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SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 321

Review of the Deep-Sea Genus Argyropeza (Gastropoda: Prosobranchia: Cerithiidae)

Richard S. Houbrick

SMITHSONIAN INSTITUTION PRESS

City of Washington

1980

ABSTRACT

Houbrick, Richard S. Review of the Deep-Sea Genus Argyropeza (Gastropoda: Prosobranchia: Cerithiidae). Smithsonian Contributions to Zoology, number 321, 30 pages, 12 figures, 8 tables, 1980.—An historical review of the genus Argyropeza is presented. The assignment of the genus within the Cerithiidae is clarified. A close relationship between Argyropeza and Bittium is suggested. Argyropeza species live on soft sediments of continental slopes and island groups in the Indo-Pacific and occur most frequently at bathyal depths. They have pelagic larvae and are sediment feeders. Five nominal species are recognized: Argyropeza divina, A. izekiana, A. schepmaniana, A. verecunda, and A. leucocephala. An appendix with species frequently assigned to or easily confused with Argyropeza is included.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus).

Library of Congress Cataloging in Publication Data

Houbrick, Richard S

Review of the deep-sea genus Argyropeza (Gastropoda, Prosobranchia, Cerithiidae)

(Smithsonian contributions to zoology; no. 321)

Bibliography: p.

Includes index.

1. Argyropeza—Classification. 2. Mollusks—Classification. I. Title. II. Series: Smithsonian Institution. Smithsonian contributions to zoology; no. 321.

QL1.S54 no. 321 [QL430.5.C4] 591s [594′.32] 80–607017

Contents

Introduction

Abbreviations

Acknowledgments

Historical Review

Superfamily CERITHIACEA Fleming, 1822

Family CERITHIIDAE Fleming, 1822

Subfamily CERITHIINAE Fleming, 1822

Genus Argyropeza Melvill and Standen, 1901

Argyropeza divina Melvill and Standen

Argyropeza izekiana Kuroda

Argyropeza schepmaniana Melvill

Argyropeza leucocephala (Watson)

Argyropeza verecunda (Melvill and Standen)

Appendix

Literature Cited

Requirements for Smithsonian Series Publication

Review of the Deep-Sea Genus Argyropeza (Gastropoda: Prosobranchia: Cerithiidae)

Richard S. Houbrick

____________

Richard S. Houbrick, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560.

Introduction

The genus Argyropeza comprises five bathyal species of small, vitreous-shelled cerithids and is not well known. The systematic position of the genus within the Cerithiacea has been uncertain since Argyropeza was first proposed and described by Melvill and Standen (1901:372). The taxonomy of Argyropeza species has also been poorly understood due to the scattered literature, lack of specimens, and inadequate analysis of shell characters. Virtually nothing has been written about radulae, opercula, or internal anatomy and no attention has been given to the ecology and zoogeography of the genus.

Numerous specimens of Argyropeza species were dredged by the U.S. Fisheries steamer Albatross in the western Pacific (1907–1910) and were deposited in the National Museum of Natural History. Ecological and bathymetric data were provided with each lot. I examined these specimens and additional material from other museums that provided adequate material for statistical analysis of each species. All measurements were made on adult specimens. The number of whorls on each shell were counted after the sharp transition between protoconch and teleoconch. No preserved animals were available for dissection or sectioning. Several shells of a few species contained dried animals from which radulae and opercula were extracted and some anatomical features were studied. In this revision I have used scanning electron micrographs of radulae, protoconchs, shell sculpture, and opercula for character analysis.

ABBREVIATIONS.—

AMS

Australian Museum, Sydney

ANSP

Academy of Natural Sciences of Philadelphia

BM(NH)

British Museum (Natural History)

MNHN

Museum National d'Histoire Naturelle, Paris

NSMT

National Science Museum, Tokyo

SEM

Scanning electron micrograph

USNM

former United States National Museum, collections in the National Museum of Natural History, Smithsonian Institution

ACKNOWLEDGMENTS.—I wish to thank Drs. Joseph Rosewater and Harald Rehder, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, for critically reading a draft of this paper and for their assistance during its preparation. I am indebted to Dr. Winston Ponder of the Australian Museum, Sydney, for the loan of specimens in his charge and for useful discussion about the relationships of some higher Cerithiacean taxa. I also thank him for critically reading an early draft of this paper. Dr. John Taylor, of the British Museum (Natural History) kindly sent photographs of some of the types. Dr. Philippe Bouchet, of the Museum d'Histoire Naturelle, Paris, kindly allowed me to examine specimens in his charge. For assistance with the SEM and preparation of the photomicrographs I thank Ms. Susanne Braden, Scanning Electron Microscope Laboratory and Mr. Victor Krantz, Photographic Services, of the National Museum of Natural History, Smithsonian Institution. Technical assistance was kindly given by Miss Cathy Lamb and Miss Cindy Gust, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution.

Historical Review

Melvill and Standen (1901:372) were unsure about the taxonomic allocation of Argyropeza when they originally proposed it and provisionally assigned it “as an outlying form of Cerithiidae or Litiopidae.” Schepman (1909:170) considered the genus related to Cerithiopsis and Litiopa because of some similarities of the radulae but noted that the operculum of Argyropeza was different. Although unsure of its relationships, he regarded Argyropeza to be a valid genus. Thiele (1918:120) observed that the radula and operculum of Argyropeza were similar to those of Bittium and he later regarded it as a subgenus of Bittium (Thiele, 1931:212). Hornung and Mermod (1926:207; 1928:115) referred Argyropeza to the Litiopidae and described two new species. Kuroda (1949:79) thought that A. izekiana was a deep sea representative of Bittium. Argyropeza was also assigned next to Bittium by Shuto (1969:64). Nothing substantial has been written about Argyropeza until recently when it was reviewed by Gründel (1976), who considered the systematic position of the genus and assigned it to the Procerithiidae Cossmann, 1905.

Superfamily CERITHIACEA Fleming, 1822

Family CERITHIIDAE Fleming, 1822

Subfamily CERITHIINAE Fleming, 1822

Genus Argyropeza Melvill and Standen, 1901

Argyropeza Melvill and Standen, 1901:371–372 [type-species, by monotypy, Argyropeza divina Melvill and Standen, 1901].—Schepman, 1909:169.—Hornung and Mermod, 1926:207.—Thiele, 1931:212.—Wenz, 1940:757.—Kuroda, 1949:76.—MacNeil, 1960:40.—Franc, 1968:281.—Götting, 1974:130.—Gründel, 1976:40.—Ladd, 1977:15.

Argyropeda [sic] Shuto, 1969:63–65.

DESCRIPTION.—Shell small, 6–8 mm in length, thin and vitreous, turreted and with 9–12 whorls sculptured with weak axial riblets and with two spiral cords bearing sharp nodules where crossed by axial riblets. Sinusigera protoconch of about three and a half whorls, sculptured with two spiral lirae and spiral band of pustules adjacent to suture. Tip of protoconch smooth, dome-shaped, white, remainder chestnut in color. Protoconch sculpture sharply separated from adult sculpture of teleoconch. Former varices present on shell, with prominent varix opposite outer lip of aperture. Suture deeply impressed, set off with inferior and superior sutural ramps. Aperture ovate with short but distinct anterior siphonal canal and weak anal canal. Outer lip thin, columella concave. Operculum thin, corneous, subcircular, and multispiral with subcentral nucleus. Animal has large snout and broad cephalic tentacles with large eyes at their bases. Mouth with triangular jaws and taenioglossate (2+1+1+1+2) radular ribbon. Radula with quadrate rachidian tooth and trapezoidal lateral tooth that is laterally elongate and is serrated with small denticles along its cutting edge. Marginal teeth long and slender and serrated, pointed tips.

REMARKS.—The name Argyropeza is derived from the Greek feminine noun arguropeza (“silver foot”), the Homeric epithet of Thetis. The genus comprises five living shelf species, A. divina, A. izekiana, A. verecunda, A. schepmaniana, and A. leucocephala. They occur throughout the tropical shelf regions of the western Pacific, southeast Asia, and the Indian Ocean. The genus may be traced back to the Pliocene in the geological record.

There have been a number of species erroneously assigned to the genus Argyropeza. Two of these, Argyropeza melvilli Schepman, 1909, from the Sulu Sea, and Argyropeza suvaensis Ladd, 1977, from Fiji, should be referred to the genus Abyssochrysos Tomlin, 1927, family Abyssochrysidae Tomlin, 1927. As Barnard (1963:144) noted, Schepman (1909:170) was doubtful about the generic assignment of A. melvilli Schepman, but at Melvill's suggestion, referred it to Argyropeza. The anatomy, shell, and radula of A. melvilli unequivocally confirm Barnard's (1963:144) transfer of Argyropeza melvilli to Abyssochrysos (Houbrick, 1979:12).

Ladd (1977:15) described Argyropeza suvaensis, a fossil from early Miocene of Fiji, but only tentatively assigned it to the genus Argyropeza. He suggested that his fossil specimens were conspecific with Argyropeza melvilli Schepman, which I have shown is an Abyssochrysos species (Houbrick, 1979). Ladd (1977:15) noted that MacNeil (1960:43) believed that Schepman's specimen was an Alipta Finlay, 1926, family Cerithiopsidae. This is clearly an erroneous assignment because the protoconch and radula of Alipta are very different from those of Argyropeza or Abyssochrysos (see Marshall, 1978:62–63, fig. 6, a-c). I have examined Ladd's type-material of Argyropeza suvaensis and believe that this species is probably conspecific with Abyssochrysos melvilli (Schepman).

Argyropeza involuta, described by Thiele (1918:120) from two immature specimens and fragments of a third without a complete outer lip, was erroneously assigned to the genus Argyropeza. Both the description and examination of the holotype convince me that this species is conspecific with Cerithium bicanaliferum Brazier, 1877, a species that is clearly unrelated to the Argyropeza group.

The species described by Hornung and Mermod (1926:208) as Argyropeza doriae is not a member of this genus. The protoconch, shell sculpture and aperture do not fit the limits of Argyropeza.

I regard Argyropeza as a valid genus for a number of reasons. (1) The shells of the five species have distinct anterior siphonal canals and deeply impressed sutures that are set off by sloping inferior and superior sutural ramps. The shells are vitreous, sculptured similarly with weak axial riblets and spiral cords set with small, sharp nodules. All Argyropeza species have small shells that are vitreous, thin and bear several randomly placed varices, the most prominent one being opposite the outer lip of the aperture. (2) They share identical protoconchs suggesting that all have similar developmental modes and planktonic larvae. (3) Although the radulae of only two species are known, they are virtually identical and indicate a homologous feeding function; moreover, the fecal pellets of these species are also identical and composed of fine sediment. (4) The two species from which animals are known have similar external anatomical features. (5) All known species live in deep water environments and are found on the same kind of fine sand and mud substrata.

PHYLETIC RELATIONSHIPS.—Argyropeza has been assigned by various workers to the families Diastomidae Deshayes, Litiopidae H. and A. Adams, Dialidae A. Adams, and Cerithiidae Fleming. The characters, limits, and taxonomic positions of the first three families are problematic because they have been proposed on shell characters alone. For instance, Diastoma Deshayes, 1850, of the Diastomidae, is based upon an Eocene species, Diastoma costellata (Lamarck), from the Paris Basin and comprises mostly fossil species. Ludbrook (1941) recently reviewed this group. The only living species, Diastoma melanoides (Reeve, 1849), is found in a restricted area in southwestern Australia and its anatomy and radula are unknown. The operculum is cerithioid. The shells of all Diastoma species are relatively large and have smooth outer lips that lack anterior siphonal canals. I thus exclude Argyropeza from this group.

The Litiopidae, as exemplified by Litiopa, which lives on pelagic algae, bears little resemblance to Argyropeza in shell characters, radula, or ecology. Moreover, Litiopa has opercular and epipodial tentacles (pers. observ.) not seen in Argyropeza. I thus dismiss the family Litiopidae as a correct assignment for Argyropeza.

The Dialidae are an unlikely family in which to place Argyropeza. Although Diala has been referred to the Diastomidae and the Cerithiidae by various workers, Diala species lack an anterior canal, a feature always present in members of the Cerithiidae; moreover, they tend to have thin, squat shells, smooth protoconchs, flatter whorls, and a lower aperture-length to shell-length ratio than do Argyropeza species. They also lack former varices and axial ribs. Living Diala snails have epipodial tentacles, an antomical feature not present in the Cerithiidae. I thus consider this group totally unrelated to Argyropeza.

The relationship of Argyropeza to other supraspecific taxonomic groups in the Cerithiidae is difficult to assess because many of the smaller shelled genera in the family are not sharply defined and are either artificial or parochial in scope. Moreover, there is little known about the anatomy, radulae, or biology of these taxa (see Houbrick, 1975; 1977). Although some anatomical features of Argyropeza species are described in this paper, the detailed anatomy of the open pallial gonoducts remains unknown because the material I examined was too poorly preserved for critical study of internal ducts. It is thus impossible to make reliable anatomical comparisons with other groups.

Argyropeza is frequently confused with the genus Fenella A. Adams, 1860 (= Obtortio Hedly, 1899; = Eufenella Kuroda and Habe, 1952), but true Fenella species all lack an anterior canal and should probably be considered members of the families Dialidae or Diastomidae. There is also some confusion about the status of the genus Alaba. Alaba species have epipodial tentacles and their shells lack an anterior canal; thus, they too should be assigned to the Dialidae or Diastomidae.

There are a number of small cerithid-like snails lacking epipodial tentacles and with slight anterior canals that are frequently placed in the genus Fenella. These are probably members of the genus Alabina (W. F. Ponder, pers. comm., 1979). Although Alabina has been considered a synonym of Fenella, it is obviously better referred to the Cerithiidae and is probably close to Bittium. More anatomical information and radular studies are needed to assess the relationship of Alabina to Bittium and Argyropeza.

Hornung and Mermod (1926:207) considered Argyropeza to be closely related to, or synonymous with, the genus Glosia Cossmann, 1921, which they placed in the family Litiopidae. Glosia species do not have an anterior siphonal canal and are here regarded as members of the Diastomidae. Hornung and Mermod also believed that Alabina Dall 1902 was a synonym of Argyropeza. As noted above, there is not enough data to justify this conclusion.

Gründel (1976:40) noted a morphological similarity between Argyropeza and the Jurassic genus Cryptaulax (Xystrella), which he referred to the family Procerithiidae. He (1976:44) thus assigned Argyropeza to the family Procerithiidae Cossmann, 1906, subfamily Cryptaulinae Gründel, 1976, and placed Bittium in the same family, subfamily Procerithiinae Cossmann, 1905. I find Gründel's (1976) revision of the “Bittium Group” unsatisfactory for a number of reasons. Although his classification is based on fossils and a few living species, his analysis employed shell characters alone and ignored biological data. Gründel (1976) placed undue emphasis on protoconch morphology in developing a phylogeny for this group. It has been shown that protoconchs differ according to the mode of larval development (direct or indirect) and that developmental modes frequently vary between species within the same genus and sometimes within a single species (see Robertson, 1976:227–232, for an excellant review). I have shown two kinds of development occur in Cerithium species (Houbrick, 1970; 1974a; 1974b) and the same phenomenon has been cited for the Cerithiopisidae (Marshall, 1978). Thus, a classification of supraspecific taxa based upon protoconch morphology does not necessarily reflect phylogeny and may be misleading. Gründel (1976:40) mistakenly interpreted the sinusigera notch of the protoconch as a varix, whereas it indicates a dramatic change in environment and the beginning of new growth and shell sculpture. It is thus not exactly the same as a typical growth varix. He also stated that the aperture of Argyropeza lacked a clear canal. This is incorrect, as a cursory glance at the plates in this paper will show. As a result of the undue emphasis on differences in shell sculpture, Gründel's (1976) classification is artificial and topheavy with supraspecific taxa. I prefer to disregard the higher taxonomic categories used by Gründel (1976) and consider Argyropeza and Bittium to be closely related genera in the family Cerithiidae.

Gründel (1976:46) proposed a new genus, Varicopeza, for a living species from the South China Sea that he named Varicopeza varicopeza. He believed Varicopeza was closely related to Argyropeza and Cryptaulax. His plates indicate that the specimens he used had missing apertures. Gründel's species, Varicopeza varicopeza, is a synonym of Cerithium bicanaliferum Brazier, 1877 (also known as Cerithium trigonostomum Melvill, 1910). I have examined numerous specimens and the embryonic whorls, radula, shell, distinctive aperture, and anal canal of Cerithium bicanaliferum are different from those of Argyropeza species.

The evidence derived from analysis of adult shell physiognomies, protoconchs, radulae, and opercula indicates that Argyropeza should be referred to the family Cerithiidae Fleming. Adult Argyropeza shells are much thinner and vitreous than those of Bittium but both genera are alike in having shells with distinct former varices present, the strongest one being opposite the outer lip of the aperture. Their general shell physiognomies are also similar but the suture of Argyropeza species is more deeply impressed. The larval shells or protoconchs of Argyropeza are distinctive due to a single spiral row of pustules adjacent to the suture but are otherwise similar to those of some Cerithium species or somewhat like those depicted for Bittium by Gründel (1976:41, figs. 9–12) and Richter and Thorson (1975:166, pls. 3–4). The protoconchs of species in both genera consist of about three and a half whorls and are sculptured with two spiral lirae that begin to appear on the third whorl. They also have a deep sinusigera notch. Some Bittium and Cerithium species have tiny pustules covering the third whorl of the protoconch. Thus, although Argyropeza protoconchs are distinctive, they share some characters with those of Bittium and Cerithium.

Both Bittium and Argyropeza species have similar radulae. The radula of Bittium differs in having marginal teeth with more spatulate tips and lateral teeth that have long vertical extensions on the lower plate of the tooth. The cutting edge of the lateral teeth is also serrated with fewer denticles than Argyropeza.

The opercula of species in both genera are cerithioid, but there are more spirals in Argyropeza.

Although these similarities may be due to convergence, they are the only lines of evidence now available for phyletic speculation and, taken in their totality, are probably reliable. I thus concur with the opinion of previous authors, as outlined above, that Argyropeza is probably closely related to the genus Bittium. Although Bittium is sometimes placed in the subfamily Bittinae, I prefer not to recognize this subfamily or other higher categories proposed for the Bittium group because our present state of knowledge lends no biological or phyletic significance to them. My views on this subject have been discussed in more detail elsewhere (Houbrick, 1977).

INTERSPECIFIC RELATIONSHIPS.—Due to the lack of anatomical characters, any remarks about interspecific phylogeny of the five Argyropeza species are of necessity largely speculative. The only consistent characters available for all species are those derived from the shell. I have used a multi-character analysis to express phylogeny by seeking to determine the primitive or derived state of each character. Evidence from ontogeny, stratigraphic position, and outgroup comparison has been used to determine the state of a character. Ontogeny assumes that a character state appearing first in development is more generalized than one appearing later; in other words, ontogeny recapitulates phylogeny often enough that it can help to determine polarity. Stratigraphic position is a useful criterion because the earlier the first appearance of a character, the more likely it is to be primitive. Outgroup comparison determines the occurrence of the characters in a related group.

While I realize that this method is unsatisfactory in many respects, it utilizes the only available information about this deep-sea group. A cladogram showing inferred relationships is presented below in Figure 1. The character states chosen for analysis are presented in Table 1. Of the five species, Argyropeza divina is unique in physiognomy, simple in shell sculpture, and attains the largest size. It has the widest geographic distribution and occurs in the greatest concentrations. This species has been recorded from the Pliocene to the Recent and is thus the oldest known Argyropeza taxon. The shell characters of this species are thus assumed to be the most primitive of the group. It is interesting to note that all species begin growth with two spiral cords per whorl. Argyropeza izekiana shares with A. divina large size, a simple shell sculpture of two spiral cords, sharp nodules, and 12.5 axial riblets. Argyropeza schepmaniana is known as a fossil from the Pleistocene, has three spiral cords and 13.5 axial riblets and appears to be related to A. leucocephala. Both of these species share sculptural similarities with A. verecunda, the smallest and most elaborately sculptured species of the group. Table 2 presents a comparative list of shell characters.

FIGURE 1.—Inferred phylogeny of Argyropeza species.

TABLE 1.—Character states used in the construction of a phylogeny for Argyropeza species

character

primitive

derived

shell length

high

low

shell width

high

low

aperture length

high

low

aperture length

shell length

low

high

number of whorls

high

low

spiral cords

few

many

axial riblets

few

many

apical angle

high

low

ECOLOGY.—All specimens of Argyropeza have been dredged from deep-sea shelves or slopes on muddy or fine grained substrata where they frequently occur in large populations. Table 3 shows the depth ranges of different species. All live in the bathyal zone as defined by Hedgpeth (1957: 18) where they appear to be confined to continental slopes.

TABLE 2.—Comparison of Argyropeza species, using shell characters (measurements in mm; based on mean values)

The stomach contents and fecal pellets of A. divina and A. izekiana contain fine particles of sand, detritus, and a few foraminifer tests. This evidence and radular morphology indicate that Argyropeza species are probably detritivores that eat the sediments on which they live.

Although the spawn of Argyropeza species is not known, the protoconchs of all species bear distinctive sculpture and have a clear sinusigera notch, indicative of a planktotrophic larval phase. This may account for the wide, but sometimes spotty distribution of most species and indicates that genetic exchanges can occur between populations, a fact well documented by Bouchet (1976) and Bouchet and Waŕen (1979) for other deep-sea prosobranchs.

TABLE 3.—Bathymetric distribution of Argyropeza species

Argyropeza divina Melvill and Standen

FIGURES 2–4

Argyropeza divina Melvill and Standen, 1901:371–372, pl. 21: fig. 3 [holotype: BM(NH) Reg. No. 1887.2.9.1749, type-locality: 24°05″N, 57°35″E., Gulf of Oman, 375 m].—Schepman, 1909:169–170, pl. 21: fig. 3.—Melvill, 1912: 246–247, pl. 12: fig. 10.—Gründel, 1976:44, pl. 1: figs. 7, 9–10.—Thiele, 1918:373.—MacNeil 1960:40, pl. 11: fig. 19.

Argyropeda [sic] divina Melvill and Standen.—Shuto, 1969: 64–65, pl. 2: figs. 7–11.

Cerithium (s. str.) spinigerum Martin, 1884:156, pl. 8: fig. 152.

Potamides spiniger (Martin).—Tesch, 1920:58, pl. 131: fig. 185.

Potamides (Tympanotonus) spiniger (Martin).—Martin, 1899: 208.

Argyropeda [sic] spinigera (Martin).—Shuto, 1969:64, pl. 2: figs. 7–11.

DESCRIPTION.—Shell: small, about 7 mm long, thin, elongate, turreted, and consisting of 9 adult whorls with apical angle of 35°. Whorls convex, angulate, and deeply impressed suturally. Adult whorls sculptured with two primary spiral cords, one weaker spiral cord adjacent to suture on upper portion of whorl, and with 12–13 weak, transverse axial ribs that form sharp nodes where they cross the two marginal major spiral cords. Axial ribs and nodes stronger on earlier whorls, nearly absent on penultimate and body whorls. Suture deep and distinct. Protoconch I smooth, one and one-half whorls; protoconch II, two whorls, sculptured with spiral band of axially elongated pustules adjacent to suture and with two spiral cords near mid-portion of whorl. Spiral cords sometimes weakly pustulate. Sinusigera sinus deep and narrow. Transition from protoconch to teleoconch sharply defined. Body whorl inflated, sometimes with varix opposite outer lip, especially in older shells. Sculpture on body whorl frequently diminished, and below the two primary cords there are 5–6 smooth spiral cords that become thinner as they progress to siphonal canal. Aperture ovate, close to one-fourth the length of the shell. Anterior siphonal canal short and broad, slightly curved to left. Small, indistinct anal canal present. Outer lip thin, smooth, and sinuous in outline. Columella slightly concave to straight with thin shiny callus. Shell covered with thin, light tan periostracum, and is shiny and vitreous in recently dead specimens, chalky in older ones. Shell frequently pigmented with light tan flammules that run transversely between axial ribs. Portions of spiral cords between axial ribs usually darker tan creating light spiral spots.

Animal: Head and foot pigmented with dark brown, especially on snout and tentacles. Tentacles large, broad, and with large dark eyes at their bases. Snout broad, bilobed at tip, and with relatively large buccal mass. Mouth with pair of jaws about 0.25 mm long, triangular in shape, comprised of 55–60 rows of hexagonal plates that become quadrate at the cutting edge. Stomach filled with fine sand, foraminifera, and detrital particles. Intestine large, filled with many ovate fecal pellets about 0.2 mm in diameter. Mantle edge papillate and slightly flaring at anterior siphon. Pallial gonoducts open. Other pallial organs not observed. Foot large, and with groove at anterior of propodium. Operculum thin, corneous, tan, nearly circular, and multispiral with subcentral nucleus. Operculum large in relation to foot, slightly concave and bent at circumference to fit aperture snugly. Attachment scar on reverse of operculum ovate. Eggs and larvae unknown.

FIGURE 2.—Argyropeza divina Melvill and Standen: a,b, typical adult specimens showing overall sculptural pattern (USNM 238517, USBF Sta 5450, off Batan Id, Lagonoy Gulf, E Luzon, Philippines, 746m); c–e adult specimens (USNM 276553, USBF Sta 5242, Pujada Bay, E Mindanao, Philippines, 349m; c and e, 14×; d, 28×); f, side view of adult shell showing sinuous outer lip, (USNM 302513, USBF Sta 5191, Tanon Str, off Refugio Id, Philippines, 258 m, 14×); g, protoconch showing larval shell sculpture (USNM 238513, locality same as in a,b); h, detail of aperture showing anterior siphonal canal and sculpture of body whorl (USNM 276553, locality same as in c–e); i, protoconch showing sinusigera notch and larval shell sculpture, 200× (USNM 238517, locality same as in c–e); j, top view of protoconch showing change between larval and adult sculpture (USNM 238517, 200×, locality same as in c–e); k, detail of adult whorls showing two spiral cords and nodules (USNM 276350, USBF Sta 5247, off Davao, Mindanao, Philippines, 40×).

TABLE 4.—Argyropeza divina, measurements of shell characters (in mm)

Radula (Figure 3): Radular ribbon taenioglossate, about one-eleventh the length of the shell, comprising 50 rows of teeth. Rachidian tooth quadrate, somewhat concave at sides. Cutting edge of rachidian with sharply pointed central cusp flanked with two, sometimes three smaller cusps on each side. Base of rachidian tooth flat with slight lateral projections at each end. Lateral tooth trapezoidal, laterally elongate and with slightly curved top. There are seven cusps, the first small, the second large and sharply pointed, and the remaining cusps becoming smaller toward the lateral portion of the cutting edge of the tooth. A blunt longitudinal projection extends from the lower mid-portion of the basal plate. Base of lateral tooth straight. Inner marginal tooth long, slender, and curved, pointed at tip and serrated with 4–6 sharp denticles on inner side and with 5–6 denticles on outer side. Outer marginal tooth same as inner but lacking denticles on outer surface.

ETYMOLOGY.—Latin divinus (“divine”).

COMPARATIVE REMARKS.—Argyropeza divina is distinguished from its congeners by a generally larger size, a deep sutural impression, sharply sloped whorls adjacent to the suture, and by sculpture of two strong spiral cords that are set with sharp nodes. The aperture length to shell length ratio is lower than in the other species and the aperture is decidedly more ovate. Although not noted in the original description, it is the only Argyropeza species that is pigmented with brown blotches. The rachidian tooth of the radula usually has two small denticles adjacent to each side of the central cusp whereas in A. izekiana, there are normally three denticles on each side of the central cusp. Argyropeza divina is the type-species of the genus and appears to be the most common and abundant species in the group. Melvill and Standen (1901:872) compared it with Royella sinon Bayle (cited as Cerithiopsis sinon), but the sculptural resemblance is only superficial for Royella is a monotypic genus in the Potamididae H. and A. Adams, having a round, multispiral operculum with a central nucleus and a large shell, and is phyletically far-removed from Argyropeza.

Schepman (1909:61) noted that the operculum is multispiral. Although there are numerous spirals, the nucleus is subcentral and cerithioid; consequently, the operculum should not be construed to be multispiral in the sense of a potamidid operculum. The radula of this species was crudely illustrated by Schepman (1909, pl. 21: fig. 3), who found it too small to accurately describe. The radular ribbon is very small: It averaged 0.9 mm in length and 0.18 mm in width and comprised 50 rows of teeth in two specimens from which I was able to extract it undamaged. Although Schepman (1909:169) said there were three smaller cusps adjacent to each side of the central cusp of the rachidian tooth, scanning electron micrographs show that there is variation in the number of cusps and that there are usually only two cusps present (see Figure 3). The inner and outer marginals are serrated with tiny cusps along their cutting edges.

FIGURE 3.—SEM micrographs of radula and operculum of Argyropeza divina (USNM 276350, USBF Sta 5247, off Davao, Mindanao, Philippines, 247m): a, portion of radular ribbon, 260×; b, close-up of half row of teeth showing tiny cusps on sickle-like marginal teeth, 420×; c, detail of rachidian tooth, 1600×; d, view of free surface of operculum showing spiral growth lines and eccentric nucleus, 50×.

ECOLOGY.—Museum records indicate that A. divina normally occurs on muddy bottom throughout its range. It is occasionally found on very fluid mud or on fine sand substratum. Station data from 75 samples indicate a bathymetric range of 58–923 meters and a mean depth range of 356 meters. Specimens from the western Pacific tend to be larger than those from the western Indian Ocean. The stomachs of several specimens from the Philippines were filled with fine sand, detritus, and a few foraminifer tests. Fecal pellets were ovoid, about 0.2 mm in length and comprised fine sand and detritus. The small radula and scythe-like lateral teeth indicate that A. divina ingests the sediment on which it lives and is probably a detritivore.

GEOGRAPHIC DISTRIBUTION.—(Figure 4). This species occurs throughout the Philippines and the Indonesian Archipelago, including New Guinea. It is also found in Madagascar and in eastern Africa, from Zanzibar to Durban, South Africa. Originally collected in the Gulf of Oman, it probably occurs in suitable habitats throughout the Indian Ocean. Argyropeza divina is geographically sympatric with A. izekiana and A. schepmaniana in the Philippines and occurs with A. izekiana in New Guinea and in eastern Africa. All three species probably occur throughout the Indian Ocean and western Indo-Pacific Oceans.

FOSSIL RECORDS.—Argyropeza divina has been recorded as a fossil from the Pliocene of Okinawa (MacNeil, 1960:40, pl. 11: fig. 9). MacNeil remarked that the fossils did not appear to be separable from living A. divina. I have examined his specimens and concur that the fossils are conspecific with A. divina. I have also seen Pleistocene fossils deposited in the Australian Museum, Sydney, from the NW bank of the Kavavas River, near Riet, Gazelle Peninsula, New Britain, Papua.

FIGURE 4.—Geographic distribution of Argyropeza divina Melvill and Standen.

Although Shuto (1969:65) noted that fossils he identified as A. divina from the Tertiary of Panay Id, Philippines differed slightly from typical A. divina in having a weakly granulated subsutural thread, I concur with him that they are probably conspecific. I believe Shuto (1969:65) was wrong in considering A. spinigera to be a valid species because examination of many specimens of A. divina shows that the arrangement of the basal spiral cords of A. spinigera falls within the range of variation of A. divina. I thus regard A. spinigera to be conspecific with A. divina.

A fossil species from the Pliocene of Java, described by K. Martin (1884:156, pl. 8: fig. 152) as Cerithium spinigerum, appears to be conspecific with A. divina. Tesch (1920:58, pl. 31: fig. 185) erroneously transferred C. spinigerum to the genus Potomides Brongniart, family Potamididae. His figures of the fossil specimens unequivocally depict Argyropeza divina.

SPECIMENS EXAMINED.—ARABIAN SEA: Gulf of Oman, 285 m (USNM 424891). EASTERN AFRICA: Baia de Laurenco Marques, Mozambique, 450 m (USNM 718491); near Inhaca, Baia de Laurenco Marques, Mozambique, 366 m (USNM 717907); 60 mi (96.0 km) NE of Durban, South Africa, 366 m (USNM 717246); 30 mi (48.0 km) NE of Durban, South Africa, 77 m (USNM 718107). MADAGASCAR: 40 mi (64.0 km) WSW off Tulear, 82 m (USNM 717535; 717516; 717613); Tulear (coll. B. Thomassin). PHILIPPINES: Tayabas Bay, off Tayabas Lt, Luzon, 347 m (USNM 285464); Tayabas Bay, off Tayabas Lt, Luzon, 152 m (USNM 285545); Tayabas Bay, off Tayabas Lt, Luzon, 291 m (USNM 285617); Tayabas Gulf, Luzon, (USNM 301903); Balayan Bay, Luzon, 291 m (USNM 235360); Regay Gulf, off Arena Pt, Luzon, 525 m (USNM 284289); off Matocot Pt, W Luzon, 311 m (USNM 775069; USNM 775068); off Matocot Pt, W Luzon, 402 m (USNM 775036); off Malavatuan Id, W Luzon, 186 m (USNM 774765); off Cape Santiago, W Luzon, 720 m (USNM 235094); off N Cebu, 130 m (USNM 280890); off Lauis Pt, E Cebu, 302 m (USNM 288515); off Lauis Pt, E Cebu, 291 m (USNM 288740); off Lauis Pt, E Cebu, 296 m (USNM 290490); off Lauis Pt, E Cebu, 320 m (USNM 289140); off Chocolate Id, N Cebu, 271 m (USNM 280842; USNM 259603); off Batag Id, N Samar, 700 m (USNM 289381); Sogod Bay, Leyte, 918 m (USNM 277844); off Tolosa, E Leyte (USNM 277768); off Lusaran Lt, Guimaras, 175 m (USNM 281313); off Apo Id, S Negros, 468 m (USNM 291201); off Apo Id, S Negros, 464 m (USNM 286654); off Cabilao Id, W Bohol, 318 m (USNM 259839); off Ponson Id, Camotes Id, 347 m (USNM 298383); NW off Panglao Id (USNM 246937); off Pescador Id, Tanon Strait, 419 m (USNM 3925; USNM 281154); off Pescador Id, Tanon Strait, 548 m (USNM 274927); off Refugio Id, Tanon Strait, 472 m (USNM 302513); off Observatory Id, Palawan, 84 m (USNM 282594); W of Cape Melville, Balabac, 214 m (USNM 237927); Lagonoy Gulf, E Luzon, 914 m (USNM 787685); off Pt Tuguan, S Luzon 731 m (USNM 285409); off Sombrero Id, Balayan Bay (USNM 262305); off Sombrero Id, Balayan Bay, 291 m (USNM 262280; USNM 262309); off Sombrero Id, Balayan Bay, 216 m (USNM 774763); off Balanja Pt, SE Mindoro, 428 m (USNM 276250); off Pt Origon, Tablas, 133 m (USNM 281489); Regay Gulf, off N Burias, 192 m (USNM 312689; USNM 775113; USNM 280510); off N Ticao Id, 413 m (USNM 285275); off Pt Dumurug, Masbate, 249 m (USNM 284160); off Pt Dumurug, Masbate, (USNM 274690); off Talajit Id, SE Masbate, 245 m (USNM 298258; USNM 234204); off Adyagan Id, E Masbate, 245 m (USNM 775119); off Sibugay Id, E of Masbate, 247 m (USNM 277536); off Destacado Id, E of Masbate, 146 m (USNM 280585); off Destacado Id, 216 m (USNM 298062; USNM 285349); SE off Bantayan Id, 58.5 m (USNM 775050); off Cape Melville, Balabac Strait, 271 m (USNM 234741; USNM 297522); off Davao, Mindanao, 247 m (USNM 276350); Iligan Bay, N Mindanao, 923 m (USNM 290235); Pujada Bay, E Mindanao, 398.5 m (USNM 276497); Pujada Bay, E Mindanao, 313 m (USNM 276414); Pujada Bay, E Mindanao, 349 m (USNM 255602; USNM 276553); Pujada Bay, E Mindanao, 393 m (USNM 380152; USNM 277461); E of Bongo Id, 289 m (USNM 775058). BORNEO: Off Silungan Id, 558 m (USNM 279078; USNM 774761; USNM 774759); Sibuko Bay, Sipadan Id, 759 m (USNM 278704); Sibuko Bay, off Si Amil Id, 534 m (USNM 289713); Subuko Bay, off Mabul Id, 475 m (USNM 278824). NEW GUINEA: 2 mi (3.2 km) S Konori Id, Mios Woendi Atoll, Padaido Ids, 457 m (ANSP 025362).

Argyropeza izekiana Kuroda

FIGURES 5–7

Argyropeza izekiana Kuroda, 1949:76–79, fig. 1 [holotype: NSMT; type-locality: off Tosa, Shikoku, Japan, 100 m].

Argyropeza izekii [sic] Kuroda.—Habe, 1964:42, pl. 12: fig. 27 [mistakenly cited as fig. 26].

DESCRIPTION.—Shell: small, about 4.6 mm long, elongate, turreted, comprising 8–11 whorls about 1.53 mm wide. There are 8 flat-sided adult whorls that are impressed suturally. Apical angle of shell 35 degrees. Adult whorls with two spiral cords, one near top and the other at bottom whorl. Lower spiral cord sometimes weak. Spiral cords weakly beaded. One microscopic spiral cord on upper portion of whorl adjacent to suture. Shell sculptured with 12–14 axial ribs per whorl that form small sharp nodes where they cross spiral cords. Axial ribs strongest on first two whorls of teleoconch. Body whorl lacks axial ribs, nodes and has weak spiral sculpture. Suture well-defined, set off by sloping inferior and superior sutural ramp on each whorl. Protoconch I smooth, comprising one and one-half whorls; protoconch II, consists of two whorls, sculptured with spiral band of ovoid pustules adjacent to suture and with two spiral cords, the lower of which is formed of two fine, spiral lirae. Sinusigera sinus deep and narrow. Abrupt transition from protoconch to teleoconch marked by distinct change in sculpture. Former varix normally on right dorsal side of body whorl. Sculpture of body whorl comprises two weak, widely-spaced, spiral cords below which are 4–5 spiral lirae that grow weaker as they approach the anterior siphonal canal. Aperture ovate-circular, a little more than one-fourth the length of the shell. Columella straight and with weak parietal callus. Anterior siphonal canal short and broad, opening to left about 45° from the shell axis. Outer lip convex, smooth, thin, slightly sinuous. Anal canal indistinct. Periostracum very thin, pale tan. Shell vitreous, shining, white, chalky in dead specimens. Operculum concave and with circumference slightly bent to fit snugly into aperture of shell.

Animal (preserved): Head-foot small in relation to shell, flesh colored. Snout bilobed at tip. Tentacles wide, more flat than round, and each with large black eye at outer side of tentacle base. Intestine large, filled with large ovoid fecal pellets composed of fine sand. Anus close to mantle edge. Buccal mass large, filling much of snout.

Radula (Figure 6): Radular ribbon long, taenioglossate. Rachidian tooth quadrate in shape, concave at sides, slightly convex at tip. Cutting edge of rachidian tooth serrated with long, sharply pointed central cusp that has a tiny lateral denticle on each side of the median portion of cusp. Base of rachidian tooth slightly convex with sharp lateral projection at each side. Basal plate of rachidian tooth thick. Lateral tooth trapezoidal, laterally elongate and with slightly curved top that is serrated with 7–8 pointed cusps. First cusp small, second large, wide, and pointed, and remainder small and decreasing in size toward the lateral portion of tooth. Blunt longitudinal projection extends from lower mid-portion of basal plate. Base of lateral tooth slightly concave. Inner marginal tooth long, slender, curved, sharply pointed at tip, and serrated with 5–6 sharp denticles on inner side and 5 denticles on outer side. Outer marginal tooth same as inner marginal, but lacking denticles on outer surface.

TABLE 5.—Argyropeza izekiana, measurements of shell characters (in mm)

ETYMOLOGY.—Named in honor of Mr. Izeki.

COMPARATIVE REMARKS.—This species is distinguished from its congeners by 9.5 flat-sided, spinose whorls and by the presence of predominant transverse axial ribs that cross two weak spiral cords on each whorl. It is closest in sculpture to Argyropeza divina, which also has only two spiral cords per whorl and which is similarly spinose. Argyropeza izekiana is smaller and less attenuate than A. divina and has a shorter anterior siphonal canal than the latter species. The sutural ramp of A. izekiana is less pronounced than in A. divina.

It should be noted that Habe (1964:42, pl. 12: fig. 27) mistakenly cited fig. 26 of his plate in reference to A. izekiana. He also erroneously assigned it to the family Cerithiopsidae H. and A. Adams. Shuto's (1969:64) statement that A. izekiana is readily distinguished from other Argyropeza species in having the upper row of pustules much closer to the suture is erroneous.

FIGURE 5.—Argyropeza izekiana Kuroda, showing variability in shell form and sculpture: a–c, apertural, side, and dorsal views of adult shells (note sinuous outer lip), 25×; d, protoconch showing larval shell sculpture, 170×; e, top view of protoconch showing disparity between larval and adult sculpture, 175×; f–h, apertural, side, and dorsal views of adult shells: note stronger axial riblets in contrast to a–c; 30×; i–k, apertural, side and dorsal views of adult shells with strong axial ribs (USNM 262893, USBF 5131, off Panabutan Pt, W Mindanao, Philippines, 49m, 24×); l, protoconch showing sinusigera notch, 215×. (a–h and l all USNM 774591, USBF Sta 5398, off Gigantangan Id, NW Leyte, Philippines.)

FIGURE 6.—SEM micrographs of radula and operculum of Argyropeza izekiana Kuroda (USNM 281893, USBF Sta 5392, off Adyagan Id, E Masbate, Philippines, 247m): a, worn portion of radular ribbon, 1000×; b, close-up of lateral and marginal teeth, 1500×; c, portion of radular ribbon, 650×; d, view of free portion of operculum, 100×.

Bittium porcellanum Watson, 1886 is similar to this species. It looks very much like those morphs of A. izekiana that have prominent axial ribs, but having examined the type-specimen, I regard B. porcellanum as distinct from A. izekiana. Moreover, the glossy shell with brown-tipped protoconch, and the depth at which it was collected (283 meters) indicate an assignment to a genus other than to Bittium. Watson (1886:559) was obviously uncomfortable in referring B. porcellanum to Bittium because he noted that it was an “aberrant form of Bittium.”

ECOLOGY.—This species lives at depths ranging from 49 to 914 meters and has a mean bathymetric distribution of 307 meters (Table 3). Station data show that it is usually found on sediments comprised of mud or finegrained sand. The small radula and fecal pellets that consist of fine sediment and detritus point to a macrophagous feeding habit. Many specimens from the Philippines had drill holes that were moderately large and of the kind made by naticid snails (see Carriker and Yochelson, 1968).

GEOGRAPHIC DISTRIBUTION (Figure 7).—Most records of A. izekiana are from the western central Pacific where it is found from southern Japan south to Indonesia, New Guinea, Australia, and east to New Caledonia and the New Hebrides. There is also a single record from Mozambique, in the western Indian Ocean. I have examined this material, which comprises three specimens, and find no essential differences in shell physiognomy between these specimens and those collected in the Philippines. Other Argyropeza species have a similar range and when more deep sea dredging occurs in the Indian Ocean it is probable that A. izekiana will be found in other localities. To my knowledge, no fossil records of this species exist.

SPECIMENS EXAMINED.—PHILIPPINES: off Matocot Pt, W Luzon, 384 m (USNM 277379); off Matocot Pt, W Luzon, 311 m (USNM 275955; USNM 278514); off Matocot Pt, W Luzon, 402 m (USNM 774607; USNM 278474); off Matocot Pt, W Luzon, 314 m (USNM 277982); off Matocot Pt, W Luzon, 362 m (USNM 276725); off Matocot Pt, W Luzon, 247 m (USNM 276060); off Malavatuan Id, W Luzon, 186 m (USNM 258402; USNM 775111); off Lauis Pt, W Luzon, 296 m (USNM 774605); SW, off Corregidor Lt Luzon, 247 m (USNM 294331); SW, off Corregidor Lt Luzon, 216 m (USNM 278316); Lagonoy Gulf, E Luzon, 914 m (USNM 282979; USNM 787684); Laguna de Bay, Luzon (USNM 283322); off Sombrero Id, Balayan Bay, 291 m (USNM 262299; USNM 787470); off Subaango, Mindoro, 296 m (USNM 244140); off Balanja Pt, SE Mindoro, 265 m (USNM 276212); off Pt Origon, Tablas, 133 m (USNM 281521); off Sibugay Id, E of Masbate, 197 m (USNM 774602); off Adyagan Id, E Masbate, 247 m (USNM 281893); off Destacado Id, E of Masbate, 146 m (USNM 775046); off Gigantangan Id, NW Leyte, 208 m (USNM 291296; USNM 774591); off Lauis Pt, E Cebu, 265 m (USNM 290603); off Lauis Pt, E Cebu, 302 m (USNM 775123); Cebu (USNM 235036); off Capitanalo Id, N Cebu, 333 m (USNM 287810); off Capitanalo Id, N Cebu, 345 m (USNM 289158); off Cabilao Id, W Bohol, 318 m (USNM 775116); off Ponson Id, Camotes Id, 347 m (USNM 775061); off Observatory Id, Palawan Pass, 79 m (USNM 775060); off Observatory Id, Palawan Pass, 84 m (USNM 775054); NE off Balabac Id, 124 m (USNM 787134); off Panabutan Pt, W Mindanao, 49 m (USNM 262865; USNM 262893); off Tagolo Pt, N Mindanao, 400 m (USNM 286753); E of Bongo Id, 289 m (USNM 230199); Port Pio V, Camiquin Id, (USNM 301346); off Dammi Id, Sulu Arch, 490 m (USNM 286270); off Dammi Id, Sulu Arch, 444 m (USNM 286468); N off Sibutu Id, Sulu Arch, 320 m (USNM 287330). CHINA SEA: Off Pratas Id, 274 m (USNM 290767; USNM 309210); off Pratas Id, 161 m (USNM 285042); off Pratas Id, 622 m (USNM 284343); off Pratas Id, 420 m (USNM 284687; USNM 312743; USNM 296999); off Pratas Id, 256 m (USNM 285101); off Pratas Id, 274 m (USNM 274663; USNM 259537; USNM 284958); off Pratas Id, 380 m (USNM 277295); off Pratas Id, 223 m (USNM 284561). BORNEO: Off Silungan Id, 558 m (USNM 774760; USNM 775120); Darvel Bay, off Sibutu Id, 296 m (USNM 287020). CELEBES: Buton Strait, 68 m (USNM 279847). MOZAMBIQUE: Near Inhaca Id, 366 m (USNM 775063). NEW CALEDONIA: Off S New Caledonia, 22°17'S, 167° 14″E, 425–430 m (MNHN). JAPAN: Tosa Bay, Shikoku, 80–150 m (AMS). NEW HEBRIDES: Espirito Santo (AMS). AUSTRALIA: 150 mi (240.0 km) W of Cape Leveque, WA, 16°16'S, 120°45″E, 330 m (AMS); N of Cape Leveque, WA, 14°07'S, 122°52″E, 256 m (AMS); 210 mi (336.0 km) N of Broome, WA, 14°50'S, 121°45″E, 230 m (AMS); 150 km NW of Melville Id, NT, 9°53'S, 130°2″E, 205 m (AMS); 386 km N of Goulburn Id, NT, 8°02'S, 133°50″E, 108 m (AMS); NE of Lady Musgrave Id, Qld, 23°38.8'S, 152°45.5″E, 365 m, HMAS Kimbla, Stn 24 (AMS); 25 mi (40.0 km) E of Lady Musgrave Id, Qld, 22°44'S, 152°49″E, 357 m (AMS); E of Lady Elliott Id, Qld, 24°00S, 153°06.5″E, 531–476 m (AMS).

FIGURE 7.—Geographic distribution of Argyropeza izekiana Kuroda. The disjunct distribution may be due to poor sampling in other areas of the Indian Ocean.

Argyropeza schepmaniana Melvill

FIGURES 8–9

Argyropeza schepmaniana Melvill, 1912:246–247, pl. 12: fig. 11 [holotype: BM(NH) Reg. No. 1912.9.17.42; type-locality: Merkan Coast, Charbar, Persian Gulf, Iran, 73 m].—Thiele, 1918:120.—Hornung and Mermod, 1926:207–208.—Kuroda, 1949:78.—MacNeil, 1960:40, pl. 2: fig. 1.

DESCRIPTION.—Shell: Small, about 4.14 mm long, 1.28 mm wide, elongate, turreted, consisting of 8 adult whorls and having apical angle of 32°. Whorls convex and impressed suturally. Adult whorls sculptured with three primary spiral cords and a fourth very thin spiral cord on the upper portion of the whorl adjacent to suture. First two primary spiral cords closer to each other than to third, which is lower on whorl. Axial ribs that are slightly transverse, about 13–14 per whorl, form small, sharp nodules or spines where they cross the spiral cords creating an overall spinose reticulate effect. Suture deep and distinct. First two whorls of teleoconch have only two spiral cords. Sculpture less distinct on body whorl. Protoconch I smooth, one and a half whorls; protoconch II two whorls, sculptured with a spiral band of ovoid pustules adjacent to suture and with two equidistant spiral cords at mid-portion of whorl. Spiral cords sometimes weakly pustulate and bottom one consisting of two fine spiral lirae. Sinusigera sinus moderately deep and narrow. Sharp transition from protoconch to teleoconch marked by sinuous growth scar. Several former varices usually present on penultimate and body whorl opposite outer lip. Sculpture of body whorls same as other whorls except for 5–6 thin spiral cords at base of whorl, becoming weaker at anterior siphonal canal. Aperture ovate, a little over one-fifth the length of the shell. Columella smooth, straight with thin, shiny callus. Outer lip thin, smooth, and slightly curved at edge. Anterior siphonal canal short, broad, and slightly curved to left. Anal canal indistinct. Shell shiny, white, chalky in dead specimens. No periostracum observed. Animal, operculum, radula, eggs and larvae unknown.

TABLE 6.—Argyropeza schepmaniana, measurements of shell characters (in mm)

FIGURE 8.—Argyropeza schepmaniana Melvill: a, b, typical adult shells showing overall sculpture and varices (USNM 288300, USBF Sta 5426, off Mantaquina Id, E Palawan, Philippines, 49m, a, 34×; b, 26×); c, protoconch showing details of larval shell sculpture, USNM 285913, USBF Sta 5348, Palawan Pass, Philippines, 30×; d, e, adult shells (USNM 285913, locality data as in c; d, 30×; e, 32×); f, detail of sculpture on adult whorl showing three spiral cords and nodules (USNM 263526, Sta 5097, off Corregidor Id, Luzon, Philippines 55m, 75×); g–i, adult shells, apertural, side and dorsal views showing former varices (USNM 263526, locality data is in f; g, 22×; h and i, 26×); j, detail of protoconch and early whorls showing sculptural disparity between larval and adult shell (USNM 263526, locality data as in f; 100×).

ETYMOLOGY.—Named after M. A. Schepman, who described the mollusks of the Siboga Expedition.

COMPARATIVE REMARKS.—This species is distinguished from its congeners by a slender shape, small aperture, and a high aperture-length to shell-length ratio. It is distinctive in that the first two whorls of the teleoconch bear two spiral cords while the remaining whorls each have three nodulose spiral cords. Numerous sharp nodules on the spiral cords give the shell a distinctive spiny look.

Argyropeza schepmaniana resembles A. verecunda Melvill and Standen 1903 in sculpture, but the former is much larger and does not have four spiral cords on most of the whorls of the teleoconch. Argyropeza verecunda is not well known and when more comparative material is available it may prove to be a subspecies of A. schepmaniana.

The sculpture and form of Scala nodifera Thiele, from the western Indian Ocean, looks very much like that of A. schepmaniana except that the upper teleoconch has only axial sculpture present. The shell of Scala nodifera, as depicted by Thiele (1918, pl. 11: fig. 6), is missing the aperture, but the marginal tooth of the radula as depicted in Thiele's (1918: pl. 34: fig. 20) illustration, is very different from those of Argyropeza species.

I have included MacNeil's (1960:40) citation of A. schepmaniana in the synonymy, but like MacNeil, have some doubt about the identity of the specimen he figured. Although it looks like A. schepmaniana, the length (9.1 mm) of the specimen is far beyond the range of numerous samples I have examined (2.3–5.9 mm). For this reason, I am hesitant to regard it as being conspecific with A. schepmaniana and am inclined to consider it as a closely related fossil species of Argyropeza.

ECOLOGY.—Argyropeza schepmaniana has a bathymetric range of 33–914 meters and a mean depth range of 145 meters. It lives on muddy bottom and is sometimes found with A. divina or A. izekiana. Although nothing is known of the animal, it presumably has a radula similar to the other species of Argyropeza and is probably a detritivore. The protoconch and the sinusigera notch indicate a pelagic larval phase and a mode of development identical to those of its congeners.

GEOGRAPHIC DISTRIBUTION (Figure 9).—Originally described as an uncommon species from the Arabian Sea, A. schepmaniana is abundant in the Philippines and South China Sea where it is sympatric with A. divina and A. izekiana. Specimens I examined from New Caledonia were typical. This species probably has a wider distribution in the Western Pacific.

FOSSIL RECORD.—MacNeil (1960:40) cited a single specimen from the Miocene of Okinawa as a possible fossil record of A. schepmaniana, but this is not enough material upon which to base a final decision (see discussion above under “Systematic Remarks”). I have examined Pleistocene fossils of A. schepmaniana deposited in the Australian Museum, Sydney, from the NW bank of the Kavavas River, near Riet, Gazelle Peninsula, New Britain, Papua.

SPECIMENS EXAMINED.—AUSTRALIA: 100 mi (160.0 km) NW of Broome, WA, 16°58'S, 120°47″E, 194 m (AMS). PHILIPPINES: Lagonoy Gulf, E Luzon, 914 m (USNM 289593); Lagonoy Gulf, E Luzon, 86 m (USNM 219366); off Sueste Pt, W Luzon, 46 m (USNM 774606); off Malavatuan Id, W Luzon, 33 m (USNM 278182); off Matocot Pt, W Luzon, 402 m (USNM 775039); off Arena Pt, Ragay Gulf, Luzon, 525 m (USNM 787469); NW off Corregidor Lt, 68 m (USNM 262440); USNM 262158); S off Corregidor Lt, 55 m (USNM 263526; USNM 291474); S off Corregidor Lt, 69 m (USNM 262777); S off Corregidor Lt, 64 m (USNM 291566); USNM 257320; USNM 257223; USNM 257224); SW off Corregidor Lt, 247 m (USNM 294299); off Sombrero Id, Balayan Bay, 216 m (USNM 262034); N off Marinduque, 353 m (USNM 277067); SE off Bantayan Id, 58.5 m (USNM 775051); N off Marinduque, 91 m (USNM 276097); Daram Channel, W Samar, 58.5 m (USNM 280754); off N Badian Id, W Samar, 64 m (USNM 258062); off Linbancauayan Id, W Samar, 91 m (USNM 277684); off Batag Id, N Samar, 548 m (USNM 289074); off Sibugay Id, E of Masbate (USNM 291740); off Balabac (USNM 787134); Linapacan Strait, off Observatory Id, Palawan, 84 m (USNM 282846; USNM 291658); Palawan Pass, (USNM 285913); off Observatory Id, Palawan Pass, 84 m (USNM 787681; USNM 75053; USNM 291619); off Observatory Id, Palawan Pass, 79 m (USNM 775045); off Toca hi Pt, Tawi-tawi, 90 m (USNM 274417): off Panabutan Pt, W Mindanao, 48 m (USNM 2933 9; USNM 282126; USNM 255745); off Panabutan Pt, W Mindanao, 49 m (USNM 262898: USNM 262892; USNM 262893; USNM 262869; USNM 262896); off Panabutan Pt, W Mindanao, 69 m (USNM 293562; USNM 787682); E of Burias, 192 m (USNM 244143). CHINA SEA: Off Pratas Id, 161 m (USNM 284988). NEW CALEDONIA: Off S New Caledonia; 22°17'S; 167°14″E, 425–530 m (MNHN).

FIGURE 9.—Geographic distribution of Argyropeza schepmaniana Melvill.

Argyropeza leucocephala (Watson)

FIGURE 10

Brittium leucocephalum Watson, 1886:558–559, pl. 38: fig. 7 [holotype: BM(NH) Reg. No. 1887.2.9.1749; type-locality: reefs off Honolulu, Hawaii, 73 m].—Tryon, 1887:157, pl. 31: fig. 31.

Cerithium (Bittium) leucocephalum (Watson).—Kobelt, 1898: 259, pl. 44: fig. 9.

DESCRIPTION.—Shell small, about 3.88 mm long and 1.20 mm wide, white, porcellaneous, elongate, turreted, with a length-width index of 5.10 and comprising 7 convex adult whorls with an apical angle of 22°. Each adult whorl sculptured with three spiral cords crossed by 16–17 weak, axial riblets forming sharp nodules at intersections. Apical angle of Protoconch I consists of 1.5 smooth whorls except for weak spiral line of pustules at base of suture. Protoconch II with two distinct spiral cords on mid-portion of whorls and a spiral row of elongate but small pustules at base of suture. Numerous microscopic pustules cover lower two-thirds of whorl. Protoconch terminated by distinct sinusigera sinus. Transition from protoconch to teleoconch sharply defined. First three juvenile whorls sculptured with two spiral cords adorned with sharp nodules and weak axial riblets. Body whorl inflated, sculptured with three spiral nodulose cords and very weak axial riblets. Base of body whorl slightly concave and with three thin spiral lirae. Suture deeply impressed, forming slight sutural ramp on upper portion of each whorl. Aperture ovate, about one-fifth the length of the shell. Outer lip smooth, rounded. Anterior siphonal canal shallow, but distinct. No anal canal. Columella smooth, concave, and with slight columellar lip.

TABLE 7.—Argyropeza leucocephala, measurements of shell characters (in mm)

FIGURE 10.—Argyropeza leucocephala Watson (USNM 783499, Mamala Bay, Oahu, Hawaii, 200m): a–c, adult shells showing overall sculptural pattern, 30×; d, protoconch showing sinusigera notch, 200×; e, protoconch showing larval sculpture, 200×: f, detail of adult whorls showing two spiral rows of nodules, 85×.

ETYMOLOGY.—Greek leukon (“white”) plus kephale (“a head”).

COMPARATIVE REMARKS.—This species most closely resembles A. schepmaniana but may be distinguished from it by larger size and lack of prominent varices. I have seen A. leucocephala specimens only from the Hawaii area, where it was first discovered and described as a Bittium species by Watson (1886). It is possible that A. leucocephala may be a large morph of A. schepmaniana. Our present knowledge of A. schepmaniana shows that it is geographically limited to the western Pacific; however, should new specimens turn up in the area between Hawaii and the western Pacific, the status of these two species will have to be reevaluated.

Tryon (1887:157) thought this species was similar to Bittium perparvulum Watson, 1887 but the protoconch of the latter lacks the two spiral cords and is much different. Kobelt (1898:259) assigned it to Cerithium, but the size, protoconch, and overall physiognomy of A. leucocephala exclude it from this genus.

The holotype of A. leucocephala is an immature individual specimen with a slightly damaged aperture and worn protoconch but it seems to agree with specimens recently dredged in Hawaiian waters and figured in this paper (Figure 10). Watson's (1886) original description appears to closely match that of A. schepmaniana. The protoconch that Watson (1886) mentioned had a white tip and brownish lower part, is identical to those of other Argyropeza species. The general shell physiognomy and the vitreous aspect of the shells of fresh specimens would indicate that Watson's species should be more properly referred to the genus Argyropeza than to Bittium.

ECOLOGY.—Specimens of A. leucocephala in hand comprise only a limited sample and the radula, operculum, and soft parts are unknown. The sinusigera protoconch points to a pelagic larval phase and suggests that this species has a wider geographic range than is now known. Nothing is known of the ecology except that Hawaiian specimens have been dredged at 200 m on a fine sandy bottom. There are no fossil records of this species and the geographical range, based upon available records, is limited to the Hawaiian Islands.

SPECIMENS EXAMINED.—Mamala Bay, Oahu, Hawaii, 200 m (USNM 783499); Reefs off Honolulu, Hawaii, 73 m (BM(NH) Reg. No. 1887.2.91749).

Argyropeza verecunda Melvill and Standen

FIGURES 11–12

Cerithium verecundum Melvill and Standen, 1903:300, pl. 21: fig. 5 [2 paratypes: BM(NH) Reg. No. 1903.12.15.90–92; 2 paratypes: ANSP 164787; type-locality: 24°58″N, 56°54″E, Gulf of Oman, 285 m].

Cerithium pervicax Melvill, 1904:161, pl. 10: fig 7 [6 paratypes: BM(NH) Reg. No. 1905.7.14.21–26; 3 paratypes: ANSP 97739; type-locality: 24°58″N, 56°54″E, Gulf of Oman, 285 m].

?Obtortio elongella Melvill, 1910:6, pl. 1: fig 14 [holotype: BM(NH) Reg. No. 1912.8.16.96, Mekran Coast, off Charbar, Pakistan].

DESCRIPTION.—Shell small, about 2.77 mm long, 0.98 mm wide, thin, moderately elongate, turreted, and consisting of 8 adult whorls that are convex and with impressed sutures. Apical angle of 32 degrees. Adult whorls each sculptured with 4 spiral cords and 14–15 axial ribs that form small nodes where they cross spiral cords giving overall nodular, cancellate appearance. Earliest whorls of teleoconch have two weak spiral cords. Remaining whorls of teleoconch each with four, equidistant spiral cords that are most fully developed on the penultimate and body whorls. First spiral cord weak and on sutural ramp; remaining spiral cords strong. Body whorl moderately inflated and with 4–5 spiral cords on base around siphonal constriction. Former varices randomly distributed but weak. Protoconch I smooth, one and one-half whorls; protoconch II, two whorls, sculptured with spiral band of pustules adjacent to suture and with two spiral cords on mid-portion of whorl. Sinusigera sinus deep and narrow; marked transition in sculpture from protoconch to teleoconch. Aperture ovate about one-fifth the length of the shell. Anterior siphonal canal short and broad, slightly curved to the left. No anal canal present. Columella straight with slight parietal callus. Outer lip thin, smooth, and semicircular in outline. Shell vitreous shining white; chalky in dead collected specimens. Operculum, radula, soft parts, eggs, and larvae unknown.

TABLE 8.—Argyropeza verecunda, measurements of shell characters (in mm)

FIGURE 11.—Argyropeza verecunda (Melvill and Standen): a, specimen from Gulf of Oman, showing overall sculptural pattern, 34×; b, detail of aperture showing anterior siphonal canal, 75×; c, protoconch, showing sinusigera notch and larval sculpture, 250×; d, e, specimens from Andaman Sea showing overall sculptural pattern, 44×; f, detail of aperture showing anterior siphonal canal, and sculptural details of body whorl, 66×; g, protoconch showing sinusigera notch, 250×; h, detail of adult whorls showing four spiral rows of nodules, 75×. (a, f–h all USNM 424893, Gulf of Oman, Arabian Sea 285m; b–e all ANSP 293078, Anton Bruun Sta 37A, IIOE, 13°28″N; 97°19″E, 91.2 km NW of Tavoy, Andaman Sea, S Burma, 39m.)

ETYMOLOGY.—Latin verecundas (“unassuming”).

COMPARATIVE REMARKS.—Argyropeza verecunda is the smallest species in the genus and except for size, is morphologically very similar to A. schepmaniana. When more material is available for comparison A. verecunda may prove to be either a subspecies or a phenotypic variation of A. schepmaniana. Although similar, A. verecunda is distinguished from A. schepmaniana by its small size and by four spiral cords on most of the whorls of the teleoconch. It also has fewer and less prominent varices and axial ribs that are most evenly spaced.

Melvill and Standen (1903:300) originally referred this species to the genus Cerithium Bruguière and noted that some individuals in their sample were smaller and less ventricose. They did not, however, believe this difference was a specific one. Later, Melvill (1904:161), pointing out a few minor morphological differences, named the smaller morphs Cerithium pervicax. I have examined the types and consider these slight sculptural differences to be within the normal range of variation A. verecunda. Additional specimens from the Andaman Sea and the Philippines have confirmed this interpretation. I thus regard A. pervicax as a synonym of A. verecunda. Obtortio elongella Melvill, 1910 also appears similar to A. verecunda. I have not seen the types of the former, but the illustration in Melvill (1910, pl. 1, fig. 14) looks very much like A. verecunda. The figured syntype of this species (BM(NH) Reg. No. 1912.8.1b.96) looks like an immature specimen and does not show a distinct anterior siphonal canal. This may also be due to a damaged aperture. I have not examined any other material; consequently, I am hesitant to place it in the synonymy of A. verecunda.

FIGURE 12.—Geographic distribution of Argyropeza verecunda Melvill and Standen.

ECOLOGY.—The few records that exist indicate that A. verecunda is a lower sublittoral-bathyal species that has a bathymetric range of 39–285 meters and a mean depth range of 162 meters. Melvill (1904:161) recorded it (cited as Cerithiumpervicax) to be abundant on a shell-sand bottom at 284 meters and specimens from the Andaman Sea were collected at 39 meters on a sand-shell substratum. It is the only species that is not found on muddy, fine grained substrata, but records are sparse and future collecting may reveal better ecological information.

GEOGRAPHIC DISTRIBUTION (Figure 12).—Argyropeza verecunda is an uncommon species. Most records are from the northern latitudes of the Indian Ocean. A record from Northern Australia indicates that this species probably has a wider distribution. There are no fossil records.

SPECIMENS EXAMINED.—INDIAN OCEAN: 24°58″N, 56°54″E, Gulf of Oman, 385 m (BM(NH)); ANSP 164787); NM Victoria F8547; Gulf of Oman (USNM 424893); (AMS 6 specimens); Mekran Coast, off Charbar, Pakistan (BMNH)); 57 mi (91.2 km) NW of Tavoy Id, Andaman Sea, 39 m (ANSP 293078, Anton Bruun Sta 37A). AUSTRALIA: 150 km NW of Melville Id, Northern Territory, 9°53'S, 130°2″E, 205 m (AMS).

Appendix

The following list of 14 species includes taxa that are easily confused with or erroneously assigned to the genus Argyropeza. They are listed in alphabetical order by species but are cited under the generic names given by original authors.

Cerithium bicanaliferum Brazier, 1877:317. (=Cerithium trigonostomum Melvill, 1910; = Argyropeza involuta Thiele, 1918.) This species, frequently collected with some Argyropeza species, may easily be distinguished from them by a large, swollen body whorl, marked anal canal, and smooth protoconch of 2.5 whorls.

Bittium diplax Watson, 1886:555–556, pl. 28: fig. 4. This species has an overall angulate appearance and may be confused with some Argyropeza species; however, the shell is nonvitreous and the protoconch consists of only 2.5 whorls and lacks the sinusigera sinus so typical of Argyropeza species.

Argyropeza doriae Hornung and Mermod, 1926: 208–209, figure. Neither the protoconch, shell sculpture, nor the aperture of this species are indicative of an assignment to Argyropeza.

Obtortio elongella Melvill, 1910:9, pl. 1: fig. 14. The figured syntype of this species (BM(NH) Reg. No. 1912.8.16.96) may be an immature specimen and appears to lack an anterior canal. It is probably a true Fenella. I have not seen any other specimens. Should this species truly have an anterior canal it would be very close to Argyropeza verecunda.

Bittium fuscocapitulum Hedley and Petterd, 1906: 217–218, pl. 38: figs 10–11. The protoconch of this species is identical to those of other Argyropeza taxa but the sculpture and shape of the shell is so different that I am hesitant to assign this species to Argyropeza. Only dead shells were collected and I have not seen any other specimens. The radula and operculum are unknown.

Argyropeza involuta Thiele, 1918:120, pl. 9: figs. 20, 20a. This nominal species is conspecific with Cerithium bicanaliferum Brazier, 1877 and is not an Argyropeza species.

Obtortio liratus Ludbrook, 1941:9–10, pl. 4: fig. 24. I have seen only the figure of this species and although it looks as if it may be assigned to Argyropeza, examination of more specimens is necessary before a decision may be made.

Argyropeza melvilli Schepman, 1909:170, pl. 12: fig. 1. This is an Abyssochrysos species.

Bittium perparvulum Watson, 1887:554–555, pl. 38: fig. 3. Although the sculpture and shape of the holotype look very much like those of Argyropeza species, the shell is non-vitreous and the smooth protoconch of 2.5 whorls is unlike those of any Argyropeza taxa. The status of B. perparvulum remains uncertain.

Argyropeza suvaensis Ladd, 1977:15–16, pl. 1: fig. 3; pl. 21: fig. 8. This early Miocene fossil is a synonym of Abyssochrysos melvilli (Schepman, 1909) and is not in the Argyropeza group (Houbrick, 1979:14).

Argyropeza tomlini Barnard, 1963:143–144, fig. 27f. I have recently shown that this species is a synonym of Abyssochyrsos melvilli (Schepman 1909) and not an Argyropeza species (Houbrick, 1979:11–12).

Cerithium trigonostomum Melvill, 1910:10, pl. 1: fig. 5. This is a synonym of C. bicanaliferum Brazier (see remarks under this taxon and under Argyropeza involuta Thiele).

Obtortio vulnerata Hedley, 1909:439, pl. 14: fig. 52. Examination of the holotype (AMS) convinces me that this taxon is not within the Argyropeza group. It does not have an anterior canal.

Fenella xanthacme Melvill, 1904:56, pl. 5: fig. 16. I have examined the figured syntype of this species (BM(NH) Reg. No. 1904.7.29. 17–19) from the Culf of Oman and believe that it is an epitoniid of the subfamily Nystiellinae rather than a Fenella or Argyropeza species. What appears to be an anterior canal is merely a break in the outer lip; moreover, the elongate protoconch with pronounced axially costate whorls is very different from those of other Argyropeza taxa.

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Manuscripts intended for series publication receive substantive review within their originating Smithsonian museums or offices and are submitted to the Smithsonian Institution Press with approval of the appropriate museum authority on Form SI–36. Requests for special treatment—use of color, foldouts, casebound covers, etc.—require, on the same form, the added approval of designated committees or museum directors.

Review of manuscripts and art by the Press for requirements of series format and style, completeness and clarity of copy, and arrangement of all material, as outlined below, will govern, within the judgment of the Press, acceptance or rejection of the manuscripts and art.

Copy must be typewritten, double-spaced, on one side of standard white bond paper, with 1¼″ margins, submitted as ribbon copy (not carbon or xerox), in loose sheets (not stapled or bound), and accompanied by original art. Minimum acceptable length is 30 pages.

Front matter (preceding the text) should include: title page with only title and author and no other information, abstract page with author/title/series/etc., following the established format, table of contents with indents reflecting the heads and structure of the paper.

First page of text should carry the title and author at the top of the page and an unnumbered footnote at the bottom consisting of author's name and professional mailing address.

Center heads of whatever level should be typed with initial caps of major words, with extra space above and below the head, but with no other preparation (such as all caps or underline). Run-in paragraph heads should use period/dashes or colons as necessary.

Tabulations within text (lists of data, often in parallel columns) can be typed on the text page where they occur, but they should not contain rules or formal, numbered table heads.

Formal tables (numbered, with table heads, boxheads, stubs, rules) should be submitted as camera copy, but the author must contact the series section of the Press for editorial attention and preparation assistance before final typing of this matter.

Taxonomic keys in natural history papers should use the alined-couplet form in the zoology and paleobiology series and the multi-level indent form in the botany series. If cross-referencing is required between key and text, do not include page references within the key, but number the keyed-out taxa with their corresponding heads in the text.

Synonymy in the zoology and paleobiology series must use the short form (taxon, author, year:page), with a full reference at the end of the paper under “Literature Cited.” For the botany series, the long form (taxon, author, abbreviated journal or book title, volume, page, year, with no reference in the “Literature Cited”) is optional.

Footnotes, when few in number, whether annotative or bibliographic, should be typed at the bottom of the text page on which the reference occurs. Extensive notes must appear at the end of the text in a notes section. If bibliographic footnotes are required, use the short form (author/brief title/page) with the full reference in the bibliography.

Text-reference system (author/year/page within the text, with the full reference in a “Literature Cited” at the end of the text) must be used in place of bibliographic footnotes in all scientific series and is strongly recommended in the history and technology series: “(Jones, 1910:122)” or “.…Jones (1910:122).”

Bibliography, depending upon use, is termed “References,” “Selected References,” or “Literature Cited.” Spell out book, journal, and article titles, using initial caps in all major words. For capitalization of titles in foreign languages, follow the national practice of each language. Underline (for italics) book and journal titles. Use the colon-parentheses system for volume/number/page citations: “10(2):5–9.” For alinement and arrangement of elements, follow the format of the series for which the manuscript is intended.

Legends for illustrations must not be attached to the art nor included within the text but must be submitted at the end of the manuscript—with as many legends typed, double-spaced, to a page as convenient.

Illustrations must not be included within the manuscript but must be submitted separately as original art (not copies). All illustrations (photographs, line drawings, maps, etc.) can be intermixed throughout the printed text. They should be termed Figures and should be numbered consecutively. If several “figures” are treated as components of a single larger figure, they should be designated by lowercase italic letters (underlined in copy) on the illustration, in the legend, and in text references: “Figure 9b.” If illustrations are intended to be printed separately on coated stock following the text, they should be termed Plates and any components should be lettered as in figures: “Plate 9b,” Keys to any symbols within an illustration should appear on the art and not in the legend.

A few points of style: (1) Do not use periods after such abbreviations as “mm, ft, yds, USNM, NNE, AM, BC.” (2) Use hyphens in spelled-out fractions: “two-thirds.” (3) Spell out numbers “one” through “nine” in expository text, but use numerals in all other cases if possible. (4) Use the metric system of measurement, where possible, instead of the English system. (5) Use the decimal system, where possible, in place of fractions. (6) Use day/month/year sequence for dates: “9 April 1976.” (7) For months in tabular listings or data sections, use three-letter abbreviations with no periods: “Jan, Mar, Jun,” etc.

Arrange and paginate sequentially EVERY sheet of manuscript—including ALL front matter and ALL legends, etc., at the back of the text—in the following order: (1) title page, (2) abstract, (3) table of contents, (4) foreword and/or preface, (5) text, (6) appendixes. (7) notes, (8) glossary, (9) bibliography, (10) index, (11) legends.