Myodocopid Ostracoda of Pillar Point Harbor, Half Moon Bay, California * LOUIS S. KORNICKER and BETH HARRISON-NJ m i SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY ? NUMBER 593 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: "It 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 Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Folklife Studies 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. I. Michael Heyman Secretary Smithsonian Institution S M I T H S O N I A N C O N T R I B U T I O N S T O Z O O L O G Y ? N U M B E R 5 9 3 Myodocopid Ostracoda of Pillar Point Harbor, Half Moon Bay, California Louis S. Kornicker and Elizabeth Harrison-Nelson SMITHSONIAN INSTITUTION PRESS Washington, D.C. 1997 A B S T R A C T Kornicker, Louis S., and Elizabeth Harrison-Nelson. Myodocopid Ostracoda of Pillar Point Harbor, Half Moon Bay, California. Smithsonian Contributions to Zoology, number 593, 53 pages, 28 figures, 6 tables, 1997.?Pillar Point Harbor, a small harbor formed in 1961 by construction of a breakwater in Half Moon Bay, California, in 1975 contained five species of benthic myodocopid Ostracoda. Analysis of the environment suggests that the distribution of individual species may, in part, have been affected by the substrate. Two new species, Rutiderma apex and Euphilomedes morini, are described and illustrated, and supplementary descriptions are provided for Euphilomedes carcharodonta (Smith, 1952) and Postasterope barnesi (Baker, 1978). The ontogenies of both species of Euphilomedes are described, and it is shown that juveniles of E. morini are capable of swimming, whereas those of E. carcharodonta are not. The abundance of the ostracodes in Pillar Point Harbor was greater than in many other continental bays for which abundances are known. Commensal protistans colonized carapaces of both species of Euphilomedes but not other species in the harbor. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Annals of the Smithsonian Institution. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus). Library of Congress Cataloging-in-Publication Data Komicker, Louis S., 1919- Myodocopid Ostracoda of Pillar Point Harbor, Half Moon Bay, California / Louis S. Komicker and Elizabeth Harrison-Nelson. p. cm. ? (Smithsonian contributions to zoology ; no. 593) Includes bibliographical references (p. 51). I. Myodocopida?California?Half Moon Bay. 1.1Harrison-Nelson, Elizabeth. II. Title. III. Series. QL1 .S54 no. 593 [QL444.O85] 590s-dc21 [595.3'3] 97-27398 @ The paper used in this publication meets the minimum requirements of the American National Standard for Permanence of Paper for Printed Library Materials Z39.48?1984. Contents page Introduction 1 Disposition of Specimens 1 Abbreviations 1 Acknowledgments 2 Material and Methods 3 Substrate and Environment 3 Ostracode Distribution in Half Moon Bay 4 Discussion of Distribution 4 Myodocopa in Other Western North American Bay Areas 8 Comparisons with Quantitative Studies Elsewhere 10 Commensal Protistans 12 Superorder MYODOCOPA Sars, 1866 13 Order MYODOCOPIDA Sars, 1866 13 Suborder MYODOCOPINA Sars, 1866 13 PHILOMEDIDAE Muller, 1906 13 PHILOMEDINAE Muller, 1906 14 Euphilomedes Kornicker, 1967 14 Euphilomedes carcharodonta (Smith, 1952) 14 Euphilomedes morini, new species 25 RUTIDERMATIDAE Brady and Norman, 1896 36 RUTIDERMATINAE Brady and Norman, 1896 36 Rutiderma Brady and Norman, 1896 36 Rutiderma apex, new species 36 CYLINDROLEBERIDIDAE Muller, 1906 45 CYLINDROLEBERIDINAE Muller, 1906 45 Postasterope Kornicker, 1986 45 Postasterope barnesi (Baker, 1978) 45 Literature Cited 51 in Myodocopid Ostracoda of Pillar Point Harbor, Half Moon Bay, California Louis S. Kornicker and Elizabeth Harrison-Nelson Introduction In 1961 Pillar Point Harbor was formed 32 km south of San Francisco by the construction of a breakwater that enclosed 245 acres (0.991 km2) of Half Moon Bay, San Mateo County (Figure 1). A biological study of the harbor was made by personnel of the Marine Ecological Institute, Redwood City, California, during 1975 (Tuel et al., 1976). A few of the samples of myodocopid ostracodes that were collected at nine study stations (Figure 1) were submitted for identification or verification. In the report of 1976, five species were identified either only to genus or to both genus and species. One of the species, Postasterope barnesi (Baker, 1978), was later de- scribed by Baker (1978:139) from samples collected off southern California, and a supplementary description of that species is presented herein. Another of the species, Asteropella slatteryi Kornicker, 1981, was later described by Kornicker (1981:260) from the Pillar Point Harbor collection. A third new species, Rutiderma apex, is described herein. Two species, Euphilomedes charcarodonta (Smith, 1952) and E. longiseta (Juday, 1907) were not separated during the specimen counts made by the Marine Ecological Institute, and the total was presented as Euphilomedes spp. in Tuel et al. (1976:140). Because the original collection could not be found, in the Louis S. Kornicker, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. Elizabeth Harrison-Nelson, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institu- tion, Washington, D.C. 20560. Review Chairman: Austin B. Williams, National Marine Fisheries Service, Systematics Laboratory, Smithsonian Institution. Reviewers: Brad L. Myers, Santa Ana, California; I.G. Sohn, Scientist Emeritus, U.S. Geological Survey, Res ton, Virginia. ecological analysis herein, these counts are presented as Euphilomedes spp. According to Tuel et al. (1976:140), E. charcarodonta appeared to be more common than E. longiseta. A supplemental description of E. charcarodonta is presented herein. A closer study of the specimens that had been identified as E. longiseta revealed them to be a new species, E. morini, and it is described herein. In addition to listing species counts at stations, Tuel et al. (1976:140,141) briefly described the distribution of ostracodes in the harbor. They reported Euphilomedes spp. to be the most abundant of the benthic crustaceans and Asteropella sp. to be the sixth most common crustacean. In the present study the distribution of the ostracodes is considered in greater detail. In addition to the collection from Pillar Point Harbor, some specimens collected north of San Francisco Bay, in Dark Gulch, Mendocino County, and in Tamales Bay, Marin County, are included in this study. DISPOSITION OF SPECIMENS.?Specimens have been depos- ited in the collections of the former United States National Museum (USNM), now the National Museum of Natural History, Smithsonian Institution; these have been assigned USNM numbers. ABBREVIATIONS.?In the figures, Arabic numerals indicate individual joints of each limb, and Roman numerals I-IV indicate the endites. The lettering of bristles of the 1st antenna are based on Skogsberg (1920:188). Arrows on illustrations indicate anterior of valve or specimen. The following abbrevia- tions are used in illustrations and legends. am central adductor muscle attachments ant antenna ap anterior process av anterior view SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY bas Bo ex dv end epip esop ex fii gen gird gl hit im iv le lft 11 lp lv me mis mnd mv mx basale Bellonci organ coxale dorsal view endopodite epipodite esophagus exopodite furca genital organ girdle gland heart inner margin of infold inside view lateral eye left lower lip lamellar prolongation of selvage lateral view medial eye medial longitudinal sclerite mandible medial view maxilla nabs ov precx prot pv rt s sens ul w Y-scl not all bristles shown outside view precoxale prodopodite posterior view right shield sensory bristle of 5th joint of 1st antenna upper lip ventral view Y-sclerite ACKNOWLEDGMENTS.?We thank James R. Chess, South- west Fisheries Center, Tiburon Laboratory, for supplying the specimens from Dark Gulch, Michael P. Wilderman, Marine Ecological Institute, for the specimens from Pillar Point Harbor, and Meredith L. Jones, Smithsonian Institution (retired), for specimens from Tomales Bay. We are grateful to several people who assisted in the preparation of this paper: Carolyn Gast rendered shaded drawings of the carapaces; Jack Schroeder inked the penciled drawings of appendages. We appreciate the helpful comments of two reviewers; namely, Brad L. Myers and I.G. Sohn. We also thank Craig Warren, Smithsonian Institution Press, for editing and preparing the manuscript. 60 m HALF MOON BAY FIGURE 1.?Locations of stations 1-9 (black stars) and the distribution of bottom sediments in Pillar Point Harbor, California. Depth contours in meters; breakwater striated; map derived from Tuel et al. (1976, fig. 1). NUMBER 593 MATERIAL AND METHODS Material and methods are described in detail by Tuel et al. (1976:132) and are briefly summarized here. Sediment samples were collected March 13, 14, June 23, 25, September 10, 11, and December 1, 2, 1975. Unfortunately, the ostracode samples of March were lost. In the benthic survey three replicate samples were made with a Ponar grab (surface area 0.0596 m2; jaws 15 cm in height). The grab sample was washed through a U.S. No. 30 sieve (mesh aperture 0.5 mm) and preserved in buffered 10% formalin. Organisms were later transferred to 70% ethyl alcohol, sorted to species, and counted. According to Tuel et al. (1976:133), "Differences in the number of organisms taken in the 3 grabs during each sampling period were assumed to represent real changes in the infauna populations and not variations in sampling success or patchiness of the popula- tions." Plankton samples were collected with a #25 plankton net. All water depths were measured below mean low or low water. SUBSTRATE AND ENVIRONMENT The following summary of the substrate and environment of Pillar Point Harbor is based mainly on Tuel et al. (1976). The crescent-shaped shore of the harbor enclosed sandy beaches except for a small marsh in the northwest corner (Figure 1). At the near-shore stations (sta 1-5), at depths of 1.8-2.4 m, the coarseness of the sediment decreased from east to west, from 82% sand at station 1 to 15% sand at station 5 (Figure 1; Table 1). Station 2 was in a kelp bed (Tuel et al., 1976:7). Cobbles were present at stations 3 and 5. The off-shore stations (sta 6-9) had a depth range of 4.3-5.2 m and a substrate of finer sediments than at most near-shore stations (sta 1-4) (Figure 1; Table 1). Stations 2 and 3 were established near the mouths of Deer Creek and Dennison Creek, respectively. Station 4 was established in the vicinity of marsh outflow. The outflow of fresh water did not reduce the salinity below about 31 ppt at the 3 stations. The remaining stations (sta 6-9) were distant from fresh water inflows. During 1975 the salinity in the harbor ranged from 30.7 ppt to 36.4 ppt. The highest salinities (about 36 ppt) were encountered at stations 1 and 2 in July. Salinities were below 35 ppt at other stations, as well as at stations 1 and 2 during the months other than July. The range of temperatures in the harbor during 1975 was 8.8?C to 16.0?C. Temperature fluctuations were greatest during the summer months mainly as the result of upwelling in the eastern Pacific Ocean bringing in colder water (Tuel et al., 1976:12). In the eastern Pacific Ocean adjacent to Pillar Point Harbor the southward flowing California Current continues from about February to November, then the strong northward Davidson Current replaces the California Current along shore. Thus, the June and September samples were collected during the southward flowing current, and the December samples were collected during the northward flowing current. According to Tuel et al. (1976:10), "The characteristics of the water in Pillar Point Harbor are greatly affected by the variations in the hydrographic conditions of the eastern Pacific Ocean." The plankton samples that were collected in the summer months, which was during times of lowest water transparency, contained mostly diatoms, dinoflagellates, tintinnids, rotifers, and a large amount of organic detritus (Tuel et al., 1976:10). Winter samples had much less plankton, and the greater turbidity that occurred in the winter was probably the result of suspended sediments from seiche and storm action (Tuel et al., 1976:30). The entire composition of the plankton samples was not listed in Tuel et al. (1976), and ostracodes, if present, were not reported. The bottom was studied by divers along two northerly- southerly transects: transect 1 began west of station 2, and transect 2 began east of station 5 and west of the marsh outflow; both transects terminated at the breakwater. Transect 1 passed through a kelp bed at 20 m from the sandy shore. The sandy bottom at the kelp bed changed to silty sand and then clayey silt covered by a red-brown film. The water at 100 m from shore became extremely turbid. On transect 2, at 100 m from shore, TABLE 1.?Station parameters and average number of specimens of each species per square meter at each station in June, September, and December, 1975. ?From Tuel et al. (1976:165, table IV-2) rounded to nearest whole number. fFrom Tuel et al. (1976:168-235, Appendix IV-A) rounded to nearest whole number. Sta 1 2 3 4 5 6 7 8 9 Depth (m) 1.8 1.8 2.4 1.8 1.8 5.2 4.3 5.2 4.3 Sediment % Sand 82 76 48 45 15 3 10 19 31 Silt 15 20 40 45 61 68 59 60 52 * Clay 4 5 12 10 24 29 31 21 17 Jun 0 0 0 0 7 20 0 33 7 Rutiderma apex\ Sep 0 0 0 0 0 33 7 0 0 Dec 0 0 0 0 13 20 7 0 13 Asteropella slatteryv Jun 125 0 13 7 60 40 7 0 0 Sep 553 92 0 0 0 0 0 0 0 Dec 402 0 0 13 46 53 7 0 0 Euphilomedes Jun 362 26 0 962 942 613 474 790 86 spp.t Sep 1462 79 0 87 336 303 263 231 40 Dec 1047 26 7 152 1054 1245 125 441 138 Postasterope i Jun 0 0 0 0 92 73 79 7 0 barnesfi Sep 0 0 0 0 40 0 0 0 0 Dec 0 0 0 0 178 40 408 0 0 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY the sandy beach changed to silty sand and then clayey silt with scattered cobbles and red-brown films. The central area of transect 2 contained much more algae than was present in the central area of transect 1, probably because of the availability of attachment sites on the rocks (Tuel et al., 1976:238). In deeper water the bottom had fewer rocks and appeared barren, and in October contained a large bed of "decaying drift algae." According to Tuel et al. (1976:238), "A conspicuous increase in the algal biomass and decrease in species was noted as the collections progresses further into the year." Ostracode Distribution in Half Moon Bay NEAR-SHORE STATIONS 1-5.?Rutiderma apex and Postas- terope barnesi were present only in the clayey silt of station 5 (Figures 2, 3; Tables 1-3). Euphilomedes spp., except for being absent in June and September and sparse in December at station 2, were numerous at all near-shore stations (Figure 4; Tables 1, 2). The species were especially abundant in the sand at station 1 and clayey silt at station 5. Asteropella slatteryi was collected at all near-shore stations but was not present in all months, except at station 1 where it was abundant (Figure 5; Tables 1, 2). OFF-SHORE STATIONS 6-9.?Rutiderma apex was collected at all off-shore stations, but except for station 6, the species was TABLE 2.?Average number of specimens of each species per square meter at each station during June, September, and December combined.* Out I 2 3 4 5 6 7 8 9 Rutiderma apex 0 0 0 0 7 24 5 11 7 Asteropella slatteryi 360 31 4 7 35 31 7 0 0 Euphilomedes spp. 957 44 2 400 111 720 287 487 88 Postasterope barnesi 0 0 0 0 103 38 162 2 0 ?From Table 1. not collected in all months (Figure 2; Tables 1,2). Postasterope barnesi was absent from station 9, and present at stations 6-8, but not in all months (Figure 3; Tables 1,2). Euphilomedes spp. were abundant at all off-shore stations (Figure 4; Tables 1, 2). Astropella slatteryi was collected only at off-shore stations 6 and 7, but was absent from both stations in September (Figure 5; Tables 1,2). TOTAL HARBOR.?The average number of specimens of R. apex per square meter in the harbor for the months of June, September, and December remained about the same; more A. slatteryi were collected in September than in either June or December; fewer Euphilomedes spp. and P. barnesi were collected in September than in June or December; and more P. barnesi were collected in December than in either June or September (Table 1). DISCUSSION OF DISTRIBUTION Euphilomedes spp. are ubiquitous in the harbor (Figure 4); possibly the lower numbers at stations 2 and 3 are related to the presence of the mouths of fresh water streams near those stations; however, the salinities at both stations do not seem to differ enough from those at other stations to support that hypothesis. The relative abundances of E. carcharodonta and E. morini at each station is unknown. Because juveniles of E. carcharodonta, unlike those of E. morini, do not swim, they may prefer different environments. Postasterope barnesi and R. apex are more-or-less restricted to the southwestern quarter of the harbor in the general vicinity of the entrance (Figures 2, 3); possibly the influx of oceanic water into the harbor through the entrance exerts some control over the distribution of those species. Asteropella slatteryi occurs in the deeper water in the western part of the harbor as well as along its shoreline (Figure 5). After the specimens enter the harbor it is possible they are carried in a clockwise direction by currents and accumulate in the eastern corner (Sta 1), where they are abundant. Euphi- lomedes spp. also are present in large numbers at station 1 (Figure 4). The eastern corner of the harbor may represent a "dead spot" where specimens accumulate. The histogram in Figure 6 shows the number of samples of TABLE 3.?Number of samples with species at each station. (From Tuel et al., 1976, Appendix IV-A.) Sta 1 2 3 4 5 6 7 8 9 Total Jun 0 0 0 0 1 2 0 2 1 6 Rutiderma apex Sep 0 0 0 0 0 2 1 0 0 3 Dec 0 0 0 0 2 2 1 0 1 6 Jun 3 1 1 1 3 3 1 0 0 13 Asteropella slatteryi Sep 3 3 0 0 0 0 0 0 0 6 Dec 3 0 0 2 3 3 1 0 0 12 Jun 3 0 0 3 3 3 3 3 2 20 Euphilomedes spp. Sep 3 3 0 1 3 3 3 2 2 20 Dec 3 1 1 3 3 3 3 3 3 23 Jun 0 0 0 0 3 1 3 1 0 8 Postasterope barnesi Sep 0 0 0 0 1 0 0 0 0 1 Dec 0 0 0 0 3 2 3 0 0 8 Total 18 8 2 10 25 24 19 11 9 126 60 m E September, and December, 1975. 6*0%! HALF MOON BAY F.OURB 3,-D.stribution rfftW * ? ' the same as in Figure 2. Point Harbor, California. The meaning of numbers is FIGURE 4.-Cistribution of Euphilomedes spp. (total of*, carcharodonta and E. morini. new species) in Pillar Point Harbor, California. The meaning of numbers is the same as in Figure 2. 60 m HALF MOON BAY FIGURE 5.?Distribution of Asteropella slatteryi in Pillar Point Harbor, California. The meaning of numbers is the same as in Figure 2. NUMBER 593 NUMBER OF SAMPLES WITH SPECIES 14 13 12 II 10 9 CO LU 8 _| 1 7 CO 6 o 5 cc 4 Ul CD 3 5 3 2 MG> I A. slatteryi - ? ? 7 2 % ? 2 2 % - - 3 9 % o l 1 1 1 13 12 II 10 9 8 7 6 5 4 3 2 1 0 . R. Apex ? ? ? - - 2 2 % - i 3 6 % i SAND SILTY SANDY CLAYEY SAND SILT SILT 35 34 33 3 2 31 3 0 2 9 2 8 2 9 2 6 2 5 2 4 2 3 2 2 21 2 0 19 1 8 1 7 16 IS 14 I ?* I O 12 I I 10 9 8 7 6 5 4 3 2 1 Euphilomedes spp. ? - . 7 9 % 72 % I 9 7 % 44 % i i i SAND SILTY SANDY CLAYEY SAND SILT SILT 1 8 1 -T 1 I 16 15 14 ? ^ 13 12 I I 10 9 8 7 6 5 4 3 2 1 P. barnesi - ? i i 4 9 % SAND SILTY SANDY CLAYEY SAND SILT SILT %SAND 76-82 45-48 31 3-19 FIGURE 6.?Histogram showing the number of samples with Asteropella slatteryi, Rutiderma apex, Euphilomedes spp., and Postasterope barnesi (percent of samples with each species indicated within bars). 8 SMITHSONIAN CON TR1BUTIONS TO ZOOLOGY each sediment type containing a particular species (percent of samples containing the species shown in each bar), and Figure 7 shows the percent of samples of each sediment type containing a particular species. Clearly R. apex and P. barnesi are restricted to finer sediments. Euphilomedes spp. live on sediments of all types, and A. slatteryi has a bimodal distribution, being more numerous on sand and clayey silt substrates than on sediments of intermediate size. Five species of ostracodes were collected in the harbor. The diversity at each station when samples for each month are combined (Table 2) differed depending on the substrate. Assuming (possibly incorrectly) that both species of Eu- philomedes were present in samples containing the genus, three substrates, namely sand (sta 1, 2), silty sand (sta 3, 4), and sandy silt (sta 9), contained three species, whereas one substrate, clayey silt (sta 5-8), contained either four or five species. The species distribution may be affected by the method of food gathering: R. apex is a carnivore, Euphilomedes spp. are detritus feeders, and P. barnesi and A. slatteryi are "filter feeders" (Cannon, 1933:756; Komicker, 1975a:38). The histo- gram in Figure 8 shows the percentage distribution of the average number of specimens per square meter of each feeding type at each station. The detritus feeding Euphilomedes spp. were abundant at all stations and were dominant at all stations except stations 2 and 3, where the filter feeding A. slatteryi dominated. Filter feeders were present at all stations except station 9. The carnivore R. apex was present at stations 5-9, and was more abundant than filter feeders at station 8 as well as at station 9, where filter feeders were absent. Whereas P. barnesi was restricted to deeper water and fine sediments, A. slatteryi lived both in the deeper water in fine sediments as well as in shallow near-shore sands; because both species are filter feeders, it does not seem likely that their distribution was controlled by feeding type. Tuel et al. (1976:134, 135) gave the total number of organisms per square meter at each station: stations 1-4 had 1,869-11,490/m2, and stations 5-9 had 13,223-21,850/m2. Possibly, the larger number of organisms at stations 5-9 was a contributing factor to the presence of the carnivore R. apex at those stations. The decrease in specimens of A. slatteryi and Euphilomedes spp. at some stations in September, and a concurrent increase at other stations, suggests that specimens may have migrated during that month. Specimens of P. barnesi were generally fewer in September, and as the species lived in the general vicinity of the entrance to the harbor, some may have left the harbor during that month. Rutiderma apex was absent from some stations during one month and from different stations during other months; the reason for this is not clear. The fact that the southward flowing California Current occurred during the June and September sampling, and the northward flowing Davidson Current during the October sampling, does not appear to have had an affect on the distribution of myodocopids in the harbor. The jutting breakwater at the opening to the harbor might divert organisms being carried by a southward current into the harbor, but this would probably have a greater affect on planktonics than on the primarily benthonic myodo- copids. Changes in abundance are often the result of the life cycle, with numbers increasing during the breeding season. The writers studied only a few samples and no attempt was made to determine variations in age classes during the months sampled. Because only three samples were collected at each station, no attempt was made to estimate sampling error. Also, because the samples were washed through a sieve with a mesh aperture of 0.5 mm, some early instars may have been lost. Clearly, more work is needed to understand the factors influencing the distribution of ostracode species in Pillar Point Harbor. Myodocopa in Other Western North American Bay Areas Juday (1907:143,145, 149) reported Cylindroleberis mariae (Baird, 1850b), Euphilomedes oblonga (Juday, 1907) (= Zeugophilomedes oblongus (Juday, 1907)), and Rutiderma rostratum Juday, 1907, from San Diego Bay, California, but additional ostracode species also may live there. In comprehensive studies, Lie (1968:271, tables 6-20, 1974:210), Lie and Kelley (1970:626), Lie and Kisker (1970:2279), and Lie and Evans (1973:125) found E. carcharo- donta and E. producta Poulsen, 1962, to be dominant and Rutiderma rostratum Juday, 1907, and Cylindroleberis mariae (Baird, 1850b) common at certain stations in Puget Sound and vicinity, Washington. Jones (1958:48) reported Sarsiella tricostata Jones, 1958 (= Eusarsiella zostericola (Cushman, 1906)), in San Francisco Bay, California. Kornicker (1975b: 130) hypothesized that the San Francisco Bay population had been introduced with oysters transported from the east coast of the United States. McKenzie (1965:57) reported six species from Scammon Lagoon, Baja California: Asteropella scammonensis McKen- zie, 1965, Rutiderma rostratum Juday, 1907 (= Rutiderma sp. indet. Kornicker and Myers, 1981:4), Rutiderma judayi McKenzie, 1965, Rutiderma californica McKenzie, 1965 (= Rutiderma rotundum Poulsen, 1965), Chelicopia komickeri McKenzie, 1965, and Sarsiella sp. McKenzie, 1965. Kornicker (1977:165) gave the number of species found in bays along the Pacific coast including those in Half Moon Bay discussed herein, and noted that the number of species is greater in southern bays. The numbers of species were as follows: Departure Bay and Ganges Harbor, Vancouver Island, Canada, 2 spp.; Puget Sound, Washington, 4 spp. (Kornicker (1977:165) incorrectly omitted one species); Tomales Bay, California, 4 spp.; San Francisco Bay (probably an introduced population), 1 spp.; Pillar Point Harbor, Half Moon Bay, 5 spp.; Monterey Bay, 6 spp.; Bahia de San Quintin, Baja California, 6 spp.; Scammon Lagoon, Baja California, 6 spp. The specific composition is unknown at present for many of the above localities. NUMBER 593 I-Sand 2-Silty Sand 3-Sandy Silt 4-Clayey Silt 100 9 0 3 ? o o ? ? N N n Jo v ^ q- o >o ?j 1 db a> in NUMBER OF SPECIMENS PER O. Im2 FIGURE 9.?Histograms showing the relative abundance of myodocopids in the Beaufort Sea, Cape Cod Bay, and Pillar Point Harbor. 12 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY Point Harbor ostracodes were collected with a 0.0506 m2 Ponar Grab. In both the Antarctic and Cape Cod Bay studies, ostracodes were removed from the fraction retained on a 1.0 mm sieve (Kornicker, 1974:8); in the Southern California shelf study the finest screen had a mesh size of 0.71 m (Baker, 1975:15); in the Beaufort Sea study, ostracodes were removed from the fraction retained on a 0.42 mm sieve (Kornicker, 1988:3); whereas in the Pillar Point Harbor study as well as in the Monterey Bay study (Oliver et al., 1980:438), ostracodes were removed from the fraction retained on a 0.5 mm sieve. The effect of using the different types of collecting gear on the number of ostracodes obtained in the samples is unknown, but more smaller specimens would be retained on sieves with smaller mesh sizes. Including samples at each station with and without myodo- copids, the average number of specimens per square meter at the nine stations in Pillar Point Harbor during June, September, and December was 526 per square meter. If the numbers at the nine stations are considered representative of the harbor, which has an area of 0.991 km2, the harbor during this period contained an average of about 520 million myodocopid ostracodes. Podocopid ostracodes in Pillar Point Harbor were not mentioned by Tuel et al. (1976), and their abundance in the harbor cannot be compared with that of myodocopids. Elsewhere, in the innermost part of Niva Bay, Denmark, a population of primarily Podocopa varied between 33,000 and 380,000 per square meter, for the period April 1957 to January 1960 (Theisen, 1967:224). Reyment (1982:40) concluded that deme-sizes of marine ostracodes are mostly in the order of "a few tens of thousands" per square meter. If any of these estimates should hold for Podocopa of Pillar Point Harbor, the ratio of Podocopa to Myodocopa would be 20-600 to 1. Commensal Protistans Many specimens of Euphilomedes carcharodonta and E. morini in the harbor have attached to their shells stalked cup-like or ovoid protistans, and some specimens have them attached to appendages. None were observed on Rutiderma apex or Postasterope barnesi, nor were they reported by Kornicker (1981:260) on the fifth species in the harbor, Asteropella slatteryi. Baker (1975:79) reported similar stalked peritrichous ciliate protozoa on five species collected on the continental shelf off southern California (Table 4). Four of those species are members of the Philomedidae and the other is in the family Cylindroleberididae (subfamily Cycloasteropinae). Kornicker (1975a:60) reported that stalked cup-like protis- tans were very common on members of the Philomedidae, and sparse on members of other families in collections from Antarctica and Subantarctica. In order to determine whether stalked cup-like protistans are really more common on the carapaces of certain families, a cursory survey of the literature was undertaken (Table 4). No doubt, many describers of ostracodes do not bother to mention attached protistans, so the list in Table 4 is incomplete and probably merely gives an indication of the actual distribution of protistans. Stalked ovoid protistans also are attached to shells and appendages, but because they could also be egg cases or various unknown other taxa, they have not been included in Table 4. In general, the ovoid forms are more abundant on those ostracode taxa also having cup-like forms. The stalked cup-like protistans have been reported attached to the carapaces of eight species of Philomedidae, six species of Cylindroleberididae (only species of Cyclasteropinae and Asteropteroninae), only one species of Rutidermatidae, and no species of Cypridinidae, Sarsiellidae, or Cylindroleberidinae (Table 4). Also, they have been reported attached to the appendages of five additional species of Philomedidae, one additional species of Cyclasteropinae, and one species of Cylindroleberidinae (Table 4). It should be noted that an unstalked protistan has been reported on the cypridinid Cypridina americana (Miiller, 1890) by Kornicker (1987:180, fig. 2a,d), and unknown egg-like protistans were attached to the posterior end of the carapace of the cylindroleberid Heptonema homelix Kornicker, 1991a (Komicker, 199la: 124, fig. 67a,b). Also, foraminiferans, diatoms, bryozoans, and hydrozoans are present on some myodocopid carapaces (Baker, 1975:76; Kornicker, 1975a:52; 1988, fig. 2a; 1994:139; Kornicker and Calder, 1995:125), but they are not considered here, nor were they observed on the examined ostracodes in Pillar Point Harbor. It is interesting to speculate as to why the stalked cup-like protistans appear to mainly colonize carapaces of members of the Philomedidae and Cyclasteropinae. Baker (1975:80) stated that the usual position of the stalked protistans along the ostracode rostrum may indicate that the ostracode does not burrow, and he also noted that in that location the protistans have a readily available supply of food from the ostracode. According to Elofson, species of Philomedes are agile burrowers (Elofson, 1969:14), and it seems likely that E. carcharodonta and E. morini are also burrowers. Possibly, after burrowing they reside in the burrow with their anterior ends projecting from the sediment, thus permitting the protistans on the rostral area to be free in the water. However, according to Fenwick (1984:262), Leuroleberis zealandica (Baird, 1850b) lives in the sediment and is not visible from above, so there is no evidence that the anterior end of burrowing ostracodes projects into the water. It seems likely that other Cyclasteropi- nae also burrow, and unlikely, therefore, that the presence of protistans indicates that the host ostracode does not burrow. It might be surmised that the host ostracode uses the protistans as bait for prey, but that seems unlikely because the Philomedidae are detritivores, not carnivores; also, that would not explain the protistans attached to appendages. The apparent absence of stalked cup-like protistans on sarsiellids and their sparsity on rutidermatids might be due, in some unknown way, NUMBER 593 13 TABLE 4.?Distribution of stalked cup-like protistans on the carapaces and appendages of myodocopid ostracodes (A = attached to appendage; C = attached to carapace). Taxon (Place of attachment) Source CYLINDROLEBERIDIDAE CYLINDROLEBERIDINAE Parasterope muelleri Skogsberg, 1920 (A) CYCLASTEROPINAE Amboleberis americana (Muller, 1890) (C) Cycloleberis squamiger (Scott, 1894) (A) Leuroleberis mackenziei (Kornicker, 1981) (C) Leuroleberis sharpei Komicker, 1981 (C) ASTEROPTERONINAE Asteropterygion oculitristis (Darby, 1965) (C) Asteropterygion setiferum Kornicker and Caraion, 1975 (C) Asteropterygion thomassini Kornicker, 1981 (C) PHILOMEDIDAE PHILOMEDINAE Anarthron dithrix Kornicker, 1975a (C) Euphilomedes agilis (Thomson, 1879) (C) Euphilomedes carcharodonta (Smith, 1952) (C) Euphilomedes climax Kornicker, 1991b (A) Euphilomedes longiseta (Juday, 1907) (C) Euphilomedes producta (Poulsen, 1962) (C) Philomedes cubitum Kornicker, 1975a (A) Philomedes lofthousae Kornicker, 1975a (A*) Philomedes minys Kornicker, 1975a (A) Philomedes ramus Kornicker, 1975a (A) Philomedes rotunda Skogsberg, 1920 (C) Philomedes subantarctica Kornicker, 1975a (C) Philomedes tetrathrix Komicker, 1975a (A) Zeugophilomedes fonsecensis (Harrmann, 1959) (C) PSEUDOPHILOMEDINAE Harbansus mayeri Kornicker, 1978 (C) RUTIDERMATIDAE RUTIDERMATINAE Rutiderma rotundum Poulsen, 1965 (C) Komicker and Caraion, 1975:11, fig. 5n-p Baker, 1975:79, fig. 17h Komicker, 1975c: 10, fig. 6i Komicker, 1981:119, pi. 21b Komicker, 1981:100, fig. 27f,g, pis. 7b, 19b Komicker, 1981:295,299 Komicker, 1975c:32, fig. 16d,e Komicker, 1981:312, pi. 145a-c,e,f Komicker, 1975a:359 Komicker, 1975a:300, 306, fig. 184e Baker, 1975:79, fig. 17e; Herein Komicker, 1991b: 16, 17, 19 Baker, 1975:79 Baker, 1975:79 Komicker, 1975a:290 Komicker, 1975a:285 Komicker, 1975a, fig. 165s Komicker, 1975a:280 Komicker, 1975a:246,248, fig. 145g Komicker, 1975a:267, fig. 161a-d Komicker, 1975a:262 Baker, 1975:79, fig. 17f Komicker, 1978:32, pi. 7a,e Komicker and Myers, 1981:22, fig. 12q ?Protistan also attached to a larva inside marsupium of ovigerous female. to members of the two families being carnivores; however, this feeding habit would not explain the absence of the protistans in the Cylindroleberidinae and their presence in the Cyclasteropi- nae, because both taxa are filter feeders. Possibly, the Cylindroleberidinae, Cypridinidae, Sarsielli- dae, and Rutidermatidae are able to chemically inhibit the attachment of the stalked cup-like protistans, or perhaps, they are mechanically capable of removing the protistans from the shell margins by manipulation of their appendages. The latter possibility could be explored by observing living specimens. The general sparsity of protistans along the ventral margins of the carapace could be the result of the ability of the ostracode to remove them more readily by appendage movement when they are in that location; however, it would not explain the absence of protistans along the hinged dorsal margins. The density of protistans along the anterior edge of the carapace could be affected by the current of water created by the flapping vibratory plate (epipodite) of the myodocopid 5th limb. Water enters the anterior end of the carapace and leaves at the posterior end (Cannon, 1931:438), where protistans are often present, but usually in lower densities. The current may bring food to the protistans. Probably, the posterior protistans would benefit more from remnants of food escaping from the ostracode. This, of course, does not explain the lack of protistans on some taxa, because the current flow is probably similar in all. Superorder MYODOCOPA Sars, 1866 Order MYODOCOPIDA Sars, 1866 Suborder MYODOCOPINA Sars, 1866 PHILOMEDIDAE Muller, 1906 This family contains two subfamilies, Philomedinae Muller, 1906, and Pseudophilomedinae Kornicker, 1967. Only the former has representatives in Pillar Point Harbor, but both have been reported in the eastern Pacific. 14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY PHILOMEDINAE Muller, 1906 This subfamily includes seven genera of which only Euphilomedes is in the collection. Three additional genera have been reported from the eastern Pacific off North America, Philomedes, Scleroconcha, and Zeugophilomedes. Euphilomedes Kornicker, 1967 Two species are in the collection from the harbor, E. carcharodonta (Smith, 1952) and?. morini, new species. Three additional species have been reported from the eastern Pacific off North America, E. climax Kornicker, 1991b, E. longiseta (Juday, 1907), and E. producta Poulsen, 1962; and E. smithi Poulsen, 1962, has been reported from San Jose, Pearl Islands (Kornicker, 1991b:3). DISTRIBUTION.?Cosmopolitan except in Arctic and Antarc- tic waters. Known depth range shallow water to 2250 m, but mostly from the continental shelf and upper slope (Kornicker, 1991b:3, 4). Euphilomedes carcharodonta (Smith, 1952) FIGURES 10-13,17m Philomedes carcharodonta Smith, 1952:16, pi. I: figs. 1-8, pi. II: figs. 1-6. Euphilomedes carcharodonta (Smith, 1952).?Poulsen, 1962:340, 359 (map), 360, 361, 362 (table), 376-382, 378, 380, 381, 411.?Tuel et al., 1976:140, 155. Philomedes sp. McHardy, 1964:557, figs. 3-7. HOLOTYPE.?None selected. SYNTYPES.?Adult male and ovigerous female (Smith, 1952:16, 18). MATERIAL.?Pillar Point Harbor: Sta 8B (Jun): USNM 194353, adult male on slide and in alcohol; USNM 194354, partly dissected ovigerous female in alcohol; USNM 194359,4 undissected adult males in alcohol; USNM 194360, 4 undis- sected adult females in alcohol; USNM 194361, instar III female on slide and in alcohol; USNM 194367, instar III female in alcohol; 194368, instar III female in alcohol; USNM 194369, instar III male on slide and in alcohol; USNM 194365, instarIV female in alcohol; USNM 194362, instar IV female on slide and in alcohol; USNM 194366, instar IV male on slide and in alcohol; USNM 194363, instar V female on slide and in alcohol; USNM 194364, instar V male on slide and in alcohol; USNM 194355,44 adult females and juveniles of both sexes in alcohol (some juveniles could be E. longiseta); unnumbered specimen, adult male in alcohol deposited in the Australian Museum, Sydney, NSW. Sta 1A (Dec): USNM 194356, adult female on slide and in alcohol; USNM 194381, partly dissected adult female in alcohol; USNM 194382, partly dissected ovigerous female in alcohol. SYNTYPE LOCALITY.?Ganges Harbor, British Columbia, depth 5.5-7.3 m. DISTRIBUTION.?Ganges Harbor, British Columbia (Smith, 1952:18). Near mouth of Indian Arm, a coastal inlet of British Columbia (single male collected with Clarke-Bumpus plankton sampler at a depth of 50-55 m in water approximately 60 m deep) (McHardy, 1964:557). Gabriele Island, Nanaimo, Pacific Coast of Canada, shallow water (Poulsen, 1962:376 (supple- mentary description)). Puget Sound, Washington, depth 23 m (Lie and Evans, 1973:123, 125). San Diego to Point Concep- tion, Southern California, depth preference 5.5-60.0 m (range 5.2-1280.2 m) (Baker, 1975:90, 91). Baker (1975:90) also lists Monterey Bay, Red Sand Hill, Morro Bay, Bodega Bay, Halfrnoon Bay, and Oceanside, California. Swain (1969:429, 473, text fig. 9, pi. VIII: fig. 5a,b) illustrated the outside views of a specimen of Pseudophilomedes sp. from La Jolla, California, from a depth of 45 m (Baker (1975:90) examined that material and placed it in the synonymy of E. carcharo- donta. Pillar Point Harbor, herein. REMARKS.?We have not examined either Baker's (1975) or Swain's (1969) specimens from California and, therefore, have left them out of the synonymy, but we have no reason to question the identifications of Baker. We have also not placed in the synonymy specimens from Puget Sound identified by Lie (1968:397) as E. carcharodonta because they are not extant and cannot be verified, but the species is likely to occur there. Because Pillar Point Harbor is a considerable distance from where the specimens described by Smith and Poulsen were collected, specimens from the present collection were studied in detail, and the supplementary description that follows points out some morphological differences between them and the Canadian specimens, and describes some characters not previously known. Differences observed in the Pillar Point Harbor specimens do not warrant proposal of a new species. SUPPLEMENTARY DESCRIPTION OF ADULT MALE (Figure 10; Table 5).?Carapace shape similar to those illustrated by Smith (1952, pi. 1: fig. 2) and Poulsen (1962, fig. 165a) (Figure 10a). Ornamentation: Poulsen (1962:377) stated that the shell pits are larger on the male than those of the female, and that the edges of the pits are fringed by numerous minute hairs. Smith (1952:19) described the outer surface of the male shell as being finely granular and with irregular depressions with short hairs. The pits or depressions (fossae) are present but indistinct on specimen USNM 194353 from Pillar Point Harbor, and the area between pits are covered by minute papillae (without hairs or spines), which may also be within fossae (typical papillae shown on tip of rostrum in Figure \0b). Long hairs on outer surface of shell similar to those described by Poulsen (1962:377). Infold: Infold of rostrum with 10 or 11 bristles (Figure 106). Anteroventral and anterior l/3 of ventral margin with 11 long bristles oriented inward on specimens examined. Posterior infold with row of about 33 bristles (posterior 24 shown in Figure 10c). Selvage: Similar to that described by Poulsen (1962:377). In vicinity of incisur, lamellar prolongation of rostrum overlaps laterally the lamellar prolongation ventral to incisur. NUMBER 593 15 FIGURE 10.?Euphilomedes carcharodonta (Smith, 1952), adult male, USNM 194353: a, complete specimen from left side, length 2.11 mm; b. anterior right valve with stemmed ectozoan, iv; c, posterior right valve with row of oval ectozoa, iv; d, portion of right 2nd antenna, mv; e, endopodite, left 2nd antenna (detail of 1 st joint showing stemmed ectozoan), mv; / endites I and II of left maxilla; g, endite III of right maxilla; h, right maxilla (endites not shown), Iv; i, endites of 5th limb, anterior to right;/ 1st and 2nd exopodial joints, 5th limb; k, inner lobe of 3rd exopodial joint and exopodial joints 4 and 5 of 5th limb;/, left lamella of furca, Iv; m,n, anterior of body from left and right sides, respectively; o, upper lip from left side; p, left Y-sclerite; q, detail of ectozoan shown in b; r, detail of ectozoan shown in c; s, tip of 7th limb; t, comb teeth of limb opposite that shown in s. 16 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY Central Adductor Muscle Attachments (Figure 1 Oa): Many attachments. Carapace Size (length, height in mm): USNM 194353, 2.11, 1.21, height 57% of length. USNM 194359,4 specimens: 2.10, 1.22, height 58% of length; 2.12, 1.22, height 58% of length; 2.10,1.18, height 56% of length; 2.16,1.20, height 56% of length. Range of length (5 specimens) 2.10-2.16 mm; range of height as percent of length 56-58. (Smith (1952:18) recorded the male length as 2.09 mm, whereas Poulsen (1962: 376) recorded the length range of males as 2.29-2.4 mm and the height as 61% of length. Poulsen's specimens are slightly longer than Smith's, as well as those from Pillar Point Harbor.) First Antenna: Tip of sensory bristle of 5th joint with 5 short filaments (Poulsen's specimen had only 3 (1962:377)). Bristle of 6th joint and a-bristle of 7th joint without long hairs present on Poulsen's specimen. Second Antenna: Protopodite with e-sclerite (Figure lOd, not all endopodial bristles shown). Endopodite (Figure lOe): proximal filament differs from that illustrated by Poulsen (1962: fig. 165d) in not being as broad relative to the narrowest part of the 3rd joint, and the 3rd joint appears longer relative to the 2nd joint. Exopodite: bristle of 3rd joint with natatory hairs; 9th joint with 6 bristles, branch otherwise similar to that described by Poulsen (1962:377). Mandible: Coxale endite: 2 small proximal teeth described by Poulsen (1962:377) not observed. Basale: 7 long bristles with wreaths of long spines on or near ventral margin; dorsal margin with 1 long bare bristle at midlength and 2 subterminal with wreaths of long hairs. Numerous rows of medial spines present on basale and 1st and 2nd endopodial joints. Long medial claw of 3rd joint pectinate proximally, not bare as in Poulsen's specimen. Medial bristles of basale and balance of limb similar to Poulsen's specimen (1962:377). Maxilla: Endite I with about 8 hirsute bristles (Figure 1 Of); endite II with about 7 hirsute bristles (Figure 10/); endite III with about 11 hirsute bristles (Figure lOg). Coxale with fairly short plumose dorsal bristle (Figure lOh). Basale with 3 long spinous bristles (1 ventral, 1 dorsal, 1 medial). Exopodite well developed, with 2 long terminal bristles and 1 shorter bristle slightly proximal to tip, all 3 bristles with long spines (Figure lOh). 1st endopodial joint with 1 alpha-bristle (with long proximal and short distal spines) and 5 hirsute beta-bristles (Figure \0h). 2nd endopodial joint with 3 a-bristles with few long proximal hairs, and 8 bristles with long hairs (detail to Figure lOh). Fifth Limb: Epipodial bristles not counted. Bristles of 3 endites difficult to resolve but endite I has 4 bristles (2 short triangular bristles described by Poulsen (1962:379) not observed) (Figure 10/); endites II and III similar to those of Poulsen's specimen (Figure 10/). 1st exopodial joint with stout triangular spinous terminal process, a smaller indistinct spinous process, and a fairly long proximal bristle (Figure 10/). 2nd exopodial joint with stout spinous terminal process, a smaller proximal spinous process (not on Poulsen's specimen), and 3 bristles (Figure 10/). 3rd exopodial joint: inner lobe with 2 terminal bristles with marginal hairs (Figure 10?) (not bare as in Poulsen's specimen); outer lobe with 2 long stout spinous bristles (not shown). Remainder of limb similar to Poulsen's specimen except fused 4th and 5th joints with total of 7 bristles (Figure 10*). Sixth Limb: USNM 194353 with 3 epipodial bristles on each limb (none seem to be missing). Remainder of limb similar to Poulsen's specimen. Seventh Limb (Figure 10s,/): Proximal and terminal groups each with 4 bristles; bristles with 5-7 bells and weak marginal spines. Terminal comb with 7 teeth: middle tooth longest, bare; 3 teeth on each side with long marginal spines (spines of shortest tooth stouter than on other teeth and could be termed alate processes). Both pegs opposite comb with marginal spines (only proximal peg bears spines on male described by Poulsen (1962:381)). Furca (Figure 10/): Similar to that described by Poulsen (1962:381). Bellonci Organ (Figure 10m): According to Poulsen (1962:382), "The distal part tapers into a finely pointed tip," and the pointed tip is also shown in an illustration of the female organ (Poulsen, 1962: fig. 165c'). The tip of the organ of USNM 194353 is narrowly rounded and closer in shape to the organ illustrated by Smith (1952, pi. II: fig. 4). Eyes: Lateral eye well developed with 33 ommatidia and black pigment (outline shown in Figure 10a). Medial eye smaller than lateral eye, with brown pigment (Figure 10/n). Upper Lip (Figure I0n,o): Lip projecting slightly anteri- orly and with 4 lateral glandular openings (Figure lOo). A flat process on each side of lip with rows of slender spines and 3 indistinct glandular openings near ventral edge (Figure lOo); anterodorsal corner of process with indistinct lateral spine (could be wrinkle) (Figure lOo). Genitalia: Not examined in detail but, in general, similar to those described and illustrated by Poulsen (1962:381, fig. 167a). Anterior of Body (Figure 10m, n): Triangular process with sclerotized finger-like tip present just ventral to attachment of 1st antenna. (Process closer to 1st antenna than anterior process of female.) Posterior of Body: Bare. Y-Sclerite (Figure lOp): With ventral branch. Epizoa: USNM 194353 and 194359 with stemmed protis- tans, some ovoid on posterior edge of shell (Figure 10c, r) and on protopodite and endopodite of 2nd antenna, some vase- shaped on rostrum and anteroventral edge of shell (Figure \0b,q). Gut Content: USNM 194353 appearing to have fine paniculate matter in gut. SUPPLEMENTAL DESCRIPTION OF ADULT FEMALE (Figure 11; Table 5).?Carapace similar in shape to those illustrated by Smith (1952, pi. I: fig. 1) and Poulsen (1962, fig. 165b) (Figure lla). NUMBER 593 17 Ornamentation: Similar to that of male except for fewer long bristles on posterior end. Infold: Rostral infold with 10 or 11 bristles. Anterior part of anteroventral infold with about 8 closely spaced striations parallel to valve margin (inner ridge thicker and interpreted to be list); posterior part of anteroventral infold with 4 striations between list and inner margin of infold and no striations on outer side of list; list extends along ventral and posterior infolds. Part of list of right valve near midlength and posterior to striated area with indistinct "crenulations." Anteroventral infold to about midlength of ventral infold with row of 10 widely spaced bristles. Posteroventral and posterior infolds with about 50 closely spaced bristles of varying lengths (most short), some forming clusters of 2-4 bristles. Selvage: Similar to that of adult male. Central Adductor Muscle Attachments (Figure 1 la): Many attachments. Carapace Size (length, height in mm): Sta 8B (Jun): USNM 194354, 2.16, 1.64, height 76% of length. USNM 194360, 4 specimens: 2.02, 1.54, height 76% of length; 1.98, 1.50, height 76% of length; 2.12, 1.61, height 76% of length; 2.01,1.51, height 75% of length. Sta 1A (Dec): USNM 194356, separated right valve, 1.99, 1.49, height 75% of length; separated left valve, 2.03, 1.55, height 76% of length. USNM 194381, 2.07, 1.55, height 75% of length; USNM 194382, 2.07, 1.57, height 76% of length. Range of length (8 specimens) 1.98-2.16 mm; range of height as percent of length 75-76. (Smith (1952:18) recorded the female length as 2.29 mm. Poulsen (1962:376) recorded the length of an ovigerous female as 2.37 mm and the height as 74% of length. The females from Pillar Point harbor are smaller than those of both Smith and Poulsen from off Canada.) First Antenna: Poulsen's specimen with many ventral spines on 1st joint (Poulsen, 1962, fig. 165c'); these absent on USNM 194356. Ventral bristle of 2nd joint long, slender, similar to that illustrated by Smith (1952, fig. 3), not short and stout as on specimen illustrated by Poulsen (1962, fig. 165c'). Small-disto-medial tooth on 4th joint described and illustrated by Poulsen (1962:377, fig. 165c') absent on USNM 194356. (Tooth also absent on adult male USNM 194353.) Second Antenna: Protopodite without e-sclerite (Figure lie). Endopodite similar to that described and illustrated as "exopodite" by Smith (1952:18, pi. II: fig. 2), 1st joint with 6 short bristles (5 proximal, 1 distal) (Figure 1 \c,e). Exopodite similar to that described by Poulsen (1962:377), 9th joint with 7 bristles. Mandible: Basale with 7 or 8 long spinous bristles on or near ventral margin; medial surface with 5 short proximal bristles (3 unringed, 2 ringed); dorsal margin with long spinous bristle at midlength and 2 long spinous bristles subterminal; medial, lateral, ventral, and dorsal margins spinous. Limb similar to that described by Poulsen (1962:377). Maxilla (Figure 11/): Endite I with 11 spinous and pectinate bristles (1 terminal medial bristle (with small spines) quite short, about XU width of endite at midlength); endite II with about 7 spinous and pectinate bristles; endite III with about 8 spinous and pectinate bristles plus 1 short spinous proximal lateral bristle. Dorsal margins of precoxale and coxale with fringe of long hairs. Coxale with plumose dorsal bristle about '/2 length of dorsal bristle of basale. Basale with 3 long spinous terminal bristles (1 ventral, 1 dorsal, 1 medial). Exopodite: short bristle only slightly subterminal, bare; long middle bristle with long stout spines; other long bristle with short hairs. Endopodite: 1st joint spinous, with 1 alpha-bristle with long proximal and short distal spines, and 5 beta-bristles, either bare or with short spines; 2nd endopodial joint obscured on USNM 194356, but with 3 stout unringed pectinate claws in addition to ringed bristles. Fifth Limb: Epipodial appendage with 55 bristles. Main tooth (Figure 1 \g): small peg described by Poulsen (1962:379, fig. 166b) not observed; bristle proximal to 3 slender teeth minutely pectinate, not bare as on bristle of Poulsen's specimen. Limb otherwise similar to that described by Poulsen (1962:379, fig. 166b,b') but endite bristles not counted. Sixth Limb: USNM 194356 with 4 epipodial bristles (Poulsen (1962:380) stated that the limb is similar in both sexes, and that it has 5 epipodial bristles; however, only 4 are shown on his illustrated male limb (1962, fig. 166c)). All 3 terminal bristles of endite II with long spines. Limb otherwise similar to that described by Poulsen (1962:380). Seventh Limb (Figure 11 A): Limb almost twice width of adult male; with 4 proximal bristles (2 on each side) and 6 terminal bristles (3 on each side); bristles with 3-7 bells and stout marginal spines. Terminal comb with 9 teeth (middle tooth longest, middle and 1 slightly shorter bristle at each side with slightly rounded curved tips, 3 shorter bristles at each side pointed and with small spine on each side of base. Both curved pegs opposite comb with fairly long spines. (Poulsen (1962:381, fig. 186d) described a 7th limb with only 7 comb teeth.) Furca: Number and distribution of claws similar to that of adult male. Claws 1 and 2 less curved than those of male. Claw 1 with medial and lateral row of teeth (proximal 4 lateral teeth larger than others); main claws 2, 3, and 5 differ from those of adult male in having only lateral row of teeth. (Poulsen (1962:382) stated that all main claws of his specimens have medial and lateral teeth.) Bellonci Organ (Figure \\b,i): Short part at midlength bare, proximal and distal parts coated with minute flat discs (possibly foreign growth, not shown). Eyes: Medial eye with area of black pigment (stippled in Figure 1 \b,i). Lateral eye absent. Upper Lip (Figure 11 /,/): In general, similar to that of adult male, but examined only at low magnification (x!5 ocular, x20 objective). Glandular openings indistinct (Figure 1 \j) and flat lateral process, which is so distinct on sides of lip of male, blends into anterior projection of lip of female. 18 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY ? / FIGURE M.?Euphilomedes carcharodonta (Smith, 1952), adult female, USNM 194354: a, complete specimen from right side, length 2.16 mm; b, anterior of body from right side; c, portion of right 2nd antenna, mv; d, right Y-sclerite. Adult female, USNM 194356: e, endopodite, left 2nd antenna, m v ; / left maxilla (nabs), lv; g, 1st and 2nd exopodial joints, right 5th limb, pv; h, tip of 7th limb; ij, anterior of body from right and left sides, respectively; k, posterior of body from right side (only posterior end of Y-sclerite shown). NUMBER 593 19 Anterior of Body (Figure Wb.i.j): Anterior process larger than that of male and farther from 1st antenna (process on Poulsen's female appears closer to base of 1st antenna (Poulsen, 1962, fig. 165c') than process on present specimens). Posterior of Body (Figure Ilk): With spines near mid- height. Genitalia: None observed. Y-Sclerite (Figure 1 Id): With ventral branch. Number of Eggs: USNM 194354 with 30 eggs in marsu- pium and no unextruded eggs; lengths of 3 eggs: 0.22 mm, 0.23 mm, 0.24 mm. USNM 194356 with unextruded eggs. USNM 194382 with 22 eggs in marsupium. Epizoa: USNM 194354 and 194360 with stemmed vase- shaped protistans on rostrum and ventral to incisur (not shown). Gut Content: USNM 194354 and USNM 194356 with amber-colored unrecognizable particles in gut. DESCRIPTION OF INSTAR III FEMALE (Figure 12a-/; Table 5).?Carapace similar in shape to that of adult female (Figure 12a). Carapace Size (length, height in mm): USNM 194361, 1.07, 0.73, height 68% of length. USNM 194367, 1.03, 0.77, height 75% of length. USNM 194368, 1.07, 0.75, height 70% of length. First Antenna: Number of bristles on joints 1-4 listed in Table 5. Joints 5-8 with same number of bristles as on adult, but filaments not counted. Second Antenna: Protopodite without e-sclerite. Endopo- dite similar to that of adult female except with only 3 bristles on 1st joint (Figure 126; Table 5). Exopodite: bristles of joints 2-8 and 9 short and bare; 9th joint with 4 bristles. Mandible: Coxale endite, exopodite, and dorsal bristles of basale similar to those of adult female. Bristles and claws noted in Table 5. Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 2 beta-bristles. Fifth Limb: Main tooth of 1 st exopodial joint with 1 stout and 2 slender teeth (Figure 120,0*). Combined 4th and 5th exopodial joints with 5 or 6 bristles (Figure 2c; Table 5). Remaining bristles of 1st, 2nd, and 3rd exopodial joints similar to those of adult female. Epipodial and endite bristles not counted. Sixth Limb: Number of bristles listed in Table 5. Seventh Limb (Figure 12e): Elongate, bare. Furca (Figure 12/): With 6 claws: claws 1-4 primary, claws 5 and 6 secondary but shape fairly similar to primary claws. Claws with marginal teeth and right lamella anterior to left by width of base of claw 1. Bellonci Organ (Figure 12g): Distal part not tapered as in adult female. Eyes: Medial eye pigmented (stippled in Figure 12g). Lateral eye absent. Upper Lip: Spinous projection. Genitalia: None observed. Anterior of Body (Figure \2g): With projecting rounded anterior process at midheight. Posterior of Body: With hairs at midheight. Y-Sclerite (Figure 12/t): Similar to that of adult female. Epizoa: Protopodite of 2nd antenna USNM 194361 with protistan with long stem attached to elongate oval (Figure 12/). Rostrum of USNM 194367 with stemmed vase-shaped protistans. Gut Content: Guts of USNM 194361, 194367, and 194368 containing amber-colored unrecognizable paniculate matter. DESCRIPTION OF INSTAR III MALE (Figure \2j-p; Table 5).?Carapace similar to that of instar III female. Carapace Size (length, height in mm): USNM 194369, 1.08, 0.67, height 64% of length. First Antenna: Similar to that of instar III female (Table 5). Second Antenna: Protopodite without e-sclerite; medial row of minute spines near posterodorsal curvature (Figure 12/). Endopodite 2-jointed (Figure \2k,l): 1st joint with 3 bristles; 2nd joint with 2 bristles and with broadly rounded tip (2nd joint broader than that of instar III female). Exopodite similar to that of instar III female. Mandible: Distribution of bristles noted in Table 5. Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 2 beta-bristles. Fifth Limb: Except for main tooth having 2 or 3 slender and 1 stout tooth, limb similar to that of instar III female, which has 2 slender and 1 stout tooth on both limbs of specimen examined. Sixth Limb: Similar to that of instar III female (Table 5). Seventh Limb (Figure 12m) and Furca: Similar to those of instar IN female. Eyes: Lateral eye small unpigmented, with several indis- tinct ommatidia (Figure I2n,o). Medial eye similar to that of instar III female (Figure I2n). Upper Lip (Figure I2p), Bellonci Organ (Figure 12/i), Anterior of Body (Figure 12/7), and Posterior of Body: Similar to those of instar III female. Genitalia: None observed. Y-Sclerite: Elongate, with ventral branch observed on USNM 194384. Epizoa: USNM 194369 with stemmed vase-shaped protis- tan near incisur, and several round protistans on short stems attached to protopodite of 2nd antenna. Gut Content: USNM 194369 with amber-colored particu- late matter and large rotaloid foram in gut. DESCRIPTION OF INSTAR IV FEMALE (Figure 13a-/; Table 5).?Carapace similar in shape to that of adult female (Figure 13a). Carapace Size (length, height in mm): USNM 194362, 1.22, 0.92, height 75% of length. USNM 194365, 1.26, 0.93, height 74% of length. First Antenna: Distribution of bristles on joints 1 -4 shown 20 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY a FIGURE 12.?Euphilomedes carcharodonta (Smith, 1952), female instar III, USNM 194361: a, outline of complete specimen from right side, length 1.07 mm; b, endopodite, left 2nd antenna, mv; c, tip of right 5th limb, pv; d. 1st exopodial joint, left 5th limb as seen through 2nd joint, pv; e, 7th l imb;/ right lamella of furca, lv; g, anterior of body from left side; h, left Y-sclerite; i, ectozoa attached to prodopodite of 2nd antenna. Male instar III, USNM 194369:/ portion of protopodite of 2nd antenna, lv; k.l, endopodites of left and right 2nd antennae, respectively, mv; m, 7th limb; n, portion of anterior of body from right side (not under cover slip); o, right lateral eye; p, portion of anterior of body from left side. NUMBER 593 21 in Table 5. Bristles of joints 5-8 not examined in detail but same number as on adult female. Second Antenna: Protopodite without e-sclerite. Endopo- dite similar to that of adult female except 1st joint with only 4 bristles (Figure 136). Exopodite with short bare bristles; 9th joint with 5 bristles. Mandible: Coxale endite, exopodite, and dorsal bristles of basale similar to those of adult female. Distribution of claws and bristles noted in Table 5. Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 3 beta-bristles. Fifth Limb: Main tooth with 1 stout and 3 slender pectinate teeth. Combined 4th and 5th exopodial joints with 6 bristles. Limb otherwise similar to that of adult female. Epipodial and endite bristles not counted. Sixth Limb: Number of bristles noted in Table 5. Seventh Limb: With 4 proximal bristles (2 on each side) and 4 terminal bristles (2 on each side); all bristles short and tapered; each bristle with 1 bell and large terminal clapper that could be interpreted to be 2nd bell, and marginal spines. Comb with 1 curved tooth at midwidth and on each side 2 teeth with 3 long prongs and 2 small basal spines (Figure 13c). Side opposite comb with blunt inner peg with long spines and pointed outer peg with short spines. Furca (Figure 13c/): Each lamella with 8 claws: claws 1,2, 3, and 5 primary and with medial and lateral teeth, claws 4,6-8 secondary and with single row of posterior teeth (teeth not shown). Right lamella anterior to left by width of base of claw 1. Bellonci Organ (Figure 13e): Distal part not tapered as in adult. Eyes: Similar to those of adult female (Figure 13e). Upper Lip (Figure 13/): Spinous projection. Genitalia: Not observed. Anterior of Body (Figure 13e,/): With rounded anterior process. Posterior of Body: With hairs at midheight. Y-Sclerite: Similar to that of adult female. Epizoa: USNM 194362 and 194365 with stemmed vase- shaped protistans on rostrum or both on rostrum and ventral to rostrum. Gut Content: USNM 194362 and 194365 with amber- colored unrecognizable paniculate matter in guts. Gut of USNM 194362 also with large rotaloid foram near posterior end. DESCRIPTION OF INSTAR IV MALE (Figure 13g-/; Table 5).?Shape similar to that of instar IV female. Carapace Size (length, height in mm): USNM 194366, 1.35, 0.96, height 71% of length. First Antenna: Similar to that of instar IV female (Table 5). Second Antenna: Protopodite and exopodite similar to that of instar IV female (Table 5). Endopodite 3-jointed (Figure 13g): 1st joint with 4 short bristles; 2nd joint with 2 ventral bristles (1 long proximal and 1 short distal); 3rd joint with 2 bristles (1 distal dorsal and 1 shorter terminal). Mandible: Except for some variability in number of bristles, limb similar to that of instar IV female (Table 5). Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 3 beta-bristles. Fifth Limb, Sixth Limb, Seventh Limb, and Furca: Similar to those of instar IV female. Bellonci Organ (Figure 13A): Tip broken off on USNM 194366. Eyes: Medial eye similar to that of instar IV female (Figure 13/z). Lateral eye small with light brown pigment and several small cells (Figure 13A). Upper Lip (Figure 13 h), Anterior of Body (Figure I3h), and Posterior of Body: Similar to those of instar IV female. Genitalia: Not observed. V-Sclerite: Fragmented on USNM 194366. Epizoa: USNM 194366 with stemmed oval protistan on protopodite of 2nd antenna. Gut Content: USNM 194366 with large rotaloid foram (stippled in Figure 13/) in addition to brown unrecognizable paniculate matter (short lines in Figure 13/). DESCRIPTION OF INSTAR V FEMALE (Figure 13/,*; Table 5).?Shape similar to that of adult female (Figure 13/). Carapace Size (length, height in mm): USNM 194363 (appendages of adult female visible within), 1.72, 1.27, height 74% of length. First Antenna: Distribution of bristles on joints 1-4 noted in Table 5. Bristles of joints 5-7 not examined in detail but same number as on adult female. Second Antenna: Protopodite without e-sclerite. Endopo- dite similar to that of adult female but 1st joint with only 5 bristles (Figure 13?). Exopodite with short bare bristles; 9th joint with 6 bristles. Mandible: Coxale endite, exopodite, and dorsal margin of basale similar to those of adult female; distribution of remaining bristles noted in Table 5. Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 4 beta-bristles. Fifth Limb: Exopodite similar to that of adult female (Table 5). Epipodial and endite bristles not counted. Sixth Limb: Distribution of bristles shown in Table 5. Seventh Limb: Same number of bristles as on adult female (Table 5); bristles tapered and with 1-4 bells and marginal spines. Comb with 1 curved claw (with proximal spines) at midwidth and on each side 3 teeth each with 3 long prongs and a basal spine on each side. Pegs opposite comb similar to those of adult female. Furca: Similar to that of adult female. Bellonci Organ: Distal part broken off on USNM 194363. Eyes: Similar to those of adult female. Upper Lip: Spinous anterior projection with indistinct lateral glandular openings along ventral edge (3 in anterior row; 4 in posterior row). 22 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY a FIGURE 13.?Euphilomedes carcharodonta (Smith, 1952), female instar IV, USNM 194362: a, outline of complete specimen from left side, length 1.22 mm; b, endopodite, left 2nd antenna, mv; c, tip of 7th limb; d, left lamella of furca, lv; e.f, portions of anterior of body from right and left sides, respectively. Male instar IV, USNM 194366: g, endopodite, left 2nd antenna, mv; h, anterior of body from right side; i, portion of of gut containing a foraminiferan. Female instar V, USNM 194363:/ outline of complete specimen from left side, length 1.72 mm; k, endopodite, left 2nd antenna, mv. Male instar V, USNM 194364: /, endopodite, left 2nd antenna, mv; m, anterior of body from right side; n, right lateral eye. NUMBER 593 23 Genitalia: Not observed. Anterior of Body: Similar to that of adult female. Posterior of Body: With hairs at midheight. Y-Sclerite: Similar to that of adult female. Epizoa: USNM 194363 with stemmed vase-like protistan on rostrum. Gut Content: USNM 194363 with unrecognizable amber- colored particulate matter in gut. DESCRIPTION OF INSTAR V MALE (Figure 13/-?; Table 5).?Carapace similar to that of adult female. Carapace Size (length, height in mm): USNM 194364, 1.75, 1.26, height 72% of length. First Antenna: Similar to that of instar V female (Table 5). Second Antenna: Protopodite and exopodite similar to that of instar V female. Endopodite 3-jointed (Figure 13/): 1st joint with 5 short bristles; 2nd joint with 1 long and 2 short ventral bristles; 3rd joint with 1 proximal and 2 terminal bristles. Mandible: Similar to that of instar V female (Table 5). Maxilla: Not examined in detail, but 1st endopodial joint with 1 alpha- and 4 beta-bristles. Fifth Limb: Similar to that of instar V female, but fused 4th and 5th joints fragmented on USNM 194364 and number of bristles could not be counted. Sixth Limb: Except for number of bristles differing slightly, limb similar to that of instar V female (Table 5). Seventh Limb: Differs from that of instar V female mainly in having only 4 terminal bristles (Table 5). Furca: Distribution and number of claws similar to those of instar V female. Spines observed along anterior and posterior edges of secondary claws. Claw 1 with teeth forming medial and lateral rows; claws 2, 3, and 5 with row of lateral teeth. Bellonci Organ (Figure 13m): Distal part tapering to narrowly rounded tip. Eyes: Medial eye similar to that of instar V female (Figure 13m). Lateral eye small with light brown pigment and many small indistinct cells (ommatidia?) (Figure 13n). Upper Lip (Figure 13m): Projecting anteriorly, spinous. Genitalia: Tapered lobes. Anterior of Body (Figure 13m): With rounded projecting anterior process. Posterior of Body: With few rows of spines at midheight. V-Sclerite: Fragmented. Epizoa: USNM 194364 with numerous stemmed vase- shaped protistans on and ventral to rostrum. Gut Content: Gut of USNM 194364 with 4 rotaloid forams in addition to unrecognizable particulate matter. REMARKS.?The main difference between the male from Pillar Point Harbor and those described by Smith (1952:16) and Poulsen (1962:376) is the papillate shell surface. It is assumed herein that papillae on the shells of the Canadian specimens were overlooked. Of possible significance is that both terminal pegs of the 7th limb of the adult male of the Pillar Point Harbor specimens are spinous, whereas only the proximal peg is spinous on the male described by Poulsen (1962:381). ONTOGENY (Table 5).?Hiruta (1980:145) described the ontogeny of Euphilomedes nipponica Hiruta, 1976, collected in shallow water off Japan, and Kornicker (1991b: 19-21) described the ontogeny of Euphilomedes climax Kornicker, 1991b, from hydrothermal vents in the eastern Pacific Ocean. Instars I-V as well as adults were available for those studies. In the present study of E. carcharodonta only instars 11 I-V were available in addition to adults (Table 5). The ontogeny of instars 11 I-V and adults of all three species are quite similar (taking into account specific differences). Both E. nipponica and E. climax have a secondary claw between primary claws 2 and 4, whereas E. carcharodonta has a secondary claw between primary claws 3 and 5. In the first two species the secondary claw is added in instar III, whereas in E. carcharodonta it is added in instar IV. The addition of 1 bristle in each developmental stage on the 9th exopodial joint of the 2nd antenna conforms with the tabular key of Kornicker (1991b:21). Poulsen (1962:382) described a single young "female" of the species. Unlike the adult female the juvenile has lateral eyes, and the endopodite of the 2nd antenna differs considerably from that of the adult female. It was mainly because of those unusual characters that the present study of juveniles was undertaken. Based on the present study, it is concluded that Poulsen's young "female" is an instar IV male. The carapace is larger than the 4th instars encountered in Pillar Point Harbor, but the endopodite of the 2nd antenna is almost identical to that of the instar IV male and is unlike that of juvenile females. In addition, juvenile females lack lateral eyes. Poulsen (1962:382) based his sex determination on the lack of any trace of copulatory limbs on the specimen. The copulatory limbs are not visible on the male 4th instar in the present collection and are either absent or difficult to identify. Poulsen (1962:382) also stated that the exopodite of the 5th limb of the following instar, which is visible inside the 5th limb of his specimen, is of the female type. That does not help establish the sex of instar IV, because the 5th limb of the instar V male is also of the female type. Poulsen was aware of this and may not have given much weight to that observation in determining sex, unless he thought that the specimen may have been a 5th instar (A-l stage), which is possible. EPIZOA.?Many specimens have long stalked cup-like protistans along the anterior end of the rostrum or on the anteroventral margin ventral to the rostrum. Fewer specimens have round protistans with or without short stems along the posterior edge of the carapace. A few specimens have a few short stemmed ball-like protistans along the edge of the protopodite of the 2nd antenna. Baker (1975:76-79, fig. 17e,j) has previously described stalked cup-like protistans along the anterior edge of E. carcharodonta. He also described a hydroid occurring in the same place. The latter was not observed on the few specimens studied herein, but hydroids have been observed on Philomedes brenda (Baird, 1850a) collected on the Alaskan continental shelf (Kornicker (1988, fig. 2a,b)). 24 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY TABLE 5.?Morphometrics and meristics for selected characters of instars and adults of Euphilomedes carcharodonta (b = bristles, c = claws, d = dorsal, 1 = lateral, m = medial, na = not applicable, nd = no data, p = proximal, t = terminal, v = ventral, - = absent, + = present). Character Carapace length (avg. mm) First Antenna 1 st joint bristles 2nd joint bristles (v/d/1) 3rd joint bristles (v/d) 4th joint bristles (v/d) Second Antenna Endopodite 1st joint bristles 2nd joint bristles 3rd joint bristles Exopodite 9th joint bristles Mandible Basale bristle (m/v) Endopodial bristles 1st joint (v) 2nd joint (v/d) 3rd joint (c/b) Maxilla Endopodite alpha-bristles beta-bristles Fifth Limb 1st joint, pectinate teeth 4th + 5th joint bristles Sixth Limb Epipodial bristles Endite bristles End joint bristles Seventh Limb bristles Bristles (p/t) Bells on bristles Comb teeth Number of pegs Pegs with spines Furca, claws Lateral eye (-/+) Carapace length (avg. mm) First Antenna 1st joint bristles 2nd joint bristles (v/d/1) 3rd joint bristles (v/d) 4th joint bristles (v/d) Second Antenna Endopodite 1 st joint bristles 2nd joint bristles 3rd joint bristles Exopodite 9th joint bristles Mandible Basale bristle (m/v) Endopodial bristles 1 st joint (v) 2nd joint (v/d) 3rd joint (c/b) III 1.06 0 1/1/1 1/2 1/1 3 2 na 4 6/2-3 3 4-5/7 3/3 1 2 3 5-6 1 17 7 0 0 na 0 0 na 6 - 1.08 0 1/1/1 1/2 1/1 3 2 na 4 6/3 4 5/8 3/3 rv 1.24 0 1/1/1 1/2 2/2 4 2 na 5 6/4 4 5/7 3/3 1 3 4 6 2 21 15 8 4/4 1 5 2 2 8 - 1.35 0 1/1/1 1/2 2/2 4 2 2 5 6/5 3 5/8 3/3 Stage V FEMALE 1.72 0 1/1/1 1/2 3/2 5 2 na 6 6/6 4-5 6/10 3/4 1 4 4 7 3 23-24 20-21 10 4/6 \^\ 7 2 2 10 - MALE 1.75 0 1/1/1 1/2 3/2 5 3 3 6 6/6 5 5-6/8-9 3/4 Adult 2.06 0 1/1/1 1/2 4/2 6 2 na 7 6/7-8 5 6/8 3/4 1 5 4 7 4 25 28 10 4/6 3-7 7 2 2 10 - 2.12 0 1/1/1 1/2 4/2 6 2 3 6 6/7 4-6 5-6/7-9 3/3-4 NUMBER 593 25 TABLE 5.?Continued. Character Maxilla Endopodite alpha-bristles beta-bristles Fifth Limb 1 st joint, pectinate teeth 4th + 5th joint bristles Sixth Limb Epipodial bristles Endite bristles End joint bristles Seventh Limb bristles Bristles (p/t) Bells on bristles Comb teeth Number of pegs Pegs with spines Furca, claws Lateral eye III 1 2 3-4 5-6 1 18 7 0 0 na 0 0 na 6 + rv I 3 4 6 2 20 15 6 4/4 1-2 5 2 2 8 + Stage V 1 4 4 nd 3 -25 -24 8 4/4 2-4 6 2 2 10 + Adult 1 5 na 7 3 25 27 8 4/4 5-7 7 2 2 10 + FEEDING.?According to Cannon (1933:755, 756), in the Philomedidae the mandible kicks up particles of detritus from the sediment, and these particles are sucked into the shell by a current created by the flapping of the epipodial appendage of the 5th limb. The particles are then pushed into the esophagous by appendages around the mouth. Elofsen (1941:465; 1969:215) observed that specimens apparently consume silt without filtering out coarse particles. This type of feeding has been termed "detritus feeder" or "collector" (Turpaeva, 1957:137; Walker, 1972:83; Kornicker, 1975a:40). One or more whole rotaloid forams were observed in the guts of three E. carcharodonta studied herein, and they were previously noted in specimens examined by Baker (1975:82). The guts contain mainly unrecognizable amber-colored paniculate mat- ter. SEX RATIO.?In order to study the ontogeny of the species, juveniles were removed from the sample from sta 8B (Jun), which contained 60 specimens, until a male and female of each represented stage were obtained. The nine specimens selected consisted of the following: Instar III?1 male, 3 females; Instar IV?1 male, 2 females; Instar V?1 male, 1 female. The sample contained six adult males; the remaining balance were ovigerous and non-ovigerous females and instars III-V of both sexes. Euphilomedes morini, new species FIGURES 14-16, \la-l,n,o, 18 Euphilomedes longiseta.?l\x\ et al., 1976:140, 155 [not E. longiseta (Juday, 1907)]. ETYMOLOGY.?Named in honor of James G. Morin, Univer- sity of California. HOLOTYPE.?USNM 194372, undissected ovigerous female in alcohol. TYPE LOCALITY.?Sta 1A (Dec), Pillar Point Harbor, Half Moon Bay, California. PARATYPES.^illar Point Harbor: Sta 1A (Dec): USNM 194357, ovigerous female on slide and in alcohol; USNM 194358, adult male on slide and in alcohol; USNM 194370, partly dissected adult male in alcohol; USNM 194371, partly dissected ovigerous female in alcohol; USNM 194373, 6 undissected adult males in alcohol; USNM 194377, instar IV male on slide and in alcohol; USNM 194375, instar IV female on slide and in alcohol; USNM 194374, instar IV female in alcohol; 194376, instar IV female in alcohol; USNM 194378,8 undissected instar IV's, sex unknown, in alcohol; USNM 194379, partly dissected instar V female in alcohol; USNM 194380, instar V male on slide and in alcohol. ADDITIONAL MATERIAL.?USNM 194383, 68 undissected adult females and juveniles (some of these could be juvenile E. carcharodonta) in alcohol. DISTRIBUTION.?Pillar Point Harbor, Half Moon Bay, California, depth 1.8 m. DESCRIPTION OF ADULT MALE (Figures 14, 15; Table 6).?Carapace elongate with shallow incisur (Figure 14a). Ornamentation: Carapace with indistinct small widely separated pits. Long bristles more common along anterior, anteroventral, and posterior margins. (Surface either without minute tubercles that cover surface of shell of E. carcharo- donta, or with smaller tubercles.) Infold: Rostral infold with row of 12 spinous bristles (Figure 146); 1 bristle at inner curvature of incisur, then space and row of 5 spinous bristles. Posterior end of ventral infold and posterior infold with row of about 50 small bristles along midwidth, and 2 bristles posterior to row (not all bristles shown in Figure 14c). Selvage: Lamellar prolongation of selvage weakly divided at inner end of incisur. Prolongation with very long marginal 26 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY hairs except along posterior margin where hairs are short on left valve and absent on right valve. Carapace Size (length, height in mm): USNM 194358, 1.73, 1.00, height 58% of length. USNM 194370, 1.65, 0.99, height 60% of length. USNM 194373,4 specimens: 1.79,1.02, height 57% of length; 1.63, 0.97, height 60% of length; 1.71, 0.99, height 58% of length; 1.68, 0.97, height 58% of length. Range of length (6 specimens) 1.63-1.79; range of height as percent of length 57-60. First Antenna: 1st joint with short dorsal spines, a few rows of short medial spines, and long lateral hairs in distal dorsal corner. 2nd joint with dorsal, ventral, lateral, and medial spines, and 3 bristles (1 dorsal, 1 ventral, 1 lateral (missing on left limb of USNM 194358)), all with long spines. 3rd joint short with medial and lateral spines and 3 bristles (2 dorsal, 1 ventral), all with short spines. 4th joint with ventral, medial, and lateral spines, and 6 bristles: 2 dorsal with long proximal and short distal spines, and 4 ventral, some with long proximal and short distal spines. 5th joint wedged ventrally between joints 4 and 6, with sensory filament with stout proximal part with numerous long slender filaments, followed by 1 short proximal filament, 3 short subterminal filaments, and 2 short terminal filaments. 6th joint with medial bristle near dorsal margin, with long proximal and short distal spines. 7th joint (Figure I4d,e): a-bristle with long proximal and short distal spines; b-bristle same length as a-bristle, with 3 proximal filaments (2 long and 1 short), 2 short subterminal filaments, and 2 short terminal filaments; c-bristle extremely long (about 3 times length of combined lengths of joints 2-8) with 13 short marginal filaments. 8th joint lateral to 7th joint (Figure I4d): d-and e-bristles about '/3 longer than b-bristle, bare with blunt tips; f-bristle slightly shorter than c-bristle, with 12 short marginal filaments; g-bristle about same length as d-bristle, with 5 marginal filaments. A flat medial shield covers basal part of 7th and 8th joints (shield indicated by letter s in Figure I4d,e). Under cover slip, joints of left limb of USNM 194358 (Figure \4d) narrower than those of right limb (Figure 14e) (possibly an artifact of mounting). Second Antenna: Protopodite with e-sclerite, and without hairs or spines (Figure 14/). Endopodite 3-jointed (Figure \4g,h): 1st joint with 5 short proximal bristles and 1 long distal bristle with wreath of long spines; 2nd joint with 2 short distal ventral bristles; 3rd joint reflexed on 2nd, with long ringed proximal bristle, 2 small subterminal bristles, and ridges at tip. Exopodite: 1st joint with small straight terminal medial bristle; 2nd joint short, with ventral bristle (with short slender ventral spines near tip) reaching joints 7 or 8; 3rd joint twice length of 2nd joint; bristles of joints 3-8 long and with natatory hairs; 9th joint with 6 bristles (4 long, 2 short) with natatory hairs; joints 3-8 with minute spines on distal dorsal corner. Mandible: Coxale endite consisting of 3 weakly developed bristles (Figure 14/). Basale: medial side with 5 small proximal bristles near ventral margin and 1 short ringed bristle at '/3 length (Figure 14/); 7 long bristles (with wreaths of long spines) on or near ventral margin; dorsal margin with 3 bristles (1 at midlength, 2 subterminal) with wreaths of long spines. Numerous medial rows of long spines on basale and 1 st and 2nd endopodial joints. Exopodite about xli length dorsal margin of 1st endopodial joint, with 2 terminal bristles (1 long with long spines, 1 about '/3 or xli length of long bristle and bare). 1st endopodial joint with 5 ventral bristles (2 long with long spines, 1 long with short spines, 2 short with short spines). 2nd endopodial joint: dorsal margin with 2 long bristles in proximal group and 6 or 7 (5 or 6 long, 1 small) in distal group; ventral margin with spines and 2 distal groups of bristles, each group with 3 long bristles. 3rd endopodial joint with 3 pectinate claws (dorsal claw about V3 length of remaining 2 subequal claws) and 4 ringed bristles. Maxilla: Limb reduced. Precoxale and coxale with hirsute dorsal fringe (Figure 156). Coxale with plumose dorsal bristle (Figure \5b). Basale with 2 long distal bristles (1 ventral, 1 dorsal). Exopodite with 3 bristles (2 long, 1 short). 1st endopodial joint narrow with 1 bare alpha-bristle and about 4 beta-bristles (Figure 15b). 2nd endopodial joint with about 8 indistinct bristles. Endites with indistinct bristles (Endite I with about 8 bristles, endite II with about 6 bristles, endite III with about 9 bristles) (Figure 15a). Fifth Limb: Endite I with 4 ringed bristles (Figure 15a*); endite II with about 9 ringed bristles (Figure 15c); endite III with about 8 ringed bristles (Figure 15c). 1st exopodial joint with broad terminal process and about 5 bristles (2 unringed) (detail in Figure I5d). 2nd exopodial joint with broad terminal process and 2 long bristles (detail in Figure I5d). 3rd exopodial joint: inner lobe with 1 short and 2 long bare bristles; outer lobe with 2 long plumose bristles (Figure 15*/). 4th and 5th joints fused, hirsute, with 1 long bristle with widely separated short spines and 5 shorter bare bristles (Figure I5d). Sixth Limb (Figure 15e): With 3 short plumose epipodial bristles. Endite I with 1 bare terminal bristle and 2 shorter plumose medial bristles; endite II with 4 bristles (1 long and 2 short terminal, 1 short plumose medial); endites III and IV each with 8 or 9 terminal bristles (endite bristles not shown in Figure 15e). End joint with 18 or 19 plumose and spinous bristles. Limb hirsute (hairs not shown). Seventh Limb: Proximal and terminal groups each with 4 bristles, 2 on each side; bristles with indistinct spines and 3-5 bells, but tips of some bristles (with possible additional bells) broken off. Terminal comb with 5 teeth with long spines, middle tooth longest (Figure 15/). Side opposite comb with 2 curved spinous pegs. Furca (Figure 15g): Each lamella with 11 claws; claws 1, 2, 4, and 6 primary; claws 3, 5, 7-11 secondary. Claw 1 with long teeth along posterior edge (proximal 6 or 7 teeth longer); other primary claws and secondary claws with smaller teeth (teeth not shown); long slender medial spines along lamellae at bases of claws (spines not shown). Right lamella anterior to left by width of base of claw 1. NUMBER 593 27 FIGURE 14.?Euphilomedes morini, new species, adult male, paratype, USNM 194358: a, outline of complete specimen from right side, length 1.73 mm; b, anterior left valve, iv; c, posteroventral comer left valve, iv; d, tip of left 1st antenna with 3 detailed illustrations, Iv; e, e', tip of right 1st antenna, mv;/ portion of left 2nd antenna, mv; g, endopodite, left 2nd antenna, mv; h, tip of 3rd joint of endopodite, right 2nd antenna, Iv; i, portion of right mandible, mv. 28 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY ?\ FIGURE 15.?Euphilomedes morini, new species, adult male, paratype, USNM 194358: a, endites I?III. right maxilla, lv; b, right maxilla with 2 detailed illustrations (nabs), Iv; c, endites II and III of 5th limb; d, 5th limb with two detailed illustrations (nabs); e, left 6th limb (endite bristles not shown), lv; / tip of 7th limb (bristles not shown); g, left lamella of furca, lv; h, portion of anterior of body from left side; i, lateral eye (black pigment stippled);/ portion of anterior of body from right side; k, copulatory organs from right side (furca, which lies between left and right organs, not shown); /, posterior of body from left side. NUMBER 593 29 Bellonci Organ (Figure 15A): Elongate with short triangu- lar terminal part with narrowly rounded tip. Eyes: Medial eye with brown pigment (Figure \5h). Lateral eye well developed with 33 ommatidia with black pigment (stippled in Figure 5/) between them (outline of eye shown in Figure \5h). Upper Lip (Figure 15/): Projecting slightly anteriorly. Genitalia (Figure \5k): Elongate with a copulatory limb dangling on each side of furca, with small terminal bristles. Anterior of Body (Figure \5h,j): With sclerotized irregular protuberance at tip of triangular process just ventral to base of 1st antennae. Posterior of Body (Figure 15/): With long spines ventral to midheight. Y-Sclerite (Figure 15/): With axe-shaped tip (structure less evident on right sclerite of USNM 194358). Epizoa: USNM 194373: rostrum of 6 specimens with vase-shaped stemmed protistans. USNM 194370 with similar protistans along rostrum and incisur. Gut Content: USNM 194370 and 194358 with unrecogniz- able amber-colored particles in gut. DESCRIPTION OF ADULT FEMALE (Figures 16, 17a-/; Table 6).?Carapace with shallow incisur (Figure 16a). Ornamentation: Carapace with indistinct small widely separated pits. Long bristles along anterior and ventral margins, sparse elsewhere. Outer surface with minute closely spaced papillae (Figure 111), smaller than those of E. carcharodonta (Figure 17m), and not visible on most specimens. Infold: Rostral infold with row of 12 or 13 spinous bristles (Figure 166); 1 short spinous bristle at inner curvature of incisur, then space and row of 7 short spinous bristles (4 shown in Figure 166) along outer edge of 5 or 6 ridges paralleling valve edge (Figure 166). 2nd or 3rd ridge from outer edge continues along ventral infold (at midwidth) as narrow list; list indistinct or absent along posterior infold; posterior end of ventral infold along outer edge of list and posterior infold with row of about 70 short bristles on right valve and 35 on left valve, and 7 widely spaced bristles outside of row of short bristles on right valve, and 4 on left valve (not all bristles shown in Figure 16c). Part of ventral list of right valve not crenate as on E. smithi (Poulsen, 1962:373, fig. 163b). Selvage (Figure 166): Lamellar prolongation broader on rostrum becoming narrower at small indentation at ventral end of rostrum (Figure 166). Selvage not clearly divided at inner end of incisur but it may be. Prolongation with very long marginal hairs except along posteroventral and posterior margins of right valve. Carapace Size (length, height in mm): USNM 194357, 1.62, 1.10, height 68% of length. USNM 194372, 1.64, 1.11, height 68% of length. USNM 194371, 1.74, 1.25, height 72% of length. Range of length (3 specimens) 1.62-1.74; range of height as percent of length 68-72. First Antenna: 1 st joint with long and short medial spines, distal lateral row of short spines, and few rows of short dorsal spines. 2nd joint with dorsal and distal lateral spines and 3 bristles (1 ventral, 1 dorsal, 1 lateral) with long spines (Figure 16a1). 3rd joint short with medial row of minute indistinct spines, row of terminal lateral spines, and 3 bristles (1 ventral with short spines, 2 dorsal bare or with short spines) (bristles not shown). 4th joint with medial and ventral spines and 6 bristles (4 ventral, 2 dorsal) with long spines (bristles not shown). Sensory bristle of long 5th joint with 7 short marginal filaments, 3 short subterminal filaments, and bifurcate tip (bristle not shown). Long medial bristle of minute 6th joint with base near dorsal margin and with long proximal and short distal spines (Figure 16e). 7th joint (Figure 16e): a-bristle similar to bristle of 6th joint; b-bristle long with 2 short filaments near midlength, 2 subterminal filaments, and bifur- cate tip; c-bristle with 5 short marginal filaments, 3 subterminal filaments, and bifurcate tip. 8th joint (Figure 16e): d- and e-bristles bare with blunt tips; 2 minute lateral papillae just proximal to d-bristle on short lateral shield (Figure \6e); f-bristle with 4 marginal filaments, 3 subterminal filaments, and bifurcate tip; g-bristle with 5 marginal filaments, 3 subterminal filaments, and bifurcate tip; b- to g-bristles about same length as sensory bristle of 5th joint, a-bristle shorter. Second Antenna: Protopodite without e-sclerite; with long hairs near anterodorsal corner and at midlength of dorsal margin, few minute medial spines in posterodorsal corner, and short spines along distal ventral margin. Endopodite 2-jointed (Figure 16/g): 1st joint with row of 5 short bare proximal bristles and 1 long spinous distal bristle; 2nd joint with very long spinous proximal bristle and short bare terminal bristle. Exopodite: 1st joint with minute medial straight terminal bristle; bristle of 2nd joint reaching well past 9th joint, with abundant slender ventral spines; bristles of joints 3-8 with natatory hairs, no spines; 9th joint with 7 bristles (4 long with natatory hairs, 3 shorter with abundant slender spines); joints 2-8 with row of terminal spines. Mandible: Coxale endite bifurcate, spinous, with small ringed bristle near base. Basale: medial surface and dorsal and ventral margins with rows of spines, and 5 bristles in proximal ventral corner (3 pectinate unringed, 2 ringed and with long spines), and 1 short ringed bristle (with either short spines only, or both long and short spines) closer to midlength; dorsal margin with 3 long bristles (1 at midlength, 2 subterminal) with long spines; 6 or 7 bristles (with long spines) on or near ventral margin. Exopodite slightly more than V2 length of dorsal margin of 1st endopodial joint (Figure \lh), with few terminal spines and 2 bristles (proximal very long with long spines at midlength and short spines distally, terminal bristle about V4 length of proximal bristle and with short spines; bristles not shown in Figure \lh). 1st endopodial joint with medial spines and 4 ventral bristles (3 long with long spines, 1 small with short spines). 2nd endopodial joint: dorsal margin with 2 long bristles (with few long spines) in proximal group and 7 bare 30 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY a FIGURE 16.?Euphilomedes morini. new species, ovigerous female, paratype, USNM 194357: a, outline of complete specimen from left side, length 1.62 mm; b, anterior right valve, iv; c, posterior right valve, iv; d, right 2nd antenna (only bristles of 2nd joint shown), lv; e, tip of right 1st antenna, lv ; / endopodite, left 2nd antenna, mv; g, endopodite, right 2nd antenna, mv; h, left maxilla (endites and bristles of 2nd endopodial joint not shown), lv; i, endites I-111, left maxilla, mv;/ 2nd endopodial joint, left maxilla (nabs), lv; k. 2nd endopodial joint, right maxilla (nabs), mv. NUMBER 593 31 bristles in distal group (1 short, others long); ventral margin with bristles in 2 distal groups, each with 3 bristles (some with short spines); joint without medial and ventral spines present on adult male. 3rd endopodial joint with 3 pectinate claws (dorsal claw short, about 'At length of longest claw; lateral long claw about 3/s length of longest claw), and 4 ringed bristles. Maxilla: Precoxale and coxale with hirsute dorsal fringe. Coxale with plumose dorsal bristle (Figure \6h). Basale with 3 terminal bristles (1 ventral, 1 dorsal, 1 medial) with long spines (Figure \6h). Exopodite with 3 bristles (short proximal bristle with few long spines, long middle bristle with long spines, other long bristle with short spines (Figure \6h). 1st endopodial joint with dorsal spines, 1 alpha-bristle with long spines, and 5 beta-bristles, bare or with short spines (Figure \6h). 2nd endopodial joint with 3 a-bristles (Figure 16/), 3 pectinate claw-like bristles, 1 anterior ringed b-bristle with long spines, and 2 ringed c-bristles (Figure \6k); right limb only with 2 small spines near base of b-bristle (Figure \6k). Endites with stout spinous and pectinate bristles (endite I with 9 bristles, endite II with 7 bristles, endite III with 8 bristles) (Figure 16/). Fifth Limb: Epipodite with 41 bristles. Endites I, II, and III with about 6, 8, and 9 bristles, respectively (Figure 17a). 1st exopodial joint: anterior side with 2 bristles (with long spines) on distal edge (Figure Mb); outer corner with 2 small bristles (Figure Mb); main tooth with 3 slender pointed teeth at midlength, 1 large distal squarish tooth with five prongs, minute peg proximal to pointed teeth, and 1 spinous proximal bristle (Figure Md). 2nd exopodial joint (Figure Mb.c): posterior side with 1 proximal and paired (usual 3rd bristle not observed, possibly obscured) distal bristles (longer unringed pectinate, shorter ringed and with few spines) near inner edge (Figure 17c), and minute spinous bristle in outer distal corner (Figure Mb). Sixth Limb: Epipodial bristles fragmented. Endite I with 3 bristles; endite II with 4 bristles; endites III and IV each with 8 bristles. End joint with 21 or 22 bristles (6 or 7 posterior bristles plumose, most remaining bristles with long proximal hairs or spines and short distal spines). Limb hirsute. Seventh Limb: Proximal group with 4 bristles (2 on each side with 4 bells) and 6 terminal bristles (3 on each side with 3-5 bells); all bristles with well defined marginal spines. Terminal comb with 7 slender teeth; 2 slender curved spinous pegs opposite comb (Figure Me). Furca (Figure 17/), Bellonci Organ (Figure Mg.h), and Upper Lip (Figure 1 Ig,k): Similar to those of adult male. Eyes: Lateral eyes absent. Medial eye similar to that of adult male (Figure Mg.h). Genitalia: Not observed. Anterior of Body (Figure Mg,h,k): Anterior process horn- like. Posterior of Body (Figure 17/): Similar to that of adult male. Y-Sclerite (Figure 17/): Similar to that of adult male. Epizoa: USNM 194371 with ovoid stemmed protistans along rostrum. Gut Content: USNM 194357 with unidentified minute brown particles in gut. Eggs: USNM 194357 with 19 eggs in marsupium, length of typical egg 0.20 mm. USNM 194371 with 15 well developed eggs, each with visible black medial eye, length excluding transparent sack, 0.32 mm. DESCRIPTION OF INSTAR IV MALE (Figure Mn-p; Table 6).?Carapace similar in shape to that of adult female (Figure Mn). (USNM 194377 with appendages of instar V indistinctly visible within appendages of instar IV.) Carapace Size (length, height in mm): USNM 194377, 1.14, 0.78, height 68% of length. Second Antenna: Protopodite without e-sclerite; with long medial hairs in distal dorsal corner, and few rows of minute medial spines in proximal dorsal corner. Endopodite 2-jointed (Figure 17o): 1st joint with 3 short proximal bristles and 1 long distal bristle; 2nd joint elongate with 1 long spinous proximal bristle, 1 small ventral bristle at midlength, and 2 short terminal bristles, all bristles ringed. Exopodite: 1st joint with minute straight medial terminal bristle; bristle of 2nd joint reaching well past 9th joint, with abundant slender ventral spines; bristle of 3rd joint slightly longer than bristle of 2nd joint, with few slender spines at midlength; bristles of joints 4-8 longer, with natatory hairs; 9th joint with 5 bristles (2 long with natatory hairs, 3 shorter with slender spines); joints 3-8 with small spines along distal edges. Seventh Limb: Proximal and terminal groups each with 4 short tapered bristles with marginal spines and 1 bell. Terminal comb with about 5 teeth; 2 curved pegs opposite comb. Furca: With 9 claws on each lamella; claws 1, 2,4, and 6 primary; claws 3, 5, and 7-9 secondary. Bellonci Organ (Figure Mp): Elongate with rounded tip. Eyes: Medial eye pigmented (Figure Mp). Lateral eye consisting of clear sac containing pigmented eye (with several ommatidia) belonging to next instar (Figure Mp). Upper Lip (Figure Mp): Projecting anteriorly. Genitalia: None observed. Anterior of Body (Figure Mp): With large projecting anterior process. Posterior of Body: With long hairs ventral to midheight. Epizoa: None on USNM 194377. Gut Content: USNM 194377 with unidentified amber- colored particles within gut. Remarks: The carapace of USNM 194377 contains large anastomosing calcareous nodules, but none are in the shell of the next instar, which lies inside the old shell. This suggests that the new shell may not contain calcium. DESCRIPTION OF INSTAR IV FEMALE (Figure \Sa-d; Table 6).?Carapace shape similar to that of adult female (Figure 18a). Carapace Size (length, height in mm): USNM 194374, 1.14, 0.79, height 69% of length. USNM 194375, 1.12, 0.75, 32 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY k FIGURE 17.?Euphilomedes morini, new species, ovigerous female, paratype, USNM 194357: a, endites I?III. left 5th limb; b, tip of left 5th limb, pv; c, detail from b; d, main tooth of 1st exopodial joint, right 5th limb, av; e, tip of 7th limb (not all comb teeth shown);/ left lamella of furca, lv; g,h, anterior of body from left and right sides, respectively; i. posterior of body from left side (Y-sclerite stippled);/ Y-sclerite from right side; *, anterior process and upper lip from right side; /, posteroventral edge of left valve, iv. Euphilomedes carcharodonta (Smith, 19S2), adult female, USNM 194356: m, edge of rostrum of left valve (drawn at same magnification as /), iv. Euphilomedes morini, new species, male, instar IV, paratype, USNM 194377: n, outline of complete specimen from left side, length 1.14 mm; o, endopodite, left 2nd antenna, mv; p, anterior of body from right side. NUMBER 593 33 height 67% of length. USNM 194376, 1.17, 0.79, height 68% of length. Second Antenna: Protopodite and exopodite similar to those of instar IV male. Endopodite 2-jointed (Figure \Sb): 1st joint with 3 small bare proximal bristles and 1 long spinous distal bristle; 2nd joint with long spinous proximal bristle and short bare terminal bristle; all bristles ringed. Seventh Limb: Bristles similar to those of instar IV male; terminal comb with a tooth consisting of 3 long prongs on each side of longer unpronged tooth (Figure 18c); 2 curved bare pegs opposite comb. Furca: USNM 194375 with 8 or 9 claws on each lamella; claws 1, 2, 4, 6, primary; claws 3, 5, and 7 to 8 or 9 secondary. USNM 194374 and 194376 with 9 claws on each lamella and claws 3, 5, and 7-9 secondary. Bellonci Organ (Figure 18*/): Similar to that of instar IV male. Eyes: Medial eye similar to that of instar IV male (Figure 18