guinee, de l'Holothurie Aspidochirote Stichopus badionotus Selenka (?St. maculatus Greef). Bulletin du Mu? seum national d'Histoire naturelle Zoologie, 210: 631-638, 1 plate, 2 figures. Chesher, R. H. 1966. The R/V Pillsbury Deep-Sea Biological Expedition to the Gulf of Guinea, 1964-65, 10: Report on the Echinoidea Collected by the R/V Pillsbury in the Gulf of Guinea. Studies in Tropical Oceanography, Institute of Marine Sciences (University of Miami), 4(l):209-223. 1972. The Status of Knowledge of Panamanian Echinoids, 1971, with Comments on Other Echinoderms. Bul? letin of the Biological Society of Washington, 2'- 139-158, figures 1-2. Clark, A. M. 1955. Echinodermata of the Gold Coast. Journal of the West African Science Association, 1(2): 16-56, figures 1-23. 1967. Notes on the Family Ophiothricidae (Ophiuroidea). Annals and Magazine of Natural History, series 13, 9:637-655. Clark, A. M., and A. H. Clark 1954. A Revision of the Sea-Star of the Genus Tethyaster. Smithsonian Miscellaneous Collections, 122(11): 1-27, 12 plates, 2 figures. Clark, H. L. 1912. Hawaiian and Other Pacific Echini: The Pedinidae, Phymosomatidae, Stomopneustidae, Echinidae, Tem- nopleuridae, Strognylocentrotidae, and Echinometri- dae. Memoirs of the Museum of Comparative Zool? ogy, 34(4):209-383, 32 plates. 1921a. The Echinoderm Fauna of Torres Strait: Its Com? position and Origin. Carnegie Institution of Wash? ington Publication, 214(10): viii + 224 pages, 38 plates. 1921b. Report on the Echinoidea of the Barbados-Antigua Expedition of 1918. Bulletin from the Laboratory of Natural History of the University of Iowa 9(5): 103-121, 2 plates. 1922. The Holothurians of the Genus Stichopus. Bul? letin of the Museum of Comparative Zoology, 65(3): 39-74, 2 plates. 1924. The Holothurians of the Museum of Comparative Zoology: The Synaptinae. Bulletin of the Museum of Comparative Zoology, 65(13):459-501, 12 plates. 1925. A Catalogue of the Recent Sea-urchins (Echinoidea) in the Collection of the British Museum (Natural History), xxviii + 250 pages, 12 plates. London: British Museum (Natural History). 1946. The Echinoderm Fauna of Australia: Its Composi? tion and Origin. Carnegie Institution of Washington Publication, 566: iv 4- 567 pages. 29 30 SMITHSONIAN CONTRIBUTIONS TO MARINE SCIENCES Cuninghame, J. 1699. A Catalogue of Shells, etc., Gathered at the Island of Ascension by Mr. James Cuninghame Chirurgeon, wi th W h a t Plants H e T h e r e Observed; Communi? cated to Mr. James Petiver, Apothecary, and Fel? low of the Royal Society. Philosophical Transactions of the Royal Society of London, 21:295-300. Cunn ingham, J. T . 1910. On the Mar ine Fishes and Invertebrates of St. Helena. Proceedings of the Zoological Society of London, 1910:86-131, plates IV-VII , figures 3-6. Daly, R. A. 1922. T h e Geology of Ascension and St. Helena Islands. Geological Magazine, 59:146-156. 1925. T h e Geology of Ascension Island. Proceedings of the American Academy of Arts and Sciences, 60(1): 1-80. Deichmann, E. 1930. T h e Holo thur ians of the Western Par t of the At? lant ic Ocean. Bulletin of the Museum of Compara? tive Zoology, 7l(3):43-226, 24 plates. 1958. T h e Holothur io idea Collected by the Velero I II and IV dur ing the Years 1932 to 1954, Par t I I : Aspidochirota. Allan Hancock Pacific Expeditions, 11:249-349, 9 plates. Devaney, D. L. 1973. Zoogeography and Faunal Composition of South? eastern Polynesian Asterozoan Echinoderms. In R. Fraser, editor, Oceanography of the South Pacific 1972, pages 357-366. Well ington: New Zealand Nat ional Commission for UNESCO. D u r h a m , J. W . 1955. Classification of Clypeasteroid Echinoids. University of California Publications in Geological Sciences, 31(4):73-198, plates Z-4. 1966. Clypeasteroids. In R. C. Moore, editor, Treatise on Invertebrate Paleontology, Par t U (Echinodermata 3 ) : U 4 5 0 ^ 9 1 . Lawrence, Kansas: University of Kansas Press. Fisher, W. K. 1940. Asteroidea. "Discovery" Reports, 20:69-306, figures A-M, 23 plates. Greeff, R. 1882. Echinodermen, beobachtet auf einer reise nach der Guinea-Insel Sao T h o m e . Zoologischer Anzeiger, 5:114-120, 135-139, 156-159. Heding, S. G. 1928. Synaptidae. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening Kj0benhavn, 85:105-323, 69 figures, plates II , I I I . Koehler, R. 1904. Ophiures nouvelles ou peu connues. Memoires Societe Zoologique Francaise, 17:54-119. 1908. Asteries, Ophiures et Echinides de l 'expedit ion ant- arct ique ecossaise. Transactions of the Royal Society of Edinburgh, 46:529-649, 18 plates. 1914. Echinoderma, I: Asteroidea, Ophiuro idea et Echi? noidea. Beitrage zur Kenntnis der Meeresfauna Westafrikas (Hamburg) , 1(2): 129-303, plates iv-xv. Lima-Verde, J. S. 1969. Primeira contr ibuicao ao inventar io dos Equinoder? mas do Nordeste Brasileiro. Archivos de Ciencias do Mar, 9(1):9-13. MacArthur , R. H., a n d E. O. Wilson 1967. The Theory of Island Biogeography. xi + 203 pages, 60 figures. Princeton, New Jersey: Princeton University Press. McPherson, B. F. 1968. Contr ibut ions to the Biology of the Sea Urchin Eucidaris tribuloides (Lamarck). Bulletin of Marine Science, 18(2)400^143, 26 figures. Madsen, F. J. 1950. T h e Echinoderms Collected by the Atlantide-Expe- di t ion 19454:6, I: Asteroidea. "Atlantide" Report, 1:167-222, plates XIV-XVI, 11 figures. 1970. West African Ophiuroids . "Atlantide" Report, 11: 151-243, 49 figures. Mayr, E. 1963. Animal Species and Evolution, xiv -f 797 pages. Cambridge: Belknap Press of Harvard University. Melliss, J. C. 1875. St. Helena: A Physical, Historical, and Topographi? cal Description of the Island; Including Its Geol? ogy, Fauna, Flora, and Meteorology, xiv 4- 426 pages, 62 plates, 1 map . London. Metcalf, W. G., A. D. Voorhis and M. C. Statcup 1962. T h e Atlant ic Equator ia l Undercurrent . Journal of Geophysical Research, 67(6):2499-2508. Mortensen, T . 1903. Echinoidea. The Danish Ingolf-Expedition, 4(1): 1-194, 21 plates, 12 figures. Copenhagen: Bianco Luno. 1909. Die Echinoiden. Deutsche Sudpolar-Expedition 1901-1903 XI (Zoologie, 1): 113 pages, 19 plates. 1921. Studies of the Development and Larval Forms of Echinoderms. 261 pages, 33 plates, 102 figures. Copenhagen: G.E.C. Gad. 1928. A Monograph of the Echinoidea, Cidaroidea. Vol? ume 1, 551 pages, 88 plates, 173 figures. Copen? hagen: Bianco Luno. 1931. Contr ibut ions to the Study of the Development and Larval Forms of Echinoderms I?II. Danske Videnskabernes Selskabs Skrifter, Naturvidenskabelig og mathematisk Afdeling, series 9, 4(1): 1-39, plates I -VII , 12 figures. 1932- New Contr ibut ions to the Knowledge of the Cida- rids I?II. Danske Videnskabernes Selskabs Skrifter, Naturvidenskabelig og mathematisk Afdeling, series 9, 4(4): 145-182, 18 figures, 10 plates. 1933a. T h e Echinoderms of St. Helena. Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kj0benhavn, 9 3 4 0 1 ^ 7 2 , plates X X - X X I I , 29 figures. 1933b. Echinoderms of South Africa (Asteroidea and Ophi? uroidea). Videnskabelige Meddelelser fra Dansk naturhistorisk Forening i Kj0benhavn, 93:215400. 1935. A Monograph of the Echinoidea, Bothriocidaroida, Melonechinoida, Lepidocentroida, and Strirodonta. Volume 2, 647 pages, 377 figures, 89 plates. Copen? hagen: Bianco Luno . NUMBER 2 31 1936. Echinoidea and Ophiuro idea . "Discovery" Reports, 12:199-348, plates I - IX . 1938. Contr ibut ions to the Study of the Development a n d Larval Forms of Echinoderms, IV. Danske Videnskabernes Selskabs Skrifter, Naturvidenskabelig og mathematisk Afdeling, series 9, 7(3): 1-59, plates I -XI I , 30 figures. 1940. A Monograph of the Echinoidea: Aulodonta. Vol? ume 3, n u m b e r 1, 370 pages, 197 figures, 77 plates. Copenhagen: Bianco Luno. 1943. A Monograph of the Echinoidea: Camarodonta, 1. Volume 3, n u m b e r 2, 553 pages, 321 figures, 56 plates. Copenhagen: Bianco Luno . 1948. A Monograph of the Echinoidea: Clypeastroida. Volume 4, number 2, 471 pages, 258 figures, 72 plates. Copenhagen: Bianco Luno. 1951a. A Monograph of the Echinoidea: Spatangoida, 2. Volume 5, n u m b e r 2, 593 pages, 286 figures, 64 plates. Copenhagen: Bianco Luno. 1951b. Repor t on the Echinoidea Collected by the "At? lan t ide" Expedi t ion. Atlantide Report 2:293-303, plates I?II. Panning, A. 1934a. Die Ga t tung Holothuria, 2. Mitteilungen aus dem Zoologischen Staatsinstitut und Zoologischen Mu? seum in Hamburg, 45:24-50, figures 22-44. 1934b. Die Ga t tung Holothuria, 3. Mitteilungen aus dem Zoologischen Staatsinstitut und Zoologischen Mu? seum in Hamburg, 45:65-84, figures 45-71. 1935. Die Ga t tung Holothuria, 4. Mitteilungen aus dem Zoologischen Staatsinstitut und Zoologischen Mu? seum in Hamburg, 45:85-107, figures 72-102. Robinson, A. R. 1976. Eddies and Ocean Circulation. Oceanus, 19(3):2-17. Rosewater, J. 1975. An Annota ted List of the Mar ine Mollusks of Ascension Island, South Atlant ic Ocean. Smithso? nian Contributions to Zoology, 189:1-41, 24 figures. Rowe, F.W.E. 1969. A Review of the Family Holo thur i idae (Holothuri- oidea: Aspidochirotida). Bulletin of the British Museum (Natural History), Zoology, 18(4): 119?170, 21 figures. Scheltema, R. S. 1968. Dispersal of Larvae by Equator ia l Ocean Currents and Its Impor tance to the Zoogeography of Shoal- water Tropica l Species. Nature, 217:1159-1162. 1971. Larval Dispersal as a Means of Genetic Exchange between Geographically Separated Populat ions of Shallow-water Benthic Mar ine Gastropods. The Biological Bulletin, 140(2):284-322. Selenka, E. 1867. Beitrage zur Anatomie u n d Systematik der Holo- thur ien . Zeitschrift fur Wissenschaftliche Zoologie, 17:291-374, plates 17-20. Sturm, M., and K. Voigt 1966. Observations on the Structure of the Equator ia l Undercurrent in the Gulf of Guinea in 1964. Journal of Geophysical Research, 71(I2):3105-3108. Sullivan, W. 1974. Continents in Motion. 399 pages. New York: Mc? Graw-Hill Book Company. Thee l , H. 1886. Repor t on the Holothur io idea Dredged by H.M.S. Challenger du r ing the Years 1873-1876, Par t 2. Report on the Scientific Results of the Voyage of H.M.S. Challenger, Zoology, 14(39):290 pages, 16 plates. Thorson , G. 1946. Reproduct ion and Larval Development of Danish Marine Bottom Invertebrates with Special Reference to the Planktonic Larvae in the Sound (Oresund). Meddelelser Kommissionen Havunders0gelser Kjob benhavn, Plankton, 4(l):343-367. 1950. Reproduct ive and Larval Ecology of Marine Bottom Invertebrates. Biological Reviews of the Cambridge Philosophical Society, 25(1): 1?45, 6 figures. Tommasi , L. R. 1966. Lista dos Equinoides recentes do Brasil. Contribui- coes avulsas do Instituto Oceanograftco Sao Paulo, 11:1-50, 9 plates, 72 figures. Tortonese, E. 1965. Echinodermata. Fauna d'ltalia. Volume 6, xv -f 422 pages, 186 figures. Bologna: Edizioni Calderini . Ut inomi, H. 1954. A Checklist of Echinoids Found in the Kii Region. Publications of the Seto Marine Biological Labora? tory, 3(3):339-358. Voight, K. 1975. T h e Atlantic Equator ia l Undercur ren t . Technical Series Intergovernmental Oceanographic Commis? sion, 11:12-19. Wilson, J. T . 1963. Evidence from Islands on the Spreading of Ocean Floors. Nature, 197:536-538. Yamaguchi, M. 1973. Early Life Histories of Coral Reef Asteroids, wi th Special Reference to Acanthaster planci (L.). In Jones and Endean, editors, Biology and Geology of Coral Reefs, II(Biology, 1):369-387. New York: Academic Press. REQUIREMENTS FOR SMITHSONIAN SERIES PUBLICATION Manuscripts intended for series publication receive substantive review within their originating Smithsonian museums or offices and are submitted to the Smithsonian Institution Press with approval of the appropriate museum authority on Form SI-36. 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First page of text should carry the title and author at the top of the page and an unnum? bered footnote at the bottom consisting of author's name and professional mailing address. Center heads of whatever level should be typed with initial caps of major words, with extra space above and below the head, but with no other preparation (such as all caps or underline). Run-in paragraph heads should use period/dashes or colons as necessary. Tabulations within text (lists of data, often in parallel columns) can be typed on the text page where they occur, but they should not contain rules or formal, numbered table heads. Formal tables (numbered, with table heads, boxheads, stubs, rules) should be sub? mitted as camera copy, but the author must contact the series section of the Press for edito? rial attention and preparation assistance before final typing of this matter. Taxonomic keys in natural history papers should use the alined-couplet form in the zoology and paleobiology series and the multi-level indent form in the botany series. If cross-referencing is required between key and text, do not include page references within the key, but number the keyed-out taxa with their corresponding heads in the text. Synonymy in the zoology and paleobiology series must use the short form (taxon, author, year:page), with a full reference at the end of the paper under "Literature Cited." For the botany series, the long form (taxon, author, abbreviated journal or book title, volume, page, year, with no reference in the "Literature Cited") is optional. Footnotes, when few in number, whether annotative or bibliographic, should be typed at the bottom of the text page on which the reference occurs. Extensive notes must appear at the end of the text in a notes section. If bibliographic footnotes are required, use the short form (author/brief t it le/page) with the full reference in the bibliography. Text-reference system (author/year/page within the text, with the full reference in a "Literature Cited" at the end of the text) must be used in place of bibliographic footnotes in all scientific series and is strongly recommended in the history and technology series: "(Jones, 1910:122)" or ".. . . Jones (1910:122)." Bibliography, depending upon use, is termed "References," "Selected References," or "Literature Cited." Spell out book, journal, and article titles, using initial caps in all major words. For capitalization of titles in foreign languages, follow the national practice of each language. Underline (for italics) book and journal titles. Use the colon-parentheses system for volume/number/page citations: "10(2) :5 -9 . " For alinement and arrangement of elements, follow the format of the series for which the manuscript is intended. Legends for illustrations must not be attached to the art nor included within the text but must be submitted at the end of the manuscript?with as many legends typed, double- spaced, to a page as convenient. Illustrations must not be included within the manuscript but must be submitted sepa? rately as original art (not copies). All illustrations (photographs, line drawings, maps, etc.) can be intermixed throughout the printed text. They should be termed Figures and should be numbered consecutively. If several "f igures" are treated as components of a single larger figure, they should be designated by lowercase italic letters (underlined in copy) on the illus? tration, in the legend, and in text references: "Figure 9b," If illustrations are intended to be printed separately on coated stock following the text, they should be termed Plates and any components should be lettered as in figures: "Plate 9b_." Keys to any symbols within an illustration should appear on the art and not in the legend. A few points of style: (1) Do not use periods after such abbreviations as " m m , ft, yds, USNM, NNE, AM, BC." (2) Use hyphens in spelled-out fractions: "two-thirds." (3) Spell out numbers "one" through "n ine" in expository text, but use numerals in all other cases if possible. (4) Use the metric system of measurement, where possible, instead of the English system. (5) Use the decimal system, where possible, in place of fractions. (6) Use day/month/year sequence for dates: "9 April 1976." (7) For months in tabular list? ings or data sections, use three-letter abbreviations with no periods: "Jan, Mar, Jun, " etc. Arrange and paginate sequentially EVERY sheet of manuscript?including ALL front matter and ALL legends, etc., at the back of the text?in the following order: (1) tit le page, (2) abstract, (3) table of contents, (4) foreword and /or preface, (5) text, (6) appendixes, (7) notes, (8) glossary, (9) bibliography, (10) index, (11) legends.