Brachiopoda from the Southern Indian Ocean (Recent) — — I mm G. ARTHUR COOPER Ml . , MB ’ P ,w NUMBER 43 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 Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in Air and Space Smithsonian Studies in History and Technology In these series, the Institution publishes small papers and full-scale monographs that report the research and collections of its various museums and bureaux or of professional colleagues in the world of science and scholarship. The publications are distributed by mailing lists to libraries, universities, and similar institutions throughout the world. Papers or monographs submitted for series publication are received by the Smithsonian Institution Press, subject to its own review for format and style, only through departments of the various Smithsonian museums or bureaux, where the manuscripts are given substantive review. Press requirements for manuscript and art preparation are outlined on the inside back cover. S. Dillon Ripley Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY • NUMBER 43 Brachiopoda from Indian Ocean the Southern (Recent) G. Arthur Cooper SMITHSONIAN INSTITUTION PRESS City of Washington 1981 ABSTRACT Cooper, G. Arthur. Brachiopoda from the Southern Indian Ocean (Recent). Smithsonian Contributions to Paleobiology , number 43, 93 pages, 30 figures, 14 plates, 1 table, 1981.—Specimens collected from 120 stations around and between the subantarctic islands: Marion, Prince Edward, Crozet, Kerguelen, Heard, Amsterdam, and St. Paul by the M/S Marion Dufresne with the support of Terres Australes et Antarctiques Francaises, Paris, greatly increase our knowledge of the brachiopoda of the Indian Ocean. Eighteen species are recognized that include 16 genera, 2 of them new: Pemphixina and Xenobrochus; 11 new species: Basiliola arnaudi\ Eucalathis magna, E. costellata , E. rotundata, Xenobrochus australis , X. anomalus\ Dallithyns ? dubia ; Dyscolia ? radiata , Platidia marionensis ; Ecnomiosa inexpectata , and Thecidellina minuta. Seven hitherto de¬ scribed species are recorded: Pelagodiscus atlanticus (King); Pemphixina pyxidata (Davidson); Liothyrella moseleyi (Davidson); Megerlina davidsoni (Velain); Megerlia gigantea (Deshayes); Aerothyris kerguelenensis (Davidson), and A. aff. A. macquar- lensis (Thomson). Six genera, which could not be identified specifically, were also taken: Crania , Basiliola , Tegulorhynchia , Eucalathis , Liothyrella , and Aerothyris. Genera recognized in the Indian Ocean for the first time are: Tegulorhynchia , Basiliola , and Ecnomiosa , the last hitherto known only from the Gulf of Mexico and Caribbean Sea. 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 trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Cooper, G. Arthur (Gustav Arthur), 1902- Brachiopoda from the southern Indian Ocean (Recent) (Smithsonian contributions to paleobiology ; no. 43) Bibliography: p. 1. Brachiopoda—Antarctic regions. 2. Brachiopoda—Indian Ocean. I. Title. II Series QE701.S56 no. 43 [QL395.75] 506s [564'.8'09165] 81-607935 AACR2 Contents Page Introduction . 1 Acknowledgments . 1 Previous Reports of Brachiopods from the Indian Ocean . 2 Species Collected . 3 Brachiopods Collected by M/S Marion Dufresne on Cruises MD.03 and MD.08 . 4 Species Collected . 5 Brachiopods and Station Records, Cruise MD.03 . 6 Brachiopods and Station Records, Cruise MD.08 . 6 Brachiopods from St. Paul and Amsterdam Islands . 10 Systematics . 10 Superfamily Discinacea Gray, 1840 . 11 Family Discinidae Gray, 1840 . 11 Subfamily Discininae Gray, 1840 . 11 Genus Pelagodiscus Dali, 1908 . 11 Pelagodiscus atlanticus (King) . 11 Superfamily Craniacea Menke, 1828 . 11 Family Craniidae Menke, 1828 . 11 Genus Crania Retzius, 1781 . 11 Crania species . 11 Superfam'ly Rhynchonellacea Gray, 1848 . 12 Family Hemithyrididae Rzhonsnitzkaya, 1956 . 12 Genus Tegulorhynchia Chapman and Crespin, 1923 . 12 Tegulorhynchia species . 12 Pemphixina , new genus . 13 Pemphixina pyxidata (Davidson), new combination . 14 Family Basiliolidae Cooper, 1959 16 Genus Basiliola Dali, 1908 . 16 Basiliola arnaudi , new species . 16 Basiliola species . 17 Superfamily Cancellothyridacea Thomson, 1926 . 17 Family Chlidonophoridae Muir-Wood, 1959 17 Subfamily Eucalathinae Fischer and Oehlert, 1890 . 17 Genus Eucalathis Fischer and Oehlert, 1890 . 17 Eucalathis magna, new species . 17 Eucalathis costellata, new species . 18 Eucalathis rotundata , new species . 18 Eucalathis species . 19 Superfamily Terebratulacea Gray, 1840 . 19 Family Terebratulidae Gray, 1840 . 19 iii IV SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Page Xenobrochus , new genus . 19 Xenobrochus africanus (Cooper), new combination 20 Xenobrochus anomalus , new species . 20 Xenobrochus australis , new species . 20 Genus Dallithyris Muir-Wood, 1959 . 21 Dallithyris? dubia, new species . 21 Genus Liothyrella Thomson, 1916 . 22 Liothyrella moseleyi (Davidson) . 22 Liothyrella? species . 23 Family Dyscoliidae Fischer and Oehlert, 1891 . 23 Genus Dyscolia Fischer and Oehlert, 1890 . 23 Dyscolia? radiata , new species . 23 Superfamily Terebratellacea King, 1850 . 24 Family Platidiidae Thomson, 1927 24 Genus Platidia Costa, 1852 . 24 Platidia marionensis , new species . 24 Family Kraussinidae Dali, 1870 . 25 Genus Megerhna Deslongchamps, 1884 25 Mergerlina davidsoni (Velain) . 25 Genus Megerlia King, 1850 . 27 Megerlia gigantea (Deshayes) . 27 Family Terebratellidae King, 1850 . 28 Subfamily Terebratellinae King, 1850 28 Genus Aerothyris Allan, 1939 28 Summary of Measurable Populations of Aerothyris . 29 Cruise MD. 03 . 29 Cruise MD. 08 . 30 Aerothyris kerguelenensis (Davidson) . 33 Aerothyris macquariensis (Thomson) . 55 Aerothyris aff. A. macquariensis (Thomson) . 56 Aerothyris ? species 1 . 59 Superfamily Dallinacea Beecher, 1893 . 59 Family Ecnomiosidae Cooper, 1977 . 59 Genus Ecnomiosa Cooper, 1977 . 59 Ecnomiosa inexpectata, new species . 59 Genus? species? . 61 Superfamily Thecideacea Gray, 1840 . 61 Family Thecidellinidae Elliott, 1958 . 61 Genus Thecidellina Thomson, 1915 . 61 Thecidellina minuta, new species . 61 Literature Cited . 63 Plates . 66 Brachiopoda from the Southern Indian Ocean (Recent) G. Arthur Cooper Introduction The brachiopods forming the subject of this monograph were collected on cruises of the re¬ search vessel M/S Marion Dufresne on two expe¬ ditions supported by Terres Australes et Antarc- tiques Francaises, Paris: MD.03 (1974) and MD.08 (1976). Included also are specimens from St. Paul and Amsterdam islands collected during a winter stay at the latter island on cruise MD.03. The southern Indian Ocean between latitudes 35°-55°S and longitudes 35°-75°E is not well known. Beside the objectives of physical ocean¬ ography these cruises were designed to collect and study the macro- and meiobenthos. Cruise MD.03 (1974) was essentially a techno¬ logical cruise with emphasis on bottom sampling at various depths with different gears (on the shelves and slopes of Kerguelen, Heard, and Crozet islands) to test the vessel and equipment under various conditions. Cruise MD.08 (1976) was an extension west¬ ward of the regional benthic survey to the shelves of Crozet, Marion, Prince Edward islands, and the intervening oceanic areas. The maps bear the station numbers that should be prefaced by MD.03 (Map 1) and MD.08 (Maps 2-4). Not all the localities appear on the maps and there is no map for Amsterdam and St. Paul islands. G. Arthur Cooper, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D. C. 20560. The following abbreviations are used: MNHN (Museum National D’Histoire Naturelle, Paris); USNM (former United States National Museum, collections now in the National Museum of Nat¬ ural History, Smithsonian Institution). Acknowledgments.— The brachiopods de¬ scribed in this monograph were obtained with the financial and logistical support of Terres Aus¬ trales et Antarctiques Francaises, Paris. Loan of the specimens was made by Dr. Patrick M. Ar- naud, Universite D’Aix-Marseille, Station Ma¬ rine D’Endoume, Centre D’Oceanographie, Rue de la Batterie-des-Lions, 13007, Marseille, France, to whom I express my gratitude for his kindness, and for making the study possible. I also thank Dr. Michel Segonzac, Chief of the Centre Na¬ tional de Tri D’Oceanographie Biologique at Brest, France for loan of specimens from Cruise MD.08 in his care. I am grateful to Dr. J. C. Hureau, Museum National D’Histoire Naturelle, Paris, for loan of specimens of Aerothyris kerguele- nensis (Davidson) from Cruise MD.03. I thank Dr. Jean-Loup D’Hondt, of the same institution, who furnished me with the necessary catalogue num¬ bers for the illustrated specimens. These are a series of numbers prefaced by NMHN-BRA-78. I am indebted to Dr. Howard Brunton, British Museum (Natural History), for measurements of Davidson’s types of Aerothyris kerguelenensis. I thank Dr. J. Thomas Dutro Jr. and Dr. Merrill W. Foster for reviewing the manuscript and offering many valuable suggestions. 1 2 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY All types and illustrated specimens are depos¬ ited in the Museum National D’Histoire Natu- relle, Paris. Duplicate specimens have been de¬ posited in the National Museum of Natural His¬ tory, Smithsonian Institution, Washington, D. C. Previous Reports of Brachiopods from the Indian Ocean Prior to 1959 our knowledge of the brachiopods of the Indian Ocean came largely from discoveries by H.M.S. Challenger (Davidson, 1878, 1880) and other less prolonged expeditions that dredged off Marion, Heard, and Kerguelen islands. The Chal¬ lenger reports a species of Terebratulina from Mar¬ ion Island, a genus not seen from there in this study and rather rare in the Southern Hemi¬ sphere. Jackson (1952:14, 15) expressed some doubt concerning this record. The Transit of Venus Expedition of 1871-1875 visited Kergue¬ len but the only brachiopod reported is now referred to Aerothyris kerguelenensis (Davidson). The Valdivia Expedition (Blochmann, 1906) visited Figure 2. —MD.08 stations south of Madagascar (Malagasy Republic). 70° 00' E Figure 1. — MD.03 stations in vicinity of Kerguelen and Heard islands. Kerguelen Island and collected the much mis¬ understood “ Terebratella ” enzenspergen Blochmann. This expedition also collected at Amsterdam Is¬ land and reported Liothyrella winten Blochmann. Helmcke (1940) described Crania valdiviae, Valdi- viathyns quenstedti, and “ Rhyne hone l la" valdiviae (now Striarina) from waters off St. Paul Island. These species were not collected by the French expeditions MD.03 and MD.08. Muir-Wood (1959) described specimens from the John Murray Expedition to the Indian Ocean but none of the species reported by her were taken in the southern part of the Indian Ocean. Cooper (1973a) described specimens from the northern Indian Ocean, along the coast of Africa off the Somali Republic, from the Mozambique Channel between Madagascar and Mozambique, and off the southeast end of South Africa. This last por¬ tion of the Indian Ocean has a fauna typified by members of the Kraussinidae. One species of Kraussina gardinen Dali was taken south of the Saya de Malha Bank. Megerlina davidsom (Velain), NUMBER 43 3 37°40' 37°50' 38° 00' 38° 10' Figure 3. —MD.08 stations around Marion and Prince Edward islands. also reported herein, is a kraussinid genus from St. Paul Island. Foster (1974) in his extensive work on Antarctic brachiopods redescribed and remarked on some of the Indian Ocean genera and species: Dyscolia , Eucalathis , Platidia , Liothyrella mosleyi (Davidson), and Notosaria? pyxidata (Davidson). He also dis¬ cussed the problems relating to Aerothyris kergue- lenensis (Davidson) and A. enzenspergeri (Bloch- mann) and pointed out the similarity of A. mac- quariensis (Thomson) to A. kerguelenensis. Species Collected Aerothyris kerguelenensis (Davidson) - Kerguelen, Crozet, and Marion islands Agulhasia davidsom (King) - Durban Argyrotheca somaliensis Cooper - Somali Republic Chlidonophora chuni Blochmann - Maldives, Mozambique Channel. Compsona alcocki (Joubin) - southern India C. suffusa Cooper - Somali Republic Crania valdiviae Helmcke - St. Paul Island Cryptopora boettgen Helmcke - Dar-es-Salaam C. cunosa Cooper - Andaman Sea 47°00' 46°50' 46° 40* S 4 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY C. maldivensis Muir-Wood - Maldives Dallithyris? cernica (Crosse) - Mauritius D. murrayi Muir-Wood - Maldives Discinisca indica Dali - Ceylon D. multiradiata Chuang - Somali Republic Dyscolia johanmsdavisi (Alcock) - Maldives Eucalathis fasciculata Cooper - Mozambique Channel Frenulma cruenta Cooper - Somali Republic Gryphus africanus Cooper (= Xenobrochus) - Durban, South Africa G. indianensis Cooper (= Xenobrochus) - Somali Republic Kraussina gardinen Dali - Saya de Malha Bank K. natalensis (Krauss) - Natal, South Africa K. rubra (Pallas) - Natal, South Africa Lacazella mauntiana Dali - Mauritius Leptothyrella ignota Muir-Wood - Zanzibar Lingula hians Swainson - Bombay L. murphiana Reeve - Durban, Karachi L. translucida Dali - Karachi Liothyrella moseleyi (Davidson) - Kerguelen Island, Crozet Is¬ lands L. winteri (Blochmann) - St. Paul Island Megerlia gigantea (Deshayes) - Reunion Island Megerlina davidsom (Velain) - St. Paul Island M. pisum (Lamarck) - Mauritius, Natal, South Africa Nipponithyris afra Cooper - Mozambique Channel Pelagodiscus atlanticus (W. King) - Abyssal, widespread Platidia anomtoides (= P. marionensis, new species) - Marion and Prince Edward islands Rhynchonella nigricans pyxidata Davidson - Kerguelen and Heard islands = Pemphixma pyxidata (Davidson) Rhytirhynchia sladem (Dali) - Saya de Malha Bank Stnanna valdwiae (Helmcke) - St. Paul Island Terebratella enzenspergen Blochmann (= Aerothyns kerguelenensis (Davidson) - Kerguelen Island Terebratuhna abyssicola (Adams and Reeve) - southeast Africa T. mendionalis Jackson - PMarion Island T. valdiviae Blochmann - Sumatra Thaumatosia anomala Cooper - Andaman Sea Thecidellina blochmanm Dali - Christmas Island Valdiviathyris quenstedti Helmcke - St. Paul Island Brachiopods Collected by M/S Marion Dufresne on Cruises MD.03 and MD.08 The collections made by the M/S Marion Du¬ fresne considerably enlarge our knowledge of the brachiopods of the Indian Ocean, adding new species of known genera and two new genera based on already known species: Xenobrochus and Pemphixina. The expedition produced only two specimens of inarticulate brachiopods: Pelagodiscus and Crania. Although most of the bottom sampling of the Marion Dufresne was in shallow to moderately deep water, one haul from 1500 m produced a single specimen of the ubiquitous brachiopod Pelagodiscus known from the deeps of all the oceans (Zezina, 1965). The Crania is a young, shallow- water specimen. Rhynchonellids are rare in all seas except, per¬ haps, the Arctic. Three genera of rhynchonellids were taken by the Marion Dufresne: Pemphixina , a new genus related to Notosana of New Zealand waters and Tertiary sediments; Tegulorhynchia, a spiny rhynchonellid known from the waters around Japan and the Philippines and the Ter¬ tiary of New Zealand; and Basiliola, a smooth form hitherto restricted to the Pacific, Japan, and the Philippines. These last two genera are new to the Indian Ocean. Of the terebratulids collected, one proves to be a new genus, Xenobrochus , based on a known spe¬ cies, 2 are doubtfully identified, Dallithyris and Dyscolia. Liothyrella , a common genus in the Ant¬ arctic, proved rare in the southern Indian Ocean collections, being represented by one known spe¬ cies and fragments of unidentifiable ones. Euca¬ lathis of the Cancellothyridacea is represented by two new species and a third not named. Terebra- tulina, a usually common genus, was not found in the parts of the Indian Ocean sampled by the Marion Dufresne. The terebratellid brachiopods are well repre¬ sented in the southern Indian Ocean. Abundant specimens of a species each of Megerlia , and Meg¬ erlina were found, the former south of Madagascar and the latter far to the east at St. Paul Island. Megerlia may have wandered in from the Medi¬ terranean while Megerlina is a kraussinid far from its other localities off South Africa or southeast Australia, where several species are known. Plati¬ dia , identified by Davidson (1880) with a Medi¬ terranean species, is fairly common in the vicinity of Marion Island. It proves different from the Mediterranean species and is probably another migrant from that region. Aerothyns is a poorly understood genus with some ambiguous characters. It is abundant around all of the islands from Kerguelen to Mar- NUMBER 43 5 IS) o o o CO Figure 4.—MD.08 stations around the islands from lie de L’Est to lie aux Cochons (Crozet Islands). ion. The extensive collections of this genus made by the Marion Dufresne give a better understanding of the species. The collection also confirms a close relationship between A. kerguelenensis (Davidson) and A. macquariensis (Thomson) that occurs far to the east around Macquarie Island southwest of New Zealand. Perhaps the most surprising and interesting discovery of the Marion Dufresne is the occurrence of Ecnomiosa in the Indian Ocean. This recently described genus (Cooper, 1977) was first taken from waters of the Caribbean Sea and the Gulf of Mexico. Although this occurrence proved a surprise, it is not the only Caribbean genus to be found in the Indian Ocean. Chlidonophora , Dyscolia , Eucalathis, Thecidellina, and Megerlia also occur both in the Indian Ocean and the Caribbean Sea. Thecidellina has a worldwide subtropical to tropical distribution as it occurs in the Caribbean and the Pacific Ocean, as well as the Indian Ocean. It is commonly a shallow water form. Its deepest known occurrence is that reported herein. The brachiopod fauna of the southern Indian Ocean proves to be a blend of genera from around Japan, the Phillippines, New Zealand, Australia, the Mediterranean, eastern Atlantic, Caribbean Sea, and southeast Africa. Species Collected Aerothyris kerguelenensis (Davidson) A. aff. A. macquariensis (Thomson) Aerothyris species Basiliola arnaudi, new species Basiliola species Crania species Dallithyris? dubia, new species Dyscolia? radiata, new species Ecnomiosa inexpectata, new species Eucalathis costellata , new species E. magna, new species E. rotundata , new species Eucalathis species Liothyrella moseleyi (Davidson) Liothyrella species Megerlia gigantea (Deshayes) Megerlina davidsom (Velain) Pelagodiscus atlanticus (King) Pemphixina pyxidata (Davidson) 6 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Plahdia manonensis , new species Tegulorhynchia species Thecidellina minuta, new species Xenobrochus anomalus, new species X. australis, new species Brachiopods and Station Records, Cruise MD.03 Abbreviations of sampling gear used: BB = Okean grab DC = Charcot dredge CB = Blake trawl DM = small Charcot dredge CL = lithodid trap RK = Reineck corer CP = Beam trawl Station, location, specimens collected (illus¬ trated in parentheses): 2, DC 1 Latitude 49°30.7' S, longitude 70°44.7' E, east of Kerguelen Island at 115 meters Aerothyns kerguelenensis (Davidson), 6 2, CB 2 Latitude 49°33.2' S, longitude 70°47.1' E, east of Kerguelen Island at 130 meters Aerothyns kerguelenensis (Davidson), 5 (1) 8, DC 6 Latitude 52°59.4' S, longitude 73°38.0' E, north of Heard Island at 900 meters Pemphixina pyxidata (Davidson), young, 1 9, DM 2 Atlas Cove, Heard Island at 6 meters Aerothyris kerguelenensis (Davidson), 2(1) 9, DM 4 Atlas Cove, Heard Island at 15 meters Aerothyris kerguelenensis (Davidson), 1 (1) 10, DC 7 Latitude 53°06.7' S, longitude 72°50.1' E, south-southeast of MacDonald Island at 255 meters Unidentifiable fragments, 3 Aerothyris kerguelenensis (Davidson), 4 11, CP 7 Latitude 53°20.3' S, longitude 72°29.2' E, west of Heard Island at 790 meters Xenobrochus australis, new species, 2(1) Eucalathis magna, new species, 1 (1) Aerothyns? uncertain, 4 14, DC 8 Latitude 49°48.4' S, longitude 64°57.9' E, west of Kerguelen Island at 250 meters Pemphixina pyxidata (Davidson), 6 Aerothyris kerguelenensis (Davidson), 79 (1) 14, CB 3 Latitude 49°45.8' S, longitude 64°50.6' E, west of Kerguelen Island at 262 meters Pemphixina pyxidata (Davidson), 4 Aerothyris kerguelenensis (Davidson), 68 (3) 17, CB 5 Latitude 47°24.9' S, longitude 66°04' E, northwest off Kerguelen Island at 585 meters Pemphyxina pyxidata (Davidson), 1 Aerothyris kerguelenensis (Davidson), young, 22 22, CP 15 Latitude 48°58.5' S, longitude 70°51.1' E, northeast off Kerguelen Island at 105-90 me¬ ters Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 8(1) 23, CP 16 Latitude 49°59.2' S, longitude 70°01.9' E, south off Kerguelen Island at 158 meters Aerothyris kerguelenensis (Davidson), 8 24, CB 6 Latitude 50° 10.7' S, longitude 69°48.7' E, south off Kerguelen Island at 195 meters Pemphixina pyxidata (Davidson), 2 Aerothyris kerguelenensis (Davidson), 6 25, CB 7 Latitude 50°01.7' S, longitude 68°27.3' E, southwest of Kerguelen Island at 172 meters Pemphixina pyxidata (Davidson), 52 (11) Aerothyris kerguelenensis (Davidson), 3 26, CP 17 Latitude 46°24.0' S, longitude 51°59.0' E, Chenal des Orques at 180 meters Platidia manonensis, new species, 1 (1) Aerothyris kerguelenensis (Davidson), 82 (5) 28, CP 19 Latitude 46°18.1' S, longitude 51°29.0' E, between Possession Island and Cochons Island at 400 meters Platidia marionensis, new species, 2 30, CP 21 Latitude 46°02.3' S, longitude 50°50.2' E, Crozet Islands between Possession and Co¬ chons Island at 187 meters Aerothyris kerguelenensis (Davidson), 105 (9) 31, CP 22 Latitude 45°57.2' S, longitude 50°32.8' E, off Cochons Island at 110 meters Liothyrella moseleyi (Davidson), 5 (1) Aerothyris kerguelenensis (Davidson), 25 Marion III, Station Z63. Marion Island, Transvaal Cove from under surface of stone at 100 cm depth below low water spring level, in a sheltered pool connected to the sea by a subterranean tunnel, A. J. de Villiers collector Aerothyris kerguelenensis (Davidson), 1 Brachiopods and Station Records, Cruise MD.08 6, DC 32 Latitude 33° 11.8' S, longitude 43°49.8' E, Walters Bank, south of Madagascar (Mala¬ gasy Republic) at 40-43 meters; calcareous algae Crania species, 1 (1) 6, DC 34 Latitude 33° 11.8' S, longitude 43°49.2 E, Walters Bank, south of Madagascar at 105-86 meters Megertia gigantea (Deshayes), 2 6, DC 35 Latitude 33°09.7' S, longitude 43°49.3' E, Walters Bank, south of Madagascar at 220- 185 meters; coarse sand Eucalathis rotundata, new species, 54 (3) Megerha gigantea (Deshayes), 612 (19) NUMBER 43 7 6, CP 36 6, DC 43 6, CC 45 6, DC 46 6, DC 47 7, DC 57 9, CP 64 9, CP 65 9, CP 66 9, DC 68 9, BB 69 9, CP 74 Latitude 33° 10.7' S, longitude 43°49.3' E, Walters Bank, south of Madagascar at 120-80 meters; calcareous algae Thecidellina minuta, new species, 21 Latitude 33° 12.0' S, longitude 43°58.2' E, Walters Bank, south of Madagascar at 360- 200 meters; coarse sand, some limy concretions Eucalalhis rotundata, new species, 9 Eucalalhis species, 1 (1) Megerlia gigantea (Deshayes), 120 (3) Thecidellina minuta, new species, 2 Latitude 33°09.5' S, longitude 43°57.2' E, Walters Bank, south of Madagascar at 260- 310 meters Megerlia gigantea (Deshayes), 1 Latitude 33°08.7' S, longitude 43°59.7' E, Walters Bank, south of Madagascar at 600 meters; fine sand Eucalalhis costellata , new species, 16 Megerlia gigantea (Deshayes), 2 Latitude 33° 11.4' S, longitude 44°00.4' E, Walters Bank, south of Madagascar at 620- 635 meters; scleractinians and dead molluscs Eucalalhis costellata, new species, 1 (1) Dyscolia? radiata, new species, 6(1) Latitude 36°48.9' S, longitude 52°07.7' E, Samper Bank, southeast of Madagascar at 380 meters Basiliola arnaudi, new species, 6 (6) Basiliola species, 1 (1) Eucalathis costellata, new species, 108 (4) Dallithyris? dubia, new species, 58 (5) Megerlia gigantea (Deshayes), 1 Thecidellina minuta, new species, 77 (11) Latitude 46° 10.8' S, longitude 51°49.6' E to 46°23.2' S, 51°53.0' E, American Bay, Posses¬ sion Island, Crozet Islands at 120-150 meters Aerothyns kerguelenensis (Davidson), 32 (3) Latitude 46°22.2' S, longitude 51°51.7' E to 46°23.2' S, 51°53.0' E, American Bay, Posses¬ sion Island at 112 meters Aerothyris kerguelenensis (Davidson), 3 Latitude 46°23.1' S, longitude 51°52.8' E to 46°22' S, 51°51.1' E, American Bay, Posses¬ sion Island at 90-110 meters Aerothyris kerguelenensis (Davidson), 6 Latitude 46°22.9' S, longitude 51°51.2' E, American Bay, Possession Island at 125 me¬ ters; fine sand Aerothyris kerguelenensis (Davidson), 49 (2) Latitude 46°22.5' S, longitude 51°51.3' E, American Bay, Possession Island at 105 meters Aerothyris kerguelenensis (Davidson), 6 Latitude 46°22.4' S, longitude 51°54.3' E to 46°20.3' S, 51°52.2' E, at 150-160 meters, 9, CP 75 12, DC 78 12, BB 79 13, CP 85 15, DC 87 15, BB 88 16, CL 95 1.7, DC 96 17, BB 97 18, DC 107 18, BB 108 18, RK 109 American Bay, Possession Island; sand and gravel Aerothyris kerguelenensis (Davidson), young, many Latitude 46° 19.8' S, longitude 51°52.3' E to 46°20.9' S, 51°54.7' E, American Bay, Posses¬ sion Island at 150-340 meters Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 34 Latitude 46°55.7' S, longitude 37°51.1' E, east of Marion Island at 103 meters; muddy sand Aerothyris kerguelenensis (Davidson), 45 (9) Latitude 46°55.7' S, longitude 37°54.1' E, off Marion Island at 95 meters; muddy sand Aerothyris kerguelenensis (Davidson) young, 21 Latitude 46°56.3' S, longitude 37°55.6' E to 46°57.2' S, 37°57.6' E, east of Marion Island at 120 meters Aerothyris kerguelenensis (Davidson), 11 (2) Latitude 46°57.7' S, longitude 38°00.0' E, southeast of Marion Island at 185-210 meters; coarse sand Platidia marionensis, new species (attached), 1 ( 1 ) Aerothyris kerguelenensis (Davidson), 39 (3) Latitude 46°57.7' S, longitude 37°59.9' E, southeast of Marion Island at 204 meters; coarse sand Xenobrochus anomalus, new species, 8 (6) Platidia marionensis, new species, 140 (6) Aerothyris kerguelenensis (Davidson), 30 Latitude 46°50.2' S, longitude 37°59.1' E, northeast of Marion Island at 138-142 meters Aerothyris kerguelenensis (Davidson), 1 (1) Latitude 46°52.1' S, longitude 37°53.8' E, northeast of Marion Island at 112 meters; muddy sand Aerothyris kerguelenensis (Davidson), 7 Latitude 46°52.5' S, longitude 37°53.5' E, northeast of Marion Island at 110 meters; muddy sand Aerothyris aff. A. kerguelenensis (Davidson), 120 ( 2 ) Latitude 46°49.8' S, longitude 37°56.2' E, northeast of Marion Island at 140 meters; sandy mud with bryozoans. Aerothyris kerguelenensis (Davidson), 22 (3) Latitude 46°49.8' S, longitude 37°56.4' E, northeast of Marion Island at 138 meters; sandy mud Platidia marionensis, new species, 2 Aerothyris kerguelenensis (Davidson), 11 Latitude 46°49.3' S, longitude 37°56.5' E, northeast of Marion Island at 138 meters; sandy mud 8 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 19, DC 110 19, BB 111 20, CP 116 21, DC 118 22, BB 125 23, DC 129 25, CP 134 26, CP 135 27, DC 136 28, DC 143 28, DC 148 Aerothyris kerguelenensis (Davidson), 5 Latitude 46°45.9' S, longitude 38°03.7' E, northeast of Marion Island at 190 meters; mud Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 6 (1) Latitude 46°46.2' S, longitude 38°03.2' E, northeast of Marion Island at 190 meters; mud Platidia marionensis, new species, 6(1) Aerothyris kerguelenensis (Davidson), 9 (1 at¬ tached Platidia) Latitude 46°47.2' S, longitude 38°03.5' E, to 46°48.0' S, 38°03.5' E, northeast of Marion Island at 180 meters Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 14 (1) Latitude 46°53.3' S, longitude 37°52.8' E, northeast of Marion Island at 50 meters Aerothyris kerguelenensis (Davidson), 4 Latitude 46°52.4' S, longitude 37°51.9' E, northeast of Marion Island at 31 meters; sand Aerothyris aff. A. macquariensis (Thomson), 112 ( 12 ) Latitude 46°57.9' S, longitude 38°01.3' E, southeast of Marion Island at 250-460 meters; sand and pebbles Xenobrochus anomalus, new species, 1 Platidia marionensis, new species, 5 Latitude 46°45.3' S, longitude 37°56.6' E to 46°43. 1' S, 37°56.0' E, north of Marion Island at 185-232 meters Platidia marionensis, new species, 13 (3 at¬ tached) Aerothyris kerguelenensis (Davidson), 54 (1) Latitude 46°50.6 / S, longitude 38°00.6' E to 46°49.8' S, 37°57.7' E, northeast of Marion Island at 135-145 meters Aerothyris kerguelenensis (Davidson), 41 Latitude 46°45.7' S, longitude 37°54.0' E, north of Marion Island at 185 meters; sandy mud with shells Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 29 (4) Latitude 46°43.5' S, longitude 37°57.2' E, south of Prince Edward Island at 246-285 meters; sand and gravel Platidia marionensis, new species, 11 (1) Aerothyris kerguelenensis (Davidson), 10 Latitude 46°42.6' S, longitude 37°58.4' E, south of Prince Edward Island at 257-280 meters; sand and gravel Xenobrochus anomalus, new species, 1 Platidia marionensis, new species (7 attached), 42(1) Aerothyris kerguelenensis (Davidson), 26 31, DC 156 32, DC 162 33, DC 164 34, DC 167 34, BB 168 36, CP 173 36, CP 175 39, DC 178 39, BB 183 40, DC 185 40, DC 186 42, CP 197 44, CP 199 Latitude 46°59.5' S, longitude 37°46.6' E, south of Marion Island at 185 meters; black sand and gravel Aerothyris kerguelenensis (Davidson), 13 Latitude 46°59.0' S, longitude 37°46.8' E, south of Marion Island at 83-100 meters; sand, gravel, and blocks Aerothyris kerguelenensis (Davidson), 11 Latitude 46°52.2' S, longitude 37°51.5' E, between Prince Edward and Marion islands at 45 meters Aerothyris kerguelenensis (Davidson) 1 Latitude 46°50.2' S, longitude 37°51.2' E, between Prince Edward and Marion islands at 115 meters; compact mud Aerothyris kerguelenensis (Davidson), 6 (2) Aerothyris species, 1 Latitude 46°50.2' S, longitude 37°51.2' E, between Prince Edward and Marion islands at 110 meters Aerothyris kerguelenensis (Davidson), 17 Latitude 46°40.7' S, longitude 38°06.7' E to 46°39.2' S, 38°04.0' E, east of Prince Edward Island at 570-315 meters Platidia marionensis, new species, 18 Aerothyris kerguelenensis (Davidson), 4 Latitude 46°40.9' S, longitude 38°07.2' E, east of Prince Edward Island at 570-375 meters; gravel Platidia marionensis, new species, 4 (1) Aerothyris kerguelenensis (Davidson), 1 (1) Latitude 46°20.5' S, longitude 51°32.5' E, east-west radial, Crozet at 330-600 meters; gravel Aerothyris kerguelenensis (Davidson), 3 Latitude 46° 18.7' S, longitude 51 °29.5' E, east west radial, Crozet at 375 meters; black mud Aerothyris kerguelenensis (Davidson), 3 Latitude 46°21.1' S, longitude 51°33.9' E, east-west radial Crozet at 171 meters Aerothyris kerguelenensis (Davidson), 6 Latitude 46°21.1' S, longitude 51°33.9' E, east-west radial Crozet at 190 meters; muddy sand Liothyrella ? species juvenile, 2(1) Aerothyris kerguelenensis (Davidson) (26 young in slides (14)), 12 Latitude 46°21.4' S, longitude 51°34.9' E, east-west radial between Possession and Co¬ chons islands at 172-220 meters Aerothyris kerguelenensis (Davidson) (8 mea¬ sured), 26 (2) Latitude 46° 18.0' S, longitude 51° 14.0' E to 46° 16.0' S, 51° 13.0' E, east-west radial Crozet, between Possession and Cochons islands at 1500 meters; greenish mud NUMBER 43 9 45, CP 203 46, CP 204 48, CP 209 50, DC 216 50, RK 217 50, BB 218 51, DC 221 52, DC 224 54, DC 234 55, CP 237 59, DC 252 59, BB 253 Pelagodiscus atlanticus (King), 1 (1) Platidia marionensis, new species, 3 (men¬ tioned) Aerothyris species, 1 (1) Ecnomiosa inexpectata , new species, 13 (11) Latitude 46° 12.2' S, longitude 50°47.0' E to 46° 10.8' S, 50°43.5' E, east-west radial, Crozet between Possession and Cochons islands at 535-400 meters Aerothyris kerguelenensis (Davidson), 2 (1) Latitude 46° 10.6' S, longitude 50° 14.7' E to 46° 12.0' S, 50°46.6' E, between Possession and Cochons islands at 375-490 meters Aerothyris kerguelenensis (Davidson), 29 (3) Latitude 46°05.0' S, longitude 50°37.1' E to 46°01.1' S, 50°33.0' E, between Possession and Cochons islands at 200-140 meters Aerothyris kerguelenensis (Davidson), 27 Latitude 45°51.5' S, longitude 50°37.8' E north-south radial, northeast of Cochons Is¬ land at 150 meters; black mud and gravel Aerothyris kerguelenensis (Davidson), 53 (5) Latitude 45°51.9' S, longitude 50°35.2' E, north-south radial at 150 meters; black mud and gravel Aerothyris kerguelenensis (Davidson), 49 Latitude 45°52.2' S, longitude 50°35.2' E, north-south radial at 145-143 meters; black sand and gravel Aerothyris kerguelenensis (Davidson), young, 6 Latitude 46°05.0' S, longitude 50° 18.4' E, east-west radial between Possession and Co¬ chons islands at 25 meters; black volcanic sand Aerothyris kerguelenensis (Davidson), 6 Latitude 46°06.4' S, longitude 50° 19.7' E, east-west radial between Possession and Co¬ chons islands at 53-50 meters; black volcanic sand Aerothyris kerguelenensis (Davidson), 1 Latitude 45°55.4' S, longitude 50°20.8' E, northeast of Isles des Apotres at 145-130 me¬ ters; fine sand Aerothyris kerguelenensis (Davidson), 5 Latitude 45°57.1' S, longitude 50°21.6' E to 45°57.1' S, 50°22.3' E, northwest of Isles des Apotres at 150 meters Aerothyris kerguelenensis (Davidson), 6 Latitude 45°59.9' S, longitude 49°59.3' E, east-west radial west of Cochons Island at 210-217 meters; black sandy mud Aerothyris kerguelenensis (Davidson), 17 Latitude 45°59.8' S, longitude 49°58.3' E, east-west radial west of Cochons Island at 215 meters; black sand mud Platidia marionensis, new species, 1 (attached) Aerothyris kerguelenensis (Davidson), 1 60, DC 248 60, RK 251 61, DC 255 62, CP 257 64, DC 268 67, DC 271 67, BB 273 68, CP 275 70, DC 280 70, RK 282 71, DC 283 71, BB 285 -286 72, DC 289 72, BB 291 Latitude 46°02.7' S, longitude 49°48.2' E, east-west radial west of Cochons Island at 245-250 meters; black compact mud Aerothyris kerguelenensis (Davidson), 10 Latitude 46°03.5' S, longitude 49°47.6' E, east-west radial west of Cochons Island at 271 meters; gluey mud Aerothyris kerguelenensis (Davidson), 2 Latitude 46°05.7' S, longitude 50°08.9' E, east-west radial west of Cochons Island at 67 meters; sand and gravel Aerothyris cf. A. kerguelenensis (Davidson), 4 Latitude 46°05.7' S, longitude 50°01.9' E to 46°05.6' S, 49°57.0' E, east-west radial west of Cochons Island at 210 meters Aerothyris kerguelenensis (Davidson), 15 Latitude 46°02.0' S, longitude 49°08.5' E, east-west radial west of Cochons Island at 930-900 meters; mud Aerothyris kerguelenensis (Davidson), 13 Latitude 46° 16.8' S, longitude 49°37.4' E, south of Cochons Island at 277-280 meters; fluid mud and basalt gravel Platidia marionensis, new species, 16 (1) Aerothyris kerguelenensis (Davidson), 13 Latitude 46° 17.0' S, longitude 49°37.0' E, south of Cochons Island at 275 meters; mud Platidia marionensis, new species, 29 Aerothyris kerguelenensis (Davidson), 6 Latitude 46° 16.6' S, longitude 49°37.0' E, southwest of Cochons Island at 270-262 me¬ ters Platidia marionensis, new species, 10 (2) Latitude 46°46.6' S, longitude 50°28.4' E, north-south radial, southeast of Cochons Is¬ land at 1350-1440 meters Platidia marionensis, new species (crushed), 1 Latitude 46°44.9' S, longitude 50°29.0' E, north south radial at 1025-1022 meters; mud Liothyrella? species, 37 Latitude 46°37.5' S, longitude 50°39.0' E, north-south radial southeast of Cochons Is¬ land at 268-270 meters; muddy sand and gravel Platidia marionensis, new species, 4 Aerothyris kerguelenensis (Davidson), 2 Latitude 46°37.5' S, longitude 50°39.0' E, north-south radial at 270 meters Platidia marionensis, new species (crushed), 5 Aerothyris kerguelenensis (Davidson) young, 1 Latitude 46°23.4' S, longitude 50°32.0' E, east of lie des Pingouins at 187-155 meters Aerothyris kerguelenensis (Davidson), 3 Latitude 46°24.5' S, longitude 50°32.0' E, east of lie des Pingouins at 187-196 meters Aerothyris kerguelenensis (Davidson), 1 10 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 72, RK 293 Latitude 46°24.8' S, longitude 50°33.0' E, east of lie des Pingouins at 187 meters; sand Aerothyris kerguelenensis (Davidson), 3 73, CP 295 Latitude 46°24.3' S, longitude 50°37.8' E to 46°24.4' S, 50°42.0' E, east of lie des Pin¬ gouins at 263-412 meters Dyscolia? radiata, new species, 1 Platidia marionensis, new species, 37 Aerothyris kerguelenensis (Davidson), 8(1) 74, DC 296 Latitude 46° 17.8' S, longitude 50°47.8' E, east of He des Pingouins at 290 meters; fine sand Liothyrella? species juvenile (mentioned), 1 Platidia marionensis , new species, 1 Aerothyris kerguelenensis (Davidson), 46 (2) 74, BB 297 Latitude 46° 18.3' S, longitude 50°48.0' E, east of He des Pingouins at 210 meters; muddy sand Aerothyris kerguelenensis (Davidson), young, 10 75, CP 303 Latitude 46° 19.9' S, longitude 51°52.9' E to 46°21.1' S, 51°55.0' E, American Bay, Posses¬ sion Island at 155-257 meters Aerothyris kerguelenensis (Davidson), 28 75, CP 304 Latitude 46°21.8' S, longitude 51°52.1' E to 46°22.5' S, 51°52.4' E, American Bay, Posses¬ sion Island at 130 meters Aerothyris kerguelenensis (Davidson), 5 75, CP 305 Latitude 46°21.0' S, longitude 51°50.7' E to 46°22.5' S, 51°52.4' E, American Bay, Posses¬ sion Island at 120 meters Aerothyris kerguelenensis (Davidson), 8 75, CL 306 Latitude 46°20.9' S, longitude 51°53.2' E, American Bay, Possession Island at 145 meters Aerothyris kerguelenensis (Davidson), 1 75, CL 308 Latitude 46°20.6' S, longitude 51°52.5' E, American Bay, Possession Island at 150 meters Aerothyris kerguelenensis (Davidson), 3 76, DC 309 Latitude 46°26.0' S, longitude 52°03.6 / E, east-west radial Possession Island to He de L’Est at 50 meters; coarse sand Aerothyris kerguelenensis (Davidson), 4 77, DC 314 Latitude 46°25.O'S, longitude 51°59.7'E east- west radial Possession Island to He de L’Est at 270-247 meters; coarse sand and gravel Platidia marionensis, new species, 1 Aerothyris kerguelenensis (Davidson), 42 (1) 77, BB 3-15 Latitude 46°24.5' S, longitude 51°59.8' E, east-west radial from Possession Island to the east at 250 meters; coarse sand and gravel Aerothyris kerguelenensis (Davidson), young, 12 78, CP 319 Latitude 46°23.7' S, longitude 51°58.1' E to 46°24.5' S, 51°55.7' E, east-west radial Posses¬ sion Island to He de L’Est at 142-170 meters. Aerothyris kerguelenensis (Davidson), 30 79, DC 322 Latitude 46°24.2' S, longitude 5T53.9' E, east-west radial Possession Island to He de L’Est at 105-95 meters; coarse sand Aerothyris kerguelenensis (Davidson), 10 79, BB 323 Latitude 46°24.6' S, longitude 51°53.8' E, east-west radial from Possession Island to the east at 100 meters Aerothyris kerguelenensis (Davidson), young, 4 79, CP 326 Latitude 46°21.0 / S, longitude 51°52.0' E to 46°23.1' S, 51°55.0' E, American Bay, Posses¬ sion Island at 145-135 meters (Station recorded on register as 75, CP 326) Aerothyris kerguelenensis (Davidson), 38 Brachiopods from St. Paul and Amsterdam Islands St. Paul Island (about latitude 38°43' S, longitude 77°32' E) St. Paul 7b Northeastern part of crater, under infralit¬ toral boulders with ascidians, sponges, and calcareous articulate algae Megerlina davidsoni (Velain), 22 (1) St. Paul 22a Northeastern part of crater, scraping in in¬ fralittoral zone, with octocoralla, tubiculous polychaetes, and encrusting bryozoa Megerlina davidsoni (Velain), 57 (15) St. Paul 35 Northeastern part of crater, 3 meters, on a sandy bottom, with sponges, compound as¬ cidians, and calcareous algae Megerlina davidsoni (Velain), 8, (1) St. Paul 90 Southern part of crater, scraping under part of infralittoral rocks Megerlina davidsoni (Velain), 59 (1) St. Paul 91 Southern part of crater with numerous green and calcareous algae; scraping in the infra¬ littoral zone Megerlina davidsoni (Velain), 46 St. Paul 98 Seamount at southeast coast of St. Paul, at 120 meters, lifted up with boulders by a lobster pot Tegulorhynchia species, 1 (1) Amsterdam Island (about latitude 37°50' S, longitude 77°30' E) Ams-D8 East coast Amsterdam Island, north to Pointe Novara, about 30 meters; J. Beurois collector Megerlina davidsoni (Velain), 1 Maria Martina (name of a lobster ship) About 200 meters off Amsterdam Island, no precise locality, bottom of gorgonians Pemphixina pixidata (Davidson), 1 (1) Systematics (hierarchy from class through family) Class Inarticulata Huxley, 1869 Order Acrotretida Kuhn, 1949 NUMBER 43 11 Suborder Acrotretidina Kuhn, 1949 Superfamily Discinacea Gray, 1840 Family Discinidae Gray, 1840 Order Uncertain Suborder Craniidina Waagen, 1883 Superfamily Craniacea Menke, 1828 Family Craniidae Menke, 1828 Class Articulata Huxley, 1869 Order Rhynchonellida Kuhn, 1949 Superfamily Rhynchonellacea Gray, 1848 Family Hemithyrididae Rzhonsnitzkaya, 1956 Family Basiliolidae Cooper, 1959 Order Terebratulida Waagen, 1883 Suborder Terebratulidina Waagen, 1883 Superfamily Cancellothyridacea Thomson, 1926 Family Chlidonophoridae Muir-Wood, 1959 Superfamily Terebratulacea Gray, 1840 Family Terebratulidae Gray, 1840 Family Dyscoliidae Fischer and Oehlert, 1891 Suborder Terebratellida Muir-Wood, 1955 Superfamily Terebratellacea King, 1850 Family Platidiidae Thomson, 1927 Family Kraussinidae Dali, 1870 Family Terebratellidae King, 1850 Superfamily Dallinacea Beecher, 1893 Family Ecnomiosidae Cooper, 1977 Order Thecideida Pajaud, 1970 Suborder Thecideidina Elliott, 1958 Superfamily Thecideacea Gray, 1840 Family Thecidellinidae Elliott, 1958 Superfamily Discinacea Gray, 1840 Family Discinidae Gray, 1840 Subfamily Discininae Gray, 1840 Genus Pelagodiscus Dali, 1908 Pelagodiscus atlanticus (King) Plate 3: figures 15, 16 Discina atlantica King, 1868:170:—Jeffreys, 1876:252.- Davidson, 1880:62, pi. 4: figs. 17, 18. PDiscinisca atlantica (King).—Dali, 1873:261.—Davidson, 1888:200, pi. 26: figs. 18-22. Pelagodiscus atlanticus (King).—Dali, 1908:440.—Thomson, 1918:38, 40.—Dali, 1920:280.—Thomson, 1927:130.— Helmcke, 1940:230.—Hertlein and Grant, 1944:21.—Ze- zina, 1965:345-358; 1970:5.—Cooper, 1972:15, pi. 4: figs. 53-56; 1973a: 10, pi. 5: fig. 36.—Foster, 1974:38. Description.— Small, round, about 4 mm in diameter, conical with apex of cone posterior to center; height of cone about 1.5 mm. Dorsal valve conical, ventral valve concave with large pedicle. Surface of dorsal valve apically smooth, periph¬ erally with fine concentric wrinkles; ventral valve smooth; margin of both valves surrounded by fringe of setae, those of dorsal valve very long, those of ventral valve short, all setae minutely barbed. Station. —MD.08: 44, CP 199. Types. —Hypotype NMHN-BRA-78-24. Discussion. —Pelagodiscus atlanticus is worldwide in its distribution as it occurs in the great deeps of all the oceans except the Arctic Ocean. Zezina (1970:5) reports it from 6160 meters in depth. Zezina (1976:68) indicates numerous localities in the Indian Ocean, most of them north of the 30th parallel. Superfamily Craniacea Menke, 1928 Family Craniidae Menke, 1828 Genus Crania Retzius, 1781 Crania species Plate 13: figures 2-4 Description.— Small, nearly circular, de¬ pressed, conical in profile, with low apex, about 1/3 valve length anterior to posterior margin; posterior slope nearly flat, gently sloping; anterior slope gently concave. Surface with smooth apex, remainder covered by short, rounded pustules. Ventral valve attached to a fragment of calcar¬ eous alga on concave surface making for a fairly deep interior; marginal rim strongly thickened, strongly and deeply pitted; posterior margin ex¬ cavated; posterior adductor scars small, deeply inserted; anterior adductor scars small, separated by a conical thickening; entire surface pierced by large punctae. Dorsal valve interior with concave marginal rim; posterior adductors small; anterior adductors small, close together on anterior side of a trian¬ gular pit bounded by a median thickening. Mid¬ valve marked by short elevation separating two 12 lateral bilobed depressions. Surface coarsely punctate. Measurements (mm).— Length 3.2, width 3.5, height ca. 1.6. Station. —MD.08: 6, DC 32. Type.— Hypotype MNHN-BRA-78-114. Discussion. —This is a well-preserved specimen with ventral valve attached to coralline material. Its small size suggests a juvenile except that the interior is well thickened. Helmcke (1940:234) described a species of similar size, Crania valdiviae , from 4.3 nautical miles (6.9 km) east of St. Paul Island at 672 meters. His species has small pus¬ tules but the interiors do not have the marginal elevated rim and depression of the Walters Bank specimen. The interior of the dorsal valve of C. valdiviae according to Helmcke’s figures is not significantly thickened. Superfamily Rhynchonellacea Gray, 1848 Discovery of genera and species of rhynchonel- lids new to the Indian Ocean brings the total to six genera and eight species. Species of Cryptopora Jeffreys, small translucent forms, are usually found in deep water. One species occurs off the Maidive Islands and two off the east coast of Africa (Cooper, 1973a). Striarina Cooper is a finely costellate genus found off Amsterdam Island. Two genera and species described below, Tegulo- rhynchia Chapman and Crespin and Pemphixina , new genus, occur in the vicinity of Amsterdam Island. Another species of Pemphixina occurs off Kerguelen Island. Basiliola is described from the Indian Ocean for the first time. It is represented by two species, one described herein, the other, a single valve, is not named. Rhytirhynchia is a rare genus related to Basiliola , represented by one species. Rhynchonellids are rare in modern seas com¬ pared to the greater abundance of the punctate Terebratulida. Of the 15 living genera of rhyn¬ chonellids, 12 occur in the Pacific and six in the Indian Ocean, three of them restricted to the Indian Ocean. Most rhynchonellids occur in wa¬ ter deeper than 200 meters. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Family Hemithyrididae Rzhonsnitzkaya, 1956 Genus Tegulorhynchia Chapman and Crespin, 1923 Tegulorhynchia species Plate 2: figures 1-7 Description.—A single small specimen refera¬ ble to this rare genus was taken at St. Pauls Island. The shell is very thin and unfortunately has been badly damaged in the posterior region of the ventral valve. The sides are well rounded and the maximum width is at midvalve. The valves are subequal in depth, the ventral valve slightly less deep than the dorsal one. The anterior commissure is broadly uniplicate. The beak is nearly straight, the foramen large and margined by disjunct deltidial plates. The surface is costel¬ late and at the intersection of costellae and growth lines a small hollow spine appears, the chief characteristic of the genus. Not much of the interior can be seen but strong dental plates were observed. Measurements (mm).—Length 11.5, dorsal valve length 8.7, width 12.5, thickness 6.3. Locality.— St. Paul station 98. Type.— Hypotype MNHN-BRA-78-16. Discussion. —This specimen was unfortunately damaged when it was dredged or in transit. The specimen is small and, when compared with ex¬ amples of Tegulorhynchia doederleini (Davidson), proves to have a somewhat finer ornament and less prominent anterior sulcus. It is also propor¬ tionately wider than T. doederleini. Tegulorhynchia is a rare genus in modern seas. It has been found off Japan, in the China Sea, off Borneo, and south of the Celebes. The St. Paul specimen was dredged at 120 meters but the other known occurrences are from depths of 120-400 meters for the Celebes specimen and 324-635 meters for the more northern occurrences. The specimen from off Borneo identified as Tegulorhynchia doederleini , figured by Jackson and Stiasny (1937, pi. 2: figs. 28-33), is more trans¬ verse and much more finely ornamented than specimens from Borneo and the China Sea in the NUMBER 43 13 National Museum of Natural History, Smithson¬ ian Institution. It is more like the St. Paul speci¬ men than like those to the north. Because of the uncertainty regarding many of the details of the species of this genus, I have been unable to link closely the St. Paul specimen to any of those described. The St. Paul form is suggestive of the fossil species T. squamosa (Hut¬ ton) from the Duntroonian of New Zealand. The two are of similar size but the St. Paul form is wider and has finer ornament. Tegulorhynchia is best known from Tertiary sediments of New Zea¬ land. Pemphixina, new genus Type Species.— Rhynchonella nigricans var. pyxi- data Davidson, 1880:59, pi. 4: fig. 14. Diagnosis. —Rotund, costellate, uniplicate Hemithyrididae with disjunct deltidial plates, narrowly elongate ventral muscle field, and mod¬ ified falcifer crura. Description.— Small to medium, globular in outline and profile. Ventral valve moderately convex, dorsal valve swollen. Sides rounded. Ap¬ ical angle 75°-100°. Anterior commissure of adult strongly uniplicate. Beak short, erect, fora¬ men hypothyridid, elongate oval, small. Deltidial plates disjunct. Surface multicostellate, costellae rounded; concentric growth lines numerous, fine. Growth lamellae numerous, anteriorly crowded in the adult. Ventral valve interior with thick teeth but¬ tressed by short dental plates; fossette deep. Ped¬ icle collar short, excavate. Muscle field well im¬ pressed, reaching midvalve or slightly beyond, subrectangular in outline. Diductor scars ante¬ rior, small; adductor scar large; ovarian impres¬ sion deep and narrow. Pallial trunks not im¬ pressed. Pedicle short, thin. Dorsal valve with thick, transverse diductor scars under beak, forming a narrow platform. Socket ridges thick, bounding wide corrugated sockets. Outer hinge plates narrow, often ob¬ scured by shell thickening. Crura short, crescentic in cross section, concave surfaces facing antero- medially. Median septum short, thin, buttressed laterally by shell thickening. Septum rising to a crest at its middle just anterior of the crura, then abruptly diminishing to a mere thread reaching to anterior margin of adductor field, which is large and reaches midvalve. Ovarian patches nar¬ row, crescentic in outline. Pallial trunks not im¬ pressed. Comparison.— This genus is so like Hemithins in appearance that it needs only to be compared to members of the Hemithyrididae, which in¬ cludes Hemithiris, Tegulorhynchia , Plicirhynchia , and Notosaria. Pemphixina differs from Hemithins in its curved beak, short crura, and stronger costellae. Pemphixina lacks the short spines characteristic of Tegulorhynchia and is not anteriorly costate with conjunct deltidial plates like Plicirhynchia. Pemphixina is most like Notosaria and was origi¬ nally identified as a subspecies of the common New Zealand Notosaria nigricans (Sowerby). Al¬ though some resemblances are obvious, so are some of the differences from Notosaria. In its shape Pemphixina has a globular form when adult (L/W = nearly 1 or slightly greater than 1, Figure 5), whereas adult Notosaria is usually transverse (L/ W=0.80-0.95, Figure 5). The growth of the two is different: some young Pemphixina may be trans¬ verse just as some Notosaria may approach equal¬ ity of length and width. Adult Pemphixina tend to form round shells with length slightly in excess of width and with maximum growth at the anterior to produce very thick individuals (T/W=0.84). The thickest specimen of Notosaria seen (USNM 549929) has T/W=0.63. The ventral muscle field of Pemphixina is rather more rectangular in outline than that of Notosaria , which is mostly rounded or somewhat heart- shaped. Inside the dorsal valve the median sep¬ tum of Pemphixina is stronger and higher than that of Notosaria. The crura of Pemphixina are similar to those of Notosaria but are broader, more concave, with a crescentic cross-section, and with the concave surfaces facing medially. These crura suggest those of the falcifer type but are shorter and with only a trace of outer hinge plates. Notosaria is commonly black; Pemphixina is ash gray. 14 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ★ 18 16 . ^ i2 : * 4/5 .. • • . LU 2 * 10 — • t- 8 6 • ’ ' I 4 2 6 0 10 12 14 16 18 20 22 24 WIDTH ★ 24 4 22 • • • • • 20 X 16 t- □ S 14 12 10 8 6 6 8 10 12 14 16 18 20 22 24 LENGTH Figure 5.—Scattergrams showing length, width, and thick¬ ness relationships of Pemphixina pyxidata (Davidson) from MD.03: station 25, CB 7, 42 specimens (star = position of large adult Notosana nigricans (Sowerby) for comparison with P. pyxidata). Etymology.— The generic epithet, Pemphixina , is derived from the Greek pemphix (“a bubble”), referring to the shape of the species within the genus. Pemphixina pyxidata (Davidson), new combination Figures 5, 26; Plate 1: figures 14-34; Plate 2: figures 8-13 Rhynchonella nigricans var. pyxidata Davidson, 1880:59, pi. 4: fig. 14; 1888:170, pi. 24: fig. 14. Tegulorhynchia pyxidata (Davidson).—Chapman and Crespin, 1923:188. Notosana pyxidata (Davidson).—Cooper, 1959:49.—Foster, 1974:50, pi. 2: figs. 15-18. Diagnosis. —Large, rounded, strongly costel- late Pemphixina. Description. —Of about medium size, thick- shelled, subtriangular to subcircular in outline in young, globular in mature and old specimens. Inequivalve, dorsal valve strongly convex, ventral valve gently convex and shallow. Length and width about equal; maximum width anterior to midvalve. Sides rounded, anterior margin gently rounded; posterolateral margin forming an angle of 75°-105° but usually near 90°. Beak pointed, short, incurved, erect, pierced by a small round hypothyridid foramen; deltidial plates disjunct in adult, lacking in young. Lateral commissure slightly oblique; anterior commissure strongly un- iplicate. Surface marked by fine, low, rounded costellae separated by spaces about equal to width of costellae. Costellae crossed by short con¬ centric lamellae that tend to crowd anteriorly. Color ashen gray. Ventral valve flatly convex in anterior and lateral profiles, maximum convexity in umbonal region, which is moderately swollen; median re¬ gion somewhat flattened; sulcus shallow, narrow, occupying slightly more than one-third to nearly half the shell width. Sulcus originating at mid¬ valve, shallow, gently concave, bounded by low ridges. Lateral slopes rounded. Dorsal valve strongly swollen in lateral profile, forming high dome in anterior profile. Umbonal and median regions swollen. Fold originating about midvalve, low, gently rounded, with short lateral slopes. Anterolateral extremities moder¬ ately swollen. Posterolateral slopes steep. Pedicle valve interior with long, thickened, an- NUMBER 43 15 teriorly excavated pedicle collar; teeth thick, stout, corrugated on their inner face, with deep fossettes; dental plates short, not strongly marked, usually with umbonal chambers well filled with shell tissue. Delthyrial cavity deep; muscle field occupying space anterior to delthyrial cavity, ex¬ tending to about midvalve or beyond; diductor scars narrowly flabellate, surrounding large ad¬ ductor scars. Genital areas lateral to muscle field, crescentic in outline. Dorsal valve interior with strongly accentuated cardinalia; no cardinal process, muscles attached to triangular patches on each side under beak and on hinge plates. Socket ridges thick and erect bounding wide, corrugated sockets. Crura welded to socket ridges, short, convex laterally, truncated distally. Adductor scars large, rounded separated by short septum tapering anteriorly and poste¬ riorly, terminating near midvalve and partly bur¬ ied in shell tissue posteriorly. Septum rising to pointed crest at its middle, its anterior slope concave, crest bearing two short points. Genital areas narrow, reniform. Measurements (mm).— Specimen Length Dorsal valve length MNHN-BRA-78-15a 6.4 6.0 MNHN-BRA-78-15k 12.0 10.3 MNHN-BRA-78-15b 14.3 13.0 MNHN-BRA-78-15c 15.5 13.7 MNHN-BRA-78-15d 18.2 16.6 MNHN-BRA-78-15f 20.0 17.8 MNHN-BRA-78-15h 22.6 20.0 MNHN-BRA-78-15i 19.6 17.8 Bathymetric Range.— 90-262 m. Stations.— MD.03: 8, DC 6; 14, DC 8; 14, CB 3; 24, CB 6; 25 CB 7. Marina Martina, 200 meters off Amsterdam Island, no definite locality. Types. —Hypotypes: MNHN-BRA-78-1 5a-k, -17. Discussion. —Attachment is by a short pedicle that expands slightly where it is attached but does not have fibers like the pedicle of Terebratu- lina. The specimens are attached to small pebbles and fragments of shell of their own species and Aerothyris kerguelenensis. Some of the pebbles are so small they must have acted as counter weights to keep the anterior end up and functional, but able to be moved by currents. Some of the specimens are liberally coated by bryozoans, sponges, and other encrusting forms. Some have bevel-sided borings. The species is variable, particularly in the re¬ lation of its thickness to other shell dimensions. The ratio of length to width is about 1.1 and the average of the specimens from station 25 is 0.99. This relationship is maintained from the very young to obese adults. As with many other rhyn- chonellid genera, old adults tend to grow more rapidly at the anterior margin, exaggerating the shell thickness. The result is a fair number of globular specimens. No deformity of specimens was noted. With growth, changes take place inside the shells. The dental plates that show clearly in the young, with marked umbonal cavities between them and the shell wall, tend to become obsoles¬ cent but are not completely obliterated by depo¬ sition of shell material in the umbonal cavities. Inside the young dorsal valve the septum is only Width Thick¬ ness Apical angle L/W 6.3 3.0 90° 1.02 12.0 6.5 kD o o 1.00 13.7 8.4 91° 1.04 16.9 9.6 99° 1.09 18.7 11.6 92° 0.97 20.1 15.6 90° 0.99 21.5 18.3 O CM 05 1.05 19.6 13.8 90° 1.00 slightly developed and is more a myophragm than a septum. With age, the septum may become a fairly strongly elevated wall tapering anteriorly and posteriorly. In old specimens that show the dorsal interior, the septum is again reduced, partly by burial and partly by resorption. In the largest and oldest specimens, the crest has been removed and the septum, with thickening on each side, has become a rounded ridge. The crura in the young are similar to those of the adult and obese individuals. The crura are short, crescent-shaped in section, and lie obliquely so that the concave surfaces face medially. There 16 is a trace of outer hinge plates making a narrow separation of the cura from the socket ridge. This species was originally described as a vari¬ ety (subspecies) of Rhynchonella (now Notosaria ) nigricans Sowerby from the waters around New Zealand. Although there is some resemblance of the one for the other, the Kerguelen forms are light colored, not black like Notosaria , and have an entirely different growth form, globular in the adult, with extreme thickness. Notosaria on the other hand tends to be more or less strongly transverse, and is only moderately thick shelled. The crura of Pemphixima tend to be hollow on the face toward midvalve and are crescentic in cross- section. Pemphixina is separated from Notosaria by approximately 90° of longitude (Figure 26). Family Basiliolidae Cooper, 1959 Genus Basiliola Dali, 1908 Basiliola arnaudi , new species Plate 3: figures 1-14 Diagnosis.— Small nearly round Basiliola. Description.— small, subcircular in outline with well rounded sides and truncated anterior margin; maximum width at midvalve; valves unequally convex, ventral valve gently convex, dorsal valve swollen. Lateral commissure slightly oblique; anterior commissure strongly and nar¬ rowly uniplicate to incipiently sulciplicate. Beak short, forming an apical angle of 90°-105°; for¬ amen small, oval, mesothyridid to submesothyri- did; deltidial plates conjunct and flared distally to form an anterior lip to foramen. Surface marked only by concentric lines of growth, some very fine, some strong. Ventral valve flatly convex in lateral profile, shallowly concave in anterior profile. Umbonal region somewhat narrowly swollen, median re¬ gion flattened; sulcus broad and shallow, origi¬ nating somewhat anterior of midvalve and form¬ ing a long flattened to gently concave tongue. Flanks slightly swollen; posterolateral slopes steep. Dorsal valve fairly evenly and strongly convex SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY in lateral profile, strongly domed in anterior view; umbonal and median regions swollen, forming a poorly defined fold best seen at the anterior com¬ missure; slopes very steep. Ventral valve interior with sessile pedicle col¬ lar; teeth small and corrugated, muscle region small, almost circular, located anterior of delthy- rial cavity and posterior of midvalve; dental plates short, receding and nearly obsolete by dep¬ osition of shell substance in umbonal chambers. Vascula media strong. Dorsal valve interior with low narrow socket ridges, bounding finely corrugated sockets; outer hinge plates fairly wide, slightly concave; crura short, falcifer. Adductor field located slightly pos¬ terior of midvalve, narrowly U-shaped. Vascula media well impressed. Measurements (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-23a 15.4 14.0 15.2 8.9 103° MNHN-BRA-78-23b 14.0 12.5 13.3 9.3 O o MNHN-BRA-78-23c 15.0 13.2 14.6 9.6 100° MNHN-BRA-78-23d 15.0 13.2 14.5 9.1 101° MNHN-BRA-78-23e 13.0 11.8 12.6 8.2 95° MNHN-BRA-78-23f 14.4 13.0 12.9 9.0 86° Station.— MD.08: 7, DC 57. Types.— Holotype: MNHN-BRA-78-23a; par- atypes MNHN-BRA-78-23b-f. Discussion.— Several species of Basiliola are known from Pacific waters around the Hawaiian Islands, Japanese Islands, and Philippine Islands. Basiliola arnaudi , the first of this genus to be found in the Indian Ocean, is much larger and rounder than the small and delicate B. lucida (Gould) from Japan and is much smaller than the larger B. pompholyx (Dali) from the Philippine Islands. It is also rounder and more swollen than B. elongata (Cooper) from the Philippines. Basiliola beechen Dali, type of the genus, is much larger and more elongate than B. arnaudi. Basiliola species de¬ scribed below represents another species. Rhytirhynchia sladem (Dali) is one of eight rhyn- chonellid species known from the Indian Ocean. It is like Basiliola in internal characters but ex¬ hibits anterior costation by having a strong costa NUMBER 43 17 in the sulcus of the ventral valve. One specimen of B. arnaudi (MNHN-BRA-78-23f) has an incip¬ ient costa in the ventral sulcus suggesting a tend¬ ency toward Rhytirhynchia but all of the other specimens in the collection show no such tend¬ ency. Rhytirhynchia sladem is a larger and stouter species than B. arnaudi and has much longer crura in the dorsal valve. Basiliola species Plate 13: figure 1 Description.— A single dorsal valve of another species of Basiliola was taken at MD.08: station 7, DC 57. Although a fragment, it is not strongly convex like that of B. arnaudi but is gently convex in both profiles. The fragment is also larger than any of the specimens of B. arnaudi. Figured Specimen.— MNHN-BRA-78-113. Superfamily Cancellothyridacea Thomson, 1926 Family Chlidonophoridae Muir-Wood, 1959 Subfamily Eucalathinae Fischer and Oehlert, 1890 All known species of Eucalathis , except E. magna, new species, described below, are small and usu¬ ally all ribbed and strongly resemble young Ter- ebratulina. Eucalathis is known from the eastern Atlantic, Caribbean, southern Pacific, Antarctic, and Indian oceans. It is often found in deep water. Genus Eucalathis Fischer and Oehlert, 1890 Eucalathis magna, new species Plate 1: figures 1-6 Diagnosis. —Large, elongate Eucalathis. Description.— Large for the genus, almond- shaped with rounded sides and narrowly rounded anterior margin. Posterolateral margins forming angle of 67°. Valves of unequal depth, ventral valve having greater depth. Lateral commissure strongly and subangularly uniplicate. Beak straight; foramen large, subtriangular. Interarea narrow. Deltidial plates lacking. Surface marked by crowded costellae of different size, intercalated in three generations; about 3 costellae of all sizes in one millimeter at anterior. Color white. Ventral valve gently convex in lateral profile with greater convexity in posterior half, anterior half flattened. Anterior profile very gently con¬ vex. Umbonal and beak regions swollen; anterior half broadly flattened with narrow, shallow, sul¬ cus extending from umbonal region to anterior margin. Posterolateral slopes rounded. Dorsal valve nearly flat in lateral profile but subcarinate in anterior view. Umbonal and me¬ dian regions somewhat narrowly swollen to pro¬ duce an ill-defined fold that plicates the anterior margin. Flanks flattened and sloping steeply to the lateral margins. Interior with long crural process and short, anteriorly pointed loop. Measurements (mm).— Length 11.1, dorsal valve length 9.7, width 8.7, thickness 4.9, apical angle 67°. Type.— Holotype: MNHN-BRA-78-12. Station.— MD.03: 11,CP7. Discussion.— This species strongly resembles various species of Terebratulina in its outline, pro¬ file, and ornament, but its loop is entirely unlike that of any known Terebratulina. Instead of having a loop in which the crural processes join with the transverse band to form a narrow ring as in Terebratulina , the loop of this Heard Island species is exactly like that of Eucalathis , which has the transverse band projecting anteriorly to form a rounded angle. Most species of Eucalathis are small, perhaps a third less long than E. magna. They are, however, somewhat similar in shape and some of them have fairly strongly beaded costellae like those of E. magna. There is no known Eucalathis like this one. Eucalathis macrorhynchus Foster from the Pacific-Antarctic Ridge, south¬ east Pacific is barely half the size of E. magna and has subdued costellae. Eucalathis murrayi (David¬ son), another species from the South Pacific, is also very small. 18 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Eucalathis costellata, new species Plate 5: figures 1-14 Diagnosis.— Eucalathis of medium size with slight ventral sulcus, strong posterior costellation, and anterior fasciculation. Description.— Small, but moderately large for genus, subtriangular in outline, maximum width anterior to midvalve; valves unequally deep, ven¬ tral valve deeper than dorsal valve. Posterolateral margins straight, forming apical angle of 70°. Lateral margins rounded; anterior margin gently rounded. Lateral commissure nearly straight; an¬ terior commissure rectimarginate to broadly un- iplicate. Beak short; foramen wide and subtrian¬ gular; deltidial plates obsolete. Surface multicos- tellate, costellae often beaded; with six or eight more prominent costellae. Ventral valve moderately convex in lateral pro¬ file, maximum convexity anterior to beak, flatten¬ ing anteriorly. Anterior profile, moderately domed. Five strong subangular costellae on umbo, expanding anteriorly, median two slightly depressed anteriorly to form shallow sulcus. Cos¬ tellae added by intercalation from near beak to anterior in 3 generations, intercalation variable, producing some anterior fasciculation. Dorsal valve moderately convex in lateral pro¬ file, most convex at swollen umbo, lessening in convexity anteriorly; anterior profile moderately domed but more so than that of ventral valve. Umbo smooth. Costellae numbering seven at umbo increasing anteriorly in width, with inter¬ calations appearing in 3 generations to anterior margin. Median fold poorly defined. Ventral valve interior with strong, excavated, short, pedicle collar. Teeth small. Dorsal valve interior with variable loop, from broad, smooth curve anteriorly (Plate 5: figure 13) to subangular at the anterior (Plate 5: figure 12). Loop wide, narrowed and slightly folded at the anterior in adult specimens. Measurements (mm).— Dorsal Specimen Length valve length Width Thick¬ ness Apical angle MNHN-78-30a 5.8 4.8 5.2 2.9 70° MNHN-78-64a 6.6 5.4 5.0 3.4 66° Stations.— MD.08: 6, DC 47; 6, DC 46; 7, DC 57. Types.— Holotype: MNHN-BRA-76-64a; paratypes MNHN-BRA-78-30a-d. Discussion.— The contrast in costellation of E. costellata and E. macrorhynchus Foster from the Antarctic distinguishes these two species. Eucalathis costellata has strong costellae while Foster’s species has only faint costellation. The specimen attributed to E. murrayi (Davidson) by Foster (1974, pi. 7: figs. 10-12) is strongly costellate but with a different pattern of costellae than that of E. costellata and the shell is wider than long. This specimen does not conform well to Davidson’s description of E. murrayi nor do the external features of E. costellata. The latter is longer than wide and much larger than E. murrayi. Unfortunately there is no good illustration of Davidson’s species. It is figured by Muir-Wood (1959, pi. 5: fig. 10) but details of the ribbing are uncertain. The species of Eucalathis occurring in the Atlantic are smaller and have different ribbing than that of E. costellata. Eucalathis rotundata, new species Plate 13: figures 5-15 Diagnosis. —Nearly circular, strongly costate Eucalathis. Description.— Small, rounded in outline, with length and width nearly equal; hinge wide, slightly narrower than midwidth, which is widest part; sides rounded; anterior margin broadly rounded; posterolateral margins forming an api¬ cal angle of about 90°. Beak erect; foramen large; deltidial plates obliquely elevated. Surface costae crossed by strong concentric elevated growth lines. Ventral valve gently convex in lateral profile, moderately rounded in anterior view. Beak marked centrally by two strong costae, slightly elevated, flanked by three lateral costae of lesser strength than median two; Median costae form¬ ing poorly defined fold. Flanks gently convex. Dorsal valve nearly circular with fairly strongly convex lateral profile, anterior view more strongly NUMBER 43 19 convex than ventral valve in same view; umbo smooth; six strong costae mark body of shell, flanks with three of lesser strength. Median one slightly depressed. Ventral valve with strong, short, excavated pedicle collar; teeth large. Dorsal valve with vari¬ able loop angulated to broad medially; cardinal process small. Measurements (mm).— Dorsal valve Specimen Length length MNHN-BRA-78-115a 3.5 2.8 MNHN-BRA-78-115b 3.1 2.5 Stations.— MD.08: 6, DC 35; 6, DC 43. Types. — Holotype: MNHN-BRA-78-115a; paratypes: MNHN-BRA-78-115b,c. Comparison. —This species differs from E. costellata, new species, in its much rounder outline and stronger costation. It differs from E. murrayi (Davidson) in its slightly smaller size, rounder form, and less number of costae. There is no resemblance to E. macrorhynchus Foster, which is strongly triangular with numerous subdued costellae. There is some variation in the species because some specimens are slightly more elongate than others but the elongate ones are, nevertheless, costate. Eucalathis species Plate 12: figures 1-4 Description.— A single specimen from station MD.08: 6, DC 43 is so unlike other individuals of Eucalathis that it is treated separately. The speci¬ men measures (in mm): length 4.6; dorsal valve length 4.6; dorsal valve length 3.8; width 4.2; and thickness 2.2. It differs from E. costellata , new species, in its smaller size, strong median sulcus, and evenness of the size of the costellae. It differs from E. rotundata, new species, in its more trian¬ gular shape, strong dorsal sulcus, and fine, even costellae. The specimen is mudfilled and may have drifted into the population of E. rotundata. Type.— Figured specimen: MNH-BRA-78- 105. Superfamily Terebratulacea Gray, 1840 Family Terebratulidae Gray, 1840 Xenobrochus, new genus Diagnosis.— Small terebratulaceans with rec- timarginate anterior commissure, erect socket ridges, large symphytium, and loop with trans¬ Mid¬ Thick¬ Hinge Apical width ness width angle 3.2 1.9 1.4 84° 3.2 1.6 2.0 91° verse band, convex anteriorly without lateral ter¬ minal points on loop. Type Species. —Gryphus africanus Cooper 1973a: 8 , pi. 4: figs. 31-38. Description.— Small, elongate oval in outline, inequivalve, ventral valve having greater depth than dorsal one. Sides moderately rounded; an¬ terior margin narrowly rounded. Beak moder¬ ately long, erect, labiate, truncated by a fairly large submesothyridid to permesothyridid fora¬ men. Symphytium wholly or partially visible. Lateral commissure straight; anterior commisure rectimarginate. Surface marked by concentric growth lines only. Ventral valve interior with large teeth, and short pedicle collar. Dorsal valve with wide, half¬ elliptical cardinal process. Socket ridges erect, bounding wide sockets floored by stout fulcral plates. Outer hinge plates narrow, not clearly separable from the socket ridges, tapering ante¬ riorly to join a narrow crus, and extending ante¬ riorly to the crural processes, which are low, broadly pointed, with large acute angle. Descend¬ ing lamellae formed by anterior slope of crural processes. Transverse band convex anteriorly, somewhat angulated medially or rounded; me¬ dian fold of transverse band slight. Etymology. —The generic epithet, Xenobrochus , is derived from the Greek xenos (“strange”) plus brochos (“noose” or “loop”), referring to the loop with transverse band that is characteristic of spe¬ cies within the genus. Discussion.— This genus is especially charac- 20 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY terized by having its transverse band directed anteriorly rather than ventrally, as is usual in most terebratulaceans. In this respect it is unlike all other genera of terebratulidae except Abysso- thyns elongata Cooper, which is readily separable because of its sulcate anterior margin. In addition to the type species, the genus in¬ cludes Gryphus? translucidus Dali, G.P indianensis Cooper and, possibly, Liothyrina? agulhasensis Helmcke, and the two new species from off Mar¬ ion Island, described below. Xenobrochus africanus (Cooper), new combination Plate 4: figures 30-35 Gryphus africanus Cooper 1973a; 8, plate 4: figs. 31-38. Figures of this small brachiopod are introduced to illustrate the unusual loop with its anterodor- sally directed transverse band. Compare with the loop of X. anomalus described below. Types.— Holotype: USNM 550375a; para- type: USNM 550375b. Occurrence.— Durban Bay, off Indian Ocean, South Africa. Xenobrochus anomalus, new species Plate 4: figures 11-20 Diagnosis.— Very small, elongate oval Xeno¬ brochus with tubular pedicle collar and extended, erect, socket ridges. Description.— Very small, elongate oval in outline, with gently rounded sides and narrowly rounded anterior margin. Posterolateral margins nearly straight, forming an apical angle of 50°- 70°. Lateral commissure straight; anterior com¬ missure rectimarginate. Beak moderately long and narrow, suberect to erect; foramen large, mesothyridid. Deltidial plates conjunct or dis¬ junct. Symphytium visible. Surface smooth. Densely punctate, about 320/mm 2 . Ventral valve deeper, more convex than dorsal valve; moderately convex in lateral profile, slightly domed in anterior profile; umbonal re¬ gion broadly swollen; flanks steep. Pedicle long and slender. Dorsal valve evenly and moderately convex in lateral profile, moderately domed in anterior pro¬ file, slightly less so than ventral valve. Umbonal and median regions swollen; flanks steep. Ventral interior with extravagent development of pedicle collar, which is tubular; teeth large, narrow. Muscle scars not discernible. Dorsal valve interior with a broad transverse cardinal process; myophore a narrow elliptical scar, cardinal process myophore on posterolateral extension of socket ridge that forms cover to proximal part of socket; socket ridges thin and erect; fulcral plates thick; outer hinge plates at¬ tached to dorsal edge of socket ridge, narrow crural bases not elevated along inner edge of outer hinge plates. Crural processes low, blunt points located at anterior limit of outer hinge plates. Descending lamellae short; transverse band not seen, but median curve of distal ends of descending lamellae suggesting a transverse band directed anteriorly. Adductor scars not visible. Measurements (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-28a 7.0 6.1 5.1 3.7 50° MNHN-BRA-78-28b 7.3 6.4 4.6 3.8 50° MNHN-BRA-78-28c 7.1 6.3 5.0 4.1 52° Stations.— MD.08: 15, BB 88; 23, DC 129. Types. — Holotype: MNHN-BRA-78-28a; paratypes: MNHN-BRA-78-28b-f. Discussion.— This little species extends the range of Xenobrochus from southern African waters to those around Marion Island. X. anomalus is smaller than X. indianensis and is more narrowly oval with maximum width near midvalve, not anterior of the middle as in the Indian Ocean form. X. africanus (Cooper) from off South Africa is most like X. anomalus but is somewhat smaller, less tapered posteriorly, with smaller foramen, and without a tubular pedicle collar, which is a strong feature of X. anomalus. Xenobrochus australis, new species Plate 1: figures 11-13 Diagnosis.— Large Xenobrochus with width 60% of length. NUMBER 43 21 Description. —Small, longer than wide, bicon¬ vex, inequivalve, the ventral valve having the greater depth. Sides gently rounded; anterior margin narrowly rounded. Lateral commissures straight; anterior commissure rectimarginate. Beak fairly long, narrow, erect, truncated by a large foramen with labiate anterior lip; foramen permesothyridid. Symphytium concave, wholly visible. Color white, surface smooth. Punctation dense, 200 per square mm at middle of ventral valve. Ventral valve fairly strongly convex in lateral view, maximum convexity in posterior half; an¬ terior half gently convex; anterior view narrowly rounded and strongly convex. Median region swollen; lateral slope steep. Dorsal valve moderately and evenly convex in lateral view; anterior view narrowly but moder¬ ately convex; umbonal region somewhat swollen. Sides with short, steep slopes. Ventral valve with long, distally frayed pedicle; pedicle collar moderately long, excavate. Dorsal valve with thin socket plates and nar¬ row, shallowly concave outer hinge plates. Crura very long, thin, and rounded, not extended as a ridge along the inside edge of the outer hinge plate. Crura supporting obtusely angular crural bases that are joined by a narrow, angularly arched, transverse band that gives the loop the appearance of a short-handled scoop. Transverse band directed anteriorly and with a median an¬ gulation. Measurements (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-14a 14.7 12.8 9.8 8.0? 55° MNHN-BRA-78-14b 15.0 13.6 10.0 8.7 O CO m Types.— Holotype: MNHN-BRA-78- 14a; paratype: MNHN-BRA-78-14b (in alcohol). Discussion.— This species resembles X. africanus (Cooper) in the form of its loop. A number of terebratulids have the transverse band of the loop directed dorsoventrally or anteriorly, not horizontally or ventrally as is more usual in true Gryphus. The loop of X. australis is unlike that of Liothyrella , which is usually triangular in shape and widened at the anterior with the transverse band more or less strongly elevated ventrally. This Heard Island species externally resembles Liothyrella multiporosa Foster but differs in having a less deep ventral valve, a more elongate outline with less narrowed anterior, a larger foramen as well as completely different loop. Genus Dallithyris Muir-Wood, 1959 Dallithyris? dubia, new species Plate 4: figures 21-29 Diagnosis. —Small, narrowly oval Dallithyris? Description.— Small, thin-shelled, elongate oval, wider than long, with maximum width at midvalve. Valves unequally convex and deep, ventral valve strongly convex and deep; dorsal valve gently convex and shallow. Sides broadly rounded; anterior margin narrowly rounded. Pos¬ terolateral extremities forming apical angle of 77°-90°, lateral commissure straight; anterior commissure rectimarginate. Beak short, suberect, not labiate; foramen fairly large, round, meso- thyridid. Symphytium short, concave, partially visible. Surface marked only by concentric lines of growth. Ventral valve evenly and moderately convex in lateral profile, fairly strongly domed in anterior view. Umbonal and median regions swollen, sides steep. Dorsal valve evenly and gently convex in lat¬ eral view, forming a broad low dome in anterior profile. Umbonal region swollen, median and anterior convex; flanks sloping gently. Ventral valve interior with small, narrow teeth; pedicle collar short, excavate. Ventral muscle area narrow; vascula median slightly divergent. Dorsal valve interior with slender socket ridges; outer hinge plates fairly long, narrow concave; crura nonexistant; crural processes small, angu¬ lar, located at distal end of outer hinge plates. Loop short, narrowing anteriorly, and with fairly broad transverse band angularly folded at its middle. 22 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurement (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-29 a 16.7 15.2 13.7 9.2 90° MNHN-BRA-78-29 b 15.5 14.4 12.0 8.2 77° Station.— MD.08: 6, DC 57. Types. —Holotype: MNHN/BRA-78-29b; paratypes: MNHN-BRA-78-29a,c,d. Discussion. — Dallithyris murrayi Muir-Wood, the type species of Dallithyris , is a large somewhat triangular brachiopod having a short, narrow loop. As figured by Muir-Wood (1959, pi. 3: figs. 1, 2b, 4a) the loop is variable, its anterolateral extremities angular or rounded, occasionally ta¬ pering. The specimen from off Samper Bank is much narrower and smaller than D. murrayi and the loop has a definite taper anteriorly. In view of the uncertainty as to the average loop character of Dallithyris , the generic designation of D.? dubia is queried. Muir-Wood assigned Terebratula? cub- ensis Pourtales to Dallithyris , but the loops of the two are so different that the Caribbean shell was reassigned by Cooper (1977:67) to Tichosina. Dal¬ lithyris? dubia is similar to Gryphus sphenoidea Jef¬ freys (not Philippi). Although the shape of the two is similar, the latter species has not yet been assigned correctly to a genus, and is doubtfully referred to Dallithyris. Genus Liothyrella Thomson, 1916 Liothyrella is a genus widely identified in south¬ ern hemisphere waters, especially in the Antarctic where it is represented by numerous species (Fos¬ ter, 1974; Cooper, 1973b). It is also known abun¬ dantly in the Tertiary of New Zealand and Aus¬ tralia and is less abundant in New Zealand wa¬ ters. So numerous are the species and so variable the loop, that more than one stock may be rep¬ resented in the genus. Unfortunately the speci¬ mens taken by the Marion Dufresne are mostly broken shells without loops. Liothyrella moseleyi (Davidson) Plate 1: figures 7-10 Terebratula moseleyi Davidson, 1878:436; 1880:30, pi. 2: figs. 12-14. Liothyris moseleyi (Davidson).—Davidson, 1886:11, pi- 2. figs. 1-4. Liothyrina moseleyi (Davidson).—Blochmann, 1908.618. Liothyrella moseleyi (Davidson).—Hertlein and Grant, 1944: 97, pi. 7: figs. 3-7, 12.—Foster, 1974:69, pi. 4: figs. 23-25. Not Gryphus moseleyi Dali, 1920:318. Description. —Small, subcircular in outline, valves subequal in convexity, ventral valve usu¬ ally slightly deeper than dorsal valve; sides and anterior margin rounded; posterolateral margins forming angle of 74°-86°. Lateral commissures straight; anterior commissure rectimarginate. Beak short, suberect, labiate; foramen small, sub- mesothyridid to mesothyridid. Deltidial plates conjunct forming a concave symphytium. Color dull white; surface smooth. Ventral value moderately convex in anterior and lateral profiles, with umbonal region most convex. Median region swollen, swelling contin¬ uing to anterior margin. Dorsal valve evenly and moderately swollen in anterior and lateral pro¬ files, slightly less so than ventral valve. Median region swollen. Ventral valve interior with short excavate ped¬ icle collar; small but rounded teeth; muscle scars lightly impressed. Dorsal valve interior with thin, erect, socket ridges; narrow outer hinge plates and crural processes located at junction of outer hinge plates and crura. Measurements (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-13a 18.9 16.6 16.0 10.4 77° MNHN-BRA-78-13b 16.5 14.4 15.7 9.6 o CO MNHN-BRA-78-13c 16.1 14.4 13.5 8.7 O CO Station.— MD.03: 31, CP 22. Types. —Hypotype: MNHN-BRA-78-13a-c. Discussion.— None of the specimens in the col¬ lection preserves a complete loop. Foster (1974: 69) discussed details of this species that separate it from other species of Liothyrella and, indeed, that may separate it generically. Foster (1974, pi. 4: fig. 25) illustrates the loop of a paratype that is distinct from the loop of Liothyrella uva (Brod- erip), the type species of Liothyrella. The loop of L. moseleyi is equal to 1/3 the length of the dorsal valve, is almost parallel-sided, and has a broad ail NUMBER 43 23 transverse band. The loop does not expand an¬ teriorly as is characteristic of the loop of Liothyrella and the crural processes are farther anterior than those characteristic of Liothyrella. Foster also points out that the density of the punctae is less than that of L. uva. Another species having a narrow loop like that of L. moseleyi is L. blochmanm (Jackson). This leads to the suspicion that there is another terebratulid stock in the Antarctic different from Liothyrella. Liothyrella? species Plate 3: figure 31 Description.— Thirty-seven valves in various stages of abrasion are referred tentatively to Lio¬ thyrella. Diagnostic generic characters are difficult to detect but the general aspect of the specimens conforms to that of Liothyrella. The specimens are large, elongate oval, variable, longer than wide, with maximum width slightly anterior to mid¬ valve. The ventral valves have a large symphy- tium and a slightly labiate beak, but in most examples the beak is damaged. The teeth are large and the diductor field squarish. No dorsal valve has a complete loop and the outer hinge plates are too badly damaged to be useful. They are wide, gently concave, nearly horizontal, and margined by a slight elevation of the crural base. The exterior surfaces are much abraded but faint traces of radial capillae may be detected. Station.— MD.08: 70, RK 282. Types.— Described specimens: MNHN-BRA- 78-123. Discussion.— The oval outline and interior characters of these specimens are most like Lio¬ thyrella. Although they show traces of capillae, a trait present in some liothyrellas, the presence of well-formed outer hinge plates eliminates them from assignment to Dyscoha. Three juveniles from MD.08: station 40, DC 186 (MNHN-BRA-78-122a-c) are also placed un¬ der this heading. The loop is incomplete as is usual with young Liothyrella and incipient outer hinge plates are visible. Another juvenile from MD.08: station 74, CP 296 is also referred here (MNHN-BRA-78-125). Family Dyscoliidae Fischer and Oehlert, 1891 Genus Dyscolia Fischer and Oehlert, 1890 Dyscolia? radiata , new species Plate 3: figures 17-30 Diagnosis. —Subtriangular, loop narrow, crural processes obtuse, surface covered by fine irregular capillae. Description.— Of about medium size, sub- triangular in outline, unequally convex, ventral valve having greater convexity and depth; pos¬ terolateral margins straight, forming apical angle of 80°-92° Sides rounded; anterior margin broadly rounded. Lateral commissure straight, anterior commissure rectimarginate. Beak short, strongly labiate; foramen small, rounded, meso- thyridid to permesothyridid. Symphytium con¬ cave, completely visible. Surface marked by fine irregular radial threads, growth lines, and growth lamellae. Ventral valve moderately and regularly convex in lateral view, fairly strongly domed, with steep sides in anterior profile. Umbonal region swollen, swelling dissipating on the swollen midvalve; an¬ terior slope steep and swollen. Dorsal valve moderately and evenly convex in lateral profile; broadly and gently domed in an¬ terior view. Umbonal and median regions mod¬ erately swollen; flanks gently convex. Pallial impressions poorly recorded; vascula media ex¬ tending directly anteriorly. Ovarian impressions narrow. Dorsal valve interior with stout socket ridges, bounding narrow sockets; outer hinge plates ob¬ solete; no inner hinge plates. Loop about 1/3 the length and about 1/7 the width of the dorsal valve; somewhat tapered anteriorly, crura long, narrow in section; crural processes obtusely an¬ gular, anterior to midloop (60% of length); de¬ scending branches broad, short; transverse band narrow and gently arched medially; anterolateral extremities bluntly rounded. Measurements (mm).— Dorsal valve Thick- Apical Specimen Length length Width ness angle MNHN-BRA-78-25 a 29.5 26.4 27.5 18.2 81° MNHN-BRA-78-25 b 27.3 24.2 26.3 16.0 92° 24 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Stations. —MD.08: 6, CP 47; 73, CP 295. Types.— Holotype: MNHN-BRA-78-25b; par- atypes: MNHN-BRA-78-25a,c-f. Discussion.— Dyscolia? radiata most resembles Dyscolia ewingi Cooper from off South America in south Atlantic waters. Although the two are ex¬ ternally similar, the loop of the South American species is wide and nearly rectangular, and its shell is larger. There is also resemblance to Lio- thyrella? neozelanica Thomson, which is a larger, indistinctly radially capillate shell. The loop of the New Zealand species is rather more triangular than that of D? radiata. A single fragmentary ventral valve (MNHN- BRA-78-97) from station 73, CP 295 is assigned here because of its strongly labiate beak and widely triangular form. The shell is quite worn but shows patches of capillae. Superfamily Terebratellacea King, 1850 Family Platidiidae Thomson, 1927 Genus Platidia Costa, 1852 Platidia marionensis, new species Plate 2: figures 37-39; Plate 5: figures 15-34 Platydia anomioides (Scacchi).—Davidson, 1880:55, pi. 4: figs. 10 , 11 . Platydia anomioides (Scacchi) Philippi species.—Davidson, 1887:152, pi. 21: fig. 16. Platidia anomioides (Scacchi and Philippi).—Foster, 1974:85, pi. 7: figs. 17-19. Diagnosis.— Small circular Platidia. Description.— Small, circular; color cream to yellowish white; valves unequally convex, ventral valve strongly swollen; dorsal valve variable, usu¬ ally flat to concave in posterior half, moderately swollen, flat to concave in anterior; foramen large, occupying nearly 1/4 length of dorsal valve and fully half its width. Anterior commissure rectimarginate. Surface marked by concentric growth undulations. Punctae count about 300 per square millimeter. Ventral valve strongly convex in lateral profile, more convex in posterior half, anterior half fla- tened; anterior profile strongly domed; beak short bluntly rounded, forming large obtuse angle; flanks convex. Dorsal valve moderately convex in lateral and anterior profiles except at umbonal region which is excavated; foramen forming a semiellipse with smooth margins. Ventral valve interior with short interarea, large teeth without buttress, low median ridge at apex. Dorsal valve interior with compact lophophore having small lateral branches, occupying about middle half of valve. Median septum short, reach¬ ing to about midvalve. Loop with delicate de¬ scending lamellae and needle-pointed, short crural processes. Ascending element at end of septum forming a wide-pronged fork. Measurements (mm).— Dorsal valve Specimen Length length Width Thickness MNHN-BRA-78 68 3.3 2.7 3.6 ? MNHN-BRA-78-69a 3.4 3.0 4.0 ? MNHN-BRA-78-70a 3.6 3.2 3.5 1.7 MNHN-BRA-78-70b 3.6 3.3 3.6 1.7 Stations.— MD.03: 22, CD 15; 26, CP 17; 28, CP 19. MD.08: 6, DC 34; 9, CP 75; 15, DC 87; 15, BB 88; 18, BB 108; 19, DC 110; 19, BB 111; 20, CP 116; 23, DC 129; 25, DC 134; 27, DC 136; 28, DC 143; 28, DC 148; 36, DC 173; 44, CP 199; 59, BB 253; 67, DC 271; 67, DC 273; 68, CP 275; 70, DC 280; 71, DC 283; 71, BB 285-286; 73, CP 295; 74, DC 296; 77, DC 314. Types.— Holotype: MNHN-BRA-78-70a; paratypes: MNHN-BRA-78-22, -78-65; -78- 66a,b; -78-67; -78-68; -78-69a,b; -78-70b-d. Discussion.— Platidia is a small brachiopod that lives closely attached to its host, which may be a pebble, other shells, its own king, or bry- ozoans. Close appression to the host often distorts these small shells, creating flat or concave dorsal valves rather than convex ones when the shell has more freedom to grow. Because all of the species of Platidia are variable, identification based on exterior details only is difficult. The specimens from Marion Island and vicin¬ ity were early identified as P. anomioides (Scacchi NUMBER 43 25 and Philippi), which was first described from the Mediterranean. The same name has been used for specimens from the Atlantic, Caribbean, Ant¬ arctic, South Africa, and the Gulf of Mexico. In this enormous expanse of sea, this species is nat¬ urally quite variable. In the Mediterranean and northeastern Atlantic, specimens are often dis¬ torted and become fairly large, upward of 7.0 mm in width (Fischer and Oehlert, 1891:95) and as adults are usually wider than long. Punctae counts are variable, a specimen (USNM 173465) of 3 mm width had a count of 268/m 2 and another (USNM 173462) of 5.4 mm width had 266-275 punctate per square mm. A specimen, from the Caribbean (USNM 550528) of 3 mm width had a count of only 200 punctae per square mm. The specimens of Platidia from northeast of Marion Island and elsewhere in the southern Indian Ocean are regarded as a new species be¬ cause they are nearly circular, attain a width of barely 4 millimeters, and have a lophophore in which the lobes extend directly laterally and do not flare toward the posterolateral margins. The lophophore generally occupies somewhat less of the interior than those of P. anomioides. The socket ridges are long and thin in the Marion specimens. The Mediterranean form is commonly brown or yellow whereas the specimens from Marion Island vicinity are yellowish white or cream colored. Furthermore, the punctae count of the Marion specimens is about 336, a figure in accordance with Platidia figured by Foster from Antarctica (Foster, 1974:85). Specimens like the Marion spe¬ cies occur on the Agulhas Bank off the Southern tip of Africa (Cooper, 1973b:21). Family Kraussinidae Dali, 1870 Genus Megerlina Deslongchamps, 1884 Megerlina davidsoni (Velain) Plate 2: figures 14-36 Kraussina pisum Velain [not Lamarck].—Frauenfeld, 1865: 894; Velain, 1876:285. Kraussina davidsoni Velain, 1877:72, 139, pi. 5: figs. 23, 24; 1878:139, pi. 5: figs. 24-26.—Davidson, 1880:21; 1886— 1888:126, pi. 21: figs. 12-14.—Deslongchamps, 1884:160, pi. 19: figs. 6, 9, 10. Description.— This species was well described by Velain (1877) and later by Davidson (1886— 1888) and Deslongchamps (1884). Velain also described the conditions under which the species lived in the narrow environment of the volcanic crater that is St. Paul Island in the Indian Ocean. This is a small brachiopod, brownish in color, with length and width subequal. The foramen is large, the anterior margin is sulcate, and the interior is reminiscent of that of Kraussina. Ac¬ cording to Velain, the animal lived on the under¬ side of stones, often crowded in crevices and subject to deformation. It lives from tide level down to 30 meters depth. Although the interior of the shell of this species is well known and has been illustrated by Des¬ longchamps (1884) some details of the muscula¬ ture and the development of the lophophore sup¬ port have not been described. The interior of both valves and especially that of the dorsal valve is marked by prominent, large, and long tuber¬ cles. These form a subperipheral rim in both valves. When the shell is slightly agape, these form a sort of sieve or screen that may have been effective for this purpose when feeding. The older tubercles in the rear of an adult are partly buried in shell tissue and are not as prominent as the younger marginal ones. The deltidial plates are widely disjunct and the foramen is a large triangular opening that is covered by an integument bearing the pedicle, to which some of the muscles are attached. The teeth are thick and solid but are not supported by dental plates. The muscle scars are lightly impressed. The scars of the large pedicle muscles can be discerned but it is difficult to distinguish the traces of the smaller diductors. The pedicle is in the midst of the integument, is short, and adhered so strongly to the substrate that particles of the rock still cling to it. In many specimens, the pedicle appears as a black solid circle sur¬ rounded by the integument. The muscle arrangement of the pedicle valve is like that of Megerlia and Argyrotheca with large, 26 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY prominent, spreading pedicle muscles that are attached on the underside of the posterior side of the pedicle, which in turn is essentially part of the integument. The diductor muscles are posterior of the pedicle muscles near the center of the delthyrial cavity and are attached to the pedicle and integument at the same place as the pedicle muscles. They then spread out on the integument and attach with the integument to the posterior shell margin, which is narrowly roughened and serves as a cardinal process. Dorsal pedicle mus¬ cles are very small and are attached to the inte¬ gument at the pedicle and to the socket ridge of the dorsal valve. The shell of this animal is so tightly pressed to the object of attachment that movement of the shell corrodes the beaks of both valves and often parts of the hinge. To open the shell, the valves must be lifted and the large pedicle muscles can effect this on contraction by stretching the pedicle. At the same time contrac¬ tion of the small diductors opens the valves. Measurements (mm).— Dorsal Specimen Length valve length Hinge width Mid¬ width Thick¬ ness MNHN-BRA-78-18a 7.9 6.0 5.6 7.3 4.1 MNHN-BRA-78-19a 6.4 5.5 5.6 7.4 3.0 MNHN-BRA-78-21a 8.3 6.2 5.6 7.7 4.4 Cardinalia and Lophophore Supports.— The cardinalia consist of stout oblique socket ridges and a fulcral plate. The cardinal process is a roughened strip along the posterior margin of the notothyrial cavity. The short and slender dorsal pedicle muscles are attached to the socket ridges, and in some specimens leave a transversely oval scar. Thickening on the anterior side of the socket ridges simulates an outer hinge plate but it never reaches the valve floor or it is likely to be misi- dentified as a hinge plate. The lophophore support consists of a Y-shaped apparatus located at the crest and anterior end of a thick median septum that reaches nearly to the posterior. The development of the internal struc¬ tures is of considerable interest. The smallest specimen (MNHN-BRA-78-19e) exhibiting the interior is 1.6 mm wide. The socket ridges and pedicle muscle scars are discernible. At midvalve a low ridge has appeared that extends from mid¬ valve nearly to the anterior margin. At the pos¬ terior terminus of the ridge a slight depressed area appears that is the site of the development of the Y. The next specimen in development (MNHN-BRA-78-19h) is much larger, 3 mm wide. Its median ridge consists of three large tubercles anterior to a ridge that extends slightly beyond midvalve. At the middle and on each side of this ridge is a tiny divergent flattened blade, the beginning of the Y. Another specimen of 3 mm (MNHN-BRA-78-19i) is still more advanced showing the septum extending posteriorly beyond midvalve. It is furrowed along the midline. The anterior tubercles have been reduced to one large one and a smaller one anterior to it. The blades of the Y are concave on the inner face and rounded distally. A specimen 4 mm wide (MNHN-BRA-78-19-1) has widened blades and the septum, still grooved, extends nearly to the notothyrial cavity. The tubercles anterior to the septum are three but reduced in size. At the posterior side of the distal end of the Y there is a slight bending toward the inside of the Y. This is better shown in a specimen 4.5 mm wide (MNHN-BRA-78-19m) and has been interpreted as representing the beginning of the transverse band of the normal loop. In a specimen 8 mm wide, a well-developed adult, the Y is wide, the limbs slightly curved and concave inward. The median septum is grooved for about half its pos¬ terior length, then extends to the notothyrial cavity where it expands to a small platform. The posterior margin of the limbs of the Y are curved inward toward each other. An additional feature appears in the form of a small blade attached to the under or dorsal side of each blade near the septum, suggesting an incipent development of the descending branch of a normal loop. This small blade never grows dorsally and no corre¬ sponding crus or trace of one appears from the socket ridge. Bathymetric Range.— Shallow water, 3-30m. Stations. —AMS-D8; St. Paul: 7b, 22a, 35, 90, 91. NUMBER 43 27 Types.— Hypotypes: MNHN-BRA-78-18; 19a-m; 78-2aa; 78-21a. Genus Megerlia King, 1850 Megerlia gigantea (Deshayes) Plate 6: figures 1-26 Morrisia gigantea Deshayes, 1863:37, pi. 5 (32): figs. 9-11. ?Miihlfeldtia truncata paucistriata Jackson, 1921:42 [not illus¬ trated]. Description.— Small, rounded, subrectangular to subpentagonal; valves unequal in depth; dorsal valve varying from slightly concave to gently convex, ventral valve fairly strongly convex. Hinge narrower than midwidth, which is widest part; sides and anterior margin rounded; lateral Specimen Length Dorsal valve length MNHN-BRA-78-7 la 8.2 6.8 MNHN-BRA-78-7 lb 7.7 5.8 MNHN-BRA-78-7 lc 7.4 6.1 MNHN-BRA-78-7 Id 8.8 7.3 MNHN-BRA-78-7 le 8.2 7.5 commissure straight, anterior commissure slightly and narrowly sulcate. Beak widely obtuse, fora¬ men hypothyridid, margined by narrow elevated (deltidial?) plates. Interarea curved, gently as- pascline to anacline. Surface of ventral valve costellate and spinose, that of dorsal valve faintly costellate but not spinose; both valves with strong concentric lamellae. Finely punctate. Ventral valve unevenly convex in lateral pro¬ file, most convex in umbonal region, flattening anteriorly. Anterior profile forming a broad dome. Middle and umbonal regions swollen; flanks flattened. Dorsal valve usually flatly convex in lateral profile but varying from slightly concave to gently convex. Anterior profile flat or gently convex. Anteromedian region narrowly and gently de¬ pressed to form a faint sulcus. Flanks gently sloping. Interarea short and laterally narrow; beak usually slightly eroded. Ventral valve interior with a broad, slightly excavate, pedicle collar; teeth strong, oblique, moderately long, and parallel to the delthyrial margin. Ventral pedicle muscles large, diductors reduced. Pedicle short. Dorsal valve interior with narrow plectolophus lophophore; no cardinal process, diductors lo¬ cated on thickening at apex; socket ridges short, elevated; crura moderately long, stout; crural processes long, narrow, and approximate; de¬ scending and ascending lamellae united to form laterally directed expansions joined dorsoven- trally by a narrow, arched, transverse band. Lat¬ eral branches united with anterior end of a low, thick, median ridge. Measurements (mm).— Width Hinge width Thick¬ ness L/W 9.1 6.7 4.1 0.91° 8.7 6.5 3.7 0.89° 8.7 7.0 3.8 0.85° 10.1 7.0 4.6 0.87° 10.0 7.6 4.3 0.82° Station.— MD.08: 6, DC 35; 6, DC 43; 6, CC 45; 6, DC 46; 7, DC 57. Types.— Hypotypes: MNHN-BRA-78-7 la-i; 78-72a-j; 78-73a-c. Discussion.— This species has not been known since its early publication. It is a misnomer be¬ cause it is small compared to other species of Megerlia. Deshayes was comparing his species with those of Morrisia (Platidia ), all of which are much smaller than M. gigantea. Deshayes (1863:37) com¬ mented on his specific name gigantea for such a small shell but justifies it in showing that it is the largest species of what he thought to be Morrisia = Platidia. Although Megerlia does not have the foramen shared conspicuously by the dorsal valve, nevertheless some specimens are abraded on the dorsal beak area. Megerlia gigantea has a strong 28 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY reentrant at the dorsal beak and no cardinal process and thus suggests the condition in Platidia and Megerlia. Dali (1920:336) suggested that De- shayes species belonged to Pantellana, which is a Megerlia having the dorsal beak excavated and the dorsal valve without costellae or granules. Following Dali’s lead Thomson (1927:229) placed Deshayes species in Pantellaria. Megerlia gigantea cannot be regarded as Pantellaria because its beak characters and ornament are not in accordance with those characters of that genus. The dorsal beak of M. gigantea is not strongly excavate and the dorsal valve is ornamented but not to the same degree as its ventral valve. The loop of M. gigantea , as figured by Deshayes (1863, pi. 5: fig. 10), is an accurate depiction of the loop of Megerlia. Jackson (1921:44) thought that M. gigantea re¬ sembled his Miihlfeldtia = Megerlia truncata paucis- triata because of the “scanty nature of the striae [= costellae].” Deshayes’ name mislead Fischer and Oehlert (1891:84) into thinking that M. gi¬ gantea was larger than M. truncata (Linne). Da¬ vidson (1887:105) believed that Deshayes species was the same as the Mediterranean M. truncata and was suspicious of its locality. Specimens of Megerlia identified as M. echinata , or similar to that species, have been found in several widely scattered areas off the coast of Florida, in the Caribbean, off the Cape of Good Hope, Africa, and off New South Wales. Unfor¬ tunately, these occurrences are rare and few spec¬ imens are known. A specimen from off the Cape of Good Hope was figured by Cooper (1973a, pi. 1: figs. 1-3). It differs from M. gigantea in having a much more strongly convex ventral valve, a concave dorsal valve, and a more excavated dor¬ sal valve beak than M. gigantea. The single speci¬ men from off New South Wales is larger, more strongly costellate, and has a more convex dorsal valve than M. gigantea. In absence of good popu¬ lations for study and comparison, it is not possible adequately or accurately to evaluate single iso¬ lated specimens. Megerlia echinata (Fischer and Oehlert) from Talisman station 74, off the coast of northwest Africa, is somewhat larger than M. gigantea , has a fairly strongly excavated dorsal valve beak, and dorsal valve generally concave and nearly with¬ out ornament. Loop Development. —A dorsal valve 1.6 mm long (MNHN-BRA-78-72a) has a minute median cone open on its anterior side and cemented to the floor of the valve without any trace of a median ridge. The peripheral margins of this specimen are armed with fairly high nodes. The specimen of the next size, 2 mm long (MNHN- BRA-78-72b), shows the cone still open ante¬ riorly, expanded laterally and ventrally. The cone is supported by a short stout pillar that extends posteriorly for a short distance. The next stage, 3.3 mm long, (MNHN-BRA-78-72d) has a much more ventrally elongated and widened cone. The median ridge extends to the notothyrial cavity, the floor of which is thickened. The socket ridges are expanded, thickened, and cuplike. An incipi¬ ent crus extends from their anterior side. A spec¬ imen 3.5 mm long (MNHN-BRA-72e) shows the crus and crural process attached to the side of the septum and an essentially adult loop. Succeeding stages to old age show a widening loop with elongating anterolateral extensions, a thickening of the median ridge and of the floor of the noto¬ thyrial cavity. Family Terebratellidae King, 1850 Subfamily Terebratellinae King, 1850 Genus Aerothyris Allan, 1939 In the southern Indian and Antarctic oceans there are numerous species of terebratellids, all in the Mage llama stage of loop development. The proper generic name to apply to these is as diffi¬ cult a problem as establishment of their correct specific names. Foster (1974) preferred to call certain of them Magellania, especially those that concern us here: M. kerguelenensis (Davidson) and M. macquariensis Thomson. These two conform to Magellania in having dorsally convergent inner hinge plates and a well-developed cardinal pro- NUMBER 43 29 cess, as well as the magellaniform loop. They do not conform to Magellama when compared to M. flavescens (Lamarck), the type species of Magel- lama. Typical Magellama is an elongate, rather narrowly oval brachiopod having strong costae around its margins and for some distance toward the smooth beak. Its beak is strongly protuberant, straight, narrow with a large foramen and large, completely visible symphytium. Allan (1939:246) proposed the name Aerothyns for M. macquariensis and considered the important generic characters its smooth shell and disjunct deltidial plates. To confuse the definition, some specimens of Aero - thyris have conjunct deltidial plates (see below) although they are usually a small minority in any population. To use the name Magellania for the several smooth but variable species with magellaniform loop in the Southern Hemisphere is confusing in the extreme. Nevertheless, it must be admitted that, although some smooth species obviously are not Magellania or Aerothyris, yet to define them in rigid terms as separate genera has still to be accomplished. Magellania? venosa (Solander), the large brachiopod from both sides of the south end of South America, is an example. More explora¬ tion and more collections of fossil as well as recent specimens are needed before the various lines of evolution of the Terebratellidae will be separated and properly defined. The numerous specimens of brachiopods with magellaniform loop collected by the cruises of M/S Marion Dufresne, offer a difficult problem because they are very variable with unlike end members and with complete intergradation be¬ tween the extremes. At one end of the series are smooth nearly circular shells while at the other end they are elongate oval, large or small. Two species have been described from the vi¬ cinity of Kerguelen Island: Waldheimia kerguelenen- sis Davidson and Terebratella enzenspergeri Bloch- mann. The former was taken by the Challenger expedition (Davidson, 1878) and was reported as abundant in the vicinity of Kerguelen and Mar¬ ion Islands. To illustrate his species, Davidson selected elongate oval specimens having a narrow, often slit-like (keyhole) foramen. He noted (1880: 40) that, “It varies in dimensions from 2 to 44 mm. Some examples were nearly circular, and as broad as long, but the majority were of an elon¬ gated oval shape, becoming ventricose with age.” It is evident therefore that Davidson was dealing with a variable species. Some of the variation and at least one of the populations taken by M/S Marion Dufresne (MD.08) proves very similar to Magellania macquariensis Thomson, from Mac¬ quarie and Antipodes islands, southwest of New Zealand. In discussing M. macquariensis and its affinities with W? kerguelenesis, Foster (1974:141) remarks: “This species appears slightly closer to Magellania [ Aerothyris] kerguelenensis than to any other terebratellid species. Rare individuals of this species \M. macquariensis] have the same type of foramen [keyhole type] as M. kerguelenensis. Some specimens of M. kerguelenensis have cardi- nalia that differ little from those of M. macquanen- sis?' 1 The interior of A. kerguelenensis is usually more heavily calcified than that of M. macquarien¬ sis. Terebratella enzenspergeri Blochmann, a round brachiopod, is the other species close to kerguele¬ nensis from Kerguelen Island. It is poorly known and there are problems concerning its true specific identity. These two species, kerguelenensis and en¬ zenspergeri, and their relation to one another, are described and discussed below. Summary of Measurable Populations of Aerothyris Cruise MD.03 Station 14, DC 8. Aerothyris kerguelenensis (David¬ son): Thirty-six specimens ranging from 14.4 to 36.0 mm in length and 14.6 to 34.0 mm in width. L/W ranges from 0.96 to 1.15, with an average of 1.10 (22 specimens 1.10 or below); T/W ranges from 0.51 to 0.74 with an average of 0.61. Of all Specimens, 94% have foramen width 2.0 mm or below (Figures 8, 23, 26). Station 14, CB 3. Aerothyris kerguelenensis (David¬ son): Twenty-one specimens measured with 30 range in length of 19.1 to 33.7 mm and in width of 18.2 to 28.0 mm. L/W ranges from 1.01 to 1.24 (11 at 1.10 or below), average 1.10; T/W ranges from 0.53 to 0.76 with 0.61 aver¬ age. All pedicle openings that could be mea¬ sured are 2.0 mm (one specimen) or below (Figures 8, 23, 26). Station 26, CP 17. Aerothyris kerguelenensis (Da¬ vidson): Fifty-Five measurable specimens rang¬ ing from 5.4 to 39.9 mm in length and 4.6 to 34.5 mm in width. L/W ranges from 0.95 to 1.30, (31 at 1.10 or below), average 1.11; T/W ranges from 0.44 to 0.80 with average of 0.55. Forty-eight percent of the specimens in which the foramen could be measured have the fora¬ men 2.5 mm or above (Figures 12, 23, 26). Station 30, CP 21. Aerothyris kerguelenensis (Da¬ vidson): Ninety-eight measurable specimens ranging in length from 22.8 to 43.5 mm and in width from 21.0 to 40.7 mm. L/W ranges from 0.98 to 1.24 (56 specimens at 1.10 or below), average 1.09; T/W ranges from 0.48 to 0.80, average 0.58. Of all specimens with measurable foramen, 83% are 2 mm or below (Figures 6, 7, 23, 26). Cruise MD.08 Station 9, CP 64. Aerothyris kerguelenensis (David¬ son): Seven measurable specimens with range of length 18.0-41.0 mm, and width 16.0-32.4 mm. The range of L/W= 1.05-1.27, with an average of 1.17. The width of the foramen varies between 4.0 and 1.5 mm. Range of T/W=0.51-0.73. Most of the specimens are young adults (Figure 26). Station 9, CP 65. Aerothyris kerguelenensis (David¬ son): Two measurable specimens respectively length 32.6 mm and 20.3 mm, width 31.0 mm and 18.0 mm. L/W is 1.05 for the larger one, 1.13 for the smaller and with foramen respec¬ tively 3 and 2 mm in width. Depth 112 mm. Station 9, DC 68. Aerothyris kerguelenensis (David¬ son): Nineteen measurable specimens with length range 9.6-35.8 mm and width range 8.7-31.4 mm. Range of L/W=0.97-1.15, with SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY an average of 1.06 (only 4 specimens 1.10 and over). The range of T/W=0.46-0.58, average 0.50. The diameter of the foramen ranges from 1.0 to 3.5 with 14 measuring two mm or lower. Most of the specimens are young adults, mostly nearly as wide as long. The loop is freed be¬ tween 11 and 13 mm of the dorsal valve length (Figures 21, 24). Station 9, CP 75. Aerothyris kerguelenensis (David¬ son): Eighteen measurable specimens ranging in length from 17.6-40.8 mm, and in width from 15.8-35.8 mm. Range of L/W= 1.04-1.24, with average of 1.14. Range of T/W=0.51- 0.66, average 0.57. Only one specimen L/W=1.04, the remainder above 1.11. The foramen is variable 41% at 3.0 mm, 47% at 2.5 and below, only 12% 2.0 mm and below. Most specimens strongly sulcate (Figures 15, 24). Station 12, DC 78. Aerothyris kerguelenensis (Da¬ vidson): Twenty-two measurable specimens ranging in length from 10.9-46.7 mm and in width from 9.9-43.5 mm. Range of L/W= 1.00-1.34, with average of 1.11, about 87% are below 1.15. Range of T/W=0.42-0.75, with average of 0.55. The foramen is mostly small and keyhole-shaped, 83% being below 1.0 mm. Many of the specimens are large and strongly sulcate (Figures 13, 21, 24). Station 13, CP 85. Aerothyris kerguelenensis (Da¬ vidson): Six measurable specimens ranging in length from 10.0-44.4 mm and in mm and in width from 8.8 to 38.2 mm. The range of L/W=0.99-1.27, with average 1.16; range of T/W=0.43-0.66, with average of 0.59. Two with keyhole aperture, 2 at 2.5-3.0 mm of foramen. Moderately sulcate. Station 15, DC 87. Aerothyris kerguelenensis (Da¬ vidson): Thirteen specimens measured ranging in length from 18.0 to 31.4 mm and in width from 15.0 to 23.7 mm. The range of L/W= 1.10-1.38, with average of 1.19; T/W=0.52-0.83, with average of 0.61. Only one specimen with foramen above 1.5 mm. Very variable lot with unusually narrow spec¬ imens with ones wider than long (Figures 21, 24). NUMBER 43 31 Station 18, DC 107. Aerothyris kerguelenensis (Da¬ vidson): Four specimens measured ranging 25.6 mm to 34.8 mm in length and from 20.3-28.6 mm in width. L/W ranges from 1.06-1.26, with average of 1.15, and T/W=0.54-0.72, with average of 0.61. Foramen 1.5 or below, three with keyhole form. Adults of middle age. Seven separated ventral valves with conjunct deltidial plates. Station 19, DC 110. Aerothyris kerguelenensis (Da¬ vidson): Four shells ranged in length from 18.0 to 29.4 mm and width 15.7-24.3 mm. L/W range= 1.09-1.21 and T/W range=0.48-0.63, with respective averages 1.21 and 0.58. Fora¬ men small, all 1 mm. Station 20, CP 116. Aerothyris kerguelenensis (Da¬ vidson) : Seven specimens range in length from 21.3 to 29.8 mm and in width from 18.0 to 27.8 mm. The L/W range= 1.06-1.18, averaging 1.11; the T/W range=0.51-0.60, with average of 0.58. Foramen all below 2.0 with most at 1.5 mm. Chiefly young adults. Station 22, BB 125. Aerothyris aff. A. macquariensis (Thomson): Fifty-seven measurable specimens ranging in length from 9.8 mm to 34.9 mm and varying in width from 8.9 mm to 30.5 mm. L/W range= 1.03-1.27, with an average of 1.11 (with 37 specimens at 1.10 or below). T/W range=0.40-0.77, with average of 0.61. Of 45 specimens with measurable foramen (those un¬ attached) 33% are 2 mm in diameter or less; the remainder above 2 with three specimens having a foramen of 4 mm diameter (Figures 21, 24, 28, 29). Station 25, CP 134. Aerothyris kerguelenensis (Da¬ vidson): Thirty-five specimens with length from 19.5 to 35.0 mm and width from 16.8 to 26.6 mm. L/W range= 1.06-1.30, with average of 1.18; T/W range=0.51-0.79, with average of 0.61. Twenty-nine specimens have L/W= 1.11-1.34, showing most specimens to be narrowly oval. The foramen is variable with 54% of the specimens measuring 2.0 mm in diameter or below (Figures 17, 21, 24). Station 26, CP 135. Aerothyris kerguelenensis (Da¬ vidson) : Eleven specimens with length ranging from 27.4 to 36.4 and width from 23.7 to 32.8. L/W= 1.09-1.18, and averages 1.12 (3 speci¬ mens only 1.10 and below); T/W range=0.55- 0.62, and averages 0.59. All measurements of the foramen are 2.0 mm or below. Mostly middle age adults (Figures 14, 21). Station 27, DC 136. Aerothyris kerguelenensis (Da¬ vidson): Eight specimens ranging in length from 22.5 to 29.9 mm and in width from 20.0 to 25.7 mm. L/W range= 1.05-1.35, with av¬ erage of 1.17 (all above 1.10); T/W range=0.54-0.82, with average of 0.64. The foramen is 2.0 mm (one specimen) or below. Several specimens with keyhole foramen (Fig¬ ure 26). Station 28, DC 143. Aerothyris kerguelenensis (Da¬ vidson): Six specimens, narrowly oval, with length ranging from 20.7 to 24.6 and width from 17.3 to 21.5 mm. L/W range= 1.14-1.30, with average of 1.19 (none below 1.14). T/W range=0.60-0.65, with average of 0.62. All specimens with foramen below 2.0 mm. Small, elongate forms that occur with Platidia. Station 28, DC 148. Aerothyris kerguelenensis (Da¬ vidson): Eighteen specimens with length rang¬ ing from 11.4 to 24.6 and width from 10.1 to 21.0. L/W range= 1.06-1.24, with average of 1.16 (all but two specimens above 1.12); T/W range=0.54-0.69, average 0.60. All specimens with measurable foramen 2 mm or below. Mostly small and elongate shells, with Platidia occasionally attached. (Figures 16, 21, 24.) Station 31, DC 156. Aerothyris kerguelenensis (Da¬ vidson): Two specimens only, length range=25.8-29.5, width 21.8-26.4 mm. L/W= 1.12-1.18 and T/W=0.57-0.60. Fora¬ men 3.0 mm and 1.5 mm (keyhole). Station 32, DC 162. Aerothyris kerguelenensis (Da¬ vidson): Five specimens ranging in length from 22.3 to 43.2 mm and in width from 22.3 to 45.5 mm. L/W range=0.95-1.24, and averages 1.09. T/W range=0.50-0.68, and averages 0.56. The foramen is large varying from 3.5 to 4.0 mm. These are mostly large variable forms. Station 34, DC 167. Aerothyris kerguelenensis (Da¬ vidson) : Four specimens ranging in length from 32 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 15.0 to 41.8 mm and in width from 14.6 to 33.3. L/W range= 1.03-1.26, average 1.12; T/W range=0.45-0.65, average 0.54. All spec¬ imens with foramen at 1.5 mm or below, two with keyhole type. Station 40, DC 186. Aerothyris kerguelenensis (Da¬ vidson) : Seven large specimens ranging in length from 31.9 to 36.0 mm and width from 29.6 to 34.6 mm. L/W range=1.03-1.15, aver¬ ages 1.08; T/W range=0.51-0.59, averages 0.55. Foramen: one at 3.0 mm, two at 1.0 mm, remainder 2.0-2.5 mm. Three specimens with keyhole type foramen. Large wide specimens. Station 42, CP 197. Aerothyris kerguelenensis (Da¬ vidson) : Nineteen specimens ranging in length from 21.6 to 42.8 mm and in width from 21.9 to 39.0 mm. L/W range=0.99-l. 19, with av¬ erage of 1.08 (14 specimens 1.10 or below); T/W range=0.46-0.66, with average of 0.56. The diameter of the foramen varies between 1.5 and 3.0 mm, with 89% 2.0 mm or above. Specimens wide and with large foramen (Fig¬ ures 22, 25). Station 45, CP 203. Aerothyris kerguelenensis (Da¬ vidson): Three specimens, adults with average L/W of 1.03 and T/W of 0.55. The foramen measures 2.0 or below for all three. Station 46, CP 204. Aerothyris kerguelenensis (Da¬ vidson): Twenty-four specimens ranging in length from 19.0 to 33.2 and in width from 16.4 to 31.1 mm. L/W range=0.98-l. 10, and averages 1.04 (only 2 specimens 1.10 and above); T/W range=0.50-0.67, and averages 0.56. Most specimens, (82%) have a foramen of 2.0 mm or less. The specimens are mostly wide and rounded, modestly sulcate (Figures 9, 22, 26). Station 48, CP 209. Aerothyris kerguelenensis (Da¬ vidson): Twenty-four specimens ranging in length from 18.7 to 44.6 mm and in width from 18.0 to 38.7 mm. L/W range= 1.04-1.48, with an average of 1.19 (21 specimens are 1.10 or above). Many specimens are unusually narrow. T/W range=0.52-0.80, and averages 0.63. Forty percent of the specimens have a foramen 2.5 mm or above; the remainder are 2.0 mm or below; one with keyhole type. These are thick, elongate forms (Figures 18, 22, 25). Station 50, DC 216. Aerothyris kerguelenensis (Da¬ vidson): Twenty-six (average L=13.0 mm), mostly small shells varying in length from 7.0 to 21.5 mm and in width from 6.5 mm to 18 mm. The L/W range=0.99-1.29, with average of 1.13; T/W range=0.44-0.62, with average of 0.52. Fifty-nine percent of the L/W is over 1.10, thus indicating a tendency toward the typical form of A. kerguelenensis. Specimens pre¬ pared to show the loop indicate a shorter growth period to free the loop from the median septum. A specimen of 12.0 mm has a free loop but the descending branches show projections of the lateral branches not yet resorbed. The largest specimen in this lot has a L/W of 1.19 and is almost a miniature of type A. kerguelenen¬ sis. (Figure 22.) Station 59, DC 252. Aerothyris kerguelenensis (Da¬ vidson): Four large specimens with average L/W of 1.12 and T/W of 0.56. Foramen 2 mm. Station 60, DC 248. Aerothyris kerguelenensis (Da¬ vidson) : Three specimens with average L/W of 1.11 and T/W of 0.60. Foramen 2.0 or below, one with keyhole type. Station 60, RK 251. Aerothyris kerguelenensis (Da¬ vidson): A single specimen of length 29.3 mm and width 26.8 mm and L/W= 1.09 and T/W=0.58; foramen 2.0 mm. Strong narrow sulcus. Station 62, CP 257. Aerothyris kerguelenensis (Da¬ vidson): Thirteen specimens ranging in length from 21.6 to 37.7 mm and in width from 20.8 to 33.7. L/W range= 1.03-1.30, and averages 1.13 (six specimens only under 1.12); T/W range=0.52-0.73, and averages 0.62. Eighty percent of the specimens have the foramen at 2.0 mm or above (Figures 14, 22, 25). Station 73 CP 295. Aerothyris kerguelenensis (Da¬ vidson): Six specimens with length range 22.8- 32.7 and width range 23.7-29.5. L/W range=0.96-l. 13 (three specimens below 1.00), and average of 1.02; T/W range=0.48-0.59, average 0.52. Foramen: 5 specimens 2.5 mm or below, one at 3.0 mm. Some specimens round, i NUMBER 43 33 nearly circular. No radial striae seen. Station 74, DC 296. Aerothyris kerguelenensis (Da¬ vidson): Twenty-three specimens ranging in length from 21.0 to 35.0 mm and in width from 20.3-32.3 mm. L/W range=0.99-l. 16, average 1.06 (only 5 specimens above 1.09); T/W range=0.45-0.59, with average 0.54. Foramen: 12% at 3.0 mm or above; 38% at 2.5 mm and the remainder 2.0 mm or below. Mostly rounded oval shells (Figures 10, 22, 25). Station 75, CP 303. Aerothyris kerguelenensis (Da¬ vidson): Twenty specimens ranging in length from 23.2 to 39.7 mm and in width from 22.0 to 34.6 mm. L/W range= 1.02-1.16 (14 speci¬ mens 1.10 or below), average 1.09; T/W range=0.45-0.61, average 0.54. Foramen mostly large, all specimens above 2.0 mm (Fig¬ ures 11, 22, 25). Station 75, CP 304. Aerothyris kerguelenensis (Da¬ vidson): A single specimen 37.8 mm long and 32.3 mm wide with L/W= 1.17 and T/W=0.58. Foramen of 3.0 mm. Station 75, CP 305. Aerothyris kerguelenensis (Da¬ vidson): Four specimens varying in length from 22.8 mm to 38.2 mm. L/W range= 1.08-1.20 (2 specimens at 1.20, average 1.16); T/W range=0.50-0.59. Foramen all 2.0 mm or above. Station 75, CL 308. Aerothyris kerguelenensis (Da¬ vidson): Three large specimens with length from 30.5 to 37.0 mm and width 28.7 to 32.3 mm. Average L/W=1.15 (with two at 1.17 and 1.21, the third at 1.06); average T/W=0.57. Size of foramen uncertain because of attach¬ ment. Station 77, DC 314. Aerothyris kerguelenensis (Da¬ vidson): Seventeen specimens ranging from 19.8 to 33.0 mm in length and 19.6 to 28.0 mm in width. L/W range= 1.01-1.27 (only 4 speci¬ mens are 1.10 or below), average 1.16; T/W range=0.52-0.69 (all but two above 0.60), av¬ erage 0.63. Foramen: mostly 2.0 or above, only one at 1.5 (Figures 16, 22, 25). Station 78, CP 319. Aerothyris kerguelenensis (Da¬ vidson): Eight specimens ranging in length from 16.4 to 42.0 mm and in width from 16.0 to 32.0 mm. L/W range= 1.03-1.31, with av¬ erage of 1.13 (5 specimens 1.10 or below); T/W range=0.51-0.79, and averages 0.59. For¬ amen: all 2.0 mm or below. Station 79, CP 326. Aerothyris kerguelenensis (Da¬ vidson): Twenty-four specimens ranging from 13.8 to 40.0 in length and 13.8 to 35.5 in width. L/W range= 1.00-1.35, with average of 1.09 (10 specimens are 1.10 or below). One specimen with L/W=1.00. T/W range=0.51-0.67, aver¬ age 0.57. Foramen 85% 2 mm or more (Figures 11, 23, 25). Aerothyris macquariensis (Thomson) (for comparison with A. kerguelenensis ): 100 adult specimens ranging in length from 19.2 to 44.7 mm and in width from 16.4 to 42.0 mm. L/W ratio range=0.99-1.36, and averaging 1.13. Thick¬ ness range= 10.0-25.6 mm. T/W range=0.52- 0.74, with average of 0.62. The foramen aver¬ ages 80% above 2 mm in width (Figures 23, 26; specimens from Harvard station 27-36, Foster 1974:158). Aerothyris kerguelenensis (Davidson) Figures 6-26; Plate 4: figures 1-3, 7-9; Plate 7: figures 1-30; Plate 8: figures 1-10; Plates 9-11; Plate 12: figures 5-27; Plate 13: Figures 16-23. Waldheimia kerguelensis Davidson, 1878:431; 1880:40, pi. 3: figs. 1-9; 1886:53, pi. 10: figs. 7-17. W. dilatata Smith, 1879:192.—Studer, et al., 1889:155. Terebratella dorsata Davidson [not Gmelin] 1880:44, pi. 4: fig. 4. ?Mage llama kerguelensis [sic] (Davidson).—Eichler, 1911:390, pi. 42: fig. 7; pi. 43: fig. 16. Magellania kerguelenensis (Davidson) Jackson, 1918:179.—Fos¬ ter, 1974:137, fig. 3, part 33; 31K,L; pi. 20: figs. 2-4, pi. 24: figs 5-7. Terebratella emenspergeri Blochmann, 1906:697.—Eichler, 1911:12, pi. 42: figs. 10a,b; lla-d. Terebratella? emenspergeri Blochmann.—Foster, 1974:109, fig. 3, part 18; 301, J; pi. 18: figs. 10-12; pi. 22: fig. 10; ?Aerothyris eichlen Allan, 1939:245. Description. —Medium to large, approaching 2 inches (51 mm) in length, valves subequal in 34 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 20 22 24 26 28 30 32 34 36 38 40 42 44 N= 9 8 LENGTH Figure 6.— Scattergram showing length/width relationship of Aerothyris kerguelenensis (Davidson) of 98 specimens from MD.03: station 30, CP 21 (circled star = position of A. enzenspergeri (Blochmann); large dot = position of type specimen of A. kerguelenensis). depth, ventral valve usually deeper than dorsal in diameter) taking the form of a keyhole. Delti- one. Outline variable, usually longer than wide dial plates usually disjunct, occasionally conjunct, with maximum width at midvalve, subcircular, often partially or wholly eliminated by pedicle subrhomboidal to elongate oval. Sides rounded, pressure. Pedicle usually short, with short “root- anterior margin broadly to narrowly rounded to lets” at its distal end. Color yellowish white, subnasute. Posterolateral margins forming an ap- surface smooth except for incremental lines of ical angle of 80°-105° Lateral commissure growth more or less strongly developed and often straight or faintly sigmoidal; anterior commissure concentrated anteriorly and marginally. Punctae sulcate from faint to fairly strong. Beak variable, varying from about 80 to slightly over 100 per often posteriorly abraded, usually short, suberect square mm. counted near midvalve, to strongly incurved (erect); beak ridges suban- Ventral valve gently and fairly evenly convex gular and strongly marked in the young, setting in lateral profile with maximum convexity in off a narrow interarea, more rounded in old shells. umbonal region; anterior profile strongly convex Foramen variable from widely circular (4 mm with a rounded, posteriorly narrow, median keel diameter) to narrowly elliptical (less than 1 mm extending from beak to anterior margin as a more WIDTH THICKNESS 36 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 32 30 I I- O £ 28 26 24 • • 22 24 26 N = 2 4 28 30 length 32 34 Figure 9. —Scattergram of 24 specimens of A. kerguelenensis (Davidson) from MD.08: station 46, CP 204 showing length/width relationship (L/W=1.04 of 24 specimens; circled star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson). or less well-marked fold, occasionally produced into a subnasute extension; lateral slopes flat¬ tened, moderately steep. Dorsal valve slightly more convex then ventral one with maximum swelling in posterior half; anterior half somewhat flattened. Umbonal re¬ gion swollen; sulcus obscure in young, beginning near midvalve, shallow and only slightly de¬ pressed, forming a channel with slightly convex to flat bottom. Sulcus when pronounced forming a short anterior tongue. Flanks bounding sulcus narrow, steeply sloping. Ventral valve interior with variable, sessile, pedicle collar. Teeth moderately large, obliquely elongated, tapering medially and supported by callus thickening. Delthyrial cavity deep; muscle field reaching 1/3 to 1/4 the valve length from the beak. Diductors large, forming an elongate patch; accessory diductors small, the two sets attached to a strap-like tendon that in turn at¬ taches to the cardinal process (Plate 8: figure 10). Muscle scars usually well impressed and divided by a low median ridge. Pallial trunks (vascula myaria) broad, extending from each side of the diductors directly to the anterior margin, with 3 lateral branches, (Plate 9: figure 5). Dorsal valve interior, variable with age. Car¬ dinal process of young broadly elliptical, bilobed, with concave roughened myophore, in old age thickened anteriorly to form a stout bulbous shaft with myophore enclosed by elevated rim. Socket ridges of young thin and erect, bounding narrow sockets, becoming greatly thickened with age; inner hinge plates* of young well defined, meet¬ ing the median septum to form umbonal cham- * Dagis (1974:15-17) suggests use of septal plates rather than inner hinge plates for these struts because they are different from the horizontal, often secondary, inner hinge plates of the terebratulaceans. NUMBER 43 37 bers, in old age becoming obsolete by filling of lateral umbonal chambers. Median septum in young forming a thin wall tapering to about midvalve, greatly thickened and partially buried in old specimens. Loop magellaniform in shells from 16 or 17 mm to full adulthood. Crura very short, flat in section. Crural processes long and needlelike. Pallial trunks forming pinnate (apo¬ copate) pattern consisting of two unbranched direct vascula media extending from anterior end of adductors to anterior margin and lateral vas¬ cula myaria extending from sides of adductors to anterior margin as two broad channels with six lateral branches. (Plate 9: figure 4). Measurements (mm) of Specimens from MD: 03, Station 30, CP 21 (Plate 7).— I am grateful to Dr. Howard Brunton, British Museum (Natural History) for the above mea¬ surements. These clearly indicate the specimens used by Davidson in creating A. kerguelenensis. It will be noted that the pedicle foramen is variable and that all specimens have disjunct deltidial plates. The L/W is very variable; all but one specimen is over 1.03 and one is 1.41. These show that Davidson selected mainly oval specimens to illustrate the species, because all of the figured specimens except one, have L/W in excess of 1.10. Bathymetric Range.— 6-930 m. Stations (underlined stations have measured populations represented by scattergrams).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle L/W T/W Foramen diam. MNHN-BRA-78-75a 43.7 37.8 40.7 26.0 98° 1.05 0.59 1.3 MNHN-BRA-78-75b 37.9 34.6 32.4 19.7 00 0 1.17 0.61 2.0 MNHN-BRA-78-75c 32.8 29.4 27.5 16.7 o 00 CO 1.15 0.61 2.5 MNHN-BRA-78-75d 26.5 24.0 22.7 13.8 97° 1.17 0.61 1.5 MNHN-BRA-78-75e 22.8 20.1 20.9 11.0 97° 1.09 0.52 1.5 MNHN-BRA-78-75f 19.2 16.8 16.7 9.3 94° 1.15 0.56 1.5 MNHN-BRA-78-75g 24.7 21.9 21.9 11.6 93° 1.13 0.53 2.0 MNHN-BRA-78-75h 14.1 12.5 13.0 7.0 81° 1.08 0.54 1.0 Measurements (mm) of Specimens from MD: 08, Station 12, DC 78 (Plate 9).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle L/W T/W Foramen diam. MNHN-BRA-78-83g 44.0 38.2 39.0 22.0 104° 1.13 0.56 1.3 MNHN-BRA-78-83h 40.8 36.4 38.6 21.3 113° 1.06 0.55 3.5 MNHN-BRA-78-83i 38.4 34.0 34.5 19.3 100° 1.11 0.56 1.0 MNHN-BRA-78-83a 36.0 30.5 30.0 20.6 92° 1.20 0.69 1.5 MNHN-BRA-78-83e 19.9 18.0 20.0 10.5 95° 1.00 0.53 1.25 MNHN-BRA-78-83f 44.3 38.6 36.9 27.8 97° 1.20 0.75 3.0 Measurements (mm) of Specimens from MD: 08, Station 42, CP 197.— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle L/W Foramen width MNHN-BRA-78-120a 35.7 36.2 33.7 20.3 102° 1.06 2.0 MNHN-BRA-78-120b 37.7 32.8 35.5 19.5 94° 1.06 2.5 MNHN-BRA-78-120c 39.3 35.0 33.8 21.6 101° 1.16 3.0 MNHN-BRA-78-120d 36.4 32.3 33.2 10.8 102° 1.09 4.0 MNHN-BRA-78-120e 34.0 29.7 31.6 17.5 102° 1.08 3.0 MNHN-BRA-78-120f 36.2 30.9 32.8 17.8 91° 1.11 3.0 MNHN-BRA-78-120g 42.8 37.6 36.8 24.3 105° 1.16 3.5 MNHN-BRA-78-120h 32.0 28.7 27.0 18.0? o CO CO 1.18 2.5 38 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Measurements (mm) of Type Specimens in the British Museum (Natural History) (Figure 19) — BMNH Cat. No. Plates and figures* Length Width Thick¬ ness Foramen width Deltidial plates L/W 77 W ZB 1007 10.5 10.2 ca. 6.0 1.0 disjunct 1.03 0.59 ZB 1078 10:16 (3:8) 28.5 25.0 p p p 1.14 p ZB 1080 10:7 (3:1) 43.5 35.0 28.2 1.5 disjunct 1.24 0.81 ZB 1081 10:8 (3:2) 39.5 35.4 24.7 1.6 disjunct 1.12 0.70 ZB 1082 10:9 (3:5) 33.6 28.0 ca. 19.5 1.3 disjunct 1.20 0.70 ZB 1083 10:10 (3:4) 30.5 25.2 17.0 2.0 disjunct 1.21 0.67 ZB 1084 26.6 24.4 15.5 (eroded) 2.6 disjunct 1.11 0.65 ZB 1085 24.5 18.5 p (eroded) 1.8 disjunct 1.32 p ZB 1086 10:12 21.0 16.5 11.2 (eroded) 1.5 disjunct 1.27 0.68 B 12436a 28.9 ca. 23.0 ca. 17.0 (eroded) 1.6 disjunct 1.26 0.74 B 12436b 26.0 ca. 18.5 13.2 (eroded) 1.9 disjunct 1.41 0.71 B 12436c 38.2 34.4 23.0 (eroded) 1.7 disjunct 1.11 0.67 * Plate 10 is in Davidson, 1886; the figures in parentheses refer to the same figures on plate 3 in the Challenger report (Davidson 1880). i i- o i • N = 23 LENGTH Figure 10.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 74, DC 296, 23 specimens (L/W = 1.06; circled star = position of A. enzenspergen (Blochmann); circled dot = position of type A. kerguelenensis). NUMBER 43 39 Q i •N = 24 •N = 20 LENGTH Figure 11.—Scattergrams of length/width of 2 lots of A. kerguelenensis (Davidson) from MD.08: station 75, CP 303, 20 specimens (large dots) and 79, CP 326, 24 specimens (small dots) (both L/W=1.09; circled dot = position of A. enzenspergeri (Blochmann); circled star = place of type A. kerguelenensis). MD.03: 2, DC 1; 2, CB 2; 9, DM 2; 9, DM 4; 10, DC 7; 11, CP 7; 14, DC 8; 14, CB 3; 23, CP 16; 24, CB 6; 25, CB 7; 26, CP 17; 30, CP 21; 31, CP 22. MD.08: 9, CP 64; 9, CP 65; 9, CP 66; 9, DC 68; 9, BB 69; 9, CP 74; 9, CP 75; 12, DC 78; 12, BB 79; 15, DC 87; 15, BB 88; 16, CL 95; 17, DC 96; 17, BB 97; 18, DC 107; 18, BB 108; 18, RK 109; 20, DC 116; 21, DC 118; 25, CP 134 ; 26, CP 135; 27, DC 136; 28, DC 143; 28, DC 148; 31, DC 156; 32, DC 162; 33, DC 164; 34, DC 167; 34, BB 168; 36, DC 173; 36, CP 175; 39, DC 178; 39, BB 183; 40, DC 185; 40, DC 186; 42, CP 197; 45, CP 203; 46, CP 204 ; 48, CP 209; 50, RK 217; 50, DC 216; 50, BB 218; 51, DC 221; 52, DC 224; 54, DC 234; 55, CP 237; 59, DC 252; 59, BB 253; 60, DC 248; 60, RK 251; 61, DC 255; 62, CP 257 ; 64, DC 286; 67, DC 271; 67, BB 273; 71, DC 283; 71, BB 285-286, 72, DC 289; 72, BB 291; 73, CP 295; 74, DC 296; 74, BB 297; 75, CP 303; 75, CP 305; 75, CL 306; 75 CL 308; 76, DC 309; 77, DC 314; 77, BB 315; 78, CP 319; 79, DC 322; 79, BB 323; 79, CP 326; Marion Island III, Z63. Types.— Hypotypes: MNHN-BRA-78-27a,b; 75a-i; -76a-e; -77a-c; -78; -79; -80; -81; -83a-e; 84; -85; -86; -87; -90a-d; -92; -93; -94a-d; -95; 96; -98; -99a-c; -100; -101; -102; -103; -104; -106; -107; -108; -109; -110; -111; -116; -117; -118; 120 ; - 121 . Discussion.— The above measurements show some of the variability in samples of 3 populations of A. kerguelenensis. Davidson in describing his species mentioned the variability in passing, but figured specimens that seem to be rather extremes in the general population of this species. The specimen figured (Davidson, 1880, plate 3: figures la,b) is unlike any in the collections available to me in the prominence of the lateral folds bound¬ ing the dorsal valve sulcus. His figure 2 on the 40 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 LENGTH Figure 12.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.03: station 26, CP 17, 50 specimens (L/W=l.l 1; circled star — position of type A. kerguelenensis ; solid star = position of A. enzenspergen (Blochmann) = A. kerguelenensis (Davidson)). same plate shows a rounder and less folded spec¬ imen such as that measured above MNHN-BRA- 78-75b. Variation.— The samples of various popula¬ tions taken by cruises MD.03 and MD.08 show extreme variability from predominantly round specimens suggestive of Aerothyris macquariensis to elongate narrow ones. The L/W of the average populations studied in this report vary from 1.02 to 1.19. The specimens figured by Davidson and specimens from the Challenger collection in the National Collection appear in the higher part of the range with L/W averaging 1.21. These spec¬ imens are narrowly elliptical and have a fairly strongly curved beak. They are not however typ¬ ical of the species. Specimens ranging in L/W between 1.15 and 1.20 are predominantly small and elongate oval. Davidson selected prominent but uncommon specimens to illustrate his species. Many of these small specimens agree in propor¬ tions with topotypes of A. kerguelenensis in all particulars but size. One of the distinctions be¬ tween A. macquariensis (Thomson) and A. kerguele¬ nensis is the greater calcification of the interior of the latter. Adults of all the populations considered in this paper, save one, are in general more heav¬ ily calcified than is usual in the Macquarie Island species. The exception is the collection from MD.08: station 22, BB 125, which is discussed below, the specimens being referred to Aerothyris aff. A. macquariensis (Thomson). Deltidial plates.— The deltidial plates are variable in all Aerothyris populations that concern us. In a population from MD.03: station 14, DC 8 an unusual 12 specimens out of 45 proved to have conjunct deltidial plates, just over 25%. Of NUMBER 43 41 N= 22 LENGTH Figure 13. — Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 12, DC 78, 22 specimens (L/W=l.l 1; solid star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson); open star = position of type A. kerguelenensis) the 12 specimens all except one are large adults. The conjunct deltidial plates or deltidium is usu¬ ally short with the foramen elongate, oval, and submesothyridid in position. At MD.03: station 30, CP 21, only 2 specimens out of 65 had con¬ junct deltidial plates. A number of isolated and broken ventral valves from MD.08: station 18, DC 107 have conjunct deltidial plates. The plates are united at their anterior extremity as a thin line and the joined edges bend ventrally and are marked externally by a depressed line of junction (Plate 12: figures 13-16). The development of conjunct deltidial plates may be a reaction to reduction in the size of the pedicle, possibly sig¬ nalling its atrophy. It is known that some tere- bratulid brachiopods, Neothyris lenticularis (De- shayes), lie loose on the seabottom weighted down by the great thickening of the ventral umbonal region (Allan, 1937:160; Lee, 1978:402; Foster, 1974:100) after reduction of the pedicle. Foramen.— Features of A. kerguelenensis empha¬ sized by Davidson and Foster are the size and shape of the foramen. In some specimens the foramen is large, measuring as much as 4 mm in diameter, but in others it is extremely narrow, often somewhat oval, and measuring one mm or slightly less at its widest part. These narrow open¬ ings often have an accompanying near conjunc¬ tion of the deltdial plates that leave a narrow slit under or anterior to the foramen, producing the “keyhole” type of foramen that is said to be a distinguishing mark of the species (Plate 9: figures 9, 12, 21, 24, 25). This type of foramen may occur in wide or narrow shells and is known also to occur spasmodically in Aerothyris macquariensis (Thomson) (Foster, 1974). Specimens with wide 42 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 20 22 24 26 28 30 32 34 36 38 40 •N=ll »N=I3 LENGTH Figure 14.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 26, CP 135, 11 specimens (small dots); L/W=1.12) and station 62, CP 257, 13 specimens (large dots: L/W=1.13; very large dot = position of type A. kerguelenensis ; star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson). foramen usually have the beak short and nearly straight, often with some sign of abrasion. These shells were undoubtedly fixed close to the sub¬ strate by a short, stout pedicle. The keyhole for¬ amen usually occurs in specimens having a sub¬ erect or incurved beak signifying a long slender pedicle. It is possible that the keyhole is a devel¬ opment toward, or as a consequence of, atrophy of the pedicle and development of free living on the bottom. No sure correlation was found be¬ tween type of bottom and size of the pedicle. Specimens from Md.08: station 75, CP 303 have a high percentage of specimens with large fora¬ men and live on sand and gravel. Specimens from MD.08: station 28, DC 148 live on coarse sand and gravel but have a predominantly small for¬ amen. Specimens from all of the stations having muddy bottom had predominantly small pedicle openings. No correlation between depth and size of pedicle opening was found. In considering the taxonomic value of the ped¬ icle opening, it was decided arbitrarily to regard lots with a pedicle predominantly above 2 mm in diameter as having a large foramen; from 2 mm and below the foramen is regarded as small. It will be noted that the lots usually contain both types, one usually predominant over the other. Loop Development. —No complete series from a single population occurs in the collection but tiny specimens 2.5-6 mm in length are present in the collection from MD.08: station 40, DC 186, together with a well-preserved loop in a specimen of 13 mm. The specimens at this station are fairly round, average L/W=1.08. A fair idea of the complete story of the loop development can be obtained from specimens from MD.03: station 26, CP 17 ranging in length from 7.5 mm to 17 mm. Specimens from this station are somewhat longer than those of the preceding series (average L/W= 1.12). NUMBER 43 43 o i N = 18 LENGTH Figure 15.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 9, CP 75, 18 specimens (L/W=1.14; large dot = position of type A. kerguelenensis ; star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson). Specimens from MD.08: Station 40, DC 186 (Plate 11: figures 13-17): Three specimens (MNHN- BRA-78-104a-c), measuring 2.5-3.0 in length of ventral valve show the dorsal median pillar in incipient stage, the younger two without any trace of crura. The specimen measuring 3 mm shows a trace of the crura and more prominent socket ridges. In this specimen the pillar is ex¬ tended posteriorly to about midvalve, the begin¬ ning of the median septum. The next specimen (MNHN-BRA-78-104d) is 4 mm long, has an elongated pillar with septum extending nearly to the notothyrial chamber. There is a slight excavation and widening of the distal end of the pillar, the incipient cone. The crura are minute nubs. The next specimen (MNHN-BRA-78-104e), 4.5 mm long, shows the pillar with a small but well-developed cone open toward the posterior, the crura short, with slight development of the crural processes. The descending lamellae ante¬ rior to the crural processes extend to midway of the distance to the cone. A sixth specimen (MNHN-BRA-78-104f), not quite 5 mm long, has a slightly more advanced cone than the preceding and with incipient de¬ velopment of the anterior part of the descending branch on the side of the pillar. The cone is irregular with anterior elongated and posterior cover recessed. The crural processes are well de¬ veloped, but the descending branch anterior to them is not advanced over the preceding stage. The descending inner hinge plates are slightly excavated anteriorly and meet the floor; the sep¬ tum is continued to meet their anterior junction. A specimen of 5 mm length (MNHN-BRA-78- 104g) has a well-developed, posteriorly open cone, well-formed septum, and inner hinge plates joined with the septum. The crural processes are well formed and the two elements of the descend¬ ing lamellae are joined. A slightly larger specimen (MNHN-BRA-78-104h) is essentially the same 44 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 10 12 14 16 18 20 22 24 26 28 30 32 34 Figure 16.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 28, DC 148, 18 specimens (small dot) and 77, DC 314, 17 specimens (medium dot), both L/ W=l. 16 (circled star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson); largest dot = place of A. kerguelenensis). except that the descending lamellae are not com¬ plete. A specimen 13 mm in length (MNHN-BRA- 78-104i) has the loop transformed from the cone with median septum, descending branches, and part of the septum just being resorbed. Other features are like those of the adult. Specimens from MD.03: Station 26, CP 17 (Plate 7, figure 25; Plate 11, figures 1, 2): The smallest specimen (MNHN-BRA-78-76b) is 6 mm long with expanded cone, the anterior part attached to the pillar undergoing resorption as shown by a deep reentrant. The posterior base of the cone is strongly attached to the pillar now expanded into a high septum joined to the inner hinge plates. The ventrad part of the cone forms a fairly wide loop. A specimen 13 mm long (MNHN-BRA-78-76c) shows a fairly well-advanced loop with narrow, curved, lateral ribbons joining the descending lamellae united, but just freed from the septum. The crural processes are now needle sharp points. Compared to the 13 mm long specimen described above, this one differs in still retaining the trans¬ verse ties of the descending branches, although the septum has been resorbed from under the lateral tying bands, leaving the loop free. The next specimen (MNHN-BRA-78-76f), 14 mm long is in essentially the same condition as the preceding, but with the loop still fixed to the median septum. A specimen 17 mm long (MNHN-BRA-78- 76g) is near adulthood because the bands tying the descending branches to the median septum are wholly free but remnants of the tying bands are still attached to the descending lamellae. NUMBER 43 45 Figure 17.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 25, CP 134, 35 specimens (L/W=1.18; star = position of A. enzenspergeri (Blochmann) = A. kerguelenensis (Davidson). Some specimens of a size larger than 17 mm exhibit traces of the tying bands on the descend¬ ing lamellae as more or less prominent irregular¬ ities. The development of the loop does not conform in all instances to definite stages. The condition at 6 mm may show variation in the development of the cone and the progress of the completion of the descending branches of the loop. Evidently, freeing the loop from the septum may take place before or after 15 mm of length has been ob¬ tained. A feature worth noting, in the specimens from 13 mm to 17 mm long, is the freeing of the distal end of the median septum before the lateral bands joining the descending lamellae have been resorbed. Five specimens show this. The loop is in the terebratelliform stage, but free of the tip end of the septum or pillar remnant. It is possible that, in clearing the flesh with Chlorox the end of the thin and delicate septum was attacked. How¬ ever, parts of the loop are as delicate as the septum and have not been injured. At any rate, the development is essentially the same as that seen in Aerothyris macquariensis. The loop development shown here is like that depicted by Foster (1974:140-141, fig. 38) for Magellania macquariensis (Thomson). He mentions that some specimens at 13.6 mm have a magel- laniform loop. He (page 140) also mentions “One specimen at 13.9 mm has the descending branches joined, but these branches do not join to the septum.” This is a rare condition like that men¬ tioned above. In order fully to understand Aerothyris kerguele¬ nensis and its variation, a discussion of Terebratula enzenspergeri Blochmann is needed to explain why this “species” is herein regarded as a synonym of A. kerguelenensis. Terebratella enzenspergeri is a species from Ker¬ guelen Island described by Blochmann, who in¬ cludes in his species a specimen collected by the Challenger expedition described and illustrated by Davidson (1880:44, pi. 4: fig. 4) under the name 46 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY x t- Q 5 N= 2 4 LENGTH Figure 18.—Scattergram of length/width of A. kerguelenensis (Davidson) from MD.08: station 48, CP 209, 24 specimens (L/W=1.19; large dot = position of large A. kerguelenensis ; star = position of A. enzenspergen (Blochmann) = A. kerguelenensis (Davidson). Terebratella dorsata (Gmelin). The specimen comes from Royal Sound, latitude 49°40' S, longitude 70°20' E, off Kerguelen Island. Davidson noted that the loop of his specimen was “doubly at¬ tached.” Blochmann (1906:697) obtained an ad¬ ditional specimen from Kerguelen Island that he identified with Davidson’s specimen and named the two specimens as a new species, Terebratella enzenspergeri. The Davidson and Blochmann specimens were further studied by Eichler (1911:392) and Foster (1974:109), both of whom refer the species to Terebratella , but Foster queries the name. Bloch¬ mann (1906) early showed that Davidson’s Tere¬ bratella dorsata (1880, pi. 4: fig. 4) was not to be referred to the South American species because there were many obvious differences, among them lack of strong costation and a lesser number of punctae per square mm in the Kerguelen form. Terebratella enzenspergeri is marked by scattered irregular striae (grooves not costellae). Eichler also pointed out differences between T. dorsata from South America and T. enzenspergeri. Foster (1974:111) notes that Davidson men¬ tioned the doubly attached loop. This British Museum (Natural History) specimen does not preserve the loop and Foster found no remnants indicating attachment. He examined other spec¬ imens said to be of T. enzenspergen , all without loop, and failed to find evidence of double at¬ tachment. He therefore queried the use of the name Terebratella for this species. The figures of T. enzenspergeri published by Eichler include Davidson’s figured specimen, an¬ other from the Challenger Expedition, and one collected by the Gauss Expedition at Kerguelen Island. Davidson’s figured specimens (the type?) is 25.8 mm long, 25.0 mm wide, and 6.5 mm thick; the second is 16 mm long and wide; the Gauss specimen is 15 mm long, 15 mm wide, and 6.5 mm thick. It will be noted that these speci¬ mens are nearly equal in length and width. The dorsal interior of the larger Challenger specimen (Eichler, 1911, pi. 42: fig. lid) shows no trace of lateral bands on the unthickened, low, median septum, and the hinge plate is well excavated. NUMBER 43 47 38 36 34 32 30 28 26 X I- Q $ 24 22 20 18 16 14 4 ★ Ls_ 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 LENGTH Figure 19.—Scattergram of length/width for 18 specimens of A. kerguelenensis (Davidson) (solid stars = A. enzenspergen (Blochmann) = A. kerguelenensis (Davidson); small dots = Challenger specimens in National Museum of Natural History; large dots type specimens in British Museum (Natural History); very large dot = Harvard University, Museum of Comparative Zoology 9520A (Foster, 1974, pi. 20, fig. 2); open star average Aerothyris macquariensis Thomson (Plate 8: figures 11-13). Foster (1974:111) notes: “The cardinalia and median septa in T.? enzenspergeri are similar to those in Magellania macquariensis Thomson, but M. macquariensis is essentially smooth, is deeper and narrower, and is without a straight hinge line.” He notes also that Magellania? kerguelenensis has a heavier, narrower, and deeper shell than enzen¬ spergeri and an essentially sessile hinge plate.” Foster (1974, pi. 18: fig. 10) illustrates a speci¬ men labelled as 77? enzenspergeri much larger and quite unlike the British Museum and Gauss spec¬ imens, taken from the Gulf of Morbihan, Ker¬ guelen Island. It is wide-hinged, with large fora¬ men. No trace of radial striae is evident in the picture. The specimen is similar to large, wide forms of A. kerguelenensis. The striae of T. enzen¬ spergeri appear to be the result of marginal injuries and not a normal feature of the shell (Plate 13). Sporadic specimens of A. kerguelenensis in the pres¬ ent collection and also A. macquariensis (Thomson), show this type of striation to a minor degree (Plate 13: figure 24). The British Museum speci¬ mens figured by Eichler are striated to an exag¬ gerated degree and suggest pathological shells. Many of the striae can be traced to irregularities in the shell margin at successive stages of growth (see Plate 13: figures 20-24). Consultation of the scattergrams (Table 1; Figures 6-20, 27-29) will show a continuum of populations from L/W=1.02 to 1.19. The former end of the series is mostly of nearly round shells while the opposite end is of elongate oval specimens. However, oval specimens occur in predominately round popu¬ lations while circular specimens appear in popu- 48 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 56 8 10 12 14 16 18 20 22 N= 26 LENGTH Figure 20.—Scattergram showing L/W ratio of small Aerothyris kerguelensis (Davidson) from MD.08: station 50, DC 216. lations of oval specimens (L/W=1.16-1.19). At station 46, CP 204, a population with average L/W of 1.04 contains one oval specimen with L/W=1.16 along with 6 specimens very close to the dimensions of enzenspergeri. A population at station 77, DC 314, with L/W=1.16, contains one specimen that is almost circular. There is little uniformity in the foramen in any of the popula¬ tions. So little is known of the variation of outline of enzenspergeri that the name cannot be intelligently applied for a species. It is not known whether or not it produces specimens with a keyhole fora¬ men. The figured specimens all have a large, round foramen. It is possible that all of the illustrated specimens of A. enzenspergeri , two of which are 15 and 16 mm in length and width and the third 25 mm, are merely young, round individuals of a population of A. kerguelenensis. As noted elsewhere, the illus¬ trated shells of A. enzenspergeri may be pathologic. Inasmuch as the size and form of the foramen are probably controlled by bottom conditions and by the niche in which any individual lived, it will be fashioned by these conditions and not be a reliable specific or generic character. Not one of the populations studied has a uniform develop¬ ment of the foramen, although some have a pre¬ dominance of one kind. The collection described herein contains 37 samples of populations from as many localities. The average L/W of these populations ranges from 1.02 to 1.19. Fifteen of them contain one or more specimens answering to the proportional dimensions of the type specimens of T. enzensper¬ geri as described by Eichler. None of these has the radial “striae” seen on the types. The average L/W of the samples containing these specimens ranges from 1.02 to 1.16. Specimens of the pro¬ portional dimensions of T. enzenspergeri may ap¬ pear in any population of A. kerguelenensis. The types of T. enzenspergeri consist of three specimens, two of which are 16 mm long, and one only 25.8 mm long. The two smaller ones are at NUMBER 43 9 - CP 75 80 60 9-DC68 22-BBI25 Figure 21.—Histograms showing percentage of L/W index in Aerothyris kerguelenensis (Davidson) in various stations of MD.08. (Station 22, BB 125 represents Aerothyris aff. A. macquanensis (Thomson).) Figure 22.—Histograms showing percentage (Davidson) in various i SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY NUMBER 43 51 80 Notosoria nigricons 60 40 20 0.90 1.00 1,05 1,10 1.15 L20 ~ 0l90 1.00 105 1.10 1.15 1.20 79-CP326 26-CP17 Figure 23.—Histograms showing percentage of L/W index in Aerothyris kerguelenensis (Davidson) in MD.08: station 79, CP 326, and 4 stations of MD.03, and for comparison, percentage of L/W in Pemphixina pyxidata, Notosaria nigricans , and Aerothyris macquanensis (from Harvard station 27-36). 3.5 I 9-DC 68 Figure 24.—Histograms showing percentage of kerguelenensis (Davidson) from 8 stations of MD.O A. macquariensis (Thomson).) SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY NUMBER 43 53 80 60 80 60 80 60 40 20 46-CP204 75-CP303 80 60 20 1.0 1.5 2.0 2.5 3.0 3.5 4.0 L0 1.5 2.0 2.5 42"CP 197 74 “DC 296 Figure 25. — Histograms showing percentage of foramen diameter measurements in Aerothyris kerguelenensis (Davidson) from 8 stations of MD.08. the critical time of resorption of the septal pillar and freeing of the loop (ca. 17 mm, see below). Well-preserved specimens of this size might give the impression of having a terebratelliform loop. Eichler’s largest specimen of the three he de¬ scribed probably had a free loop. The cardinalia of the dorsal interior of 71 enzenspergeri figured by Eichler are not strongly 54 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 60 40 20 9-CP 64 26 “CP 17 80 60 40 20 78 " CP 319 14-CB 3 Figure 26.— Histograms showing percentage of foramen diameter in Aerothyris kerguelenensis (Davidson) in 3 stations of MD.08, 4 stations of MD.03, and Aerothyris macquanensis (Thomson). calcified because the illustrated shell is a young not until more maturity is reached, individual. Calcification of the cardinalia in A. I conclude from the above that T. enzenspergeri kerguelenensis , like its other characters, is variable, is probably a young form representing a wide or some young shells thickening early in life, others nearly circular outline of Aerothyris kerguelenensis. NUMBER 43 55 Aerothyris macquariensis (Thomson) Figures 23, 26, 27; Plate 8: figures 11-13; Plate 13: figure 24 Magellama macquariensis Thomson, 1918:30, 31, pi. 15: figs. 13-17; pi. 16: fig. 40.—Foster, 1974:139, figs. 31G, 38; pi. 19: figs. 17-27; pi. 20: fig. 1; pi. 21; figs. 17, 18; pi. 24: figs. 8-12; pi. 25: fig. 12, Aerothyris macquariensis (Thomson).—Allan, 1939:245.— Bowen 1968:146: fig. 10. Description.— One hundred specimens from 112-124 meters off the northeast side of Mac¬ quarie Island were studied (Harvard Station 27- 36). These have a length range of 19.2-44.7 mm and width range of 16.4-42mm. The range of L/W=0.99-1.36 with an average of 1.13. The range of T/W=0.52-0.73, with average of 0.62. The foramen varied in diameter from 1.5 to 4.0 mm. Eighty percent of the specimens have the foramen above 2.0 mm in diameter. One speci¬ men is provided with a keyhole foramen like that of A. kerguelenen.su. Two specimens have conjunct deltidial plates. That A. macquariensis is very close to A. kergue- lenensis was suggested by Foster (1974) and is apparent. It has an exterior form identical to many specimens of the Kerguelen species, vari¬ able anterior sulcation, the same type of cardi- nalia, and similar abberations of size and form of the foramen. Its average L/W of 1.13 places it in lj 16 IB 20 22 24 26 28 30 3 2 34 36 3 8 4 0 42 44 46 N = 100 length Figure 27.—Scattergram of length/width for 100 specimens of Aerothyris macquariensis (Thomson) from Harvard station 27-36 off Macquarie Island (L/W=1.13; large dot = A. enzenspergen (Blochmann) = A. kerguelenensis (Davidson); circled star = A. kerguelenensis type). 56 the middle range of L/W of A. kerguelenensis. The keyhole type of foramen occurs sporadically. The chief differences between the species is the usually predominately larger foramen (80% above 2 mm diameter) in a usually massive, only slightly curved beak and the lesser calcification of the interior in adult or old specimens. Most examples of A. kerguelenensis thicken their cardinalia early in their development and often create bizarre abberations in old age (see Plates 12, 13). The loop development of A. macquariensis closely matches that of A. kerguelenensis from some local¬ ities. A. macquariensis occupies a medial position in the series of A. kerguelenensis when its external form is considered, but its foramen is constantly larger than that of most populations of A. kergue¬ lenensis. As noted, a population from station 22, BB 125 has affinities with A. macquariensis, the Marion Island form, varying only in being collectively SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY slightly less elongate. The range of A. macquariensis is larger than hitherto known because Bowen (1968:146) reports empty shells of this species off Otago Peninsula, South Island, New Zealand, at 180-220 fathoms (329-402 meters), fairly deep water for the species. The Marion Island speci¬ mens extend the range of the species to the west. Possibly their similarity to A. macquariensis is rather a matter of local conditions affecting a stock of A. kerguelenensis than the wider geographic extension of a species. The specimens, however, are too different from average A. kerguelenensis to be identified with it. Types.— Hypotype: Figured specimen USNM 550251-61. Aerothyris aff. A. macquariensis (Thomson) Figures 28, 29; Plate 8: figures 14-29 Magellama macquariensis Thomson, 1918:30, 24, 27; pi. 15: figs. 13-17; pi. 14: fig. 40. 28 27 26 25 24 23 22 21 18 17 16 15 14 13 12 11 10 II 12 )3 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 LENGTH Figure 28. — Scattergram of length/width of Aerothyris aff. A. macquariensis (Thomson) from MD.08: station 22, BB 125, 52 specimens (L/W=1.10; circled star = position of specimen with keyhole foramen). NUMBER 43 57 5 6 7 8 9 10 11 12 13 U 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 WIDTH Figure 29.—Scattergram (top) of Aerothyns aff. A. macquariensis (Thomson) from MD.08: station 22, BB 125, 58 specimens, showing thickness-width relationship. Description.— Specimens from MD.08: station 22, BB 125 deviate strongly from other lots here assigned to A. kerguelenensis. The specimens are yellowish white, rather thin-shelled, and of about medium size when compared to the extremes of A. kerguelenensis. The L/W averages 1.11 and the T/W averages 0.61. Most specimens have a large foramen, 66% over 2 mm in diameter. The fora¬ men is bounded by small deltidial plates or none at all, but one specimen in the lot has a keyhole Measurement (mm).— Specimen Length Dorsal valve length MNHN-BRA-78-82a 33.3 28.5 MNHN-BRA-78-82b 28.8 24.7 MNHN-BRA-78-82c 30.0 25.7 MNHN-BRA-78-82d 27.3 23.7 MNHN-BRA-78-82e 18.6 16.6 MNHN-BRA-78-82f 28.2 23.7 MNHN-BRA-78-82g 34.1 30.0 MNHN-BRA-78-82h 28.7 24.1 foramen and another has conjunct deltidial plates. The cardinalia of the dorsal valve are not thickened and have well-excavated inner hinge plates and a modest development of the cardinal process. The median septum is short and low, reaches to midvalve or posterior thereto. The muscle scars are not deeply impressed. One small precocious specimen preserves the pallial marks in the dorsal valve that conform to the pattern seen in A. kerguelenensis (Plate 10: figure 4). Width Thick ness Apical angle Foramen width L/W 29.0 17.4 o 00 2.8 1.15 26.0 16.4 92° 2.8 1.11 25.2 16.4 CO o 3.7 1.19 23.7 17.0 82° 2.7 1.15 15.7 13.7 0 CO 2.0 1.18 24.6 17.3 90° 3.0 1.15 30.7 18.8 89° 2.5 1.14 27.6 17.3 kO CO o 1.5 1.04 58 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Table 1 . —Percentage of length/width ratios and percentage of foramen widths in populations of Aerothyris kerguelenensis (Davidson) and one lot of A. macquariensis (Thomson) Range of length/width ratio Station Depth (in m) Ave. L/W 0.90- 1.00 1.01- 1.05 1.06- 1.10 1.11- 1.15 1.16- 1.20 1.21 plus Range of foramen width (in mm) <1.0 <1.5 <2.0 <2.5 <3.0 <3.5 <4.0 73, CP 295 263- 412 1.02 50 33 0 17 0 0 17 17 17 32 17 0 0 46, CP 204 375- 490 1.04 8 60 28 0 4 0 9 43 30 18 0 0 0 74, DC 296 290 1.06 4 52 24 16 4 0 19 13 19 37 6 6 0 9, DC 68 125 1.06 10 32 42 16 0 0 36 32 20 0 6 6 0 42, CP 197 172- 220 1.08 5 21 47 11 16 0 0 11 17 39 33 0 0 75, CP 303 155- 257 1.09 0 19 48 29 4 0 0 0 21 47 32 0 0 79, CP 326 81 1.09 0 13 21 38 14 14 3 11 22 50 11 3 0 14, DC 8 250 1.10 14 22 25 36 3 0 20 34 40 6 0 0 0 14, CB 3 262 1.10 0 30 25 25 5 15 25 67 8 0 0 0 0 30, CP 21 187 1.10 2 14 45 24 13 2 14 30 39 13 4 0 0 12, DC 78 103 1.11 0 25 33 29 8 5 83 9 4 0 4 0 0 22, BB 125 31 1.11 0 7 31 32 20 10 4 16 14 33 22 4 7 26, CP 17 165 1.12 2 18 32 22 18 8 4 8 40 24 24 0 0 26, CP 135 145 1.12 0 0 27 55 18 0 12 55 33 0 0 0 0 50, DC 216 150 1.13 4 7 30 15 37 7 p p p p p p p macquariensis 124 1.13 1 7 33 33 17 9 0 3 17 40 28 9 3 62, CP 257 210 1.13 0 31 15 16 15 23 0 20 20 40 20 0 0 9, CP 75 150- 340 1.14 0 5 0 68 16 11 6 0 6 41 47 0 0 77, DC 314 270 1.16 0 5 11 17 39 28 0 10 20 50 20 0 0 28, DC 148 280 1.16 0 0 10 42 32 16 73 18 9 0 0 0 0 25, CP 134 232 1.18 0 0 17 26 23 34 13 27 14 46 0 0 0 48, CP 209 200 1.19 0 4 24 12 24 36 8 12 40 36 4 0 0 Types.— Hypotypes: MNHN-BRA-82a-m. Station.— MD.08: 22, BB 125. Discussion. —Davidson (1880:40) reported A. kerguelenensis in great numbers off Marion Island. The specimens he illustrated in the Challenger report and in his later work on Recent brachio- pods (1886-1888:53, pi. 10) show a fair range of sizes and variation, but most of the pictures show specimens with a narrow keyhole foramen. Sev¬ eral specimens from Marion Island are illustrated (1880, pi. 3: figs. 3-9) and each has a narrow foramen. The National collection has 3 specimens (USNM 110883 and 550374a,b) collected by the Challenger expedition, the former from Kerguelen Island and latter two from Marion Island. All are elongate oval, have incurved beaks, are provided with a keyhole foramen, and all have thickened cardinalia and a high L/W (all but one 1.10 or above). They are typical A. kerguelenensis kerguele¬ nensis. The specimens from northeast of Marion Island (MD.08: station 22, BB 125) cannot be identified as M. kerguelenensis because of their poorly calci¬ fied cardinalia, and predominance of a large foramen. The sea bottom from which they were taken was sand. These specimens are very close to A. macquariensis (Thomson) in all details, espe¬ cially to specimens from Antipodes Island. The chief difference between the Marion Island form and that from Macquarie Island is the predomi¬ nantly greater thickness and a slight difference in L/W ratio. NUMBER 43 59 Aerothyris? species 1 Plate 4: figures 4-6 Description.— Small, roundly pentagonal, slightly longer than wide, unequally convex, ven¬ tral valve deeper than dorsal valve; sides rounded; anterior margin broadly rounded; pos¬ terolateral margins forming an angle of 90°. Lat¬ eral commissure straight, anterior commissure slightly sulcate. Beak short, suberect; beak ridges rounded; foramen large, submesothyridid; delti- dial plates narrowly conjunct. Surface smooth. Ventral valve with short, sessile, pedicle valve; teeth narrow, elongate. Dorsal valve circular, gently convex; hinge re¬ gion narrow; beak incurved; cardinal process un¬ formed; socket ridges short, thin, bounding nar¬ row sockets; inner hinge plate short, concave, and attached to median septum, which is deeply ex¬ cavated; median septum high, long, extending nearly to anterior margin. Crural processes short, acute, defining very short crura. Descending la¬ mellae thin, expanding anteriorly and supporting broad ascending branches and a broad transverse band. Loop narrow and long, occupying 60% of length and 28% of valve width. Measurements (mm).—length 15, dorsal valve length 14.7, width 14.7, thickness ?; apical angle 90°. Station. —MD.08 44, CP 199. A B Figure 30. —Young specimen of Ecnomiosa mexpectata, new species, showing early campagiform stage of loop with an¬ teriorly spiny cone, (ca. X 11.5; A = ventral view; B = side view). Type. —Figured specimen: MNHN-BRA-78- 26. Discussion.— The single specimen described and figured is unlike any other in the collection, differing strongly in its conjunct deltidial plates, exceptionally long median septum; narrow, short, notothyrial cavity bounded by concave hinge plates attached to a high median septum with deep umbonal chambers. The specimen is from much deeper water (1500 m) than any other specimens of Aerothyris recorded herein. Superfamily Dallinacea Beecher, 1893 Family Ecnomiosidae Cooper, 1977 Genus Ecnomiosa Cooper, 1977 Ecnomiosa inexpectata, new species Figure 30; Plate 14: figures 1-20 Diagnosis. —Medium size, faintly sulcate Ec¬ nomiosa. Description. —About medium size, subcircular in outline, slightly longer than wide; valves un¬ equal in depth and convexity, ventral valve hav¬ ing greater convexity and depth. Terebratalia-like in appearance. Sides rounded, anterior margin slightly nasute; posterolateral extremities forming an obtuse apical angle of 96°-106°. Lateral com¬ missure straight, anterior commissure with a slight ventrad wave. Beak moderately long, wide, foramen large, occupying entire pedicle opening; no deltidial plates. Surface marked by very fine, regular lines of growth. Periostracum rich light brown to dark brown; shells white. Ventral valve moderately and evenly convex in lateral profile, fairly strongly domed in anterior view with steeply sloping sides. Umbonal region somewhat narrowly swollen, swelling continuing to anterior margin to form a perceptible median fold that produces the anterior sinuation of the anterior commissure. Flanks gently convex and steep. Dorsal valve gently and unevenly convex in later view, most convex in posterior, becoming 60 less so anteriorly. Anterior view a low dome some¬ what flattened medially. Beak small, umbo gently swollen; poorly visible sulcus originating at mid¬ valve and extending to anterior margin where it forms a slight tongue. Ventral valve interior with large, thick, nearly horizontal teeth separated from the shell margin by a groove; pedicle collar broad, sessile; dental plates short, separated from valve wall by short, shallow, delthyrial cavities. Ventral muscle field located posterior to midvalve, subrectangular in outline. Vascula media slightly oblique. Dorsal valve interior with stout socket ridges, small outer hinge plates, and short crura. Crural processes short and angular; median septum not reaching midvalve. Loop long, transverse band with medial vertical ring attached to distal end of median septum; descending branches of loop also attached to distal end of median septum. Measurements (mm).—Length 25.6, dorsal valve length 22.8, width 23.7, thickness 14.1, apical angle 96°. Station.— MD.08: 44, CP 199. Types.— Holotype: MNHN-BRA-78-119a; paratypes: MNHN-BRA-78-119b-1. Discussion.— This Indian Ocean species of Ec- nomiosa is much smaller than that from the Gulf of Mexico, has a shallow dorsal sulcus, and is anteriorly slightly sulcate. Ecnomiosa gerda Cooper from the Gulf of Mexico, although somewhat nasute, has a rectimarginate anterior commissure in the adult. Loop Development.— The collection of Ecnom¬ iosa from the Indian Ocean is small, consisting of two adults, a broken adult ventral valve, a young complete adult with loop, and several immature specimens showing details of the loop develop¬ ment. The smallest specimen (MNHN-BRA-78-119e) 3 mm wide, has well-defined dental plates in the ventral valve. In the dorsal valve, the socket ridges are strong. The crura are short, the crural pro¬ cesses low. The descending lamellae flare widely and attach to the floor of the valve at about midlength. The area surrounded by the loop is greatly thickened and divided medially by a low ridge, the incipient pillar. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY A specimen 4.5 mm long and 4.0 mm wide (MNHN-BRA-78-119g) exhibits the interior of both valves. In the ventral valve the dental plates are short but well developed. In the dorsal valve, prominent socket ridges support short crura that extend posteriorly along the base of the socket plate as a narrow ridge. Crural processes are short and blunt. The descending branches of the loop meet the valve floor at about midvalve and form two curved ridges extending medially to meet at the median pillar. The pillar is a low, triangular plate with a low ridge extending posteriorly from it that does not reach the notothyrial cavity. Another specimen with dorsal valve of 5.5 mm width (MNHN-BRA-78-119h) has cardinalia similar to the preceding but with a more elevated pillar, now with a somewhat rectangular outline and the median ridge from its posterior more elevated but not reaching the notothyrial cham¬ ber. The anterior edge of the median pillar is provided with small spines. The descending branches of the loop are broken anteriorly but there is a trace of inner loops on the valve floor. A specimen with dorsal valve 5.5 mm in width (MNHN-BRA-78-119i) has the socket ridges meeting the valve floor. The pillar is elevated, wide longitudinally, and spinose along its dorsal edge. It is expanded distally to form a narrow cone, the point of which passes into the posterior edge of the pillar. The crura are very short and the descending branches are very broad proxi- mally and just clear of the valve floor for slightly more than half their length, at which point more slender extensions attach to the sides of the pillar. This arrangement forms an intermediate step between the young in which the pillar has not formed a cone, and those young in which the descending branch is wholly attached to the valve floor. A specimen with dorsal valve 6 mm (MNHN- BRA-78- 119j) wide shows a considerable and sud¬ den advance over the preceding. The descending branches are less flaring and their anterior ends are attached to the lower part of the median pillar, with no part attached to the valve floor. This pillar has widened to form a narrow cone open toward the ventral valve. The dorsal side of NUMBER 43 61 the cone is provided with small spines. The pillar descends rapidly in the posterior direction and becomes a low septum that extends to the noto- thyrial chamber. The ridges on the dorsad edges of the socket ridges extend medially as incipient inner hinge plates. There is no cardinal process. A specimen with dorsal valve 8.5 mm wide (MNHN-BRA-78-119k) shows a widening and lengthening cone, spiny along its dorsad surface, and open at both ends. The descending lamellae are wider ribbons but less flared laterally. The inner hinge plates approach the low median sep¬ tum. The median ridge has become a high septum and the inner hinge plates are excavated beneath and attach to the floor on the sides of the median septum. The pillar attaching the cone is narrow at its base and widens ventrally in the long direc¬ tion of the shell, and attaches along the entire length of the cone to its narrowly open apex. The apex of the cone coincides with the posterior edge of the pillar. A specimen of 11 mm width of dorsal valve (MNHN-BRA-78-119-1) was broken in transit or collecting but the remainder of the loop is quite revealing. The pillar at its base is now very nar¬ row and the descending branches of the loop attached to the pillar at the base of the cone are broad and concave. The anterior of the cone is deeply cleft but other details have been lost. The inner hinge plates are thickened and attach to the valve floor on each side of the median septum. At 12 mm of width of the dorsal valve (MNHN-BRA-78-119d) the loop is essentially adult except for the stoutness of its parts. The inner hinge plates are welded to the median septum. The pillar is greatly reduced and the cone has been deeply cleft. The proximal end of the cone now breached forms the ring that at¬ taches the median part of the transverse band, the distal part of the cone, to the pillar, now the septum. The descending branches are attached to the median septum by lateral extensions. The loop is essentially adult. Genus? species? Description. —Four specimens from MD.03: 11, CP 7 differ markedly from Aerothyris. They all have short, truncated beaks with a large foramen set off by conjunct deltidial plates. The pedicle collar is short and rimmed in one specimen. The other ventral valves have no pedicle collar and their umbonal regions are subcarinate, suggesting that they are different from the one with pedicle collar. A fragment of dorsal valve has a long, low, median septum. Without dorsal cardinalia it is impossible to assign these specimens correctly. Superfamily Thecideacea Gray, 1840 Family Thecidellinidae Elliott, 1958 Genus Thecidellina Thomson, 1915 Thecidellina minuta , new species Plate 6: figures 27-40 Diagnosis.— Minute, peripheral papillose bands narrow; lacy skeleton over interbrachiai sac. Description.— Very small, length about 2 mm, variable in outline, usually subpentagonal, either elongate or transverse; cicatrix of attachment variable from apical to about 2/3 the ventral valve. Interarea usually narrow, flat, in length about equal to 1/3-1/6 valve length depending on ventral notch for cardinal process. Hinge usu¬ ally fairly wide but variable; depth of ventral valve variable. Dorsal valve subcircular, with straight hinge; flatly convex in lateral profile, with low median elevation from interarea to mid¬ valve and short interarea. Color white. Ventral valve interior with thick, narrow teeth; hemispondylium narrow, with thin plates that attach to valve floor. Inner surface of old speci¬ mens granulose. Granulose border confined to anterior and lateral edge of shell. Dorsal valve interior with very narrow granu¬ lose border; median ascending element or septum extending dorsally for about 2/3 valve length obliquely in posteroventral direction. Cardinal process short and squarish as usual in the family. Bridge or transversarium broad, strongly curved, with short septum at its middle that extends to cardinal process. Interbrachia covered in part or wholly by lacy framework of interbrachiai sac 62 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY over which the schizolophus lophore is laid. Lo- phophore groove narrow. Measurements (mm).— Specimen Length Dorsal valve length Width Thick¬ ness Apical angle MNHN-BRA-78-74a 2.1 1.6 2.0 1.3 80° MNHN-BRA-78-74d 1.9 1.5 1.9 1.2 CO o o Station.— MD.08: 7, DC 57. Types.— Holotype: MNHN-BRA-78-74c; par- atypes MNHN-BRA-78-74a,b, d-k. Discussion.— This is the smallest living species of Thecidellina. In the Indian Ocean Thecidellma blochmanni Dali occurs at Christmas Island south of Java and Europe Island off Madagascar (Mal¬ agasy Republic). This species is much larger than T. minuta and is shaped differently. Thecidellia minuta differs from T. blochmanni also by lacking a broad, interior, peripheral margin. Thecidellina minuta is also unusual in inhabiting deeper water (380 m) than is customary for Thecidellina , which is commonly found in water less than 200 meters deep. Literature Cited Allan, R. S. 1937. On a Neglected Factor in Brachiopod Migration. Records of the Canterbury Museum, 4(3): 157-165. 1939. Studies of the Recent and Tertiary Brachiopoda of Australia and New Zealand. Records of the Can¬ terbury Museum, 4(5):231-248, plates 29-31. Beecher, C. E. 1893. Revision of the Families of Loop-bearing Brachio¬ poda. Transactions of the Connecticut Academy of Arts and Sciences , 9:376-399, 3 plates. Blochmann, F. 1906. Neue Brachiopoden der Valdivia- und Gaussex- pedition. Zoologischen Anzeiger, 30(21-22):690-702. 1908. Zur Systematik und Geographischen Verbreitung der Brachiopoden. Zeitschnft fur wissenschaftliche Zoologie, Leipzig , 90:596-644, plates 38, 39, map. Bowen, Z. P. 1968. A Guide to New Zealand Recent Brachiopods. Tuatara, Journal of the Biological Society, Victoria Uni¬ versity of Wellington, New Zealand, 16(2): 127-150, 11 figures. Chapman, F., and I. Crespin 1923. The Austral Rhynchonellacea of the ' nigricans Se¬ ries’ with a Special Description of the Genus Te- gulorhynchia. Proceedings of the Royal Society of Victoria, 35:170-193, plates 11-13. Cooper, G. A. 1959. Genera of Tertiary and Recent Rhynchonelloid Brachiopods. Smithsonian Miscellaneous Collections, 139(5): 1-90, 22 plates. 1972. Homeomorphy in Recent Deep-Sea Brachiopods. Smithsonian Contributions to Paleobiology, 11: 25 pages, 4 plates. 1973a. New Brachiopoda from the Indian Ocean. Smith¬ sonian Contributions to Paleobiology, 16: 43 pages, 8 plates. 1973b. Verna’s Brachiopoda. Smithsonian Contributions to Paleobiology, 17: 51 pages, 9 plates. 1977. Brachiopoda from the Caribbean Sea and Adja¬ cent Waters. Studies in Tropical Geography, 14: 211 pages, 35 plates. Coral Gables, Florida: University of Miami Press. Costa, O. G. 1851-52. Brachiopods. In Fauna del Regno di Napoli ossia enumerazione di tutti gli Animale-contenente la descnzione de nuovi o poco esatlamente conosciuti-di Costa (continuata da A. Costa), part V: 60 pages, 9 plates. Naples. Dagis, A. 1974. Triassic Brachiopods (Morphology, Classification, Phylogeny, Stratigraphical Significance, and Bio¬ geography). “Nauka" Siberskoe Otdelenie, Novosibirsk, 387 pages, 49 plates. [In Russian.] Dali, W. H. 1870. A Revision of the Terebratulidae and Lingulidae, with Remarks on and Descriptions of Some Re¬ cent Forms. American Journal of Conchology, 6(2) :88- 168, figures 1-38, plates 6-8. 1873. Catalogue of the Recent Species of the Class Bra¬ chiopoda. Proceedings of the Academy of Natural Sci¬ ences of Philadelphia, 177-204. 1908. The Mollusca and Brachiopoda ( Albatross Expe¬ ditions). Bulletin of the Museum of Comparative Zoology at Harvard University, 43:205-487, 22 plates. 1920. Annotated List of the Recent Brachiopoda in the Collection of the United States National Museum, with Descriptions of Thirty-three New Forms. Pro¬ ceedings of the United States National Museum, 5 7(2314): 261 —377. Davidson, T. 1878. Extract from a Report to Professor Wyville Thom¬ son, F.R.S., Director of the Civilian Scientific Staff, on the Brachiopoda Dredged by H.M.S. Challenger. Proceedings of the Royal Society of London, 27(188):428-439. 1880. Report on the Brachiopoda Dredged by H.M.S. Challenger during the Years 1873-1876. Report of Scientific Results of the Challenger (Zoology), 1: 67 pages, 4 plates. 1886-1888. A Monograph of Recent Brachiopoda. Transactions of the Linnaean Society of London, series 2 (Zoology), 4: 248 pages, 30 plates. Deshayes, G. P. 1863. Catalogue of the Mollusques de Pile de la Reunion (Bour¬ bon). 144 pages, plates 24-41. Paris. [Brachiopoda on plate 32.] Deslongchamps, E. Eudes 1863-87. Etudes Critiques sur des Brachiopodes Nouveaux ou Peu Connus. Societe Linneenne de Normandie, Bul¬ letins, series 2, 7:248-295, plates 1-8; 8:249-286, plates 9-11; series 3, 8:161-350, plates 1-14; 10: 31-158, plates 27, 28. Eichler, P. 1911. Die Brachiopoden. In Deutsche Siidpolar Expedition, 12(4):383-401, plates 42, 43. 63 64 Elliott, G. F. 1958. Classification of Thecidean Brachiopods. Journal of Paleontology, 32(2):373. Fischer, P., and D. P. Oehlert 1890. Diagnoses de Nouveaux Brachiopodes. Journal de Conchyliologie, series 3, 38(1):70-74. 1891. Brachiopodes. In Expedition Scientifique du Travail- leur el du Talisman (1880-1883), 140 pages, 8 plates. Paris. Foster, M. A. 1974. Recent Antarctic and Subantarctic Brachiopods, Antarctic Research Series, 21: 189 pages, 25 plates. Washington, D.C.: American Geophysical Union. Frauenfeld, G. R. von 1865. Ueber Zwei Meeresschnecken von St. Paul, Zool- ogische Miscellen, VI. Verhandlung der Kaiserlichen Kdmglichen Zoologische-Botamschen Gesellschaft in Wien, 1865:893-895. Gray, J. E. 1840. Synopsis of the Contents of the British Museum. 42nd edition, 370 pages. London. 1848. On the Arrangement of the Brachiopoda. Annals and Magazine of Natural History, series 2, 2:435-440. Helmcke, J. G. 1940. Die Brachiopoden der Deutschen Tiefsee-Expedi¬ tion. In Wis sense haft lie he Ergebmsse der Deutschen Tiefsee-Expedition auf dem Dampfer Valdivia 1898 - 1899, 24(3):217-316, 43 figures. Hertlein, L. G., and U. S. Grant, IV 1944. The Cenozoic Brachiopoda of Western North America. Publication of the University of California at Los Angeles in Mathematical and Physical Sciences, 3: 236 pages, 21 plates. Huxley, T. H. 1869. An Introduction to the Classification of Animals. 147 pages, 47 figures. London: John Churchill and Sons. Jackson, J. W. 1918. Brachiopoda. In British Antarctic Terra Nova Expe¬ dition, 1910, 2(8): 177-203. 1921. On the Occurrence of Lusitanian Brachiopods in the Persian Gulf. Annals and Magazine of Natural History, series 9, 7:40-49. 1952. A Revision of Some South African Brachiopoda, with Descriptions of New Species. Annals of the South African Museum, 41(1): 1-40, plates 1-3. Jackson, J. W., and G. Stiasny 1937. The Brachiopoda of the Siboga Expedition. In Siboga Expedite, 27: 20 pages, 2 plates. Leiden. Jeffreys, G. 1876. On Some New and Remarkable North-Atlantic Brachiopoda. Annals and Magazine of Natural History, series 4, 18:250-253. King, W. 1850. A Monograph of the Permian Fossils of England. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Palaeontographical Society Monograph, 3: 258 pages, 29 plates. 1868. On Some Palliobranchiate Shells from the Irish Atlantic. Proceedings of the Natural History Society of Dublin, 5:170-173. Kuhn, O. 1949. Lehrbuch der Palaozoologie. 326 pages, 244 figures. Stuttgart: E. Schweizerbart. Lee, D. E. 1978. Aspects of the Ecology and Paleoecology of the Brachiopod Notosana nigricans (Sowerby ). Journal of the Royal Society of New Zealand, 8(4):395-417, 8 figures. Menke, K. T. 1828. Synopsis methodica Molluscorum generum omnium et spe- cierum earum, quae in Museo Menkeano Adservantur. 91 pages. Piermonte. Muir-Wood, H. M. 1955. A History of the Classification of the Phylum Brachiopoda. 124 pages, 12 figures. London: British Museum (Natural History). 1959. Report on the Brachiopods of the John Murray Expedition. The John Murray Expedition 1933-34, Science Reports, 10(6):283-317, 5 plates. Pajaud, D. 1970. Monographic des Thecidees (Brachiopodes). Mem- oires de la Societe Ge'ologique de France, new series 49(112): 349 pages, 140 figures, 16 plates. Retzius, A. J. 1781. Crania oder Todenkopf-Muschel. Schnften der Ber- limschen Gesellschaft Naturforschenden Freunde, 2:66— 76, plate 1. Rzhonsnitskaya, M. A. 1956. Systematization of Rhynchonellida. Resumenes de los Trabajos Presentados, Mexico, 20th Congress Geolo- gico International, 125-126. Smith, E. A. 1879. Mollusca. Philosophical Transactions of the Royal So¬ ciety, 168:167-192. Studer, T., et al. 1889. Die Forschungsreise S.M.S. “ Gazelle” in den Jahren 1874-76, 3: Zoologie und Geologie. 322 pages, 33 plates. Berlin. Thomson, J. A. 1915. A New Genus and Species of Thecidiinae. Geolog¬ ical Magazine, new series, 6(2):461-464. 1916. Additions to the Knowledge of the Recent and Tertiary Brachiopoda of New Zealand and Aus¬ tralia. Transactions of the New Zealand Institute, 48: 41-47, plate 1. 1918. Brachiopoda. Australasian Antarctic Expedition, 1911-14, Scientific Reports, series C, 4(3): 1-76, plates 15-18, map. 1926. A Revision of the Subfamilies of the Terebratuli- dae (Brachiopoda). Annals and Magazine of Natural NUMBER 43 65 History, series 9, 18:523-530. 1927. Brachiopod Morphology and Genera (Tertiary and Recent). New Zealand Board of Science and Art, Manual, 7: 388 pages, 103 figures, 2 plates. Velain, C. R. 1876. Sur la Faune Malacologique des lies St. Paul et Amsterdam. Academie Science Paris, Comptes Rendus, 83:284-287. 1877. Passage de Venus sur le Soleil (9 Decembre 1874), Expedition Francaise aux lies Saint-Paul et Am¬ sterdam, Zoologie: Observations generates sur la Faune des Mollusques. Archives de Zoologie Experi¬ mental et Generale, 143 pages, 5 plates. Waagen, W. H. 1883. Salt Range Fossils, part 4 (2): Brachiopoda. Pa- laeontologia Indica Memoir, series 13, 1 (2): 391-546. Williams, A., et al. 1965. Brachiopoda. In R. C. Moore, editor. Treatise on Invertebrate Paleontology, part H, 927 pages, 746 figures. Lawrence: The University of Kansas Press. Zezina, O. N. 1965. The Distribution of the Deep Water Brachiopod Species, Pelagodiscus allanlicus (King). Okeanologiya , 5(2):345-358. 1970. Brachiopod Distribution in the Recent Ocean with Reference to Problems of Zoogeographic Zoning. Paleontologichesky Zhurnal (Akademia Nauk SSSR), Paleontologichesky Institut, 2:1-21. [In Russian.] 1976. Ecology and Distribution of Recent Brachiopods. In Scientific Council on the Problem “Evolutionary Trends and Patterns of Animal and Plant Organisms”, Academy of Sciences USSR, 138 pages, 19 figures. [In Rus¬ sian.] 66 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 1 Figures 1-6.— Eucalalhis magna, new species: 1-4, Anterior, ventral, side, and dorsal views of holotype, MNHN-BRA-78-12, X 3; 5, interior of holotype showing eucalathid loop, X 3; 6, part of spicular skeleton of lophophore, X 3 (all from MD.03: station 11, CP 7, at 790 meters). Figures 7-10.— Liothyrella moseleyi (Davidson): 7-9, Anterior, side, and dorsal views, X 1, of complete specimen, hypotype MNHN-BRA-78-13a; 10, dorsal view of preceeding, X 2, showing foramen and symphytium (from MD.03: station 31, CP 22, at 110 meters). Figures 11-13.— Xenobrochus australis , new species: 11, 12, Dorsal and side views of holotype, X 2, MNHN-BRA-78-14a; 13, side view of holotype showing loop with its long, slender crura and spatula-like anterior, X 2.5 (from MD.03: station 11, CP 7, at 790 meters). Figures 14-34.— Pemphixina pyxidata (Davidson): 14, Immature specimen, X 2, hypotype MNHN-BRA-78-15a; 15, dorsal view of more mature specimen, X 1 , hypotype MNHN- BRA-78-15b; 16-18, side, anterior, and dorsal views, X 1, of still more mature individual, hypotype MNHN-BRA-78-15c; 19-21, dorsal, anterior, and side views, X 1, of mature specimen, hypotype MNHN-BRA-78- 15d; 22, dorsal view of preceding specimen showing ornament, X 2; 23, 24, side and anterior views of old, rotund, obese specimen, X 1, hypotype MNHN-BRA-78-15h; 25, interior of dorsal valve of young individual, X 2, hypotype MNHN- BRA-78-15e; 26, rubber impression of posterior of ventral valve interior showing muscle scars, X 2, hypotype MNHN-BRA-78-15j; 27, 28, dorsal valve interior, X 2, showing the crura in posterior and partial lateral views, hypotype MNHN-BRA-78-15f; 29, interior of posterior part of specimen, X 3, showing crura and parts of mantle with ovarian region, hypotype MNHN-BRA-78-15g; 30, same specimen with parts of mantle removed to show muscles and crura, X 3; 31, 32, dorsal and ventral views, respectively of ventral and dorsal valves of another individual showing muscle scars and cardinalia, hypotype MNHN-BRA- 78-15i; 33, 34, same dorsal valve tilted posteriorly to show short median septum and tilted laterally to show wide corrugated socket, X 2 (MD.03: station 25, CB 7, at 172 meters). NUMBER 43 67 68 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 2 Figures 1-7.— Tegulohynchia species: 1, Dorsal view, X 1, MNHN-BRA-78-16; 2-6, anterior, posterior, ventral, side, and dorsal views of preceding specimen, X 2; 7, dorsal view, X 3, of preceding showing spiny exterior and long, slender pedicle (St. Paul, station 98). Figures 8-13. — Pemphixina pyxidata (Davidson): 8, Dorsal view of complete specimen, X 1, hypotype MNHN-BRA-78-17 with posterior of ventral valve X 2; 9, side and ventral views of dorsal valve showing crura, X 3; 10-13, dorsal, posterior, side, and anterior views, X 2, of preceding specimen (Amsterdam Island). Figures 14-36. — Megerlina davidsoni (Velain): 14-17, Dorsal, side, ventral, and anterior views of large individual, X 4, showing abraded foramen, hypotype MNHN-BRA-78-18a (St. Paul, 35). 18-21, Dorsal, ventral, anterior, and side views of smaller specimen, X 4, hypotype MNHN- BRA-78-19a; 22, 31, ventral and dorsal interiors, of young specimen, X 6, hypotype MNHN- BRA-78-19j; 23, 29, ventral and dorsal interiors of a somewhat larger specimen than preceding, X 6, hypotype MNHN-BRA-78-19m; 30, interior of another immature dorsal valve, X 6, hypotype MNHN-BRA-78-19-1; 32, 33, two immature, dorsal valve interiors, X 6, hypotypes MNHN-BRA-78-19i,e; 34, 35, interior of dorsal and ventral valve of same individual showing lophophore and pedicle muscles, X 10, hypotype MNHN-BRA-78-19d; 36, interior of adult dorsal valve, X 6, showing well-preserved lophophore, hypotype MNHN- BRA-78-19b (St. Paul, 22a). 24, 26, 27, Ventral valve interior and dorsal and side views of dorsal valve of same individual, X 4, hypotype MNHN-BRA-78-20a (St. Paul, 7b). 25, 28, Interior of ventral and dorsal valves of same individual showing teeth, deltidial plates, and cardinalia, X 4, hypotype MNHN-BRA-78-21a (St. Paul, 90). Figures 37-39. — Platidia marionensis, new species: Ventral, anterior, and dorsal views, X 6, of a complete specimen paratype MNHN-BRA-78-22 (MD.03: station 26, CP 17). NUMBER 43 69 70 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 3 Figures 1-14.— Basiliola arnaudi, new species: 1, Dorsal view X 1 of complete specimen, paratype MNHN-BRA-78-23c; 2-5, anterior, side, ventral, and dorsal views, X 2, of preceding paratype, with attached Thecideliina minuta, new species; 6, dorsal view of holotype, X 1, MNHN-BRA-78-23a; 7-10, side, dorsal, ventral, and anterior views, X 2, of holotype showing strong uniplicate anterior commissure; 11, interior of the ventral valve, X 2 and X 4, showing upturned margin of deltidial plates, paratype MNHN-BRA-78-23d; 12, interior of dorsal valve of same specimen, X 2, X 4, showing details of hinge plates, crura, and corrugated socket, counterpart to ventral valve above; 13, 14, partial side view and anterior view of the cardinalia of dorsal valve of paratype, X 2, MNHN-BRA-78-23d (MD.08: station 7, DC 57). Figures 15,16. — Pelagodiscus atlanticus (King): Ventral and dorsal views of small specimen, X 5, MNHN-BRA-78-24 (MD.08: station 44, CP 199). Figures 17-30. — Dyscolia? radiata, new species: 17-19, Side, anterior, and dorsal views of paratype, MNHN-BRA-78-25a; 20, enlargement of exterior of preceding showing radial lines, X 4; 21-23, anterior, dorsal, and side views, X 1, of another complete specimen, holotype MNHN-BRA-78-25b; 24, interior of ventral valve, X 2, paratype MNHN-BRA-78- 25c; 25, posterior of ventral valve of holotype, X 3, showing symphytium, teeth, and labiate beak; 26, interior of dorsal valve of holotype, X 1; 27, 28, ventral and side views, X 2, of preceding dorsal valve of holotype showing spatulate loop; 29, same, X 3, showing loop in detail; 30 rubber impression of ventral valve, X 1, showing muscle scars prepared from paratype MNHN-BRA-78-75c (MD.08: station 6, CP 47). Figure 31.— Liothyrella? species: Ventral view of interior of juvenile dorsal valve showing incomplete loop, paratype MNHN-BRA-78-122b (MD.08: station 40, DC 186). NUMBER 43 71 72 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 4 Figures 1-3.— Aerothyns kerguelenensis (Davidson): Anterior, side, and dorsal views of topotype, X 1, USNM 110883, at 150 fathoms (275 meters) (off Kerguelen Island, Indian Ocean, Challenger Expedition specimen). Figures 4-6.— Aerothyns? species 1: 4, 5, Side and ventral views of dorsal valve showing loop, X 3; 6, posterior of ventral valve showing conjunct deltidial plates and teeth, X 3, MNHN- BRA-78-26 (MD.08: station 44, CP 499). Figures 7-10.— Aerothyns kerguelenensis (Davidson): 7-9, Anterior, side, and dorsal views, X 1, of round specimen with large foramen suggesting affinities with A. macquariensis (Thomson), hypotype MNHN-BRA-78-27a; 10, interior of dorsal valve, X 1.5, hypotype MNHN-BRA- 78-27b (MD.08: station 46, CP 204). Figures 11-20.— Xenobrochus anomalus, new species: 11-13, Anterior, dorsal, and side views, X 4, of holotype, MNHN-BRA-78-28a; 14-16, dorsal, anterior, and side views, X 4, of another complete specimen, paratype MNHN-BRA-78-28b; 17, 18, posterior of ventral valve showing symphytium and teeth, and same ventral valve tilted to show pedicle collar X 4, paratype MNHN-BRA-78-28e; 19, 20, posterior of dorsal valve and complete dorsal valve interiors showing hinge plates, X 4, respectively, paratypes MNHN-BRA-78-28d, f (MD.08: stationl5, BB 88). Figures 21-29.— Dallithyns? dubia, new species: 21, 22, Dorsal view, X 1, X 2, of small complete specimen, paratype MNHN-BRA-78-29a; 23-26, dorsal view, X 1 , and side, anterior, and dorsal views, X 2, of holotype MNHN-BRA-78-29b; 27, posterior of ventral valve and dorsal valve interior, X 3, showing symphytium, teeth, and spatulate loop, hypotype MNHN-BRA- 78-29c; 29, side view of same loop, X 4; 28, ventral view of same loop, X 6 (MD.08: station 7, DC 57). Figures 30-35. —Xenobrochus afncanus (Cooper): 30-32, Dorsal, side, and anterior views, X 4, of holotype, USNM 550375a; 33, interior of dorsal valve of holotype, X 6, showing loop with transverse band directed anteroventrally; 34, another dorsal valve showing anteriorly directed transverse band, X 6, paratype USNM 550375b; 35 posterior of ventral valve interior of holotype, showing foramen, large symphytium, and teeth, X 6 ( Anton Brunn Station 358A, latitude 29°19'S, longitude 32°00' E, at 366 meters off north Natal, vicinity of Durban Bay, South Africa). NUMBER 43 73 74 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 5 Figures 1-14 .—Eucalathis costellata, new species: 1-4, Dorsal, side, ventral, and anterior views, X 5, holotype MNHN-BRA-78-64a; 5, interior of holotype showing anteriorly rounded loop, X 5, station 6, DC 47. 7-10, Anterior, ventral, side, and dorsal views of wider specimen than preceding with gastropod? boring, X 5, paratype MNHN-BRA-78-30a; 11, 12, interior of preceding speci¬ men, X 5, X 10, showing loop in detail; 13, 14, interior of two dorsal valves, X 10, showing variation in loop, paratypes MNHN-BRA-78-30c,d; 6, dorsal interior showing loop X 5, paratype MNHN-BRA-78-30b (MD.08: station 7, DC 57). Figures 15-34.— Platidia manonensis, new species: Fragment of volcanic rock with several attached specimens, X 3, paratype MNHN-BRA-78-65 (MD.08: station 26, CP 175). 16, 17, Three attached Platidia marionensis , respectively X 1, X 2, on Aerothyris kerguelenensis (Davidson), paratype MNHN-BRA-78-67 (MD.08: station 28, DC 148). 18, 19, Dorsal and ventral views of round specimen, X 4, paratype MNHN-BRA-78-68 (MD.08: station 67, DC 271). 20, 21, Ventral and dorsal views of specimen somewhat wider than preceding, X 4, paratype MNHN-BRA-78-69a; 34, side view, X 10, of dorsal valve showing loop, paratype MNHN- BRA-78-69b (MD.08: station 68, CP 275). 22, 23, Specimens attached to fragments of old Aerothyris shells, X 3, showing close attachment to host, paratypes MNHN-BRA-78-66a,b; 24-26, ventral, dorsal, and side views X 6, holotype, MNHN-BRA-78-70a; 27-30, anterior, side, dorsal, and ventral views of specimen with slightly distorted beak, X 6 paratype MNHN-BRA-78-70b; 31, interior of dorsal valve X 20, showing lophophore, MNHN-BRA-78-70c; 32, interior of ventral valve showing knoblike teeth, interarea, and low median ridge, X 10, paratype MNHN-BRA-78-70d; 33, 34, ventral and posterior views, ca. X 14, of dorsal valve of preceding specimen showing loop (MD.08: station 15, BB 88). NUMBER 43 75 76 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 6 Figures 1-26 .—Megerha gigantea (Deshayes): 1-3, Anterior, side, and dorsal views of an average specimen, X 2, hypotype MNHN-BRA-78-71a; 4, exterior of ventral valve of same specimen showing short spines on costellae, X 5; 5, exterior of ventral valve of small specimen, X 5, showing spiny surface, hypotype MNHN-BRA-78-7li; 6, interior of ventral valve showing interarea and teeth, X 2, paratype MNHN-BRA-78-7lg; 7-9, posterior and side views X 2 and ventral view, X 3, showing Joop, hypotype MNHN-BRA-78-7lh; 10-12, side, dorsal, and anterior views of large worn specimen, X 2, hypotype MNHN-BRA-78-7 If; 13, posterior of preceding hypotype, X 3, showing upturned edges of deltidial plates; 21-26, series of dorsal valve interiors showing development of the loop, hypotypes 21, = X 3, MNHN-BRA-78-72g; 22 = X 4, MNHN-BRA-78-72i; 23 = X 4, MNHN-BRA-78-72f; 24 = X 4, MNHN-BRA-78- 72d; 25 = X 4, MNHN-BRA-78-72c; 26 = X 4, MNHN-BRA-78-72b (MD.08: station 6, DC 35). 14-16, Side and posterior views, X 2 and ventral view, X 3 of dorsal valve interior showing loop, hypotype MNHN-BRA-78-73a; 17, 18, dorsal and ventral views of interior of ventral and dorsal valves, X 3, showing lophophore of dorsal valve and body wall and major pallial trunks of ventral valve, hypotype MNHN-BRA-78-73b; 19, 20, ventral view of dorsal valve interior and dorsal view of ventral valve interior showing same features as preceding, hypotype MNHN-BRA-78-73c (MD.08: station 6, DC 43). Figures 27-40. — Thecidellina minuta, new species: 27, Dorsal view of two specimens attached to piece of shell, X 9, paratype MNHN-BRA-78-74a; 28, another complete attached specimen, X 10, in posterior view, paratype MNHN-BRA-78-74b; 29, dorsal view of complete specimen, X 10, paratype MNHN-BRA-78-74d; 30-32, dorsal, ventral, and side views of holotype, X 10, MNHN-BRA-78-74c; 33, 34, interior of ventral and dorsal valves, X 18, showing hemispondylium and median pillar, paratype MNHN-BRA-78-74e; 35, 36, ventral views of two dorsal valves, respectively X 18, X 20, showing lophophore, paratypes MNHN-BRA-78- 74f, g; 37, 38 ventral view of two dorsal valves showing median pillar, respectively X 20, X 18, paratypes MNHN-BRA-78-74h, i; 39, 40, ventral views of two dorsal valves showing inner network that lies under the lophophore, X 2, paratypes MNHN-BRA-78-74k,l (MD.08: station 7, DC 57). NUMBER 43 77 78 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 7 Figures 1-30. — Aerolhyris kerguelenensis (Davidson): 1, Dorsal view, X 1, of young adult with “keyhole” foramen collected by Challenger , topotype USNM 110883 for comparison with more variable specimens (off Kerguelen Island at 150 fathoms (=275 meters); for comparison with figures below and for additional views, see Plate 4: figures 1-3). 2-4, Dorsal, side, and anterior views of young specimen, X 1, hypotype MNHN-BRA-78- 75h; 5-7, dorsal, side, and anterior views of young, slightly sulcate adult, X 1, hypotype MNHN-BRA-78-75e; 8-10, anterior, side, and dorsal views of young sulcate adult, X 1, hypotype MNHN-BRA-78-75d; 11-13, side, dorsal, and anterior views of nearly full-grown specimen, X 1, hypotype MNHN-BRA-78-75c; 14-16, anterior, side, and dorsal views, X 1, of adult, gently sulcate individual, hypotype MNHN-BRA-78-75b; 17-19, dorsal, anterior, and side views, X 1, of very large specimen with well-defined sulcation, moderately elevated fold, and “keyhole” foramen, hypotype MNHN-BRA-78-75a; 28, ventral view of interior of dorsal valve, X 1, showing free loop and enormous cardinal process, hypotype MNHN-BRA- 78-75i; 29, side view of preceding dorsal valve, X 1.5 (all from MD.03: station 30, CP 21, at 187 meters). 20, Interior of fragmentary, old ventral valve, X 1.5 showing muscle scars, hypotype MNHN- BRA-78-76a; 25, specimen 6 mm long with loop attached to septum, 5 hypotype MNHN- BRA-78-76b; 27, specimen 14 mm long with loop nearly free but showing remnants of attachment to septum on descending branches, X 3, hypotype MNHN-BRA-78-76d; 30, specimen 22 mm long with loop completely free and septum reduced, X 2, hypotype MNHN- BRA-78-76e (all from MD.03: station 26, CP 17, at 180 meters). 21, Interior of fragmentary old dorsal valve showing huge cardinal process, hypotype MNHN- BRA-78-77c; 22, interior of posterior of specimen with both valves attached and showing all muscles of ventral valve except adductors, X 3, hypotype MNHN-BRA-78-77a; 23, same view of another specimen showing all muscles, X 3, hypotype MNHN-BRA-78-77b (from MD.03: station 14, CB 3, at 262 meters; for enlarged view of figure 22, see Plate 8: figure 10). 24, Specimen 5 mm long having well-developed ring and with descending lamellae attached to septum, X 5, hypotype MNHN-BRA-78-121 (MD.03: station 9, DM 2, at 15 meters). 26, Dorsal valve interior showing well-developed pallial trunks, X 1.5, hypotype MNHN- BRA-78-78 (MD.08: station 15, DC 87). NUMBER 43 79 80 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 8 Figures 1-3.— Aerothyris kerguelenensis (Davidson): Side, anterior, and dorsal views, X 1, of large rounded individual with keyhole foramen, hypotype MNHN-BRA-78-79 (MD.03: station 14, DC 8). Figures 4-7.— Aerothyris aff. A. kerguelenensis (Davidson): 4, 5, Dorsal and anterior views, X 1, of wide and circular form with conjunct deltidial plates and small foramen, MNHN-BRA-78- 80a; 6, 7, ventral and side views of young specimen with loop, X 5, in terebratelliform stage, MNHN-BRA-78-80b (MD.08: station 17, BB 97). Figures 8, 9. — Aerothyris kerguelenensis (Davidson): 8, Interior of dorsal valve, X 1.5, showing adult loop, hypotype MNHN-BRA-78-81 (MD.08: station 74, DC 296). 9, Another elongate oval specimen from Challenger Expedition, X 1, showing narrow form and narrow foramen, hypotype USNM 550374 (off Marion Island at 100 fathoms (= 183 m)). Figure 10.—Interior of adult specimen showing arrangement of diductors and dorsal adjustor muscles, X 6 (large diductors in foreground and between them short accessory diductors, both sets attached to straplike integument fixed to cardinal process; pedicle attached to strap; dorsal adjustors visible, attached to hinge plates and to pedicle strap. Hypotype MNHN- BRA-78-77a, MD.03: station 14, CB3). Figures 11-13. —Aerothyris macquanensis (Thomson): Anterior, side, and dorsal views of an average specimen, X 1, hypotype USNM 550251-61 (Recent at 112-124 meters, off northeast side of Macquarie Island, Introduced for comparison with specimens (figures 14-28) from Marion Island). Figures 14-29.— Aerothyris aff. A. macquariensis (Thomson): 14-16, Side, dorsal, and anterior views of specimen with large foramen and vestigial deltidial plates, X 1, hypotype MNHN- BRA-78-82c; 17-19, side, dorsal, and anterior views of slightly smaller specimen with large foramen, X 1, hypotype MNHN-BRA-78-82f; 20, dorsal view of fully grown specimen with foramen approaching the “keyhole” type characteristic of A. kerguelenensis , X 1, hypotype MNHN-BRA-78-82h; 21, dorsal view of another adult with large foramen and conjunct deltidial plates, X 1, hypotype MNHN-BRA-78-82a; 22, rubber impression of interior of ventral valve, X 1.5 showing muscle scars and vestiges of pallial marks, hypotype MNHN- BRA-78-82i; 23, 24, interior of dorsal valve showing cardinalia and pallial trunks and rubber impression of interior to show pallial trunks in relief, X 2, hypotype MNHN-BRA-78-82j; 25, posterior of a dorsal valve, X 2, showing socket, ridges, hinge plates, and poorly developed cardinal process, hypotype MNHN-BRA-78-82k; 26, posterior of ventral valve showing teeth and small deltidial plates, MNHN-BRA-78-82i; 27, interior of dorsal valve X 1.5 showing loop, hypotype MNHN-BRA-78-82-1; 28, 29, ventral and side views of young specimen with loop in terebratellid stage, X 5, hypotype MNHN-BRA-78-82m (MD.08: station 22, BB 125). NUMBER 43 81 82 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 9 Figures 1-28. — Aerothyris kerguelenensis (Davidson): 1-3, Dorsal, anterior, and side views, X 1, of compact, sulcate, rather wide individual, with “keyhole’' foramen, hypotype MNHN-BRA- 78-83a; 4, 5, rubber impressions of interior of dorsal and ventral valve, X 1, showing pallial trunks and muscle scars, and vascula media and myaria hypotype MNHN-BRA-78-83f; 6, dorsal view of specimen from which preceding rubber impressions were taken, X 1; 7, interior of elongate dorsal valve, X 1, showing pallial trunks (vascula media and myaria), hypotype MNHN-BRA-78-83b; 8, young round specimen in dorsal view, X 1, hypotype MNHN-BRA- 78-83d; 9-11, dorsal, side, and anterior views, X 1, of large, rounded specimen with narrow, small foramen and conjunct deltidial plates, hypotype MNHN-BRA-78-83i; 12, posterior of preceding specimen, X 2, showing small foramen and conjunct deltidial plates; 13, interior of adult dorsal valve X 1 , showing loop hypotype MNHN-BRA-78-83c; 14-16, dorsal, side, and anterior views, X 1, of exceptionally large, wide, sulcate specimen, with small “keyhole” foramen, hypotype MNHN-BRA-78-83g; 17-19, anterior, side, and dorsal views, X 1, of another large, round individual having a large foramen, hypotype MNHN-BRA-78-83h; 20, dorsal view of young specimen, hypotype MNHN-BRA-78-83e (MD.08: station 12, DC 78). 21-23, Dorsal, side, and anterior views of elongate, narrow specimen, X 1, having a small “keyhole” foramen and almost conjunct deltidial plates, hypotype MNHN-BRA-78-84; 24, posterior of previous specimen, enlarged X 2, to show details of foramen and deltidial plates (MD.08: station 13, CP 85). 25-27, Dorsal, side, and anterior views, X 1, of large oval specimen with “keyhole” foramen, hypotype MNHN-BRA-78-85 (MD.08: station 34, DC 167). 28, Dorsal interior of large elongate individual, X 2, showing loop, hypotype MNHN-BRA- 78-86 (MD.08: station 28, DC 143). NUMBER 43 83 84 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 10 Figures 1-37. — Aerothyris kerguelenensis (Davidson): 1-3, Dorsal, anterior, and side views of young, round individual, X 1 , hypotype NMHN-BRA-78-87; 4, interior of dorsal valve of same specimen showing loop, X 1.5 (MD.08: station 45, CP 203). 5-7, Side, dorsal, and anterior views of small, elongate, oval specimen with keyhole foramen X 1 , hypotype NMHN-BRA-78-88a; 8-10, dorsal, side, and anterior views of smaller, oval specimen, X 1, with attached Platidia marionensis, new species, hypotype NMHN-BRA-78-88b (MD.08: station 15, DC 87). 11-13, Small elongate specimen in side, dorsal, and anterior views, having large foramen, X 1 , hypotype NMHN-BRA-78-89 (MD.08: station 77, DC 314). 14-16, Dorsal, anterior, and side views, X 1, of small elongate specimen with narrow foramen and widely disjunct, deltidial plates, hypotype NMHN-BRA-89-90a; 33, interior of dorsal valve showing loop, X 2, hypotype NMHN-BRA-78-90d (MD.08: station 27, DC 136). 17-19, Anterior, dorsal, and side views, X 1, of stout, rounded specimen with wide foramen, hypotype NMNH-BRA-78-91 (this is a variant in small sample of population with L/W = 1.02; MD.08: station 73, CP 295). 20-22, Dorsal, anterior, and side views, X 1, of wide, rounded specimen, hypotype NMHN- BRA-78-92 (MD.08: station 9, CP 64). 23-25, Side, anterior, and dorsal views, X 1, of large, wide specimen with large foramen, hypotype NMNH-BRA-78-93; 26, interior of dorsal valve of same specimen, X 1 , showing adult loop (MD.08: station 40, DC 186). 27, Dorsal view of small, round specimen, X 1, from population predominately oval, hypotype MNHN-BRA-78-81 (for the interior showing its loop, see Plate 8, figure 8; MD.08: station 74, DC 296). 28, Fairly large, elongate specimen in dorsal view, X 1 , hypotype NMHN-BRA-78-94a; 29- 31, anterior, dorsal, and side views, X 1, of specimen rounder than preceding with large foramen, hypotype NMHN-BRA-78-94c; 32, interior of dorsal valve of another elongate specimen, X 1.5, hypotype NMHN-BRA-78-94b (MD.08: station 25, CP 134) 34-36, Anterior, side, and dorsal views, X 1, of exceptionally large individual with elongate, large foramen, hypotype MNFIN-BRA-78-95 (MD.08: station 42, CP 197). 37, Interior of large dorsal valve showing free loop, X 1.5, hypotype MNHN-BRA-78-96 (MD.08: station 9, DC 68). NUMBER 43 85 86 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 11 Figures 1-17 .—Aerothyris kerguelenensis (Davidson): 1, 2, Ventral and posterior views, X 3, of specimen with loop well preserved and lateral branches united but free of septum, hypotype MNHN-BRA-78-76c (MD.03: station 26, CP 17). 3, Incomplete specimen of ventral valve showing conjunct deltidial plates, X 1, hypotype MNHN-BRA-78-98; 4, same specimen as preceding enlarged, X 2, showing conjunct deltial plates and tilted to show inner junction of plates (MD.08: station 13, CP 85). 5, 6, Posterior of ventral valve with conjunct deltidial plates, X 2, and tilted to show inner junction of plates with curled edges, X 2, hypotype MNHN-BRA-78-99a (MD.08: station 18, DC 107). 7, Ventral view of dorsal valve interior, X 2, showing inner hinge plates straddling median septum, hypotype MNHN-BRA-78-100 (MD.08: station 19, BB 111). 8, Interior of dorsal valve showing extravagantly thickened cardinalia, X 2, hypotype MNHN-BRA-78-101; 9, same in dorsal view, X 2, to show ponderous cardinal process (MD.08: station 74, DC 296). 10, Another dorsal valve interior, X 2, showing bizarre thickening of cardinalia and pallial trunks, hypotype MNHN-BRA-78-102 (MD.08: station 40, DC 186). 11,12, Dorsal and ventral views of greatly thickened dorsal valve, X 2, showing pallial trunks and overgrown median septum, hypotype MNHN-BRA-78-103 (MD.08: station 9, CP 64). 13-17, Series of 5 specimens showing loop development, all X ca. 7.5: 13, dorsal valve of a specimen with ventral valve about 2.8 mm in length showing early pillar and initial development of septum; 14, specimen with ventral valve 3.2 mm in length showing expanded pillar and septum and nubs of beginning crura; distal end of pillar expanding to form a cone; 15, specimen with ventral valve 4.6 mm in length and showing expanded cone, beginnings of crural processes and descending lamellae, anterior edge of pillar with spines; 16, specimen with ventral valve about 5 mm long showing expanded and posteriorly open cone with narrow cover destined to become transverse band; crural processes well established and descending branches complete; 17, specimen with ventral valve 5.5 mm in length, more retarded than previous specimen because descending branches are not united; respectively hypotypes MNHN-BRA-78-104c,d, f-h (MD.08: station 40, DC 186). NUMBER 43 87 88 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 12 Figures 1-4 .—Eucalathis species: Dorsal, side, anterior, and ventral views, X 5, of fairly evenly costate specimen, MNHN-BRA-78-105 (MD.08: station 6, DC 43). Figures 5-27. — Aerothyris kerguelenensis (Davidson): 5, 6, Ventral and posterior views, X 1.5, of dorsal valve showing bizarre thickening of cardinal process and associated structures, hypotype MNHN-BRA-78-106 (MD.08: station 42, CP 197). 7, Ventral view of another dorsal valve with extravagantly thickened cardinal process, X 1.5, hypotype MNHN-BRA-78-107 (MD.08: station 9, DC 68). 8, Interior of dorsal valve, X 1.5 showing unusual development of inner hinge (septal) plates and septum, hypotype MNHN-BRA-78-108 (MD.08: station 46, CP 204). 9, 10, Dorsal valve, X 1.5, with septum rising to crest at midvalve, hypotype MNHN-BRA- 78-109 (MD.08: station 20, CP 116). 11, Dorsal valve interior, X 1.5, showing extravagant anterior thickening of cardinal process and inner hinge plates, hypotype MNHN-BRA-78-110 (MD.08: station 9, CP 64). 12, Interior of dorsal valve, X 1.5, showing thickened cardinalia and one resorbed lateral attachment of descending branch to median septum; although precocious in its thickening of shell, this specimen was retarded in its loop development, hypotype MNHN-BRA-78-111 (MD.08: station 16, CL 95). 13-16, Interior of ventral valve, X 1, X 1.5, showing conjunct deltidial plates and great thickening of shell in muscle Field, hypotypes MNHN-BRA-78-99b,c; note inwardly depressed ends of deltidial plates in figures 14, 16 (MD.08: station 18, DC 107). 17, Dorsal view, X 1 , of largest specimen in population sample, hypotype MNHN-BRA-78- 112a; 18-20, dorsal, side, and anterior views of preceding specimen, X 1.5; 21, small, somewhat rounded specimen, X 1, hypotype MNHN-BRA-78-112b; 22, 23, same specimen, X 1.5, showing growth lamellae; 24, early development stage of loop, ca. X 9, showing early ring and incipient descending and ascending branches, hypotype MNHN-BRA-78-112d; 25, interior of dorsal valve, ca. X 9, of another young specimen showing elaborated ring with descending lamellae complete and attached to septum hypotype MNHN-BRA-78-112e; 26, 27, interior of dorsal valve of specimen with ventral valve 14 mm long showing complete magellaniform loop, hypotype MNHN-BRA-78-112c, X3 (MD.08: station 50, DC 216). NUMBER 43 89 90 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 13 Figure 1.— Basiliola species: Interior of large, flattish dorsal valve, X 3, showing cardinalia, MNHN-BRA-78-113 (MD.08: station 7, DC 57). Figures 2-4. — Crania species: Interior of ventral valve, interior of dorsal valve, and exterior of dorsal valve, ca. X 10, showing pitted anterior rim of ventral valve and concave rim of dorsal valve and pustulose exterior, MNHN-BRA-78-114 (MD.08: station 6, DC 32). Figures 5-15.— Eucalathis rotundala , new species: 5-8, Ventral, side, anterior, and dorsal views, X 5, of strongly costate specimen, holotype MNHN-BRA-78-115a; 9, dorsal view of same specimen, X 9; 10, 11, interior of preceding specimen, X 5, X 9, showing rounded loop; 12- 15, anterior, ventral, side, and dorsal views, X 5, of paratype MNHN-BRA-78-115b (MD.08: station 6, DC 35). Figures 16-23. — Aerothyris kerguelenensis (Davidson): 16-18, Anterior, side, and dorsal views, X 1, of round specimen, hypotype MNHN-BRA-78-116; 19, interior of dorsal valve of preceding specimen, X 1, showing loop (MD.08: station 34, DC 167). 20, Dorsal view of specimen with length and width nearly equal, X 1 , hypotype MNHN- BRA-78-1 17; 21, dorsal view of same specimen, X 3, showing irregular radial striae (MD.03: station 22, CP 15). 22, Dorsal view of another but more elongate specimen, X 1 , hypotype MNHN-BRA-78-118; 23, Same specimen, X 3, showing numerous radial striae, many of which can be related to shell irregularities (MD.03: station 2, CB 2). 24, Aerothyris macquarienensis (Thomson): Dorsal view, X 1, X 3, of specimen showing radial striae similar to those shown above and often linked to shell imperfections, hypotype USNM 550251-58 (Harvard Station 27-36). NUMBER 43 91 92 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 14 Figures 1-20 .—Ecnomiosa inexpectata, new species: 1-3, Anterior, dorsal, and side views, X 1, holotype MNHN-BRA-78-119a; 4, dorsal view of holotype, X 2; 5, interior of fragmentary pedicle valve, X 1.5, showing muscle scars and dental plates, paratype MNHN-BRA-78- 119b; 6, rubber impression of ventral valve interior of preceding showing muscle scars, X 1; 7-11, dorsal valve in direct ventral view, posterior, anterior, side, and partially tilted ventral views, X 2, of nearly adult dorsal valve showing posterior ring attaching transverse band to median septum, paratype MNHN-BRA-78-119c; 12-14, posterior, anterior, and ventral views, X 2, of complete loop of young but adult individual, paratype MNHN-BRA-78-119d; 15, ventral view of dorsal valve about 4.3 mm wide, at X 12, showing incipient pillar and early loop welded to valve floor, paratype MNHN-BRA-78-119g; 16, dorsal valve interior at X 10, showing broken loop with descending lamellae not attached to valve floor and pillar in its early stages of elongation, paratype MNHN-BRA-78-119h; 17, interior of dorsal valve nearly 6 mm wide, X 5, X 9, showing early development of cone expanding at distal end of pillar, its spiny anterior edge and descending lamellae just released from attachment to valve floor in their proximal half, paratype MNHN-BRA-78-119i; 18, same specimen in ventral view, and side view, X 11, X 10, showing somewhat more expanded cone on pillar, descending lamellae less expanded laterally and free of valve floor; 19, another dorsal valve nearly 9 mm wide, at X 4, showing much expanded cone, still spiny anteriorly, much narrowed descending lamellae, inner hinge plates attached to low but elongated median septum, paratype MNHN- BRA-78-1 19k; 20, same specimen as preceding, X 8 showing cone open posteriorly, its spiny anterior and inner hinge plates joined to septum, including 2 views of same specimen in partial side (X 6) and side (X 8) views showing anteriorly spiny cone, descending lamellae free of valve floor, and beginning of lateral lacunae (MD.08: station 44, CP 199). NUMBER 43 93 REQUIREMENTS FOR SMITHSONIAN SERIES PUBLICATION Manuscripts intended for series publication receive substantive review within their originating Smithsonian museums or offices and are submitted to the Smithsonian Institution Press with approval of the appropriate museum authority on Form SI-36. 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 1 %" 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 establish¬ ed 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 unnum¬ bered footnote at the bottom consisting of author's name and professional mailing address. Center heads of whatever level should be typed with initial caps of major words, with extra space above and below the head, but with no other preparation (such as all caps or underline). Run-in paragraph heads should use period/dashes or colons as necessary. Tabulations within text (lists of data, often in parallel columns) can be typed on the text page where they occur, but they should not contain rules or formal, numbered table heads. Formal tables (numbered, with table heads, boxheads, stubs, rules) should be sub¬ mitted as camera copy, but the author must contact the series section of the Press for edito¬ rial attention and preparation assistance before final typing of this matter. Taxonomic keys in natural history papers should use the alined-couplet form in the zoology and paleobiology series and the multi level indent form in the botany series. If cross-referencing is required between key and text, do not include page references within the key, but number the keyed-out taxa with their corresponding heads in the text. Synonymy in the zoology and paleobiology series must use the short form (taxon, author, year:page), with a full reference at the end of the paper under "Literature Cited." For the botany series, the long form (taxon, author, abbreviated journal or book title, volume, page, year, with no reference in the "Literature Cited”) is optional. Footnotes, when few in number, whether annotative or bibliographic, should be typed at the bottom of the text page on which the reference occurs. Extensive notes must appear at the end of the text in a notes section. If bibliographic footnotes are required, use the short form (author/brief 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 sepa¬ rately as original art (not copies). All illustrations (photographs, line drawings, maps, etc.) can be intermixed throughout the printed text. They should be termed Figures and should be numbered consecutively. If several "figures” are treated as components of a single larger figure, they should be designated by lowercase italic letters (underlined in copy) on the illus¬ tration, in the legend, and in text references: "Figure 9b.” If illustrations are intended to be printed separately on coated stock following the text, they should be termed Plates and any components should be lettered as in figures: “Plate 9b,” Keys to any symbols within an illustration should appear on the art and not in the legend. A few points of style: (1) Do not use periods after such abbreviations as “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 list¬ ings or data sections, use three-letter abbreviations with no periods: "Jan, Mar, Jun,” etc. Arrange and paginate sequentially EVERY sheet of manuscript —including ALL front matter and ALL legends, etc., at the back of the text—in the following order: (1) 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.