a na waka its wie seg! toate tat M5. : aie at % is! than ; ee iat a Seas yh as} HARVARD UNIVERSITY e Library of the Museum of Comparative Zoology Gilbert Dennison Harris (1864 - 1952) Founder of the Bulletins of American Paleontology (1895) LUME 103, NUMBER 341 JUNE 26, 1992 Eocene Euthecosomatous Pteropoda (Gastropoda) of the Gulf and Eastern Coasts of North America by Kenneth A. Hodgkinson, Christopher L. Garvie, and Allan W. H. Bé Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION ~ Ue ” Officers IPRESUDENIOY Fo cor eats eee a te ie 7 a HARRY A. LEFFINGWELL WICH PRESIDENT D ieee ai Pie Ee ee eats oe en J. THOMAS DuTRO, JR. SECRETAR Yet iets Mea en Ea te Ae 0 Ct ae HENRY W. THEISEN TREASURER) Mechs altel 5 See heel en seeiirs Larch «eeu mde ere eee . JAMES C. SHOWACRE IANSSISIFAINT: CUIREASUIRERY Si-re.c acy ocrie SLOmy AA onaen seek eee eee ROGER J. 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WALLER ALBERT D. WARREN, JR. Gary D. WEBSTER RALPH H. WILLOUGHBY ARMOUR C. WINSLOW THOMAS E. YANCEY Victor A. ZULLO OLUME 103, NUMBER 341 JUNE 26, 1992 Eocene Euthecosomatous Pteropoda (Gastropoda) of the Gulf and Eastern Coasts of North America by Kenneth A. Hodgkinson, Christopher L. Garvie, and Allan W. H. Bé Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York, 14850 U.S.A. Library of Congress Card Number: 92-64047 Printed in the United States of America Allen Press, Inc. Lawrence, KS 66044 U.S.A. CONTENTS Page “UPSERTGY CR RR a erin a creicee cro a necro erate ceo it Pan Rrra recat th aR eae IAT eA ree Si Rene nec a cm 5 BROPRA SCA UNCTA OTN aN oe 5 ee taco aie oe Meats ashe aes ee ctay sian ace eran S veg oes Rar COP O PRIS raya GE Nay Tey ei oe AG Me hca aS Fa ado 1SYE os NS AL Fe TaNB = TOP STONES TEE ole Teac be Palas ORE PRCT: 5 PRECIOUS VEStICATIONS Of EOCCNEMRtErOPOGS, acre vere cheteysvetere rete ta sia eate eer ae eee ese eaves ek ol =e settavoy ete acto) sletarerer sya etccehe tole ieee rs istereeier 6 BPMPSCOTS CRS EUICE Vi col 60sec yeas oo occ rar esi See Setaya acces ese Paech eC inp deve ve eeu ona eNers) adstn/anot ceney ashe aye rel save evel ai-vaye cal stsvatarebenaisiadersl sea le Qucta erent tomato svete q BENEODIOLCOLTAP HY” (ejc6c.2:5 5 acco con slave pitas mas ey nc sec Bie: stn eke ed dcedpus fal taco als fo. 8 Ceoyd att fab Ss) Hie Geshe va a oY as. a Gia) Auda) 9794 a hap ado a a SYaGVapa far sabcsaroheratelpelets 7 BANEVSETACL OT APY, 0) oes zesezcen chav ecco as val Sere es eB Oi MCw ah nurs i nears eel 'a anh sve thy ox0/@ SIE 4 Siu 6y Spe, a15v0: atelonsitt ey onal nate) ais, otaheapl si yePote. s eV/avevep suave bovsuors Gren 9 PAST MIVET GIO SCI UICTUITE oc, 0551s vie ens, Cosas ssepesecasa) escceset seples Poeiov eet anesaverecunts corsue ac RTs telass; ate asaya sera yal susie sssiaudy echo tapas cevevorecous et eiee sustetays Sakeea aveisvenane reels 9 BERR TIOW IOC OIN GM TS oo ices. cvcis esis Soars cSoe ere: ai ee ore wreter‘a s/s o: arex cpevte vet ole) eiereitevels salves wherever eravey Suave) & [etalie obs (o Susu Ieee Fan ai (evar) wlemnsv a wuaveysyanslsieee rahe 11 EH HrLevIa ONS Of REPOSILOry INSLITULIOMS) 2h,2, sc.ceiee esses eel ai ececsiess.sco.avelsoe sievensin,ayatieracst ans etatele custae(s oust euslis suerevagsusyslieroysias ays sy cee serave) aieareveraeae 11 Systematic Paleontology ESNTEROCUICEI ON jee ssakatersecircauaraisiacsy snes cnevs oie autde ons \a7az e.ebagsee tev ais Glonasavonstndade byt alisuetoselsveamtes(euz da ceveseste, susy vse, ou ayes Gisheriay tre r sie acer ademas petniciavecsusuetenre ate 12 ROLASSISICALL OM mree terete ere Greiner otek re eon Sem Tr tiey Mos Perse A TRR IST oney aN CANN SS CIA ROS REI CSV eI SRT SIRE ence metetetene tare 12 YSGOL ys re ise ers chetnrt rch ea ar Pg AR OP PRT tN he a ra 12 SWITARGS Oper lelo) e) 5:1 Vel cy Ee aan a ee eee le ee eee ee ace eee rei roach tec 12 rel Or NGCOSOMIMATAT eerste eect rere esa nae ec ERNST ES SES TaN Pence TERE eS eR ELE a ErG STOTT PRISM CIS Te CIC RTS Tne Ne 12 Suborder Euthecosomiata: .0 95s ope reesei nce a ee ree eee ena le area ae oe aione Seca Totoneacre wie Ol aye Crtarege 13 FENN J Esti to bil Fok eee een a eer et ere ac pies oe isa An AM DAT aera ac Me ODE 13 Genus Alfaspiratellas2. © eek, SO rr ne choses eM TEE eee EEE en Oe RET EIS e Ce Eee 13 (Crh G1 TeH (17 lati ea Re Her LaPierre BER HEA en Sse ORE GO Rao UUNTS COGS DUO ORUDUCUDUAad oun CoDEoaeT 14 GenusiSKAplOlion ve. cares sh, Sa entre I ate alana EE I EE TS ate NS Ae Me ee eon eee oops 21 amily GCavolintidaes ...2.23.s0es ei hornet ats cre ices rears tnd aye couay aye abe oe ave tavern ctevars (opayeleve Sie Ryac Ts oe reie ai iar te AIO re ee Ree 24 SubfamilyiGlionae’, £5 f0 5.2 5.2 te cde ecors Aro tea oie s rose eye he pee eae ToD ER ay OTR OEE ee eee 24 (GENUSUBOVICONTIAT Fie errs s ee Ie oi aan rth Ue ee ESTE TOYS VO NS [STEP STE SIE RRS E Sree OA OPN enor Rafe Ee poe 24 GENUS! Cam pPloceratOD sy a crore crceic ce esaTe ses ee LTT en a ESOP ESE LS ate eR ee TE er enn 25 (GenustEherlospicaiar ne sere Mtoe TT Re ee ee REET CORY Scie ae OEE ee COO ne 26 CONUS TCT ESEIS eee = cic coseiel hance ceived yelt sa eteeteibiae. ele Ne ore AT Ioan coded thavadane fee eons tiah Pesce teeter eT ee oe 26 GENUSPEUCKILOIN ECE A ose not NOE Oe eA OT AT TTS TTT SANT eee ETS LT REO ee 29 (GSN ¢ 1 1(416))) | Ca ere ee A PSR SP Oe ee eee rip ws rnin an eerie reer neon ire OG 29 Gen UsHPraehnyalocy lis a0 85 rr. noosa ts ayes 5) 0 o.oo 6 ee CO 6 io ab 01 STOR LTONS TOY HAG (ovo Ta oveTaL DEG VTSPEFSTSICSLGINY sks He TeveTeT Tone NTT n TTA 30 Subfamily¢@uvierininae eke nn eae ion rahi aot nsf Lie RO EA OE CO OCCT URC ER REEL Cee ERE 31 GENUS! BUCANOIAES ses Hee SPR LTV or sf ne raph ori loe oe Ct Moron eho Los etek CTs STL IOTSE ETO ET Tae are iota eres 31 (CXS EH Gi79 01271 7 haere ar a en ee CE Re OAR Com ir fern ROO P Oa AT ce ATO OU Onda a tdeoes DUO eee 32 Genus? Loxobidens Pesos a2 noah ee Oe EMAC Se ee OSs BREE EE En GREE CnC ROTEL Choe 33 (GINS ITAL ole ea ae ean rece an EN AA ano SEAR ROSNER CRAG SOHO RAO A HOD Sa ROD Heo oS dh OSM aRoOaee 34 EePPENGIK A COMECTIN GS COCALIEIES 59 2 pho esraratconistcd create oN VAP STOLE IO oslo ACES Re OO Eon eT eee neers 35 ELST CGC oss cacao So rR ee Pca PA oS RiP er PA een Seals one 8 cis a Roa mn acta nance dee 38 PENES 0.1 RE eR ea Nea eR etree ee Te en ree, ae eer Crain eer tate ene aac cio cies oieicreres Mis eec 43 CREIEES 5 sero phenieg Cee SPE ELER OPER SR SAE eE art IE apron AD Eean atn a Pha Sat Mee era hed oom Sarees aE 57 LIST OF ILLUSTRATIONS Text-figure 1. Correlation chart of Eocene and some Oligocene formations in Texas, Louisiana, Mississippi, and Alabama ................... Ab wWhy LIST OF TABLES Table 1. The taxonomic status of the 12 species of American Eocene pteropods discussed by Collins (1934) . 2. Shellimicrostructure of:selected American! Eocene|pteropods! ].--- e+. cect ee eee sec ricciecniiae 3. Measurements (in mm) and diameter/length ratios of specimens of Creseis simplex used in this study 7 Eocenestratipraphicunitsjim) Dexas: (reece cyecsees siete ese selec sroresce esha saat alaiheey sretel area area eyvevey eee erase oe . Distribution of selected Eocene pteropod species in North America .................00 050000000 e . States bordering the northern Gulf of Mexico, showing the locations of several collecting sites ...... . The location of cited exploratory wells in offshore eastern Canada ...................0..-2..0005. EOCENE EUTHECOSOMATOUS PTEROPODA (GASTROPODA) OF THE GULF AND EASTERN COASTS OF NORTH AMERICA by KENNETH A. HODGKINSON! CHRISTOPHER L. GARVIE? AND ALLAN W. H. BE? ABSTRACT Euthecosomatous pteropods of Early Tertiary seas were equally or more diverse than they are in present-day oceans, and probably as abundant. Twenty-eight new species (A/taspiratella gracilens, Limacina adornata, Limacina aegis, Limacina cana- daensis, Limacina convolutus, Limacina davidi, Limacina heatherae, Limacina helikos, Limacina labiata, Limacina planidorsalis, Limacina smithvillensis, Limacina stenzeli, Limacina texana, Limacina voluta, Limacina wechesensis, Skaptotion? reklawensis, Skaptotion spirale, Camptoceratops americanus, Cheilospicata repanda, Creseis cylindrica, Bucanoides basiannulata, Bucanoides divaricata, Bucanoides tenuis, Cuvierina gutta, Cuvierina lura, Loxobidens aduncus, Tibiella annulata, and Tibiella reflexa) and three new genera (Bucanoides, Cheilospicata, and Loxobidens) are described from the Eocene of Texas, Louisiana, Alabama, Mississippi, and the Nova Scotian shelf. In addition, seven species that previously were not reported from North America were found in these localities. These 35 species plus 13 previously described North American Eocene pteropod species constitute a total of 48 species now known to occur in North America. All of these species are formally described here except for single specimens of Hyalocylis sp. A, Creseis sp. A, and Praehyalocylis cretacea (Blanckenhorn, 1889). The latter species has been described from the late Eocene of Oregon and Washington (Squires, 1989). It is basically a worldwide species with additional reported occurrences in Russia, Turkey, and Australia. The genera Camptoceratops and Euchilotheca are reported from North America for the first time. INTRODUCTION Pteropods are one of the most abundant and ubiq- uitous members of the plankton community in modern seas, and their skeletal remains are preserved in large quantities in some areas of the deep-sea floor. The shells of these small mollusks are often abundant enough to form pteropod oozes. These oozes occur in the Mediterranean Sea, Red Sea, Persian Gulf, Carib- bean Sea, Gulf of Mexico, Blake Plateau, Bermuda Platform, and in parts of the Atlantic, Pacific, and Indian oceans. Fairbridge (1966) estimated that these oozes, together with those of foraminifers and coccol- ithophores, cover 128 million km?, or about 35% of the ocean bottom. Sverdrup, Johnson, and Fleming (1942) estimated that pteropod oozes cover about 2 million km?, or about 1% of the sea floor. Pteropods are opisthobranch gastropods that have adapted to a planktonic existence. According to Bé and Gilmer (1977, p. 744), there are 28 modern eutheco- somatous pteropod species, of which seven belong in the family Limacinidae (= Spiratellidae) and 21 in the family Cavoliniidae. Unlike the gymnosomatous and pseudothecosomatous pteropods, which have a shell ‘9285 W. 9200 N., R. F. D. 1, Box 428-F, Lehi, Utah 84043, U.S.A. ? Backerstrasse 4, [IV Stock, 8000 Munich 60, GERMANY. > Deceased. in the larval stage but not in the adult, euthecosoma- tous pteropods possess aragonitic shells throughout their life cycle. The shells of the Limacinidae are sin- istrally coiled [technically the coiling is hyperstrophic (Keen, 1971, p. 805)], but we follow most other authors in describing the coiling as sinistral. For a discussion of hyperstrophic coiling see p. 13. Most species be- longing to the Cavoliniidae have bilaterally symmet- rical, straight or slightly curved shells. Several North American creseid genera, like Bovicornu and Camp- toceratops, have shells with a very loose spiral. Euthecosomatous pteropods are abundant and wide- spread in the world’s oceans, and range from polar to tropical regions. Twenty-one species inhabit the cir- cum-global belt of tropical and subtropical waters, where the surface-water temperature is 18°C or higher. Only four species live in sub-Antarctic and/or Antarc- tic waters, of which three also occur in Arctic and/or sub-Arctic regions. Thus species diversity among pter- opods follows a trend seen in many other marine in- vertebrates; namely, that species diversity is greater in lower latitudes and decreases toward the higher lati- tudes. For detailed discussions of the biogeography, taxonomy, and comparative anatomy of modern pter- opods, see Boas (1886), Pelseneer (1888a, 1888b), Mei- senheimer (1905, 1906a, 1906b), Schiemenz (1906), Bonnevie (1913), Tesch (1904, 1913, 1946, 1948), Vayssiére (1915), Massy (1932), Morton (1954), and Pruvot-Fol (1954). More recent publications are those 6 BULLETIN 341 by McGowan (1960, 1968, 1971), Chen and Bé (1964a, 1964b), Spoel (1967, 1972), Rampal (1968, 1973, 1974, 1975), Herman (1978), Lalli and Wells (1978), Spoel and Pierrot-Bults (1979), Bé and Gilmer (1977), Rott- man (1980), Stepien (1980), and Wormuth (1981). Ab- bott (1974) and Keen (1971) have also described and illustrated most of the Recent pteropod species in the oceans contiguous to the North American continent. Most euthecosomatous pteropod species live in the upper 500 m of the ocean, but three species [Limacina helicoides Jeffreys, 1877, Clio balantium (Rang, 1834), and Clio chaptalii (Gray, 1850)] are known to inhabit deeper waters. Several species exhibit diurnal migra- tion, descending below the photic zone during daylight and ascending at night to surface waters where they may feed on phytoplankton, microzooplankton and small organic particles (Boas, 1886; Pelseneer, 1888a, 1888b; Morton, 1954; and Gilmer, 1974). Pteropods are not commonly preserved: their shells are thin, fragile and composed of aragonite, which is less stable and more susceptible to dissolution than the calcitic shells of planktonic foraminifers and cocco- lithophorids. The aragonitic shells are rarely found in the relatively organic-rich sediments that border the continents or in oceanic regions below the aragonite compensation depth (ACD). In the ocean, the ACD is that level below which the rate of aragonite solution exceeds the rate of deposition. Thus pteropod shells will not be found below this level. The ACD, according to Berger (1978), varies in depth from ocean to ocean as well as within the same ocean. Its average depth in the Atlantic Ocean is near 1.5 km in low latitudes and between 2 and 3.4 km in middle latitudes. It is between 0.5 and 1.5 km in the Pacific and Indian Oceans. The ACD decreases towards high latitudes and continental slopes. Fossilization of pteropods clearly requires special paleoenvironmental conditions. Herman (1978, p. 151) noted that pteropods are better preserved in basins having high bottom temperatures, sluggish circulation and rapid rates of sedimentation, such as the Medi- terranean and Red seas. She also observed (p. 153) that pteropod distribution is controlled by salinity, food and oxygen availability, and by water depth. Well- preserved pteropods of Pleistocene age have been found in many oceanic regions (see Stubbings, 1938; Herman, 1971, 1973; Jung, 1973; Sarnthein, 1971; Bé et al., 1976; Diester-Haass and Spoel, 1978; Almogi-Labin and Reiss, 1977; and Almogi-Labin, 1982). Preserved pteropod shells are abundant in Recent and Pleistocene sediments, and, in general, pteropod remains become less abundant as geologic age increases. The shells of certain mature pteropods closely re- semble the juvenile stages of other gastropods. For example, the coiled shells of Limacina may closely resemble the initial whorls of gastropods with a sin- istrally coiled protoconch. Most gastropods have dex- trally coiled shells, but many of these have embryonic whorls that are coiled sinistrally (e.g., pyramidellids and many of the opisthobranchs). These protoconchs are often small, smooth, and thin-walled, and super- ficially resemble spiratellid pteropods. Pteropod shells can also resemble the thin, unornamented, sinistral shells of freshwater gastropods. Other groups of animals have small, elongated con- ical shells that superficially resemble some cavoliniid pteropods. Such shells can nevertheless be differenti- ated. For example, scaphopod shells and worm tubes are open at both ends, whereas pteropod shells are closed at the apex. Caecid gastropods are also closed at the apex but usually have an expanded lip or varix at an intermediate stage of growth and a relatively thick shell, which may be ornate with a distinctively pointed extension of the septum. Curry (1965, p. 358) noted the following useful char- acteristics for distinguishing mature pteropod shells from the juvenile shells of other gastropods: (1) pter- opods have thinner walls, whose thickness is usually in the range of from 5 to 40 um; (2) they have a closed apex; (3) they are normally not ornamented except for growth lines or corrugations of the shell wall (we note that the Peraclidae, not recorded as fossils, and Li- macina adornata, n. sp., have surface ornamentation and are exceptions to this rule); (4) the apertural lip of the shell may be thickened or expanded locally, but such expansion or thickening occurs only when the shell is fully grown; and (5) pteropod shells, if coiled, exhibit a sinistral coiling direction. Some pteropods (e.g., Cuvierina Boas, 1886, Hyalo- cylis Fol, 1875, and Diacria Gray, 1847) truncate and discard the juvenile portions of their shells in the same manner as scaphopods (Hodgkinson, 1974, p. 8) and many other mollusks. Before truncation, the pteropod secretes a caudal septum. PREVIOUS INVESTIGATIONS OF EOCENE PTEROPODS North American Eocene pteropods have been de- scribed by Meyer (1884, p. 110; 1886, pp. 78, 79; 1887, p. 9), I. Lea (1833, p. 124), Aldrich (1887, p. 83; 1895, p. 5), de Gregorio (1890, pp. 16, 17), Gardner (1927, p. 377; 1951, pp. 10-12), Collins (1934, pp. 137-234), Curry (1965, pp. 357-371), and Squires (1989, pp. 440-442). Collins (1934) discussed 12 ‘‘Eocene” species from six locations in Alabama, Mississippi, and Texas in his monograph of American Tertiary pteropods (see Table 1). Of these, nine are now considered valid, one is not correctly identified, and two are invalid. The two invalid species (Creseis elba de Gregorio, 1890 and C. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE a Table 1.—The taxonomic status of the 12 species of American Eocene pteropods discussed by Collins (1934). Creseis corpulenta (Meyer) valid Creseis elba de Gregorio discarded Creseis hastata (Meyer) valid Creseis nimba de Gregorio discarded Creseis simplex (Meyer) valid Creseis sp. cf. C. hastata (Meyer) = C. simplex Bovicornu eocenense Meyer valid Bovicornu gracile Meyer valid Tibiella marshi Meyer valid “Tibiella” texana Collins valid Spiratella choctavensis (Aldrich) valid Spiratella elongatoidea (Aldrich) valid nimba de Gregorio, 1890) were referred to by Collins as “‘questionable species of Creseis.’’ He suggested that these two specific names be discarded from American Tertiary pteropods because the tips of the specimens were not preserved and they had no other well-defined features to prove that they were pteropods. Palmer and Brann (1965) state that the types of these species are lost. They were curated in the de Gregorio Collection, University of Palermo, Palermo, Sicily. We agree that these species should be discarded from the list of valid pteropod species. To our knowledge, Spiratella augustana Gardner, 1951 and Praehyalocylis cretacea (Blanckenhorn, 1899), reported by Squires (1989), are the only North Amer- ican Eocene pteropods found since Collins prepared his monograph on American Tertiary pteropods in 1934. Two molluscan species in Palmer and Brann’s 1965 catalogue are now considered to be pteropods. These are: Planaria nitens I. Lea, 1833 [= Skaptotion nitens] and Planorbis andersoni Gardner, 1927 [= Skaptotion andersoni). Thus, prior to the present study, there were a total of 13 valid Eocene pteropod species recognized in North America. Now there are 48 species. PRESENT STUDY Most of the pteropods described in this paper were obtained either by examining sediment from the in- terior of larger mollusks or by searching through large volumes of washed residue. Fossil shells of Conus (Lithoconus) sauridens Conrad, 1833, a large (5 to 8 cm long) gastropod from the Stone City and Cook Mountain formations of Texas, frequently harbored pteropod shells. Pteropods trapped in larger mollusk shells usually are protected from post-depositional compaction, solution, and destruction by other organ- isms. A good practice to follow when searching for fossil pteropods is to collect large fossil marine gastro- pods and closed bivalve shells and examine the sedi- ment in them for pteropod remains. It is possible to recover pteropods in perfect condition by removing sediment from the shell interior. We commonly found pteropod-containing bivalve or gastropod shells buried in sediment otherwise devoid of pteropod remains. These pteropods usually were recovered as internal molds, but in some instances their shells were pre- served. Washed residues were prepared by heating and dry- ing bulk samples of sediment, treating the heated sam- ples with Varsol® (a petroleum-based solvent manu- factured by Exxon), soaking the treated material in hot water and washing the disaggregated sediment through a 150-mesh screen. This method is effective if the pteropod shells are relatively strong and resistant, but it is ineffective for the recovery of more delicate forms [Specimens of Skaptotion nitens (I. Lea, 1833) from Little Stave Creek, Alabama were recovered intact by washing the sediment, but a very delicate form, Tibiella marshi Meyer, 1884 was found only by examining the dry unwashed sediment.]. Although the washing pro- cess is relatively gentle, the more delicate forms are frequently destroyed by: (1) the jets of water used dur- ing preparation of the sample; (2) the surface tension of water; (3) the abrasive action of various types of particles and the screen on the pteropod shells; and (4) the expansion of water-soaked clays inside the fossil pteropod shells. Pteropod specimens were frequently found filled, or replaced with pyrite, glauconite, calcite, clay, or other foreign material, which aided in their preservation. The Eocene and early Oligocene formations in which these pteropods were found are shown in the strati- graphic charts of Text-figures | and 2. Text-figure 1 is from Dockery (1986). Another excellent treatment of the stratigraphy of this area is found in the American Association of Petroleum Geologists COSUNA chart series for the Gulf Coast (1988). Text-figure 2 is from Stenzel, Krause, and Twining (1957). We have used the criteria set forth by these authors to identify the formations in this study. There is, however, still some disagreement as to the true stratigraphic positions and validity of several of these formations and members. For example, Nelms (1979) would refer to the Stone City Formation as the Stone City Member of the Crockett Formation. She, like many others, would use the term Crockett rather than Cook Mountain. PALEOBIOGEOGRAPHY Recent pteropods are most commonly found in deeper marine water, usually from water depths of 50 m or more (Janssen, 1990). However, Furnestin (1979) reports that Creseis acicula Rang, 1828 develops rap- idly during the wet season in the bays of Nosey-Bé off the northwest coast of Madagascar. Andrews (1971) states that the shells of this species can be easily over- 8 BULLETIN 341 Pocn STAGE LITHOSTRATIGRAPHIC UNITS TEXAS LOUISIANA | MISSISSIPPI | ALABAMA Vicksburg Vicksburg ra) i“ Co w = [tender Serenity Ww ” j : Pima \Glenaon > ° 35190 Mint Spring g = Forest HilIN| Marianna a ° Red Bluff Red Bluff Red Bluff Red Bluff Whitsett Yazoo Yazoo Yazoo giz McElroy 40 Caddell :] Moodys Br. | Moodys Br, | Moodys Br. U NP 17 Cook Mtn./ Cook Cook : . Upper Lisbon Stone City Mountain Mountain Kosciusco [Middle Lisbon 45 Sparta Sparta Zilpha- : Lower Lisbon Weches Winona 50 Cane River Queen City Tallahatta Tallahatta EOCENE MIDDLE LATE EARLY CLAIBORNE LUTETIAN BARTONIAN| PRIABON. RUPELIAN Hatchetigbee } Hatchetigbee YPRESIAN NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 9 looked if the beach drift is not carefully screened, but that at times they come ashore by the thousands. She has also found the shells of other pteropods in beach sands. It is important to understand this Recent distribu- tion pattern, because many of the sediments that yield fossil pteropods have been identified as shallow-water deposits. These include strata in the Stone City For- mation, Cook Mountain Formation, and Gosport Sand (see Scott, 1963; Nelms, 1979). Controls on the distribution of Recent pteropods include: (a) salinity; (b) temperature [decrease in num- ber of species from low to high latitudes]; (c) depth; (d) oxygen content of the marine waters; (e) nutrients [because most pteropods feed on phytoplankton and detritus, there is a close association between pteropod abundance, seasonal phytoplankton blooms, and nu- trient levels (Bé and Gilmer, 1977)]; (f) light penetra- tion [/.e., clarity of the water]; (g) seasonal abundance; (h) characteristics and movement of oceanic water masses [pteropods tend to be abundant in active cur- rent systems in regions of upwelling]; (i) saturation of sea water with respect to aragonite; and (j) species tol- erance to other environmental factors. Herman and Rosenberg (1969) reported that the ratio of Creseis spp. to Limacina inflata d’Orbigny, 1836 was depth-de- pendent in sediments. This ratio was high in water less than 100 m deep and decreased rapidly with increasing depth. Factors that control the distribution of Recent pter- opods certainly were important during the Eocene. It is necessary to understand these controls when trying to determine the causes for ancient pteropod distri- butions. It is also important to realize that during the Eocene the climate was warmer (more widespread tropical and subtropical environments), sea level was higher, and oceanic currents may have been signifi- cantly different. BIOSTRATIGRAPHY The biostratigraphic distribution of pteropods is not well-known, but Janssen and King (1988) and Janssen (1990) have published significant preliminary range charts with suggested pteropod zones. Pteropod zones suggested by Janssen and King (1988) in the Eocene include part of zone 6, and zones 7 through 12. We have been unable to tie our ranges to Janssen and King’s pteropod zones, and their scheme is not used in this paper. We have tried to tie North American pteropod biostratigraphic distributions to the nanno- plankton zones used by Dockery (1986) [see NP zones in Text-figs. | and 3]. The nannoplankton zones on Text-figure 1.—Correlation chart of Eocene and some Oligocene formations in Texas, Louisiana, Mississippi, and Alabama (adapted from Dockery, 1986, p. 584). Dockery’s biostratigraphic chart are from Berggren ef al. (1985). Improved biostratigraphic zonation will result as more data on the geographic and stratigraphic disri- bution of pteropods become available. SHELL MICROSTRUCTURE All euthecosomatous pteropods possess aragonitic shells. The internal shell microstructures of the two extant families are, for the most part, strikingly differ- ent. Members of the family Limacinidae build a crossed-lamellar shell microstructure (Pl. 5. fig. 7, Pl. 6, fig. 1), whereas those of the family Cavoliniidae have a helical microstructure (Pl. 10, figs. 9, 10). The latter shell microstructure was first described in pteropods Mount Tabor Spiller COOK MOUNTAIN Landrum Hurricane Wheelock SPARTA THERRILL WECHES CLAIBORNE Marquez Newby CARRIZO Text-figure 2.—Eocene stratigraphic units in Texas (from Stenzel, Krause, and Twining, 1957). REKLAW NP 17 Cheilospicata repanda n. sp. e dere eocenense | reseis hastata Creseis corpulenta ——— Bovicornu gracile =—_— Tibiella marshi =— Limacina labiata n. sp. = Skaptotion andersoni Limacina adornata n. sp. Cuvierina gutta n. sp. Bucanoides divaricata n. sp. Praehyalocylis maximus denseannulatus Loxobidens aduncus n. sp. == Euchilotheca succincta == Skaptotion ten EE Bucanoides tenuis 1. Sl, $a nares = ae wee abort = i mes | C/A NEMOrIS al = 8 ft Kren ears Creseis cylindrica n. sp. Limacina pygmaea mums Hyalocylis sp. A. mums | 7 ibiella annulata n. sp. 10 BULLETIN 341 Limacina convolutus n. sp. Tibiella reflexa n. sp. mums | /imacina smithvillensis n. sp." Creseis simplex Tibiella texana Limacina wechesensis n. sp. Cuvierina lura n. sp. Bucanoides basiannulata n. sp. Altaspiratella bearnensis Skaptotion? reklawensis Limacina texana Nn. sp. Limacina taylori Limacina stenzeli n. sp. Camptoceratops americanus n. Sp. ; ns A/S Piratella gracilens n. sp. Limacina augustana Limacina aegis n. sp. Limacina helikos n. sp. Limacina davidi n. sp. Limacina heatherae n. sp. Limacina choctavensis ! Altaspiratella elongatoidea lext-figure 3.— Distribution of selected Eocene pteropod species in North America. The ranges of several species are omitted because their biostratigraphic distributions are not well known. European distributions are not shown but are cited in the text. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 11 Table 2.—Shell microstructure of selected American Eocene ptero- pods. Crossed-lamellar (all coiled shells) Limacina nemoris (Curry) Limacina pygmaea (Lamarck) Altaspiratella bearnensis (Curry) Limacina wechesensis, n. sp. Skaptotion nitens (1. Lea) Helical microstructure (straight or loosely coiled shells) Bucanoides basiannulata, n. sp. Bucanoides tenuis, n. sp. Creseis simplex (Meyer) Cuvierina lura, n. sp. Tibiella reflexa, n. sp. by Bé, MacClintock, and Chew-Currie (1972, pp. 45- 79) for Cuvierina columnella (Rang, 1827). It is not known to exist in any other living or fossil molluscan group. Both the crossed-lamellar and helical micro- structures consist of first-order elongated rods, which in turn are made up of second-order blocks whose dimensions are approximately 0.2 um x 0.2 um x 0.4 um. In the living cavoliniid species, such as Cuvierina columnella, the helices of aragonite rods always coil clockwise when viewed from the outer side of the shell. Their central axes are perpendicular to the shell sur- face. Within a shell wall about 40 um in thickness, the helix spiral makes four turns on the average and the helix radius increases from about 1.6 um at the outer shell surface to about 14 um at the inner shell surface. The helical rods are nested in such a manner as to give omnidirectional continuity and flexibility as well as maximum strength to the thin, fragile shell. This is a decided advantage for an organism with a planktonic life-style. The phylogenetic significance of these two contrast- ing microstructures has been considered by Bé, MacClintock, and Chew-Currie (1972), Rampal (1973, pp. 133, 134), Richter (1976), Curry and Rampal (1979, pp. 23, 24), and Boltovskoy (1974). According to Bé, MacClintock, and Chew-Currie, the helical micro- structure of the Cavoliniidae may indicate that they are evolutionary neomorphs derived from ancestors with reduced or no shells, which have regained the ability to construct an exoskeleton on a new architec- tural plan. If this supposition is correct, the Limacin- idae, with a crossed-lamellar microstructure that is ba- sically similar to other molluscan shell structures, is a more primitive group than the Cavoliniidae. It is curious that in the course of their long evolu- tionary history so few marine gastropods have adapted to a holopelagic, shell-bearing existence in the ocean, although they live in great diversity and abundance in shallow-water marine environments where the veliger stages are meroplanktonic. The percentage of gastro- pod taxa that belong to the holoplankton community in contemporary seas is small indeed in comparison with the eminently successful cephalopods. The occurrence ofa helical microstructure in straight or loosely coiled shells and that of a crossed-lamellar microstructure in coiled Eocene pteropods bears wit- ness that this fundamental difference in shell structure has existed since at least the early Eocene (56.0 m.y.). Bé examined some of the pteropods discussed in this report, and divided them into two categories of shell microstructure (see Table 2). ACKNOWLEDGMENTS We are grateful to those who prepared the scanning electron micrographs, including Saijai Tuntivate-Choy (Lamont-Doherty Geological Observatory, Columbia University, Palisades, NY), Hardie Turnbull and Wil- liam Martin (Esso Resources, Calgary, Alberta, Can- ada), Edie Griffin (Exxon Production Research Com- pany, Houston, Texas), and Lisa Donaghe (Texas A. & M. University Electron Microscopy Center, College Station, Texas). We thank Dr. Robert J. Stanton and Dr. Thomas E. Yancey of Texas A. & M. University for making their facilities available to us. We appreciate the help of Frederick J. Collier, who made available type specimens from the United States National Museum of Natural History, Washington, DC, and the help of Mary A. Garback of the Academy of Natural Sciences, Philadelphia. Ms. Garback located the holotype of Skaptotion nitens (1. Lea, 1833), which had been lost for many years. R. L. Squires of Cali- fornia State University at Northridge provided an En- glish translation of an article by Korobkov and Mak- arova (1962). We thank Shirley R. Garvie for critically reading the manuscript before it was submitted for review. David T. Dockery, HI and Richard L. Squires served as re- viewers. We appreciate their suggestions and help in improving the manuscript. Ken Hodgkinson is grateful to his wife, Erlene, for her support and patience. Special appreciation is due to Dr. Peter R. Hoover for his insight, editing abilities, and friendship. Exxon Company, U. S. A. and Esso Resources, Can- ada provided research facilities and gave permission to publish these findings. Exxon Company, U.S. A. paid the authors’ share of publication costs of this pa- per. Bé received support from U.S. National Science Foundation grants OCE78-25450 and OCE81-17715. ABBREVIATIONS OF REPOSITORY INSTITUTIONS Types and figured specimens described in this paper are deposited in the following repositories: 12 BULLETIN 341 ANSP: Academy of Natural Sciences, Philadephia, Pennsylvania, U.S. A. BM(NH): British Museum (Natural History), London, England, U. K. USNM: United States National Museum of Natural History, Smithsonian Institution, Washington, DC, WE SS AL SYSTEMATIC PALEONTOLOGY INTRODUCTION In this paper we discuss a total of 14 genera and 47 species of pteropods from the Gulfand Atlantic coastal plains of North America. Many of the species are rep- resented by numerous specimens, the result of field work over many years by both Hodgkinson and Gar- vie. Other species are represented by only a few spec- imens, which may indicate that they are very rare, that they are not commonly preserved in sediments, or that they have been missed because of inadequate sampling. Holotypes from United States institutions and the BM(NH) were examined by Garvie and Hodgkinson. Curry’s types were examined with particular care be- cause their stratigraphic range is well-known. As our study involves planktonic forms, stratigraphic corre- lation has been possible between units in Europe and North America. Coiled species are illustrated in the traditional North American orientation with the apex up (dorsal) and the aperture below (ventral). Uncoiled or tubular spe- cies are described with the aperture up (ventral) and the protoconch down (dorsal). In our study of fossil pteropods and our examination of numerous Recent pteropods, we have noted that most specimens within a species are remarkably sim- ilar. This is probably because their planktonic exis- tence eliminates many of the stresses that benthonic gastropods would experience. We consider consistent morphological differences in the fossil populations as justification for assigning the specimens in question to separate species. In the case of pteropods, these differences may be minor, due to their relative lack of ornamentation. CLASSIFICATION Of the eight Recent euthecosomatous pteropod gen- era (Cavolinia Abildgaard, 1791, Clio Linnaeus, 1767, reseis Rang, 1828, Cuvierina Boas, 1886, Diacria ray, 1847, Hyalocylis Fol, 1875, Limacina Bosc, 1817, ind Styliola Gray, 1850) only Creseis and Limacina have been reported from the Eocene. We report, for the first time, Eocene species of Cuvierina. We also found truncated conical shells with transverse grooves and basal septae, which appear to be Eocene species of Hyalocylis. We describe one such specimen as Hy- | alocylis sp. A. Clio is found in the Oligocene to lower Miocene of Washington (Squires, 1989). Cavolinia, Diacria, and Styliola have their first occurrences in the Miocene. SYSTEMATICS Some of the species descriptions given in this paper are incomplete because specimens are very rare or poorly preserved. In some species (e.g., Tibiella reflexa Hodgkinson, n. sp.), only the aperture and adjacent shell material are preserved, whereas in several other species [e.g., Creseis simplex (Meyer, 1886)], the shell at the aperture is so thin and delicate that most shells are broken. We follow the classification used in the Treatise of Invertebrate Paleontology (Cox, 1960) and Spoel (1967) — for phylum through subfamily designations. All su- prageneric names have been verified by reference to original publications. For cases such as Limacina Bosc, 1817 vs. Spiratella Blainville, 1817, where priority can- not be ascertained, Spoel’s nomenclature has been ac- cepted. Phylum MOLLUSCA Linnaeus, 1758 Class GASTROPODA Cuvier, 1797 Subclass OPISTHOBRANCHIA Milne-Edwards, 1848 Description.—Shell small, external, internal, or ab- sent; visceral nerve cords not crossed; one internal gill or with external gills in shell-less forms; usually with- out operculum; all hermaphroditic and marine. De- vonian?, Mississippian—Recent. Discussion.— During the long geologic history of this subclass, there have been trends toward loss of the shell and toward obtaining symmetry. Bilateral symmetry is well-developed in the shells of several Recent ptero- pod genera (Creseis Rang, 1828, Cuvierina Boas, 1886, Clio Linnaeus, 1767, Diacria Gray, 1847, Hyalocylis Fol, 1875, and Cavolinia Abildgaard, 1791). This subclass is one of three into which gastropods are divided (Prosobranchia Milne-Edwards, 1848, Opisthobranchia, and Pulmonata Cuvier, 1817). Some authors combine the Opisthobranchia and Pulmonata into the subclass Euthyneura Spengel, 1881. Order THECOSOMATA Blainville, 18244 Description.—Pelagic, free-swimming. Epipodia greatly expanded, modified into swimming flaps or wings. Mouth with jaws and a small triserial radula. No definite head, no eyes, one pair of tentacles. Shells variously shaped, usually a sinistral spiral, conical, or += Pteropoda Cuvier, 1804 of some authors. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 13 bilaterally symmetrical, generally calcareous, delicate and glassy. Late Paleocene—Recent. Suborder EUTHECOSOMATA Meisenheimer, 1905 Description.— External calcareous shell always pres- ent; spirally and sinistrally coiled, conical, or bilaterally symmetrical. Epipodia laterally separated, tentacles not paired and symmetrical. Proboscis and rostrum ab- sent. Late Paleocene—Recent. Family LIMACINIDAE Gray, 1847° Description.—Shell small, thin, vitreous, smooth, with or without an umbilicus. Trochoid to nearly dis- coidal. Hyperstrophically coiled. Late Paleocene—Re- cent. Discussion.— Keen (1971) indicated that the coiling in the Spiratellidae is hyperstrophic. Coiled pteropods are anatomically dextral, with genitalia on the right, but they have a falsely sinistral shell. A bona fide sin- istral shell is formed only by gastropods with genitalia on the left side of the head-foot mass or pallial cavity, and with other soft parts and the shell arranged in mirror-image of dextral gastropods. Thus, when we describe pteropod shells as being sinistral, as we do in this paper, it is only in the loose sense. Genus ALTASPIRATELLA Korobkov, 1966 Altaspiratella Korobkov, 1966, p. 74. Plotophysops Curry, 1981, p. 39. Type species.—Altaspiratella elongatoidea (Aldrich, 1887). Early Eocene, Alabama. Description.— Elongated, fusiform species with a large last whorl, an elongate oval aperture, and a narrow umbilicus. Early—middle Eocene. Discussion.— Korobkov (1966) established the genus Altaspiratella for five species that shared the charac- teristics described above. Curry (1981) proposed the genus Plotophysops to cover two species, Plotophysops bearnensis Curry, 1981 and P. multispira Curry, 1981. He indicated that Altaspiratella differed from Ploto- physops by the presence of an umbilicus, and the com- plete absence of a twisted columella and modified lip. Janssen (1990) referred the type species of Plotophy- sops (Plotophysops bearnensis) to Altaspiratella. He correctly noted that A/taspiratella elongatoidea, the type species of Altaspiratella, is very similar, although not identical, to A/taspiratella bearnensis (Curry, 1981). He also observed that a final conclusion as to the identity of A. elongatoidea is hampered because it is exclusively known by its holotype, which is a damaged and/or 5 = Spiratellidae Dall, 1921. immature specimen. We have found it very difficult to distinguish immature or broken specimens of these two species (see Pl. 1, figs. 2, 3). We follow Janssen’s usage and assign these elongated forms to A/taspira- tella. Altaspiratella bearnensis (Curry) Plate 1, figures 1, 2 Plotophysops bearnensis Curry, 1981, p. 40, pl. 1, figs. 9a—c. Altaspiratella bearnensis (Curry). Janssen, 1990, p. 68. Description.— Montres les caractéres du genre. Coquille lisse de 5, tours arrondis, assez allongés, angle spiral 35—40°. La protoconque, de 2 tours, est terminée par un sillon sinueux qui comprend un fort enfondement bordé de deux proéminences d’une égale grandeur ... Ouverture ovale, avec dans le stade adulte, un bord évasé, épaissi et aplati qui est sinueux antérieurement et montre une large échancrure prés de la columelle. Longueur maximale: 2,7 mm (Curry, 1981). Free translation.—Shows the characters of the genus. Shell smooth, 514 whorls, quite elongated, spiral angle 35-40°. The protoconch, of two whorls, ends in a sin- uous groove that includes a strong re-entrant edge with two equally large prominences. Aperture oval. In the adult stage, the lip is flared, thickened, and flattened. The anterior edge is sinuous and has a wide indenture near the columella. Maximum length, 2.7 mm. Measurements.—Hypotype (USNM 180480): height, 2.8 mm; width, 1.4 mm; apical angle, 30°; 6.5 whorls. Average of ten specimens: height, 3.1 mm; width, 1.5 mm; apical angle, 31°; 6.7 whorls. Discussion.— Broken specimens, with the spiral whorls most commonly preserved, resemble Limacina tutelina (Curry, 1965) and Altaspiratella elongatoidea (Aldrich, 1887). There is, however, little resemblance between complete specimens of these forms. Neither of the latter species has the well-developed anterior indenture that is so prominent in A. bearnensis. Occurrence.—Early Eocene of France to middle Eo- cene of the Texas Gulf Coast. Holotype from the early Eocene (NP13) of Gan, France (see Curry, 1981, p. 36). Other specimens from London Clay division E (NP12 or NP13) at Highgate, London; one specimen from division C or D on the Isle of Sheppey, and in the North Sea Basin (Janssen, 1990, p. 68). All of our specimens are from the middle Eocene Weches Formation at localities 7 and 8. Material.—Specimens examined in this study were recovered from localities 7 (26 specimens) and 8 (63 specimens, including the hypotype). Most of the spec- imens from each locality are incomplete, with the spire being preserved more often than the apertural end. Types.—Holotype, BM(NH) GG 21255; hypotype, USNM 180480, 360382. 14 BULLETIN 341 Altaspiratella elongatoidea (Aldrich) Plate 1, figure 3 Physa elongatoidea Aldrich, 1887, p. 83. Spiralis elongatoidea (Aldrich). Aldrich, 1895, p. 5, pl. 2, fig. 9; G. D. Harris, 1899, p. 103, pl. 12, fig. 25. Limacina elongatoides [sic] (Aldrich). Collins, 1934, p. 177, pl. 7, fig. 1. Limacina elongatoidea (Aldrich). Palmer and Brann, 1965, p. 358. Spiratella (Altaspiratella) elongatoides (Aldrich). Korobkov, 1966, p. 74. Description. — Shell thin, minute, strongly sinistral, whorls five, smooth, suture strongly impressed and very oblique to the axis, aperture almost quadrate, inner lip meeting the parietal wall abruptly and reaching down nearly straight (Aldrich, 1887). Measurements.—USNM 638862 (holotype): height, 2.5 mm; width, 1.2 mm; apertural height, 1.3 mm; apertural width, 0.7 mm; spiral angle, 36°; 54 whorls. Discussion.— Although Collins included this species in the Pteropoda with some hesitation, it now appears that A. elongatoidea (Aldrich) definitely is a pteropod. It is similar to several high-spired forms [e.g., Lima- cina tutelina (Curry, 1965) and Altaspiratella bearnen- sis (Curry, 1981)]. Future work may show that A. elongatoidea and A. bearnensis are very closely related or even the same species. At the present, however, it appears that 4. bearnensis differs in the absence of an umbilicus and the presence of a twisted columella, an anterior sulcus, and a broad outer lip. Occurrence.— Early Eocene, Wilcox Group, Hatch- etigbee Formation, Bashi Member at locality 1. Material.—The holotype, from locality 1, is the only known specimen. Types.— Holotype, USNM 638862. Altaspiratella gracilens Hodgkinson, new species Plate 1, figures 4, 5 Etymology of name.—The species name refers to the slender shape of this form (L. gracilis = slender, thin). Description.—Shell small, smooth, sinistrally coiled, extremely high-spired, whorls increasing slowly in width and height. Umbilicus very small or absent. Aperture inclined to shell axis, ventral edge of lip has a prom- inent sulcus and outer lip is flanged. Whorls rounded, in a fairly loose spiral, sides nearly parallel, sutures deep. Measurements. —USNM_ 180481 (holotype): two whorls (only the last two whorls are preserved on the holotype), height, 2.6 mm; width of last whorl, 1.1 mm; greatest dimension of aperture, 1.1 mm; smallest di- mension of aperture, 0.6 mm. Discussion.—This species resembles A/taspiratella bearnensis (Curry, 1981) but differs in being more loosely coiled, having deeper sutures, nearly parallel sides, and a much smaller spiral angle (about 11° rather than 36°). Occurrence.— Middle Eocene. Weches Formation, at localities 7 and 8, and Cane River Formation at well locality 41 (cuttings at 9,950 ft). Material.—Specimens examined in this study were recovered from localities 7 (3 specimens, including the paratype), 8 (3 specimens, including the holotype), and 41 (1 specimen). Types.— Holotype, USNM 180481; paratype, USNM 180482. Genus LIMACINA Bosc, 1817 Limacina Bosc, 1817, p. 42. Spiratella Blainville, 1817, p. 407. Type species.—Limacina helicina Phipps, 1774, a Recent species. Description.—Shell small, thin, glassy, little or no exterior ornamentation. Trochoid to nearly planispir- al, hyperstrophic coiling with rounded, closely wound whorls. Last whorl , to % of the entire shell. Aperture wide, rounded, prolonged at base; columella project- ing; umbilicus broad and deep or almost absent. Latest Paleocene—Recent (see Janssen and King, 1988). Discussion.—Spoel (1967, 1972), Keen (1971), and Janssen and King (1988) have given reasons for using the generic name Limacina in preference to Spiratella. Limacina adornata Hodgkinson, new species Plate 1, figures 6-9 Etymology of name.—The trivial name refers to the unusual ornamentation on the surface of this pteropod (L. adornare = to decorate, embellish). Description.—Shell thin, small, broad, subtriangular in axial section, sinistral, about 44 whorls. External surface of whorls smooth or faintly ornamented with about 25 very fine, discontinuous spiral threads that are more continuous near the base. The segments of these discontinuous threads are aligned vertically to give an appearance of rough axial sculpture. Just below the suture are very short axial ribs that are more or less aligned with the raised portion of the axial threads. Thus the impression of axial sculpture is reinforced. Aperture subquadrate with a strong vertical columella, inner lip reflected, umbilicate, sutures distinct, slightly impressed. First several whorls smooth and polished without ornamentation. Measurements.—USNM 180483 (holotype): height, 1.6 mm; width, 1.4 mm; height of aperture, 0.7 mm; apical angle (of last formed whorls), 50°. Average of 20 measured specimens: height, 1.1 mm; width, 1.1 mm; height of aperture, 0.5 mm; apical angle (of last- formed whorls), 65°. Discussion.—There is a possibility that L. adornata, NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 15 n. sp. is not a pteropod, but instead is the sinistrally coiled juvenile portion of a larger dextral gastropod, or may belong to one of the rare sinistrally coiled gas- tropod species not related to pteropods. The uncer- tainty exists because the shell surface of L. adornata, n. sp. usually is ornamented. No other known fossil pteropod has an ornamented shell, although Recent pteropods in the family Peraclidae are ornamented with a delicate noncalcareous hexagonal meshwork. Limacina adornata, n. sp. does have other basic characteristics that help separate pteropods from other gastropods. These include its small size, sinistral coil- ing, and thin shell wall. It also has more whorls than most of the Eocene sinistrally coiled protoconchs of dextrally coiled gastropods. We believe the larger shells are mature because: (1) the later-formed whorls have a much more acute apical angle than the first-formed whorls; (2) they have a distinct smooth protoconch, which consists of approximately the first two whorls; and (3) there appears to be a maximum size limit. Of the specimens found, none appear to grow beyond 2 mm in height. We have examined most of the gastro- pod species that occur with L. adornata. None of these species has a juvenile shell similar to this new ptero- pod. Limacina adornata, n. sp. occurs in beds that contain other species of pteropods, and it is also very similar in shape to smooth pteropods from certain Louisiana oil wells. One such form, Limacina helikos, n. sp., is described in this paper. It is our opinion that L. adornata, n. sp. isa pteropod with a smooth or ornamented shell. Occurrence.— Middle Eocene. Holotype and para- types from the Wheelock Member of the Cook Moun- tain Formation at locality 18. Other specimens from this member were found at locality 16. Specimens were also found in the Hurricane Lentil of the Cook Moun- tain Formation at localities 22, 23, and 25. Material.—Specimens examined in this study were recovered from localities 16 (2 specimens), 18 (69 spec- imens), 22 (3 specimens), 23 (1 specimen), and 25 (5 specimens). Types.— Holotype, USNM 180483; paratype, USNM 180484. Limacina aegis Hodgkinson, new species Plate 1, figures 10-15 Etymology of name.—The specific name refers to the flat nature and the resemblance of the dorsal surface to the round shields of the Norwegian Vikings (L. aegis = a shield). Description.—Shell small, smooth, sinistral, almost twice as wide as high, lenticular in cross-section. Um- bilicus narrow and deep (about % to , width of shell). First 114 whorls flat on dorsal side, subsequent whorls inclined at about 133°. Measurements.—USNM 180485 (holotype): height, 0.8 mm; width, 1.5 mm; height of aperture, 0.4 mm; width of aperture, 0.5 mm; spiral angle (of last-formed whorls), 133°. Average of eight measured specimens: height, 0.8 mm; width, 1.5 mm; height of aperture, 0.7 mm; width of aperture, 0.5 mm; spiral angle, 133°: 3.75 whorls. Discussion.—This form differs from other species of Limacina in being much wider in relation to height. The whorls of L. aegis, n. sp. are sharper at the pe- riphery than those of other species, most of which have gently rounded whorls. Occurrence.—Early Eocene? Rare in cuttings from several wells of offshore eastern Canada. The holotype, from cuttings at well locality 53 (2,940 ft), and a spec- imen from well locality 47 (3,300 ft) are early Eocene in age. A paratype from well locality 45 (7,780 ft) and several specimens from well locality 50 (3,600 ft) are from the Cretaceous interval. The occurrences in Cre- taceous age sediments are believed to have resulted from downhole caving of Eocene sediments into older strata. Material.—Specimens examined in this study were recovered from well localities 45 (1 specimen, the para- type), 47 (1 specimen), 50 (4 specimens), and 53 (1 specimen, the holotype). Types.— Holotype, USNM 180485; paratype, USNM 180486. Limacina augustana (Gardner) Plate 2, figures 1-3 Spiratella augustana Gardner, 1951, p. 10, fig. 2; Palmer and Brann, 1965, p. 359. Description. — Shell very small. Whorls 4—4¥, sinistrally coiled in a nearly hori- zontal plane, the body embracing the whorls of the spire as in Plan- orbis. The aperture higher than it is wide, the body expanding at the aperture both vertically and horizontally; the outer surface of the preceding whorl forming the inner wall of the aperture; posterior margin of the body folded into the suture. The visible surface of the apical whorls rounded, scarcely elevated above the plane of the body. Umbilical area narrowly funicular. No sculpture other than obscure incrementals and the cording of the adult margin of the outer lip. Dimensions of holotype USNM 560589: Maximum diameter, 3 mm; diameter at right angles to the maximum diameter, 2.6 mm; minimum diameter, 2.3 mm; height, 1.5 mm (Gardner, 1951). Discussion.—The holotype of L. augustana (Gard- ner) is an internal mold and exact characteristics are difficult to determine. Additional material was col- lected from the Tallahatta Formation at locality 5 (ho- lotype locality) and many poorly preserved and highly variable specimens were recovered. Some specimens have depressed apical and umbilical sides (like Skap- totion Curry, 1965), some have a flat dorsal side and a depressed umbilical side, and others are moderately 16 BULLETIN 341 high-spired [like Limacina pygmaea (Lamarck, 1804)]. Probably more than one species is represented by these internal molds. Until better preserved specimens are collected, the exact characteristics of L. augustana can- not be determined accurately. Gardner’s illustration of the holotype shows an ap- parent aperture significantly below the horizontal plane ofan otherwise nearly planispiral test. This illustration, although accurately drawn, is misleading. The upper part of the aperture is eroded away and the configu- ration and location of the entire aperture cannot be determined. If the complete aperture were present, the shell would appear more planispiral than it does in Gardner’s drawings and in our photographs of the ho- lotype. Occurrence.—Early—middle Eocene. Holotype from the Tallahatta Formation, locality 5. We have collected many specimens, almost planispirally coiled and with a nearly flat dorsal surface, from Eocene and Oligocene deposits in Alabama, Mississippi, and Louisiana. Most are internal molds composed of glauconite, pyrite, cal- cite, or clay. Because of their poor preservation, iden- tification is difficult, but they may well belong to this species. Material.—Specimens examined in this study were recovered from locality 5 (51 specimens). Types.— Holotype, USNM 560589. Limacina canadaensis Hodgkinson, new species Plate 2, figures 4-6 Etymology of name.—The species name refers to the location (Canada) where this species was first found. Description.—Shell small, sinistral, smooth, medi- um- to low-spired; juvenile whorls more nearly in a plane than latter whorls, all involute and a little wider than high, sutures strongly impressed. Aperture about half as high as entire shell. Measurements.—USNM 180487 (holotype): height, 1.0 mm; width, 1.2 mm; 3% whorls; spiral angle, 153°. Average of 16 specimens: height, 0.9 mm; width, 1.1 mm; 3% whorls; apical angle, 139°. Discussion.— The spiral angle varies from low to me- dium (118° to 160°). This species resembles Limacina taylori (Curry, 1965) [p. 363, figs. 21a, b] from the early Eocene of England, but is much smaller, has a greater spiral angle, and a shorter inner lip. Occurrence.—Early—late Eocene. Holotype from ear- ly Eocene sediments at well locality 49 (5,380 ft). Be- cause these specimens of L. canadaensis were recov- ered from well cuttings, age determinations are apt to be inaccurate. Late Eocene; well localities 45 (4,530 ft) and 54 (6,940 ft); middle Eocene, well localities 48 (2,100 ft), 49 (4,840 ft), 50 (2,640 ft), and 55 (4,770 ft); and early Eocene, well localities 45 (7,420 ft), 48 (2,220 ft), 49 (5,380 and 5,500 ft), and 53 (2,670 ft). Material.—Specimens examined in this study were recovered from well localities 45 (2 specimens), 48 (2 specimens), 49 (7 specimens), 50 (3 specimens), 53 (1 specimen), 54 (1 specimen), and 55 (1 specimen). Types.— Holotype, USNM 180487. Limacina choctavensis (Aldrich) Plate 2, figure 7 Physa choctavensis Aldrich, 1887, p. 83. Spiralis choctavensis (Aldrich). Aldrich, 1895, p. 5, pl. 2, fig. 10; G. D. Harris, 1899, p. 103, pl. 12, fig. 24; Brann and Kent, 1960, p. 807. Limacina choctavensis (Aldrich). Collins, 1934, p. 176, pl. 7, fig. 2; Palmer and Brann, 1965, p. 358. Description.— Shell thin, minute, rather obtuse and broad, whorls probably five, somewhat shouldered, outer lip slightly patulous, inner lip reflected and reaching well upon the body wall, surface showing lines of growth only (Aldrich, 1887). The type is 2.9 mm. long and 2.1 mm. in diameter. . . . The lower half of the outer lip of the fossil specimen is slightly produced and a small umbilicus is present. The nucleus, preserved on two of the additional specimens, consists of about one and a quarter whorls, smooth and polished, with a slight ridge developed at the apertural end beyond which enlarging whorls bear irregularly-spaced wrinkles near the suture (Collins, 1934). Measurements.— Apical angle of the figured syntype (USNM 638860) is 70°. Average apical angle of three syntypes (USNM 638861) is also 70°. Discussion.—The apical whorls are missing from Aldrich’s figured syntype, but are present on several other syntypes. The first whorl is nearly planispiral and is followed by trochoid whorls. For additional notes, see Collins (1934). Occurrence.—Early Eocene. Upper Wilcox Group, Hatchetigbee Formation, Bashi Member at locality 1. Material.—Specimens examined in this study were recovered from locality 1 (5 specimens, the syntypes of Aldrich, 1895). To our knowledge, these are the only known specimens. Types.—Syntype, USNM 638860 (Aldrich, 1895, pl. 2, fig. 10); syntypes, USNM 638861 (three smaller un- figured specimens); and syntype, USNM 638863 (one unfigured specimen, presumably one of Aldrich’s five syntypes). Limacina convolutus Hodgkinson, new species Plate 2, figures 8-10 Etymology of name.—The trivial name refers to the coiling habit of this species, with portions of all whorls visible (L. convolutus, -a, -um = rolled together, one part upon another). Description.—Shell small, very thin, smooth, dis- coidal (almost planispiral), sinistral, all whorls visible on the apical side. Spire depressed and umbilicus prominent. Aperture reniform with a simple, un- NORTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 17 flanged lip. Very faint fold on inner lip just below base of previous whorl. Measurements.—USNM 180488 (holotype): height, 0.9 mm; width, 1.2 mm; height of aperture, 0.9 mm; width of aperture, 0.4 mm; 4% whorls. Average of ten specimens: height, 0.7 mm; width, 1.0 mm; length of aperture, 0.7 mm; width of aperture, 0.5 mm; 34% whorls. Discussion.—Limacina convolutus, n. sp. resembles several of the species of Skaptotion Curry, 1965, but this new species does not have a flanged lip, a turbi- niform protoconch (which is often inclined to the axis of the mature shell in Skaptotion), or part of one of the earlier whorls completely covered by the next whorl. This new species also resembles L. planidorsalis, n. sp. but they differ significantly in the shape of the dorsal side. In Limacina convolutus it is distinctly depressed; in L. planidorsalis it is flat or nearly so. Occurrence.—Middle Eocene. Holotype from the Stone City Formation at locality 12. Also found in the Wheelock Marl Member of the Cook Mountain For- mation at localities 17, 18, and 19. Material.—Specimens examined in this study were recovered from localities 12 (5 specimens), 17 (36 spec- imens), 18 (11 specimens), and 19 (23 specimens). Types.— Holotype, USNM 180488. Limacina davidi Hodgkinson, new species Plate 2, figures 11-14 Etymology of name.—The species is named for the senior author’s son, who helped collect samples for this study. Description.—Shell small, smooth, sinistrally coiled, nearly round in axial section. Umbilicus narrow and deep (about 4 width of shell). First two whorls flat or slightly depressed on dorsal side, remaining whorls added in a broad spiral. Measurements.—USNM 180489 (holotype): height, 1.3 mm; width, 1.4 mm; height of aperture, 0.3 mm; apical angle, 90°. Discussion.—This species differs from other Eocene pteropods in its almost round shape when viewed both from the side and top or bottom. Occurrence.—Early Eocene, very rare in cuttings at well locality 42 (10,040 ft: Wilcox Formation). Material.—Specimens examined in this study were recovered from well locality 42 (10,040 ft, 2 speci- mens). Rare in several Louisiana oil and gas wells. We are unable to release confidential well data on wells other than those of Exxon Company, U. S. A. and Esso Resources, Canada. Types.— Holotype, USNM 180489. Limacina heatherae Hodgkinson, new species Plate 2, figures 15-18 Etymology of name.—The species is named for the senior author’s daughter, who helped collect specimens for this study. Description.—Shell small, smooth, sinistrally coiled, subquadrate in axial section. Spire depressed to slightly elevated. Aperture narrow in width, oblique to the shell axis. Gradual increase in whorl width. Last whorl sig- nificantly below plane of earlier whorls. Umbilicus nar- row and deep (% to % of maximum width). Measurements.—USNM 180490 (holotype): height, 0.9 mm; width, 1.1 mm; 4 whorls. Discussion.—This species differs from other ptero- pods by its gradual increase of whorl width and its subquadrate shape. Occurrence.—Late Paleocene?-early Eocene?. Ho- lotype from well locality 42 (12,370 ft) in sediments near the base of the Wilcox Formation. However, the possibility of downhole caving of younger sediments exists and the holotype could be of Eocene or younger age. Material.—Specimens examined in this study were recovered from well locality 42 (12,370 ft, 2 speci- mens). Types.—Holotype, USNM 180490. Limacina helikos Hodgkinson, new species Plate 3, figures 1-5 Etymology of name.—The trivial name refers to the shape of this species (Gr. helikos = a spiral, anything of a spiral shape). Description.—Shell small, smooth, sinistrally coiled, umbilicate; about as wide as high, first two whorls almost planispiral, later whorls with a spiral angle of about 62°. Whorl profile and aperture quadrate. Su- tures only slightly impressed. Aperture about ', as high as shell and a little wider than high. Umbilicus small (poorly preserved in our specimens). Sides nearly straight but never parallel. Measurements.—USNM 180491 (holotype): height, 1.3 mm; width, 1.3 mm; spiral angle, 63°; 54 whorls. Discussion.—Limacina helikos, n. sp. differs from other described high-spired species of Limacina by its nearly straight sides. It resembles L. adornata, n. sp., but the latter has curved sides and slight ornamenta- tion. Occurrence.—Early Eocene. The holotype is from the Upper Wilcox Formation, and the paratype is from the Lower Wilcox Formation at well locality 42. Material.—Specimens examined in this study were recovered from well locality 42 (2 specimens). Four specimens from three other industry wells. We are un- able to release confidential well data on wells other 18 BULLETIN 341 than those of Exxon Company, U. S. A. and Esso Re- sources, Canada. Types.— Holotype, USNM 180491, well locality 42 (12,290 ft: Lower Wilcox Formation); paratype, USNM 180492, well locality 42 (10,070 ft: Upper Wilcox For- mation). Limacina labiata Hodgkinson, new species Plate 3, figures 6-8 Etymology of name.—The trivial name refers to the prominent flange around the aperture (L. /abiata = bearing a lip). Description.—Shell thin, small, smooth, sinistral, of about five whorls. Suture strongly impressed. Aperture roughly hemispherical, higher than wide. Inner lip flanged, straight and slightly oblique to the shell axis. Outer lip also flanged and circular in outline. A shallow sulcus is at the ventral edge of the aperture. Initial 1 whorls almost planispiral, remaining whorls form a relatively high spiral. Measurements.—USNM 180493 (holotype): height, 1.5 mm; width, 0.9 mm; spiral angle, 51°. Discussion.—Limacina labiata n. sp., Altaspiratella gracilens, n. sp., and Altaspiratella bearnensis (Curry, 1981) are the only described high-spired Eocene pter- opods with distinctly flanged apertures. These aper- tural flanges resemble those of the nearly planispiral pteropod Skaptotion Curry, 1965. Occurrence.— Middle Eocene. Very rare in the Cook Mountain Formation, Hurricane Lentil, at locality 23. Material.—Specimens examined in this study were recovered from locality 23 (1 complete and 2 broken specimens). One broken specimen has the juvenile whorls missing; the other lacks the outer lip. Types.— Holotype, USNM 180493. Limacina nemoris (Curry) Plate 3, figures 9, 10 Spiratella nemoris Curry, 1965, p. 362, figs. 16a—b; Curry, 1981, p. 37, pl. 1, figs. Sa—b. Description.— Shell very small, sinistral, smooth, umbilicate, naticiform, with a spire of four whorls, which forms about one-third of the total height. First 1'4 whorls almost planispiral, later whorls with a spiral angle of about 80°. Aperture roughly semicircular, suture impressed. Outer lip slightly oblique to axis, sloping forward abapically. Inner (colu- mellar) lip straight. The whole unattached margin of the lip slightly expanded in the adult shell. Dimensions of holotype, height, 1.0 mm, width, 0.8 mm (Curry, 1965). Measurements.— Average of 20 specimens: height, 0.9 mm; width, 0.7 mm; height of aperture, 0.6 mm; height of spire, 0.3 mm (spire about 4 of total height); spiral angle, 81°. Discussion.—The above measurements show that the North American specimens conform very closely to those from England. Several minor differences exist between the English specimens described by Curry and those illustrated here. Only the first 11, whorls of the Gulf Coast spec- imens are planispiral and the inner lip is folded toward the umbilicus. These differences are minor and may be as much the result of description and preservation as true morphological differences between two widely separated populations. Squires (written commun., 1990) noted that the populations are widely separated now, but that the Atlantic Ocean was narrower during the Eocene. In shape and size, L. nemoris resembles the Recent pteropod Limacina trochiformis (d’Orbig- ny, 1836). Occurrence.—Middle-late Eocene. From the middle Eocene upper Bracklesham Beds of England and the late Eocene “‘marnes bleues’’ of France. In North America the species is found in the following middle Eocene formations: Stone City Formation, localities 11 and 12; from the Wheelock Member of the Cook Mountain Formation, localities 16 and 18; and from the upper Lisbon Formation, locality 6. The species is also found in undifferentiated Eocene sediments at well locality 53 (2,940 ft). Material.—Specimens examined in this study were recovered from localities 6 (29 specimens), 11 (4 spec- imens), 12 (4 specimens), 16 (2 specimens), 18 (61 specimens, including the hypotype), and 53 (1 speci- men). Types.—Holotype, BM(NH) GG 7100; hypotype, USNM 180494. Limacina planidorsalis Hodgkinson, new species Plate 3, figures 11-13 Etymology of name.—The species name refers to the nearly flat dorsal surface of this species. Description.—Shell small, smooth, without orna- mentation, 4—4', whorls, sinistrally coiled in a nearly horizontal plane. Dorsal side may be slightly depressed or with a slight spire, but usually is flat. All whorls are visible on the dorsal surface and are coiled in the same plane. Maximum width is near the dorsal surface; ven- tral side has a deep and moderately wide umbilicus (about '4, as wide as shell). Aperture simple, higher than wide. Measurements.—USNM 180495 (holotype): height, 0.7 mm; maximum diameter, 1.0 mm; 4 whorls. Av- erage of five specimens: height, 0.7 mm; maximum diameter, 1.1 mm; 3.9 whorls. Discussion.—Limacina planidorsalis, n. sp. is sim- ilar to Limacina augustana (Gardner, 1951), but is smaller, even though it has as many whorls and is also not as high in relation to its width. It also is similar to Limacina convolutus, n. sp., but the latter species has a distinctly depressed dorsal side. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 19 Occurrence.—Early to middle Eocene. Middle Eo- cene, holotype and a second specimen from cuttings at well locality 51 (1,250 ft). Early Eocene, from well localities 48 (2,220 ft), 51 (1,470 ft), and 53 (2,700 ft). Material.—Specimens examined in this study were recovered from well localities 48 (1 specimen), 51 (3 specimens), 53 (1 specimen). Types.— Holotype, USNM 180495. Limacina pygmaea (Lamarck) Plate 3, figures 14, 15 Ampullaria pygmaea Lamarck, 1804, p. 30. Spirialis pygmaea (Lamarck). Deshayes, 1862, p. 520. Spirialis bernayi Laubriére, 1881, p. 377, pl. 8, fig. 5. Spirialis parisiensis Watelet and Lefevre, 1885, p. 101, pl. 5, figs. 3a-c. Spirialis pygmaea (Lamarck) var. pezanti Cossmann, 1913, p. 238. Spiratella pygmaea (Lamarck). Curry, 1965, p. 362, figs. 18a—b, 19. Description.— Shell small, smooth, sinistrally coiled, almost globular. Spire of about four whorls. The relative height of the spire is variable, from flush to nearly half of the height of the shell, suture impressed. Umbilicus narrow. Outer lip thin, not expanded, in approximately the same plane as the axis. Adaxial wall of the shell gently folded spirally but not thickened. Inner (columellar) lip expanded towards the axis. Dimensions. Height about 1.7 mm; width, about 1.5 mm (Curry, 1965). Measurements.— Average of five specimens: height, 1.0 mm; width, 1.0 mm; height of aperture, 0.8 mm; spiral angle, 103°. Discussion.—Curry’s illustrations of Spiratella pyg- maea show a species with an apical angle of about 115°. The specimens from Texas are different from those illustrated by Curry in being as wide as high, in being smaller, and in having a lateral periphery which is sharper (less rounded) than the English specimens. The differences do not appear to be sufficient to warrant placing these forms in different species or subspecies. Occurrence.— Middle Eocene. Very rare in the Stone City Formation at localities 11 and 12; more common in the Cook Mountain Formation, Wheelock Marl Member, at localities 16 and 18, and in Lutetian strata, Paris Basin, France, and England. Material.—Specimens examined in this study were recovered from the Stone City Formation at localities 11 (3 specimens) and 12 (2 specimens), and from the Cook Mountain Formation, Wheelock Marl Member, at locality 16 (2 specimens) and 18 (11 specimens). Types.—Hypotype, USNM 180496. Limacina smithvillensis Hodgkinson, new species Plate 3, figure 16 Etymology of name.—The species name refers to the location (Smithville, Texas) where this species was first found. Description.—Shell small, with about five whorls, sinistrally coiled, smooth, naticiform, sutures de- pressed. Aperture a little more than half as wide as high, also a little more than half as high as the entire shell. Both inner and outer lip oblique to the shell axis. Umbilicus a small elongated slit mostly covered by the inner lip. Measurements.—USNM 180497 (holotype): height, 1.5 mm; width, 1.1 mm; apical angle, 89°. Average of four other specimens: height, 1.4 mm; width, 1.0 mm; apical angle, 90°. Discussion.—Similar to Limacina nemoris (Curry, 1965) but less umbilicate, also different in the character of initial whorls (the first 14 whorls of L. nemoris are nearly planispiral). In L. smithvillensis, n. sp., the ju- venile whorls are trochoid. In L. nemoris, the inner lip of the aperture is straight, whereas in L. smithvillensis, n. sp., it is curved and oblique to the shell axis. In overall shape, L. smithvillensis is also similar to L. stenzeli, n. sp., but the latter species has a large um- bilicus, a columellar fold, and an outer lip that is pro- duced submedially. Occurrence.— Middle Eocene. Very rare in the Vies- ca Member of the Weches Formation at locality 8. Material.—Specimens examined in this study were recovered from locality 8 (5 specimens). Types.—Holotype, USNM 180497. Limacina stenzeli Garvie, new species Plate 4, figure 1 Etymology of name.—The species 1s named in honor of H. B. Stenzel, the geologist who did much to elu- cidate the geology and paleontology of Texas. Description.—Shell minute, holostomatous, sinis- tral, thin and shining. Whorls 5¥,, nucleus inflated and depressed, just visible above the plane of the next whorl. Postnuclear whorls showing lines of growth only, su- ture deeply impressed, bordered by a high rounded collar. Aperture elliptical, slightly flaring posteriorly and next to the umbilicus. Outer lip very slightly pro- duced submedially and thickened behind the sharp outer edge. Umbilicus teardrop-shaped and bounded on the left by the inner lip; weak columellar fold pres- ent. Measurements.—USNM 180498 (holotype): height, 2.8 mm; width, 2.0 mm; height of aperture, 1.4 mm; width of aperture, 0.8 mm; apical angle, 77°; 6 whorls. Average of 20 other specimens: height, 1.7 mm; width, 1.5 mm; height of aperture, 1.2 mm; width of aperture, 0.6 mm; apical angle, 81°; 4.6 whorls. Discussion.—This species is similar to Limacina choctavensis (Aldrich, 1887), but the umbilicus of the latter species is larger, and there is no columellar fold. Limacina stenzeli would seem to be the species figured but not described in Stenzel (1953, p. 82, fig. 42). 20 BULLETIN 341 Occurrence.—Early Eocene. Reklaw Formation, Marquez Shale Member, locality 2. The form figured by Stenzel is from locality 4. Material.—One-hundred-twenty-two specimens have been collected from locality 2. Types.— Holotype, USNM 180498. Limacina taylori (Curry) Plate 4, figure 2 Spiratella taylori Curry, 1965, p. 363, figs. 21a, b; Curry, 1981, p. 37, pl. 1, figs. 3a—b. Spiratella sp. Venables, 1963, p. 262. Description. — Internal mould in pyrite of a small, sinistral, naticiform, umbilicate shell, with a spire of 414 turns forming one-quarter of the total height of the shell. First turn almost planispiral, later turns with a spire angle of about 100°. Whorl profile rounded, apical and abapical portions of the profile somewhat flattened, giving the whole shell a somewhat angulate appearance. Shell smooth, though in some moulds faint spiral ridges are present in the neighbourhood of the periphery. Apertural features difficult to distinguish because only faint traces of growth-lines have been seen in some specimens. However these suggest that the aperture lies in the plane of the axis and that the outer lip is sharp and slightly sinuous. Inner (columellar) lip has a slight fold as described in L. pygmaea. Dimensions of holotype. Height, 2.5 mm; width, 2.3 mm. Top- otypes may range up to 3 mm or more. (Curry, 1965). Measurements.— Average of five specimens: height, 1.8 mm; width, 1.8 mm; aperture height, 1.2 mm; aperture width, 0.7 mm; spiral angle, 100°; 4.5 whorls. Discussion.—The characters of our specimens are similar to those described for Limacina taylori by Cur- ry, even though the species was described from pyritic molds. Curry’s specimens (from England) and our specimens are the same size, possess the same apical angle, and have a weak columellar fold. This species can be distinguished from L. stenzeli, n. sp. by its smaller size, more globose form, and by the round umbilicus which is not covered by the reflected inner lip. It is interesting that we found Limacina taylori in the Taylor Branch of Two Mile Creek. The species was named, however, after Mr. J. E. Taylor, who collected the type specimens from the seashore at Bognor Regis, Sussex, England. Occurrence.—Early Eocene. The holotype is from the seashore at Bognor Regis, Sussex, and is believed to have come from the Beetle Bed of the London Clay (Venables, 1963, p. 252). Our specimens are from the Reklaw Formation at locality 3. Material.—Specimens examined in this study were recovered from the Marquez Shale Member of the Rek- law Formation at locality 3 (8 specimens). Types.— Holotype, BM(NH) GG 7101; Hypotype, USNM 180499. Limacina texana Garvie and Hodgkinson, new species Plate 4, figures 3-6 Etymology of name.—The species name refers to the location (Texas) where this species was first found. Description.—Shell small, smooth. Whorls 4%, sin- istrally coiled. Aperture reniform, about one-half as wide as high, with a pronounced reflected outer lip and a slight columellar fold. Dorsal side flat to slightly de- pressed. Measurements.—USNM 180500 (holotype): height, 2.0 mm; width, 2.4 mm; height of aperture, 2.0 mm; width of aperture, 0.9 mm. Discussion.— Limacina texana resembles Limacina wechesensis, n. sp., but the shoulders of that species are much more rounded, and it lacks the columellar fold and the reflected outer lip. It also resembles Li- macina augustana (Gardner, 1951), but because the holotype of Gardner’s species is an internal mold, exact comparisons are difficult to make. In general, it appears that the aperture of L. texana comprises a larger por- tion of the test and that it is higher in relation to its width than L. augustana. Occurrence.— Early Eocene. Marquez Shale Member of the Reklaw Formation, locality 3. Material.—Specimens examined in this study were recovered from the Marquez Shale Member of the Rek- law Formation at locality 3 (33 specimens). Types.— Holotype, USNM 180500; paratype, USNM 180501. Limacina tutelina (Curry) Plate 4, figures 7, 8 Spiratella tutelina Curry, 1965, p. 363, figs. 20a—b. Description. — Shell small, smooth, sinistral, oval-conic, with a spire forming one- half or more of the height of the shell. Spire is markedly cyrtoconoid and has an apical angle of about 40°. Whorl profile rounded, um- bilicus narrow. Aperture lies in the plane of the axis of the shell; outer lip is slightly sinuous, apparently not expanded. Dimensions of holotype: height, 3.5 mm; width, 1.9 mm (Curry, 1965). Measurements.—BM(NH) GG 7102 (holotype): api- cal angle, 40°. Average of five North American spec- imens: apical angle, 42°. Discussion.—In nearly all respects the specimens from eastern Canada offshore locations resemble the illustration of the holotype. The shape and proportions of Limacina tutelina are very close to Altaspiratella bearnensis (Curry, 1981), but there are significant dif- ferences in the characteristics of the aperture. Limacina tutelina lacks the well-developed flange and sulcus that are found in A. bearnensis. Occurrence.—Early Eocene-late Eocene. Early Eo- NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 21 cene specimens are described by Curry (1965) from the middle or upper London Clay (Ypresian) of En- gland. This species is rare in several wells on the Nova Scotian Shelf off eastern Canada. These include mid- dle—late Eocene specimens from well localities 48 (1,680 ft) and 50 (2,640 ft). Material.—Specimens examined in this study were recovered from well localities 48 (1,680 ft: 1 specimen) and 50 (2,640 ft: 1 specimen). Types.— Holotype, BM(NH) GG 7101; hypotypes, USNM 180502, 180503. Limacina voluta Hodgkinson, new species Plate 4, figure 9 Etymology of name.—The species name refers to the spiraled nature of the test (L. voluta = spiral). Description.—Shell small, about 414 whorls, smooth, sinistrally coiled. Aperture oval, a little less wide than high and a little more than half as high as the entire shell. Whorls rounded, sutures strongly depressed. Umbilicus small. Measurements.—USNM 180504 (holotype): height, 1.8 mm; width, 1.7 mm; spiral angle, 86°. Average of ten specimens: height, 1.2 mm; width, 1.2 mm; spiral angle, 94°. Discussion.— Most high-spired species of Limacina have sutures that are not nearly as depressed as those of L. voluta, n. sp. Occurrence.—Eocene. Holotype from cuttings at well locality 50 (3,720 ft). This specimen was recovered from a horizon which is Cretaceous in age, but prob- ably represents caved material from the overlying Eo- cene section. Other specimens were obtained from Eo- cene sediments. Late Eocene, well localities 45 (6,880 and 7,000 ft), 49 (4,880 ft), 53 (2,250 ft), and 56 (2,130 ft). Middle Eocene: localities 50 (2,580 and 2,640 ft) and 56 (2,340 ft). Early Eocene: locality 53 (2,820 ft). Material.—Specimens examined in this study were recovered from well localities 45 (2 specimens), 49 (2 specimens), 50 (3 specimens), 53 (2 specimens), and 56 (2 specimens). Types.—Holotype, USNM 180504. Limacina wechesensis Hodgkinson, new species Plate 5, figures 1-7; Plate 6, figure 1 Etymology of name.—The species name refers to the formation (Weches) from which this species was first collected. Description.—Shell small, smooth, sinistrally coiled, slightly depressed to slightly raised apical whorls. All whorls visible and about equally involute. Upper part of all whorls in about the same plane. Aperture simple, outer lip semicircular, inner lip almost straight and essentially parallel to the shell axis. Umbilicus small (4 to % of shell diameter) and circular, but on some specimens appears to be teardrop-shaped because of the way the inner lip meets the outer wall of the pre- ceding whorl. Measurements.—USNM 360337 (holotype): height, 0.8 mm; width, 1.1 mm; width of umbilicus, 0.2 mm; 3.6 whorls. Average of 20 specimens: height, 0.8 mm; width, 1.0 mm; width of umbilicus, 0.1 mm; 3.5 whorls. Discussion.—This form bears a close resemblance to the Recent pteropod Limacina helicina (Phipps, 1774) but L. wechesensis, n. sp. has a lower spire, a differently shaped aperture, and is only about one-half the size of L. helicina. It is also similar to L. elevata Collins, 1934 from the middle Miocene of Veracruz, Mexico, but that form has a depressed apex and a distinctly elevated protoconch. Limacina wechesensis is also similar to L. texana, n. sp. from the Reklaw Formation, but this latter form is more quadrate, has a columellar fold, and a strongly developed lip. Occurrence.—Middle Eocene. Common in the Weches Formation at localities 7 and 8. Material.—Specimens examined in this study were recovered from localities 7 (12 specimens), and 8 (38 specimens, including the holotype). Types.— Holotype, USNM 360337. Genus SKAPTOTION Curry, 1965 Skaptotion Curry, 1965, p. 368. Description. — Shell small, smooth, discoidal, sinistral, involute except for the first whorl or so, which are [sic] turbiniform. Shell wall very thin, ap- ertural lip of adult shell thickened and expanded into a platform (Curry, 1965). Middle-late Eocene. Discussion.—We have collected many specimens of Skaptotion and have found considerable variation in these forms. Only four of these have been recognized as existing or new species; namely S. andersoni (Gard- ner, 1927), S. nitens (I. Lea, 1833), S.? reklawensis, n. sp., and S. spirale, n. sp. There is much variation, especially in the depth of apical depression and umbilicus, and the degree to which the whorls are involute. Probably Skaptotion could be studied best in thin-section. Statistical data could then be obtained on whorl shape, number of whorls per unit diameter, angle of the apical depression and umbilicus, and height/width ratios of the shell and its aperture. Type species.—Skaptotion bartonense Curry, 1965, from the Barton Beds (Bartonian), Hampshire, En- gland. nN i) Skaptotion andersoni (Gardner) Plate 6, figures 2—4 Planorbis andersoni Gardner, 1927, p. 377, figs. 36, 37; Gardner, 1951, p. 11; Henderson, 1935, pp. 19, 38, 244; Palmer, 1937, p. 504, pl. 76, figs. 1, 2 (copies Gardner); Palmer and Brann, 1966, p. 826. Description. — Shell small, exceedingly thin, discoidal, depressed on the umbilical, and to a lesser degree, on the apical surface. Whorls five in number, the two earliest included in the protoconch; first whorl of conch constricted at its opening and depressed below the plane of the pro- toconch; later whorls increasing rather rapidly in diameter and al- titude; body relatively high, broadly rounded along the periphery; obtusely rostrate on both the apical and umbilical surfaces. Surface sculpture not developed. Aperture reniform, adnate to the body wall upon the inner surface; less produced and more sharply rounded anteriorly than posteriorly. Umbilical surface funnel-shaped and somewhat scalariform, revealing all of the obtusely carinated pos- terior extremities of the component whorls. Dimensions: Altitude, 1.0 millimeter; maximum latitude, 2.2 mil- limeters; latitude, at right angles to maximum latitude, 2.0 milli- meters (Gardner, 1927). Discussion.— Gardner (1951) and Curry (1965) have suggested that Skaptotion andersoni is a pteropod, rather than a fresh-water planorbid gastropod as earlier reported. This conclusion appears valid since this spe- cies is found in the Cook Mountain Formation, which is a marine unit containing numerous other marine invertebrates and very few, if any, freshwater gastro- pods. Skaptotion andersoni is also similar to Skapto- tion nitens (1. Lea, 1833), but these two forms appear to be separate and distinct species. The apex of S. andersoni is much more depressed than it is in spec- imens of S. nitens. The apertural lip is not preserved on the holotype and has not been described from other specimens. If S. andersoni has a distinct lip, it should be placed in the genus Skaptotion. We are tentatively placing it in this genus because of its similarity to S. nitens both in shape and size. Occurrence.— Middle Eocene. Holotype from Clai- borne Group, Cook Mountain Formation at locality 15. Specimens are fairly common at this locality (Gard- ner, 1927). Material.—We are not aware of any specimens in collections other than the holotype in the USNM. Types.— Holotype, USNM 369235. Skaptotion nitens (I. Lea) Plate 6, figures 5-10 Planaria nitens 1. Lea, 1833, p. 124, pl. 4, fig. 113; H. C. Lea, 1849, p. 104; Conrad, 1865, p. 33; Conrad, 1866, p. 11; Dall, 1892, p. 332; G. D. Harris, 1895, p. 30. Cyclostrema (Daronia) nitens (1. Lea). de Gregorio, 1890, p. 138, pl. 12, fig. 64; Cossmann, 1893, p. 21. Homalaxis sp. Burton, 1933, p. 157. BULLETIN 341 “Planaria” nitens (1. Lea). Palmer, 1937, p. 474, pl. 90, fig. 17; Palmer and Brann, 1966, p. 826. Skaptotion bartonense Curry, 1965, p. 368, figs. 1la—c, 13a—b, 14. Description.— Shell discoidal, impressed above and below, smooth and shining, diaphanous; substance of the shell very thin and fragile; whorls three, convex; mouth lunate; outer lip reflected. Length less than '4,th; breadth less than ',,th of an inch (I. Lea, 1833). Curry (1965) makes the following additional ober- servations: Exhibits the characters of the genus .... The first two whorls are turbiniform; two later whorls are discoidal and involute, with an umbilicus on each side. The adapical umbilicus has a spiral angle of about 240°, the abapical umbilical angle is variable between about 30° and 90°. Shell wall gently rounded, aperture kidney-shaped, ap- ertural lip approximately in one plane which is inclined forward abapically at about 10° to the axis of the shell. In the juvenile shell, the lip is very thin and not expanded. When the shell has attained full size, the lip becomes expanded and thickened to form a heavy flange, which is much stronger than the rest of the shell and is frequently found fossil in a detached state. Measurements.— Average of 20 specimens from the Stone City Formation at locality 11: height, 1.0 mm; width, 1.4 mm; average of 20 specimens from the Gos- port Sand at locality 26: height, 0.9 mm; width, 1.4 mm. Curry’s type of Skaptotion bartonense [BM(NH) GG 7103] has a height of 1.8 mm and a width of 2.5 mm. Discussion.—Because Skaptotion nitens was de- scribed long before S. bartonense, it has priority. Shells from the Gosport Sand differ slightly from those found in other (older) beds. They are a little smaller and have fewer whorls; the aperture is more rounded and the flanged lip is simpler and less well-developed. The lip of those specimens found in the Cook Mountain For- mation of Texas and the Barton Beds of England is wider and more pointed at the base (PI. 6, figs, 8-10). These differences are consistent, but so slight that they do not warrant division of these forms into two species or subspecies. The axis of the nuclear (juvenile) whorls of S. nitens is invariably tilted at an angle of about 35° to the axis of the mature shell and part of the second whorl is completely involute and hidden by the third whorl. Occurrence.—Middle-late Eocene. Middle Eocene specimens are found in the Lisbon Formation at lo- cality 6; in the Stone City Formation at localities 11 and 12; in the Wheelock Member of the Cook Moun- tain Formation at localities 17 and 18; in the Hurricane Lentil of the Cook Mountain Formation at locality 23; in the Gosport Sand at localities 26, 27 (holotype), and 28: at well localities 50 (2,580 and 2,640 ft); 51 (1,400 ft); 53 (2,240 ft); and 54 (4,700 ft); in England in the Upper Bracklesham Beds; and in the North Sea Basin. Late Eocene shells are found in the Barton Beds at NORTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 23 Hampshire, England; in the North Sea Basin; and at well localities 48 (between 1,740 and 2,220 ft); and 51 (between 1,070 and 1,250 ft). For additional locality data, see Curry (1965, p. 368); and Janssen and King, (1988, p. 360, figs. 188, 190, 191). Material.—Specimens examined in this study were recovered from the upper Lisbon Formation at locality 6 (1 specimen); from the Stone City Formation at lo- calities 11 (19 specimens) and 12 (23 specimens); from the Cook Mountain Formation, Wheelock Marl Mem- ber at localities 17 (3 specimens) and 18 (12 speci- mens); from the Cook Mountain Formation, Hurri- cane Lentil at locality 23 (30 specimens); from the Gosport Sand at localities 26 (800 specimens), 27 (2 specimens), and 28 (3 specimens); from well localities 48 (1,740 ft, 1 specimen; 1,860 ft, 1 specimen; 2,220 ft, 3 specimens); 50 (2,580 ft, 6 specimens; 2,640 ft, 7 specimens); 51 (1,070 ft, 2 specimens; 1,100 ft, 1 spec- imen; 1,130 ft, 1 specimen; 1,160 ft, 1 specimen; 1,190 ft, 1 specimen; 1,220 ft, 3 specimens; 1,250 ft, 3 spec- imens; 1,400 ft, 1 specimen); 53 (2,240 ft, 1 specimen); and 54 (4,700 ft, 1 specimen). We also have six spec- imens from the Barton Beds of England in our collec- tion. Types.— Holotype, ANSP 5635. The holotype spec- imen is broken and lacks the flanged lip, but the nuclear and mature whorls are exactly like those of the spec- imens we have collected from the Gosport Sand. There is no doubt that they are the same species and that they are pteropods. Hypotypes, USNM 360338, 360339. Curry’s type of S. bartonense is BM(NH) GG 7103. Skaptotion? reklawensis Garvie, new species Plate 7, figures 1-4 Etymology of name.—The species is named after the formation in which it occurs. Description.—Shell small, thin-shelled, globose. Whorls three or four, rapidly expanding, surface smooth with microscopic collabral growth lines that swing back feebly over the midpoint of the whorls. Biumbilicate, above small and circular, below moderately wide, showing the previous whorls. Aperture arcuate, pro- duced above and below, below wider and flaring. La- bium with very thin callus deposit, hardly distinguish- able from the rest of the shell. Measurements.—USNM 360340 (holotype): height, 2.3 mm; width, 2.4 mm. Largest specimen (paratype, USNM 360380): height, 3.0 mm; width, 3.2 mm. Discussion.—This is a very strange species, which superficially resembles a small nautiloid, but broken specimens show no chambers or siphuncle. The inter- nal whorls seem to be partially resorbed, and one bro- ken specimen shows a very thin internal whorl that is apparently entirely composed of nacre. The shell is composed of two layers, an inner one with no observ- able structure, and a thicker outer one that shows fine collabral striae over the entire surface. A very closely allied species is Skaptotion cossmanni Curry, 1981, from the middle Eocene (Lutetian) of southern France. The microstructure of the shell of both species is the same. The aperture of the French specimens flares a little more. Due to their extreme fragility, attempts at cleaning have usually broken the specimens. This form and S. cossmanni Curry, 1981 appear to have dextral, rather than sinistral, coiling. The speci- mens collected from the Reklaw Formation of Texas have very deep umbilici, and we could not observe the juvenile whorls. Broken specimens show that if the species indeed has sinistral coiling, the dorsal (poste- rior) umbilicus must be much deeper than the ventral (anterior) umbilicus. This would be very unusual. Occurrence.—Early—middle? Eocene. From the Rek- law Formation at locality 2; several specimens, with a slightly more planispiral shape (PI. 7, figs. 3, 4), were collected by Hodgkinson from the Weches Formation at locality 8. Material.—Specimens examined in this study were recovered from localities 2 (18 specimens, including the holotype and paratype) and 8 (2 specimens). Types.— Holotype, USNM 360340; paratype, USNM 360380. Skaptotion spirale Hodgkinson, new species Plate 7, figures 5-8 Etymology of name.—This species was named for its spiral shape (L. spiralis = spiral). Description.—Shell small, smooth, almost planis- piral, juvenile whorls turbiniform, axis of nuclear whorls just barely inclined to axis of mature shell, part of second or third whorl completely covered by the succeeding whorl. Whorls involute, spire strongly de- pressed and nearly as deep as the umbilicus. Aperture reniform. Aperture of adult shell may have a lip or flange, but no complete specimens were found. Measurements.—USNM 360341 (holotype): height, 0.5 mm; width, 0.8 mm. Average of ten specimens: height, 1.1 mm; width, 1.9 mm. Discussion.—In contrast to Skaptotion nitens (1. Lea, 1833), S. spirale is more nearly planispiral, its apical depression and the umbilicus are much narrower, and its whorls are much more involute. Skaptotion ander- soni (Gardner, 1927) is as nearly planispiral as S. spir- ale, n. sp., but, like S. nitens, differs in being less in- volute, and consequently has a more open apical depression and umbilicus. Occurrence.—Eocene. This form was found at the following localities: Undifferentiated Eocene, well lo- cality 49 (5,380 ft); middle Eocene, well localities 41 24 BULLETIN 341 (9,590 ft: Sparta Formation), 43 (11,190 ft: Cockfield Formation), and 51 (1,260 ft, the holotype). Material.—Specimens examined in this study were recovered from well localities 41 (1 specimen), 43 (1 specimen), 49 (1 specimen), and 51 (1 specimen). Type.— Holotype, USNM 360341. Family CAVOLINIIDAE Gray, 1850 Description.—Shell thin, vitreous, variable in shape, often bilaterally symmetrical with a median axis, sometimes with radial symmetry, never strongly coiled, non-operculate. Shell relatively large (up to 15 mm long). May be conical, pyramidal, or cylindrical (bul- bous). Eocene—Recent. Subfamily CLIONAE Jeffreys, 1869 Description.—Shell a long cone, needle-like; oval, round, or triangular in cross-section. Embryonic shell usually retained during the entire life of the animal, except for that of the Recent genus Hyalocylis Fol, 1875 and in some cases that of the fossil form Euchilotheca Fischer, 1882. Dorsal and ventral differentiation not well-developed. Eocene—Recent. Discussion.— Recent pteropods in this subfamily in- clude Clio Linnaeus, 1767, Creseis Rang, 1828, Hy- alocylis, and Styliola Gray, 1850. Fossil forms are Boy- icornu Meyer, 1886, Camptoceratops Wenz, 1923, Cheilospicata Hodgkinson, n. gen., Clio, Creseis, Eu- chilotheca, Hyalocylis, and Praehyalocylis Korobkov in Korobkov and Makarova, 1962. Euchilotheca has an internal septum and some individual specimens of this species have a truncated apex. In these respects, it is similar to genera in the subfamily Cuvierininae, but because the apex is usually retained, we include this form in the subfamily Clionae. Genus BOVICORNU Meyer, 1886 Description.— Shell minute, subulate, pointed, spirally contorted (Meyer, 1886). Collins (1934) expanded the description based on Meyer’s type specimen as follows: Shell very small, slender, evenly tapering conical and spirally twisted, circular in section. The apex of the shell is quite sharp, a more or less well defined bulb-like inflation is developed just above the tip and separated from the more mature part of the shell by a well defined constriction. Eocene-—Oligocene. Discussion.— Meyer erected a new genus because the type species is spirally twisted and thus differs from the straight or slightly curved, needle-like species of Creseis Rang, 1828. Subsequent authors have suggest- ed that these unusual forms are: (1) perhaps synony- mous with Euchilotheca Fischer, 1882, from the Paris Basin Eocene (Collins, 1934, p. 165; G. D. Harris and Palmer, 1946-1947, p. 464); (2) synonymous with Camptoceratops Wenz, 1923 (Curry, 1965, p. 360); or (3) the second stage of Meioceras Carpenter, 1858, a caecid gastropod (Dall, 1892, p. 302 [in part]; Coss- mann, 1912, p. 155). There is little doubt, however, that Bovicornu is a pteropod and is not closely related to any of these. Euchilotheca has a septum that is either internal or at the truncated apex. Camptoceratops has a lipped aperture and the shells are more inflated than those of Bovicornu. Meioceras has a much thicker shell wall, a lipped aperture, and a septum at the truncated apex. We found none of these features in the holotypes of the two species in this genus, none in the numerous specimens of Bovicornu eocenense Meyer, 1886 that we collected from the Red Bluff Formation at locality 33, and none in specimens from oil and gas wells in Louisiana. Type species.— Bovicornu eocenense Meyer, 1886. Bovicornu eocenense Meyer Plate 7, figures 9, 10 Bovicornu eocenense Meyer, 1886, p. 79, pl. 3, fig. 12; Cossmann, 1893, p. 51; Collins, 1934, pp. 212, 213, pl. 9, fig. 3; pl. 13, fig. 5; MacNeil and Dockery, 1984, pp. 243, 244, pl. 66, figs. 22-25, pl. 67, figs. 1-6; Dockery and Zumwalt, 1986, pp. 9, 10, pl. 1, figs. 1-6. Meioceras eocenense (Meyer). Dall, 1892, p. 302 (in part). Description. — Smooth, somewhat inflated at the closed end; section circular. Lo- cality — Red Bluff, Miss. (Meyer, 1886). We expand the Description as follows: Exterior smooth and polished, apex bears a prominent apical bulb separated from the rest of the shell by a definite constriction. Shell conical, spirally twisted and circular in cross-section, aperture round, not thickened. Measurements.—USNM 644596 (holotype): length, 2.8 mm; maximum diameter, 0.7 mm. Discussion.—We have collected numerous speci- mens from the Red Bluff Formation at the type locality, the source of Meyer’s type specimen. Most of them have tighter coiling than the holotype. Except for the spiral coiling, B. eocenense is almost identical to Creseis hastata (Meyer, 1886). At equiv- alent lengths, the diameters of these two forms are almost equal, as are the shapes and sizes of the apical bulbs. Occurrence.— Bovicornu eocenense was so named because it came from the Red Bluff Formation which, in 1886, was regarded as being Eocene in age. The unit is now regarded as of early Oligocene age (MacNeil, 1944; Mancini, 1979; Dockery, 1986). Eocene speci- mens have been described from the Upper Yazoo For- mation at locality 33 (Dockery and Zumwalt, 1986, p. 9). NortTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 25 Material.—Specimens examined in this study were recovered from locality 34 (30 specimens). Type.— Holotype, USNM 644596. Bovicornu gracile Meyer Plate 7, figures 11, 12 Bovicornu gracile Meyer, 1887, p. 9, pl. 2, fig. 17; Collins, 1934, p. 213, pl. 9, fig. 8; pl. 13, fig. 4; G. D. Harris and Palmer, 1947, p. 464, pl. 62, figs. 21, 22 (copies Collins); Palmer and Brann, 1965, p. 356. Caecum (Meioceras) gracile (Meyer). Cossmann, 1912, p. 155. Description. — Schlanker und starker spiralig gewunden als Bovicornu eocenense M’r. von Red Bluff; auch fehlt die auftreibung an der Spitze. Diese Art diirfte typischer fiir das Genus Bovicornu sein, als die zuerst von mir beschriebene (Meyer, 1887). Free translation.—Slenderer and more strongly twisted than Bovicornu eocenense Meyer from Red Bluff; also lacks the swelling at the apex. This species is typical of the genus Bovicornu, which was first described by me [Meyer, 1887]. We revise the Description as follows: exterior smooth and polished, apex bearing a slight bulb-like inflation separated from the remainder of the shell by a weak, but definite constriction. Shell conical, spirally twisted and circular in cross-section, aperture round and sim- ple. Measurements.—USNM 638880 (holotype): length, 2.7 mm; maximum diameter, 0.5 mm. Discussion.— Meyer noted that this species is slen- derer and more strongly twisted than is Bovicornu eoce- nense Meyer, 1886 from locality 33. Most specimens of B. eocenense that we collected from this same lo- cality are more strongly twisted than the holotype and the two species cannot be distinguished on the degree of twisting. They can, however, easily be identified when the apical bulb is preserved. The bulb of B. grac- ile is small and oval, while that of B. eocenense is larger and has a distinctive shape. The illustration of the apex of B. gracile by Collins (1934) is misleading. The tip of the holotype is smaller and more nearly oval than shown in his figure. Differences between the apices of these two species can best be observed by examining the holotypes or by referring to our photographs of these specimens. The only noticeable difference between Creseis sim- plex (Meyer, 1886) and B. gracile is the loose spiral coiling of the latter species. Most specimens of C. sim- plex are straight or slightly curved, but a few specimens do have a very slight spiral (Pl. 9, fig. 7). In all other respects they are nearly identical. The bulbs are very similar and the maximum width of the shell at equiv- alent lengths (untwisted length of B. gracile) is almost the same. There is a close relationship between these two species. Even though we recognize that Bovicornu may be little more than a coiled species or variety of Creseis Rang, 1828, we follow the previous division of these forms into two genera because nearly all specimens of Creseis are straight or slightly curved and a only few are slightly coiled. All specimens of Bovicornu are strongly coiled. This difference is easily recognized. Occurrence.—Late Eocene. Moodys Branch For- mation at locality 31, fide Collins (1934, p. 214), not locality 34 as stated in Meyer (1887, p. 9). Material.—The specimen examined in this study was recovered from locality 31. Type.— Holotype, USNM 638880. Genus CAMPTOCERATOPS Wenz, 1923 Description.—Shell conical, smooth, apical end straight with the remainder of shell prominently coiled in an open spiral. Aperture of mature shell may be thickened and expanded and may be extended into a broad test or rostrum [e.g., Camptoceratops prisca (Godwin-Austen, 1882)] or may have a strongly re- flected lip (e.g., Camptoceratops americanus Garvie, n. sp.). Apex conical, slightly swollen at the tip. No evident septae. Eocene. Type species.—Camptoceratops prisca (Godwin- Austen, 1882). Camptoceratops americanus Garvie, new species Plate 7, figures 13-15 Etymology of name.—The specific name notes the first reported occurrence of this genus in North Amer- ica. Description.—Shell small, smooth, initially straight, followed adorally by about 14 sinistral whorls that are prominently coiled in an open spiral. Aperture oval, bordered by a prominent flange. The aperture is in- complete but enough is preserved to show a well-de- veloped, anteriorly produced, outer lip. A thickened columella is present at the apertural end. Measurements.—USNM 360342 (holotype): length, 2.8 mm; maximum width, 0.9 mm. Average of holo- type and three other specimens: length, 2.8 mm; max- imum width, 0.8 mm. Discussion.—This is the second species assigned to the genus. The type species, C. prisca (Godwin-Austen, 1882), is from the London Clay on the Isle of Sheppey in England. Curry (1981) also reported C. prisca from the lower Eocene of Gan in southwestern France. Camptoceratops americanus, n. sp. can be distin- guished from C. prisca by the far greater development of the reflected outer lip and lack of a broad tooth or rostrum. Bovicornu gracile Meyer, 1887 and Bovicornu eocenense Meyer, 1886 are also spirally twisted, but show no reflection and thickening of the outer lip. 26 BULLETIN 341 Occurrence.— Early Eocene. Rare in the Reklaw For- mation at localities 2 and 3. Material.—Specimens examined in this study were recovered from localities 2 (10 specimens, including the holotype and paratype) and 3 (1 specimen). Types.— Holotype, USNM 360342; paratype, USNM 360343. Genus CHEILOSPICATA Hodgkinson, new genus Etymology of name.—The generic name is derived from Gr. cheilos = lip, rim + L. spica = ear of grain, point, spear. Description.—Shell small, conical, smooth and with- out ornamentation. Aperture circular, bordered by a distinctive rounded flange. Widest at the aperture. Middle Eocene. Discussion.— Cheilospicata, n. gen. is similar to Cre- seis Rang, 1828, but that genus has a simple aperture without a lip or flange. The genus is also similar to Tibiella Meyer, 1884 and Euchilotheca Fischer, 1882, but these genera have basal septa. Euchilotheca also has an axis that describes a gentle sinistral spiral and an aperture that may have a slight lip, but does not bear a distinct flange. We have not observed these shell characters in Cheilospicata. Type species.—Cheilospicata repanda Hodgkinson and Garvie, n. sp., from the Stone City Formation at locality 12. Cheilospicata repanda Hodgkinson and Garvie, new species Plate 8, figures 1-6 Etymology of name.—The species name refers to the characteristics of the lip (L. repandus = bent back- ward). Description. —Shell small, tubular, straight or slight- ly curved. Shell walls essentially parallel in the mature portion of the shell, smooth. Apertural end thickened; a recurved lip borders the shell just below the apertural end. Measurements.—USNM 360344 (holotype): length (apical bulb missing), 6.9 mm; maximum diameter (including lip), 1.3 mm; maximum diameter (excluding lip), 1.1 mm. Average of ten specimens: maximum diameter (including lip), 1.4 mm; maximum diameter (excluding lip), 1.2 mm. Discussion.— The thick lip surrounding the apertural end makes that portion of the shell much stronger than the thin apical end. We have, however, found several shells with only the apical bulbs missing. Occurrence.—Middle Eocene. Holotype, paratypes (USNM 360345, 360346, 360348), and other speci- mens from the Stone City Formation at locality 12. Paratype (USNM 360347) and several other specimens from the same formation at locality 11. Material.—Specimens examined in this study were recovered from localities 12 (13 specimens: most are apertural fragments, but two are nearly complete) and 11 (3 specimens, which are apertural fragments). Types.—Holotype, USNM 360344; paratypes, USNM 360345-360348. Genus CRESEIS Rang, 1828 Description.—Shell long and conical; straight, slight- ly curved, or with a very slight sinistral spiral; circular in cross-section, smooth exterior. Aperture at widest part of shell, sharp-edged, not constricted. Apex re- tained. One or two slight constrictions near the apical end of the shell. Middle Eocene—Recent. Type species.—Creseis virgula Rang, 1828, a Recent pteropod. Creseis corpulenta (Meyer) Plate 8, figures 7-9 Styliola corpulenta Meyer, 1887, p. 9, pl. 2, fig 16; Cossmann, 1893, p; oil: Meioceras eocenense (Meyer). Dall, 1892, p. 302 (in part). Creseis corpulenta (Meyer). Dall, 1892, p. 430; MacNeil and Dock- ery, 1984, p. 243, pl. 66, figs. 19-21. Caecum (Meioceras) corpulenta (Meyer). Cossmann, 1912, p. 155. Cleodora (Creseis) corpulenta (Meyer). Collins, 1934, p. 206, pl. 9, fig. 4; pl. 13, fig. 3. Clio (Creseis) corpulenta (Meyer). G. D. Harris and Palmer, 1947, p. 462, pl. 62, figs. 25, 26; Palmer and Brann, 1965, p. 357. Description.— Verlangert kegelformig; gerade oder schwach gebogen, Querschnitt kreisformig. Spitzes Ende mit Auftreibung. Diese Art ist seltener als Styliola simplex Mr. von derselben Lokalitat (Meyer, 1887). Free translation.—Elongated, cone-shaped, straight or slightly curved. Circular in cross-section. Apex swol- len. This species is rarer than Styliola simplex Meyer from the same locality. Measurements.—USNM 638879 (holotype): length, 3.3 mm; maximum diameter, 1.0 mm. Discussion.—The holotype is very small. The shell is smooth, slightly curved, and expands rapidly with increased length. The apex of the shell has a bulb very similar to that of Creseis hastata (Meyer, 1886), and Bovicornu eocenense Meyer, 1886. Although the apical ends of C. corpulenta, C. hastata and B. eocenense are very similar, there is no difficulty in distinguishing one species from the other. C. corpulenta, as the name suggests, has a much more expanded shell than the slenderer C. hastata and the slender, but twisted B. eocenense. Occurrence.— Late Eocene-late Oligocene. From the middle to late Eocene Moodys Branch Formation at locality 31 (holotype); from the early Oligocene Byram Formation at locality 39; and from well locality 44 (late Oligocene: cuttings). This last occurrence is youn- ger than other reported occurrences of C. corpulenta. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 27 Material.—The pyritized, but well-preserved spec- imen examined in this study was recovered from well locality 44 (13,050-13,086 ft: cuttings). Types.—Holotype, USNM 638879; hypotype, USNM 360349. Creseis cylindrica Hodgkinson, new species Plate 8, figures 10-14 Etymology of name.—The species name refers to the cylindrical nature of the apertural end. Description.—Shell small, conical, tubular near the apertural end, straight or slightly curved, oval in cross- section, smooth, without ornamentation. Shell wall at aperture thickened on inner side, hence apertural end is stronger and more apt to be preserved. The sides of the mature portion of the shell are straight and almost parallel. Measurements.—USNM 360350 (holotype): diam- eter at aperture, 1.2 mm. Longest specimen (USNM 360353): length, 9.8 mm; flattened apertural width, 1.7 mm. Average of 70 specimens: diameter at aperture, 1.3 mm. Discussion.—The apertural ends of C. cylindrica are very similar in size and shape to those of Tibiella re- flexa, n. sp., but the added apertural shell material in the latter species is on the outside of the shell and has a narrow open space between the two layers of shell material (Pl. 13, figs. 2, 3). A few specimens have a narrow outward-projecting lip. This lip is better de- veloped in smaller tests and in specimens from the Stone City Formation. Specimens from this unit are geologically the oldest specimens of C. cylindrica col- lected. Creseis cylindrica, n. sp. is assigned to the genus Creseis Rang, 1828 because the overall shape is very similar to other species of the genus. The thickened apertural end is not typical in this genus, and in this respect C. cylindrica has features noted in the genus Tibiella Meyer, 1884. The shells of this species must have been abundant on the sea floor during certain times during the middle Eocene. Many specimens are found which contain a number of successively smaller nested shells (PI. 8, fig. 1D): Occurrence.—Middle Eocene. The holotype, two paratypes, and additional specimens are from the Wheelock Member of the Cook Mountain Formation at locality 18. One paratype is from the Cook Mountain Formation, Wheelock Marl Member at locality 17. Other specimens from the Wheelock Marl were found at localities 16 and 19. The species is also found in the Stone City Formation at localities 11 and 12, and in the Hurricane Lentil of the Cook Mountain Formation at localities 22, 23, and 25. Material.—Specimens examined in this study were recovered from localities 1 1 (S specimens), 12 (18 spec- imens), 16 (3 specimens), 17 (1 specimen), 18 (66 spec- imens), 19 (5 specimens), 22 (8 specimens), 23 (6 spec- imens), and 25 (6 specimens). Types.—Holotype, USNM 360350; paratypes, USNM 36035 1-360353. Creseis hastata (Meyer) Plate 9, figures 1-3 Styliola hastata Meyer, 1886, p. 78, pl. 3, fig. 11; de Gregorio, 1890, p. 15, pl. 17, figs. 56, 57. Creseis hastata (Meyer). Dall, 1892, pp. 430, 432; MacNeil and Dockery, 1984, p. 243, pl. 66, figs. 6-13, 15-18. Cleodora (Creseis) hastata (Meyer). Collins, 1934, p. 204, pl. 9, fig. Ips sfhigssey2: Clio (Creseis) hastata (Meyer). Shimer and Shrock, 1944, p. 517, pl. 213, figs. 32-34; G. D. Harris and Palmer, 1947, p. 463; Palmer and Brann, 1965, p. 357. Description.— Shell subulate, nearly straight; section circular; closed end inflated (Meyer, 1886). The shell is very small, slender, conical, slightly arched, and the exterior smooth and polished. The tip of the shell is relatively sharp, with a prominent bulb-like swelling just above it. Length 2.25 mm; maximum diameter 0.4 mm (Collins, 1934). Discussion.—The most characteristic feature of this species is the sharp point and prominent bulb at the apex. Although C. hastata, C. corpulenta (Meyer, 1887), and Bovicornu eocenense Meyer, 1886 have similar tips and bulbs, they are easily distinguished. Creseis cor- pulenta is much more inflated than the other species, and B. eocenense has a definite and prominent open coil. Occurrence.—Middle Eocene to early Oligocene. Collins (1934) referred to Eocene specimens from the Moodys Branch Formation at localities 29 and 31. We have examined specimens from this same formation at localities 29 and 30. Both de Gregorio (1890) and Dall (1892) noted the occurrence of C. hastata in the Claiborne Eocene, but no specimens were found in our examination of Claiborne sediments (including the Gosport Sand, which previously was referred to as the Claiborne Sands). The holotype and other specimens were collected from the Oligocene Vicksburg Group at locality 35. We have examined 11 Oligocene specimens (collected by C. Wythe Cooke and currently on deposit in the USNM) from the Mint Spring Formation at locality 36. We have also collected specimens from the basal part of the Bucatunna Formation (Oligocene), locality 37, and from the type section of the Byram Formation, locality 38. MacNeil and Dockery (1984) have figured Oligocene specimens from the Red Bluff Formation at locality 34; from the Mint Spring Formation at locality 36; from the Byram Formation at localities 39 and 40; 28 BULLETIN 341 and from the Stampian (Oligocene), Gaas, Aquitaine Basin, France. Material.—Specimens examined in this study were recovered from localities 29 (7 specimens) 30 (2 spec- imens), 37 (8 specimens), and 38 (24 specimens). Types.— Holotype, USNM 644595. Creseis simplex (Meyer) Plate 9, figures 4-9 Styliola simplex Meyer, 1886, p. 78, pl. 3, fig. 10; Cossmann, 1893, DiI: Creseis simplex (Meyer). Dall, 1892, p. 430; MacNeil and Dockery, 1984, p. 243, pl. 66, fig. 14. Creseis sp. Aldrich, 1895, p. 5, pl. 1, fig. 5. Cleodora (Creseis) simplex (Meyer). Collins, 1934, p. 207, pl. 9, fig. 5; pl. 13, fig. 6. Cleodora (Creseis) sp. cf. C. (C.) hastata (Meyer). Collins, 1934, p. 205, pl. 9, fig. 2. Clio (Creseis) simplex (Meyer). G. D. Harris and Palmer, 1947, p. 463, pl. 62, figs. 23, 24; Palmer and Brann, 1965, p. 358; Dockery, 1977, p. 106, pl. 18, figs. 6, 7. Clio (Creseis) sp. Palmer and Brann, 1965, p. 358. Description.— Shell subulate, nearly straight, smooth; section circular. The closed end of this species is not inflated. Locality.—Jackson, Miss. (Meyer, 1886). Collins (1934) supplemented the original description with the following: ... the tip of this species is quite sharp, slightly constricted above the closed end, above this constriction the shell enlarges gradually, but somewhat irregularly and is slightly and somewhat unevenly curved. Length 4.5 mm., maximum diameter 0.6 mm. This species has an apex that is intermediate in outline between that of the Recent C. virgula Rang and C. acicula Rang.... Discussion.— Although the holotype is from the Jackson Eocene, this species probably is more abun- dant in the Claiborne. Aldrich (1895) described and illustrated as Creseis sp. a form from the Cook Moun- tain Formation, at Wheelock, Robertson Co., Texas. He stated, “It is more slender than typical Styliola simplex M’r, but is probably that species.’’ Collins (1934) assigned Aldrich’s figured specimen to Creseis sp. cf. C. hastata (Meyer, 1886) and Palmer and Brann (1965) later classified it as Clio (Creseis) sp. We have collected numerous specimens of Creseis simplex from the Weches, Stone City, and Cook Moun- tain formations of Texas and the Lisbon Formation and Gosport Sand of Alabama. They are the same form illustrated and described by Aldrich. Those that we have collected have a very small oval bulb at the apex, followed adorally by two slight constrictions (PI. 9, fig. 9). The apex of the middle Eocene C. simplex is smaller, less well-defined, and more oval than that of the late Eocene and early Oligocene C. hastata. Meyer (1886) stated that the closed end of this species was not in- flated, but because the bulb at the tip of this species is very small, it might easily have been overlooked by him. Cossmann (1893) and Collins (1934) noted that there is a small swelling at the apex. Specimens collected for this study show considerable variation in their width/length ratios (width about Yo to ¥, of length). Aldrich stated that the form sent to him was more slender than typical “Stvliola”’ simplex, but calculations of width/length ratios for 100 speci- mens from the Stone City and Cook Mountain for- mations (Table 3) show that about half of the speci- mens are more inflated and about half are more slender than the holotype of C. simplex. Despite considerable variation in maximum diam- eter as a function of length, all of the examined spec- imens are identified as Creseis simplex because of the similarity of their apices, and because there is a con- tinuous gradation from the slender to the inflated spec- imens. Most specimens of C. simplex are straight or slightly curved but a few show loose, yet distinct sinistral spiral coiling (PI. 9, fig. 7). This coiling is similar to, but much weaker than that of Bovicornu eocenense Meyer, 1886 and B. gracile Meyer, 1887. Occurrence.—Middle Eocene. This species is very common in many Eocene outcrops. We have found other specimens in the following formations and lo- calities: Weches Formation, localities 7, 8, and 9; Stone City Formation, localities 11 and 12; Wheelock Marl Member of the Cook Mountain Formation, localities 11, 16, 17, 18, 19, and 20; Hurricane Lentil of the Cook Mountain Formation, localities 22 and 23; Cook Mountain Formation, locality 13; Lisbon Formation, locality 6; Gosport Sand, locality 26; and the Moodys Branch Formation, localities 31 (holotype) and 32.. Material.—Specimens examined in this study were recovered from localities 6 (5 specimens), 7 (29 spec- imens), 8 (47 specimens, including paratype, USNM 360354), 9 (5 specimens), 11 (8 specimens), 12 (19 specimens), 13 (5 specimens), 16 (6 specimens), 17 (10 specimens), 18 (114 specimens), 19 (19 specimens), 20 (S specimens), 22 (6 specimens), 23 (24 specimens), 26 (15 specimens), 31 (1 specimen, the holotype), and 32 (10 specimens). Type.— Holotype, USNM 638841; hypotype, USNM 360354. Creseis species A Plate 9, figures 10, 11 Description.—Shell small, conical, slightly curved, smooth, and circular in cross-section. Apex sharp, heart-shaped, slightly constricted near the tip, and with a second constriction about 0.5 mm from the apical end. Shell diameter expands rapidly as length increas- es. Measurements.—USNM 360355 (figured speci- NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 29 Table 3.— Measurements (in mm) and diameter/length ratios of specimens of Creseis simplex used in this study. number of unit locality specimens Weches Fm. 7 21 Weches Fm. 8 47 Stone City Fm. 12 20 Cook Mountain Fm. 18 20 Gosport Sand 26 10 Moodys Branch Fm. 32 5 men): length, 2.0 mm; maximum diameter, 0.5 mm. Discussion.— Creseis sp. A differs from other Eocene species of Creseis Rang, 1828 in having a distinct heart- shaped apical bulb followed adorally by two distinct constrictions. The curved shell, which increases rap- idly in width as a function of length, is also distinctive. Occurrence.—?Eocene. Figured specimen from well locality 52 (2,080 ft: cuttings). Foraminifera recovered at this depth are Cretaceous in age, but in all proba- bility the figured specimen came from Eocene sedi- ments that caved into the hole. Other, less well-pre- served specimens were found at the following well localities: early Eocene, locality 45 (7,240 and 7,420 ft); middle Eocene, locality 56 (2,340 ft); and late Eo- cene, locality 51 (1,100 ft). Material.—Specimens examined in this study were recovered from localities 45 (2 specimens), 51 (1 spec- imen), 52 (1 specimen), and 56 (1 specimen). Type.— Figured specimen, USNM 360355. Genus EUCHILOTHECA Fischer, 1882 Description.—Shell approximately conical with the axis of the cone describing a very gentle sinistral spiral that gives the shell a slightly undulating appearance. The apex of the shell is ovoid and slightly inflated. An internal septum is commonly present at about one- tenth of the distance from the apex to the aperture of the adult shell (see Curry, 1965, p. 359). Type species.—Euchilotheca succincta (Defrance, 1828). Euchilotheca succincta (Defrance) Plate 9, figures 12-17 ?Vaginella succinta [sic] Defrance, 1828, p. 427, pl. 97, figs. 5, Sa, Sb. Cleodora (Creseis) chastelii Potiez and Michaud, 1838, p. 44, pl. 10, figs. 11-14. Cleodora parisiensis Deshayes, 1861, p. 187, pl. 3, figs. 15-17. Euchilotheca succincta (Defrance). Wrigley, 1934, p. 10, pl. 1, fig. 2; Curry, 1965, p. 359, figs. 3-S. Description.—Our description is based primarily on apertural fragments. These fragments show a shell that is small, tubular, circular, smooth, and without orna- mentation. The aperture is circular, has a flanged lip, and is slightly oblique to the shell axis. Shell walls maximum diameter length (da) (I) d/l 0.4 2.2 0.1818 0.5 3.7 0.1351 0.7 3.9 0.1795 0.6 4.9 0.1224 0.6 2.9 0.2069 0.4 De 0.1481 adjacent to the aperture are essentially parallel. Discussion.—A single apical fragment in our collec- tion shows a gentle sinistral spiral. We cannot deter- mine if the apical fragment belongs to the same species as the apertural fragments, but if the two are regarded as a single species, the combined fragments bear a re- markable similarity to EF. succincta. We could not ob- serve an internal septum. Measurements.— Average of ten specimens: maxi- mum diameter (including lip), 0.8 mm; maximum di- ameter (excluding lip), 0.6 mm. The small size of these specimens is similar to spec- imens described and illustrated by Curry (1965). He gives the following measurements: length, about 3.5 mm; diameter, 0.7 mm. Occurrence.— Middle Eocene. EF. succincta occurs in the Lutetian of France and England. In North America, we have found this species only in the Wheelock Mem- ber, Cook Mountain Formation at locality 19. Material.—Specimens examined in this study were recovered from locality 19 (18 apertural fragments and a single apical fragment). Types.—Hypotypes, USNM 360356, 360357. Genus HYALOCYLIS Fol, 1875 Description.—Shell small, fragile, conical, slightly curved dorsally. Apex truncated in adults, tip closed by a very thin septum. Transverse annulations on shell surface. Middle Eocene?, middle Miocene—Recent. Type species.—Hyalocylis striata (Rang, 1828), the only Recent species. Hyalocylis species A Plate 9, figures 18, 19 Description.—Shell small, conical with raised an- nulations and a basal septum. The only specimen is a pyritic internal mold. Measurements®.—USNM 360358 (figured speci- men): length, 1.5 mm; maximum diameter, 2.2 mm; minimum diameter, 1.1 mm. Discussion.—This specimen differs from the Recent © The specimen is apparently crushed so a measurement of the width is difficult. Perhaps a reconstructed width of 1.7 mm is a close approximation. 30 BULLETIN 341 Hyalocylis striata (Rang, 1828) in being much larger at the apical end. If this form is a true Hyalocylis, it would mark the earliest worldwide occurrence of the genus. Occurrence.— Middle Eocene. Sparta Formation, at well locality 41. Material.—The single specimen examined in this study was recovered from well locality 41 (9,740-9,770 ft) Types.— Figured specimen, USNM 360358. Genus PRAEHYALOCYLIS Korobkov in Korobkov and Makarova, 1962 Description. — The shells are comparatively large (up to 23 mm long), in the shape of a high, straight-sided cone with a straight apex, and are circular in cross-section both in the initial and the apertural parts of the shell. The initial part has the form of a very narrow, elongated, smooth- surfaced or annular-striated tube. The embryonic chamber (prod- issoconch) is papillate and separated by a neck from the initial part of the shell. Both the initial and basal parts of the shell lack septation. The external surface bears numerous annular ribs whose number varies sharply within a single species. The shell wall is very thin, homogeneous, and lacks canals (Korobkov and Makarova, 1962; translated from Russian). Middle Eocene to lower Miocene. Type species.—Praehyalocylis chivensis Korobkov and Makarova, 1962, from the Upper Eocene in the southern part of the U.S. S.R. Praehyalocylis maximus denseannulatus (Ludwig) Plate 10, figures 1-5 Tentaculites maximus var. dense-annulatus Ludwig, 1864, p. 42, pl. 50, figs. 21a, b.; Blankenhorn, 1889, p. 602, pl. 22, figs. 10, 11. Praehyalocylis maximus var. densecostatus (Ludwig). Blanckenhorn, 1889 (copied in Korobkov and Makarova, 1962, pl. 3, fig. 11). Praehyalocylis maximus (Ludwig) var. dense-annulatus (Ludwig). Korobkov and Makarova, 1962, pl. 3, figs. 12, 13. Description.— Gehause gross, conisch, oben grade abgeschnitten, mit dickwandiger, geschlossener, in ein kleines Knétchen endender Spitze. Die Schale wird nach oben sehr diinn; sie ist von dicht stehenden, nach oben runden, nach unten scharfkantig umgebogenen Ringeln umgeben, im Querschnitte kreisrund, ohne Langsspalte. Lange 23,0 Mm., ob- ere Weite 6,0 Mm, Anzahl der Ringel 200. Die Gehause sind fast simmtlich platt gedriickt und waren wohl schon ehe sie auf den feinen Kalkschlamm, worin sie liegen, nied- ersanken, zusammengefaltet. Sie sind so diinn, dass sie im Gestein obenher nur als ein leiser Anflug erscheinen, dessen beide Wande durch einen schwachen Steinkern getrennt uber einander liegen. Ge- gen die Spitze hin verdicken sie sich allmahlich; das ausserste Ende, aus weissem Kalk bestehend, ist mit einer kleinen Kugel ausgestattet und dickwandig. Die Schalchen sind haufig durch Langsbriche in viele Stiicke zertrimmert, wobei die Ringelchen gegenseitig ver- schoben wurden. Die Gehaduse haben alle Merkmale, welche die Tentaculiten auszeichnen, und k6nnen vorlaufig nur mit diesen ver- einigt werden; obgleich sie in der Tertiar-Formation gefunden wer- den. Es ist nicht unwahrscheinlich, dass sie der das Mittelmeer und den Ocean bewohnenden Styliola striata Rang, welche zwar von ovalen Querschnitt, an ihrem Unterende nach hinten gekriimmt, auch nur 6 Mm. lang ist, nahe stehen, denn auch die Gehause dieses lebenden Pteropoden sind fein geringelt, und dann wiirden vielleicht alle Tentaculiten mit den Styliolen zu vereinigen seyn (Ludwig, 1864). Free translation.—Shell large, conical, aperture nor- mal to shell axis, terminating in a small thick-walled expanded globular apex. The shell wall thins consid- erably toward the aperture and is ornamented by crowded annulations whose profile is rounded abapi- cally, sharp adapically, and with a smoothly rounded cross-section; longitudinal slit absent. Length 2.0 mm, apertural diameter 6.0 mm, number of annulations 200. The shells are all essentially squashed flat and were probably deposited in a fine carbonate mud in which they fractured. The shell walls are so thin that only the slightest impressions remain, separated by the thinnest deposit of sediment; toward the apex the remains are more substantial and the small thicker-walled globular apex is composed of white limestone. The shells are frequently longitudinally fractured into many pieces such that the annulations are shifted relative to one another. In all characters, the shells can be referred to the tentaculitids although they are found in the Tertiary formations. Possibly this species can be placed near Styliola striata Rang, a species from the Oceans and Mediterranean Sea, due to its size (6 mm) and its sim- ilarly fine annulations, although that species is oval in cross-section and curved at the apex; if that were the case all tentaculitids might be referred to the styliolids. Discussion.—Squires (1989, p. 444) described the first species of Praehyalocylis Korobkov in Korobkov and Makarova, 1962 from the Western Hemisphere. His late Eocene specimens of Praehyalocylis cretacea (Blanckenhorn, 1889) were found in the northwestern states of Oregon and Washington. The genus is now recognized in the Gulf Coast of the United States but our specimens are narrower, have more closely spaced annulations and belong to Praehyalocylis maximus denseannulatus. We have included a composite drawing (PI. 10, fig. 5) to show some of the features found in the specimens from the Gulf Coast of the United States. The apical bulb is very small, unornamented and teardrop-shaped. There is no ornamentation for a short distance beyond the constriction adoral of the bulb, but the remainder of the shell has regular annulations. There is a distinct flaring lip at the aperture. Measurements.—Most complete specimen (USNM 360360): length, 9.5 mm; maximum flattened width, 1.5 mm; apical angle, 9°; annulations per mm, 7.4; widest flattened specimen (USNM 360361): apertural width, 3.8 mm. Occurrence.— Middle Eocene—middle Oligocene. In North America, this species has been found in the middle Eocene Wheelock Marl Member of the Cook Mountain Formation, at locality 17. The species has been reported previously from the Upper Eocene near the southern coast of the Aral Sea, Soviet Union and from the middle Oligocene of Germany. Material.—Specimens examined in this study were recovered from locality 17 (1 nearly complete speci- men, 2 specimens that may be as much as 50% pre- served, and numerous partial specimens). Types.—Hypotypes, USNM 360359-360361. Subfamily CUVIERININAE Gray, 1840 Description.—Shell smooth, bottle- or vase-shaped with a round, oval, trigonal, or reniform aperture. The juvenile shell is discarded at maturity leaving the apical end of the mature shell closed by a distinctive septum. Discussion.—Characteristics of the subfamily are based on the only Recent species, Cuvierina columnella (Rang, 1827), and on fossil species discussed in this paper. Fossil pteropods with characteristics similar to C. columnella include the genera Bucanoides Hodgkin- son, n. gen., Loxobidens Hodgkinson n. gen., and 7i- biella Meyer, 1884. We place these in the subfamily Cuvierininae. Eocene—Recent. Genus BUCANOIDES Hodgkinson, new genus Etymology of name.—The generic name is derived from Gr. bykane = trumpet + Gr. -oides = like, re- sembling. Description.—Shell small, like a truncated cone, smooth. Aperture round and simple without flanges or thickened lip. Widest at the aperture, septum at apex of adult shell. Discussion.— Differs from Cuvierina Boas, 1886 in being widest at the aperture, and from Tibiella Meyer, 1884 in having a simple aperture without flanges or thickened lip. Species in the genus include B. basian- nulata Hodgkinson, n. sp., B. divaricata Hodgkinson, n. sp., and B. tenuis Hodgkinson, n. sp. Middle Eocene. Type species. — Bucanoides tenuis Hodgkinson, n. sp. Bucanoides basiannulata Hodgkinson, new species Plate 10, figures 6-10 Etymology of name.—The species name refers to the annulations near the apical end of the shell. Description.—Shell a truncated cone, small, curved, smooth, thin-walled. Maximum diameter at the rounded aperture. Apex truncated and closed by a slightly oblique septum, which makes a sharp and dis- tinctive junction with the shell wall. Faint annulations occur near the truncated apical end. Moderate to strong increase in maximum diameter as a function of length. NORTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 31 Measurements.—USNM 360362 (holotype): length, 2.2 mm; maximum diameter, 0.9 mm. Average of ten specimens; length, 2.0 mm; maximum diameter, 0.9 mm. Discussion.— Differs from Bucanoides tenuis Hodg- kinson, n. sp. in being more curved, possessing a great- er maximum diameter in relation to length, and in having faint annulations at the apical end of most spec- imens. Bucanoides divaricata Hodgkinson, n. sp. is similar to B. basiannulata, but it flares to a greater degree as a function of length. Occurrence.— Middle Eocene. Weches Formation at localities 7, 8, and 9. Material.—Specimens examined in this study were recovered from localities 7 (5 specimens), 8 (10 spec- imens, including the holotype and paratype), and 9 (4 specimens). Types.— Holotype, USNM 360362; paratype, USNM 360363. Bucanoides divaricata Hodgkinson, new species Plate 11, figures 1-3 Etymology of name.—The species name (L. divari- catus = spread apart) refers to the rapid increase in maximum diameter as a function of increased length. Description.—Shell subconical, small, short, slightly curved and rapidly expanding, aperture round. Trun- cated apical end closed by a prominent septum, which is flat to slightly rounded and makes a distinctive, sharp contact with the shell wall. Shell thin, especially at aperture. Measurements.—USNM 360364 (holotype): length, 2.0 mm; maximum diameter, 1.1 mm; largest speci- men (USNM 360381)’: length, 7.4 mm; width, 4.3 mm. Average of 110 specimens: length, 1.3 mm; max- imum diameter, 0.8 mm. Discussion.—This species is short and flares rapidly at the apertural end. In these respects, it bears no close resemblance to any other described pteropod. It bears a superficial resemblance to Bucanoides basiannulata Hodgkinson, n. sp., but B. divaricata flares more rap- idly and does not have basal annulations. Occurrence.— Middle Eocene. Wheelock Member, Cook Mountain Formation at localities 16, 17, and 18, and in the Hurricane Lentil of the Cook Mountain Formation at locality 23. Material.—Specimens examined in this study were recovered from localities 16 (S specimens), 17 (4 spec- imens, including paratype, USNM 360381), 18 (165 specimens, including the holotype and paratype, USNM 360365), and 23 (2 specimens). Types.—Holotype, USNM 360364; paratypes, USNM 360365 and 360381. Our largest specimen (PI. 11, fig. 3: USNM 360381) is on the same rock frag- ’ A flattened specimen still in the matrix [Pl. 11, fig. 3]. B32 BULLETIN 341 ment, but on the opposite side, as a paratype (USNM 360353) of Creseis cylindrica Hodgkinson, n. sp. Bucanoides tenuis Hodgkinson, new species Plate 11, figures 4-6 Etymology of name.—The species name (L. tenuis = thin) refers to the slender, narrow shape of the shell. Description.—Shell a truncated cone, small, smooth, straight to slightly curved. Shell wall thin throughout, but especially so at the apertural end. Apex truncated, blunt, closed by a slightly oblique septum, junction with shell wall sharp and distinct. Measurements.—USNM 360366 (holotype): length, 3.0 mm; maximum diameter, 0.8 mm. Average of 40 specimens: length, 1.9 mm; maximum diameter, 0.6 mm. Discussion.— This species has an unornamented, thin and unflanged apertural lip. Although most specimens have the aperture completely broken away, a few in- dividuals have just enough shell remaining at the ap- erture to show its characteristics. There is a significant variation in the length/maximum diameter ratio, with some shells being more inflated than others. Bucanoides tenuis Hodgkinson, n. sp. is much like Euchilotheca elegans G. F. Harris, 1894 from England and France, which also truncates its posterior end. However, the axis of E. elegans describes a very gentle sinistral spiral, which gives the shell a slightly undu- lating appearance; it may have a slight lip. Bucanoides tenuis, n. sp. has neither of these characteristics. Occurrence.— Middle to late? Eocene. Bucanoides tenuis, N. sp. is widespread. It is found in the Stone City Formation at localities 11 and 12 (paratype, USNM 360366); and in the Wheelock Member of the Cook Mountain Formation at localities 11, 16, 17, 18, and 20. It occurs in the Hurricane Lentil at localities 23 (includes the holotype, and paratype, USNM 360367), 24, and 25; and in the upper Lisbon For- mation at locality 6. It is also found at well locality 53 (2,250 ft: late Eocene). Material.—Specimens examined in this study were recovered from localities 6 (1 specimen), 11 (15 spec- imens), 12 (4 specimens), 16 (52 specimens), 17 (16 specimens), 18 (81 specimens), 20 (4 specimens), 23 (26 specimens), 24 (25 specimens), 25 (3 specimens), and well locality 53 (1 specimen). Types.—Holotype, USNM 360366; paratypes, USNM 360367, 360368. Genus CUVIERINA Boas, 1886 Description.— Adult shell cylindrical, shaped like a flask or fat cigar, may be slightly constricted behind aperture, surface smooth. Widest near middle of shell length. Oval in cross-section, but apertural end may be compressed. Aperture reniform, oval, or round. Apex blunt in adult, closed by a thin curved caudal septum. Juvenile shell straight, with an apex which is slightly constricted above the tip. Shell caducous (i.e., the con- ical section, the juvenile stage, breaks off at or near the caudal septum after the adult portion of the shell de- velops). The generic description of Cuvierina has been ex- panded here to include forms with a round or oval aperture and species which are not necessarily con- stricted near the apertural end. To date Eocene species of Cuvierina have been found only in Texas. Eocene- Recent. Type species.—Cuvierina columnella (Rang, 1827), a Recent species. Cuvierina gutta Hodgkinson, new species Plate 11, figures 7-10 Etymology of name.—The trivial name (L. guttus = a narrow-necked flask) refers to the flask-shaped shell. Description.—Shell small, flask-shaped, smooth, lat- erally compressed, slightly constricted about one-fifth of distance from aperture, maximum diameter just slightly adoral of midlength. Apical end truncated and closed by a convex septum, aperture laterally com- pressed, ventral edge of aperture strongly recessed and resembles the sinus of some other gastropods. Dorsal edge slightly recessed. Shell laterally symmetrical. Measurements.—USNM 360369 (holotype): length, 2.2 mm; dorso-ventral maximum inflation, 0.7 mm; lateral maximum inflation, 0.6 mm; dorso-ventral di- ameter of aperture, 0.7 mm; lateral diameter, 0.3 mm. Discussion.—In some respects, this form is similar to the Recent pteropod, Cuvierina columnella (Rang, 1827), but it is laterally rather than dorso-ventrally compressed, and is much smaller (C. col/umnella is up to 10 mm long). Occurrence.— Middle Eocene. Very rare in the ben- tonite bed (see Scott, 1963, fig. 4), Wheelock Member, Cook Mountain Formation at locality 18. Also very rare in the Hurricane Lentil of the Cook Mountain Formation at locality 23. Material.—Specimens examined in this study were recovered from localities 18 (2 specimens, the holotype and an apertural fragment) and 23 (1 apertural frag- ment, paratype USNM 360370). Types.— Holotype, USNM 360369; paratype, USNM 360370. Cuvierina lura Hodgkinson, new species Plate 11, figures 11-15 Etymology of name.—The species name (L. /ura = sack, bag) refers to the sac-like shape of this form. Description.—Shell small, barrel-shaped, highly in- NortH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 33 flated and globose, maximum diameter near mid- length. Aperture circular and slightly oblique to shell axis. Apex truncated, blunt, closed by a septum that is adorally concave and slightly oblique to the shell axis; junction of septum and shell wall sharp and dis- tinct. Shell wall thin and polished, varying in thickness from about 11 to 22 um. Measurements.—USNM 360371 (holotype): length, 1.0 mm; maximum diameter, 0.8 mm; diameter of aperture, 0.4 mm. Average of ten specimens of the highly inflated form similar to the holotype: length, 1.0 mm: maximum diameter, 0.8 mm. Average of ten specimens of the less inflated form: length, 1.1 mm; maximum diameter, 0.6 mm. Discussion.—Shells of this species can be divided into two distinct forms. One form has shells similar to the holotype described above (PI. 11, fig. 11). Shells of the second form are less inflated with sides that are almost parallel in some specimens. Their maximum diameter is about one-third of the distance from the truncated apex to the aperture (PI. 11, fig. 12). In cross- section, the shell is slightly compressed laterally. Squires (written commun., 1990) suggested that the differences in shell shape could be attributed to ecologic or reproductive features, especially since the two forms are from the same beds. We agree that both should be placed within a single species. However, it is important to recognize that all modern pteropods are hermaph- roditic. Hence, they are less likely to have differences in morphology based on male or female characteristics than do animals that have separate and distinct sexes. Further, one could argue equally as well that since these forms occur in the same beds at the same locality, ecologic conditions might not be a factor in determin- ing shell shape. Perhaps future studies will help in de- termining whether these two forms represent a single or two separate species. Cuvierina inflata (Bonelli, 1872) from the early Plio- cene of Italy, Cuvierina globosa Collins, 1934 from the middle Miocene of Veracruz, Mexico, and C. senonica inflata Avnimelech, 1945 from the Miocene of Syria are all much larger than C. Jura, n. sp. The shell wall of most specimens terminates abrupt- ly at the septum, but in a few instances the juvenile portion of the shell truncates a short distance from the septum (PI. 11, figs. 14, 15). Occurrence.—Middle Eocene. Rare in the Weches Formation. Both the inflated and less-inflated forms are found at locality 8; only the less-inflated form has been found at locality 7. Material.—Specimens of the highly-inflated form examined in this study were recovered from locality 8 (26 specimens), and specimens of the less-inflated form were recovered from localities 7 (3 specimens, includ- ing the paratype) and 8 (12 specimens). Type.— Holotype, USNM 360371; paratype, USNM 360372. Genus LOXOBIDENS Hodgkinson, new genus Etymology of name.—The generic name (Gr. /oxos = slanting, + L. bidens = two-toothed) is based on the nature of the lip and its ornamentation. Description.—Shell small, tubular, smooth, straight, or slightly curved. Sides parallel. Well-developed flanged lip with two distinct but continuous crenula- tions associated with two slight projections that extend into the apertural opening. Discussion.—Only apertural fragments have been found, so the nature of the apex is unknown. To date found only in Texas. Middle Eocene. Type species.— Loxobidens aduncus Hodgkinson, n. sp. Loxobidens aduncus Hodgkinson, new species Plate 12, figures 1-5, 6[?] Etymology of name.—The species name (L. aduncus = bent, hooked) refers to the characteristics of the ap- erture. Description.—Shell small, tubular, straight or slight- ly curved, smooth, unornamented. Sides of shell es- sentially parallel, may constrict slightly just before the aperture. Cross-section mainly circular, but becomes compressed laterally at the apertural end. Well-devel- oped flanged lip that is oblique to the shell axis. The lip has two distinct crenulations of the shell wall con- nected with two slight projections that extend into the apertural opening. One crenulated projection on each lateral side, with one being significantly larger than the other. Measurements.—USNM 360373 (holotype): maxi- mum dorso-ventral diameter (including flanged lip), 0.7 mm; maximum dorso-ventral diameter (excluding lip), 0.6 mm; maximum lateral diameter (including lip), 0.5 mm; maximum lateral diameter (excluding lip), 0.4 mm. Discussion.—Several small apical fragments of a pteropod were collected with essentially the same max- imum diameter as L. aduncus. These broken speci- mens expand slowly from a basal septum (PI. 12, fig. 6). There is no evidence, however, that these apical fragments are the apical ends of this species. They might be the apical end of some other pteropod species. These apical fragments closely resemble the apex of Bucanoides tenuis, n. sp., but are smaller and the sep- tum is much more rounded. Occurrence.—Middle Eocene. Holotype and all specimens from the Wheelock Member, Cook Moun- tain Formation, locality 19. 34 BULLETIN 341 Material.—Specimens examined in this study were recovered from locality 19 (12 apertural fragments, and a larger number of apical fragments). Types.— Holotype, USNM 360373; paratype, USNM 360374. Genus TIBIELLA Meyer, 1884 Etymology of name.—Tibiella was so named be- cause the specimen described by Meyer (1884) resem- bled the tibia of mammals. Description.—Shell small, tubular, straight or slight- ly curved, smooth, round in cross-section at apex and throughout most of the shell. Aperture round or round- ed triangular with a flanged or significantly thickened lip, apex closed by a curved oblique septum. Discussion.— The type species, Tibiella marshi Mey- er, 1884, has a subtriangular aperture and a flared lip. “Tibiella” texana Collins, 1934 has a round aperture and a distinct lip. Prior to the publication of this paper, these two species were the only ones included in the genus. New species are 7. annulataand T. reflexa. Both have been found only in the Gulf Coast of North Amer- ica. Middle Eocene. Type species.— Tibiella marshi Meyer, 1884. Tibiella annulata Garvie, new species Plate 12, figures 7, 8 Etymology of name.—The species name (L. annu- /atus = beringed, ornamented with rings) refers to the annulations that are so prominent on the shell of this species. Description.—Shell a small, slightly curved, cigar- shaped tube, closed at the posterior end by a septum resembling a low rounded cone, the apex of which diverges at an angle of about 130°. The aperture is ovate-elliptical, constricted parallel to the axis of cur- vature of the tube. On the flattened sides, it is some- what anteriorly extended, and terminates in a thick- ened reflected lip. The posterior two-thirds of the shell is radially costate with about 10.7 annulations per mm. The remainder of the shell is smooth or has very faint to obsolete costae. Measurements.—USNM 360375 (holotype): length, 3.5 mm; maximum diameter (including lip), 1.4 mm; maximum diameter (excluding lip), 1.1 mm; mini- mum diameter (including lip), 1.0 mm; minimum di- ameter (excluding lip), 0.8 mm. (USNM 464544; al- most complete paratype): length, 3.1 mm; maximum diameter (including lip), 1.2 mm; maximum diameter (excluding lip), 1.0 mm; minimum diameter (including lip), 0.9 mm; minimum diameter (excluding lip) 0.7 mm. Discussion.—The species most closely allied to T. annulata, n. sp. is “T.”’ texana Collins, 1934, but it can be easily differentiated from the latter species by its compressed aperture and well-developed annula- tions. Occurrence.—Middle Eocene. Viesca Member, Weches Formation at locality 10. Material.—Specimens examined in this study were recovered from locality 10 (2 well-preserved specimens and 3 broken specimens). Types.— Holotype, USNM 360375; paratype, USNM 464544. Tibiella marshi Meyer Plate 12, figures 9, 10 Tibiella marshi Meyer, 1884, p. 110, unnumbered text-fig.; Dall, 1892, p. 432; Collins, 1934, p. 226, pl. 14, fig. 1, Palmer and Brann, 1965, p. 360. ?Tibiella marshalli [sic] Meyer. Zilch, 1959, p. 49, fig. 165. Etymology of name.—The species was named after a Professor Marsh that Meyer does not further identify. Description.— Shell thin, tubular. The closed end little convex. The lower part, about one-third of the whole length, of a circular section, then by tapering a little forming a kind of neck, above which the shell is of a rounded trigonal section. Aperture dilated. Length 3, mm (Meyer, 1884). Emended description.—Shell thin, tubular, slightly curved, smooth. Apical end truncated and closed by a rounded, slightly oblique septum. Junction of septum and shell wall sharp and distinct. Lower part of shell circular in section, upper part subtriangular. Growth from truncated apex to aperture even and regular. Shell flared at aperture to form a distinct lip. Measurements.—USNM 360376 (neotype, herein designated): length, 5.2 mm; dorso-ventral diameter (including lip), 1.3 mm; dorso-ventral diameter (ex- cluding lip), 1.2 mm; lateral diameter (including lip), 1.2 mm, lateral diameter (excluding lip), 1.0 mm. Discussion.—Meyer’s figure shows a specimen that is considerably different from ours. We have collected several deformed or injured specimens, which have some characteristics similar to Meyer’s specimen. Even these, however, do not duplicate the shell shape shown by Meyer. Because the aperture is rounded trigonal on Meyer’s specimens and on those collected by us, and because all were found in the Gosport Sand, we are confident that they are the same species. Meyer’s spec- imen probably is not typical of the species; it is perhaps not mature and may have been injured or damaged during life. His specimen probably had a basal septum as suggested by his statement: If the figured specimen is adult, in the young ones the apex may be perhaps acute and afterwards partitioned off, as in the genus Triptera Quoy et Gaimard .. . (Meyer, 1884, p. 110). Meyer also wrote: Pteropoda are described from the Miocene and Oligocene, but as NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 35 far as I am acquainted with the literature this is the first Pteropod from the Eocene. Occurrence.— Middle Eocene. The type described by Meyer (1884) was from the “Eocene sand, Claiborne, Ala.” Palmer and Brann (1965, p. 360) correctly listed the formation and locality as Gosport Sand, Claiborne Bluff, Alabama River, Monroe Co., Alabama (loc. 27). All of the specimens described in this paper are from the Gosport Sand (loc. 26). Material.—All specimens examined in this study were recovered from the Gosport Sand at locality 26 (2 well-preserved and 11 broken specimens). These include an almost complete specimen donated by the late Mr. and Mrs. Gus Lindveit (neotype) and a well- preserved shell contributed by Mr. and Mrs. Jim Knight, all of Houston, Texas. Types.—The type was originally in the Aldrich Col- lection at Johns Hopkins University. It could not be located by Collins (1934, p. 226) or Palmer and Brann (1965, p. 360), nor during a search initiated by museum personnel on our behalf. All of these searches were made after the Aldrich Collection had been transferred to the USNM. Because the type specimen apparently is lost, we designate USNM 360376 as the neotype. Tibiella reflexa Hodgkinson, new species Plate 12, figures 11, 12; Plate 13, figures 1-3 Etymology of name.—The species name (L. reflexus = bent or turned back) refers to the reflexed lip. Description.—Only apertural ends have been recov- ered by us. The apertural end is small, tubular, round in cross-section, smooth, unornamented. Shell walls essentially parallel. A distinctive, strongly recurved lip is added externally at the aperture. A narrow gap, seen only on broken specimens, separates the outer recurved lip from the normal shell wall. Measurments.—USNM 360377 (holotype): maxi- mum diameter (including lip), 1.5 mm; maximum di- ameter (excluding lip), 1.3 mm. Average of five spec- imens: maximum diameter (including lip), 1.6 mm; maximum diameter (excluding lip), 1.5 mm. Discussion.—In size and shape, T. reflexa, n. sp. resembles Creseis cylindrica Hodgkinson, n. sp., but the lip at the aperture of the latter form is produced by an internal, rather than external, thickening of the shell wall. We are also assuming that when a complete specimen is found, 7. reflexa will be shown to have a basal septum, whereas C. cylindrica does not. Occurrence.—Middle Eocene. Stone City Forma- tion, locality 12. Material.—Specimens examined in this study were recovered from locality 12 (8 apertural fragments). Types.— Holotype, USNM 360377; paratype, USNM 360378. Tibiella texana Collins Plate 13, figures 4-8 ‘“Tibiella” texana Collins, 1934, p. 227, pl. 14, figs. 2-5; Palmer and Brann, 1965, p. 360. Description. — Shell small, subcylindrical, smooth and polished, growth lines faint. Posterior end tapering slightly; irregularly truncated and closed by a smooth oblique septum. Median part of shell slightly inflated. Aperture subcircular, slightly expanded, and oblique to axis of shell. A strongly developed flange lies directly below the margin of the aperture (Collins, 1934). Measurements.—USNM 644568 (holotype): length, 4.5 mm; diameter (including lip), 1.7 mm; diameter (excluding lip), 1.5 mm. USNM 360379 (topotype): length, 3.9 mm; diameter (including lip), 1.7 mm; di- ameter (excluding lip), 1.5 mm. Discussion.—The holotype of ** Tibiella” texana and an additional broken specimen were the only ones available to Collins for study. We have found several well-preserved specimens and many apertural frag- ments that further illustrate the nature of the apertural flange. The illustrations prepared by Collins show a double flange. We have examined the holotype and note that the second flange is that of another specimen of 7. texana nested within the holotype. The flange on the holotype is sharp and strongly developed and is similar to the flanges on most of our specimens; the flange on our best specimen (topotype, USNM 36034) is rounded. There is complete gradation from sharp to rounded flanges (Pl. 13, figs. 5, 6). Collins (1934, p. 227) placed this species in the genus Tibiella Meyer, 1884 with hesitation because he had no access to the type of Tibiella marshi Meyer, 1884 and because Meyer’s illustration of that specimen showed neither a basal septum nor a prominent flange. We feel that Collins was correct in his assignment of the species to Tibiella, because we have had access to well-preserved specimens of 7. marshi that do have a basal septum and a well-developed apertural flange. Occurrence.— Middle Eocene. Fragments of 7ibiella texana are common in the Weches Formation at lo- calities 7, 8, and 9. Material.—Specimens examined in this study were recovered from localities 7 (23 specimens), 8 (22 spec- imens, including the holotype and topotype, and 20 broken specimens), and 9 (5 specimens). Types.—Holotype, USNM 644568, topotypes, USNM 360379, 360383, and 360384. APPENDIX COLLECTING LOCALITIES The pteropods included in this study were obtained from locations in Texas, Louisiana, Alabama, Missis- 36 BULLETIN 341 sippi, and offshore eastern Canada (Text-figs. 4, 5). All of the specimens from the Reklaw Formation in Texas were found by Garvie, who is preparing a manuscript on the molluscan fauna of this unit. Garvie also found Tibiella annulata Garvie, n. sp. (Weches Formation) and the first North American specimens of Praehyal- ocylis maximus denseannulatus (Ludwig) from the Cook Mountain Formation. Other species were first found by Hodgkinson. Texas Bureau of Economic Geology (TBEG) num- bers are included in our locality descriptions for most Texas localities. For localities outside of Texas, we have used numbers listed by Toulmin (1977) or Mac- Neil and Dockery (1984). The localities cited in the latter publication bear United States Geological Survey (USGS), Mississippi Geological Survey (MGS), and Paleontological Research Institution [Ithaca, New York] (PRI) numbers. Locality 1.—Wilcox Group, Hatchetigbee Formation, Bashi Member, Choctaw Corer, Clarke Co., Alabama. Unfortunately we are unable to give more precise data for Aldrich’s locality [source of the holotype of A/taspiratella elongatoidea (A\- drich, 1887)]. Locality 2.—TBEG locality 11-T-7, Reklaw Formation, Marquez Shale Member, Ridge Creek, bluff approximately 30 m (100 ft) long exposed on the north side of creek; about 250 m (825 ft) south of the Missourn, Kansas, and Texas Railroad trestle and the county road bridge across the creek. Approximately 8 km (5 mi) W of Smithville or 1 km (0.6 mi) E of Upton, Bastrop Co., Texas. Locality 3.—Reklaw Formation, Marquez Shale Member, 0.2 km (0.1 mi) from TBEG loc. 165-T-13. Taylor Branch, exposures in Two Mile Creek (also called Joe Taylor Branch) downstream from a county road. The point at which the road crosses the creek is given on the USGS map of the Gause Quadrangle (1989: 1:24,000) as 96°39'06" N., 30°48'48” E., Milam Co., Texas. Locality 4.—Reklaw Formation, Marquez Shale Member, NE Cherokee Co., Texas (Stenzel, 1953).§ 8 Stenzel (1953) gave only this very general location for the ptero- pod specimens that he found and illustrated but did not formally describe. MISSISSIPPI ALABAMA © 30 FLORIDA GULF OF MEXICO Text-figure 4.—States bordering the northern Gulf of Mexico. The locations of several collecting sites are shown. These site locations show the general Eocene outcrop trend around the northern Gulf Coast. NortTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 37 QUEBEC 60° ANTICOSTI ISLAND eastern Canada. Locality 5.—Toulmin locality ACI-4, Tallahatta Formation, Little Stave Creek, a westward-flowing tributary of Stave Creek, 5.6 km (3.5 mi) N of Jackson and W of U. S. Highway 42, in secs. 19 and 20, T. 7 N., R. 5 E., Clarke Co., Alabama. Locality 6.—Toulmin locality AMo-4, Lisbon Formation, Clai- borne Bluff, a high bluff on the left bank of the Alabama River at E end of bridge on U. S. Highway 84 and extending southward for about 1.6 km (1 mi). NEY,, sec. 30, T. 7 N., R. 6 E., and sec. 25, T. 7N., R. 5 E., near Claiborne, Monroe Co., Alabama. Locality 7.—TBEG locality 26-T-6, Weches Formation, Colliers Ferry (Burleson Bluff), right bank of Brazos River, 21.9 km (13.6 mi) NE of Caldwell, Burleson Co., Texas. Locality 8.—TBEG locality 11-T-2, Weches Formation, Viesca Member, in bluff on right bank of Colorado River at Smithville, approximately 180 m (200 yd) downstream from bridge on State Highway 71, Bastrop Co., Texas. Locality 9.—Weches Formation, in ditch on W side of dirt road 3.5 km (2.15 mi) S of Augustana, Houston Co., Texas. Locality 10.—Weches Formation, Viesca Member, outcrops along both banks of Cedar Creek, 8.9 km (5.5 mi) NNW of Leona, Leon Co., Texas. Locality 11.—Stone City Formation, Rocky Creek, 0.8 km (0.5 mi) W of Stone City Bluff, Burleson Co., Texas. Locality 12.—TBEG locality 26-T-1, Stone City Formation, Stone City Bluff, S or right bank of the Brazos River 19.3 km (17.4 mi) W of Bryan, Burleson Co., Texas. Locality 13.—TBEG locality 11-T-29, Cook Mountain Forma- tion, right bank of Colorado River, 1.3 km (0.8 mi) downstream Text-figure 5.—The location of cited exploratory wells in offshore NEWFOUNDLAND from Bastrop—Fayette Co. line, 2.6 km (1.6 mi) NE of Kirtley, Fayette Co., Texas. Locality 14.—TBEG locality 11-T-26, Cook Mountain Forma- tion, Pin Oak Creek, at crossing of Smithville-Winchester road, Bastrop Co., Texas. Locality 15.—Cook Mountain Formation, 1.2 km (0.75 mi) S of Elkhart, Anderson Co., Texas. 38 Locality 16.—TBEG locality 26-T-1, Cook Mountain Formation, Wheelock Marl Member, Stone City Bluff, S or nght bank of the Brazos River 18.3 km (11.4 mi) W of Bryan, Burleson Co., Texas. Locality 17.—Cook Mountain Formation, Wheelock Marl Mem- ber, stream bed of Little Brazos River about 90 m (100 yd) upstream from Little Brazos Bluff, Brazos Co., Texas.” Locality 18.—TBEG locality 21-T-1, Cook Mountain Formation, Wheelock Marl Member, Little Brazos Bluff, on E side of Little Brazos River just upstream from Texas Highway 21 bridge over the Little Brazos River, 15.5 km (9.6 mi) W of Bryan, Brazos Co., Texas. Locality 19.—Cook Mountain Formation, Wheelock Marl Mem- ber, Little Brazos River, exposures 1.0 km (0.6 mi) downstream from Texas Highway 21 bridge, at the base ofa small waterfall caused by a resistant ironstone ledge, Brazos Co., Texas. Locality 20.—TBEG locality 21-T-6, Cook Mountain Formation, Wheelock Marl Member, outcrop near junction of Little Brazos and Brazos rivers, Brazos Co., Texas. Locality 21.—Cook Mountain Formation, Wheelock Marl Mem- ber, Wheelock, Robertson Co., Texas.'° Locality 22.—TBEG locality 113-T-2, Cook Mountain Forma- tion, Hurricane Lentil, type section of Hurricane Lentil in Hurricane Bayou, 0.3-0.8 km (0.2-0.5 mi) upstream from bridge on Crockett— Rusk Co. road, 5.6 km (3.5 mi) NE of Crockett, Houston Co., Texas. Locality 23.—TBEG locality 113-T-9, Cook Mountain Forma- tion, Hurricane Lentil, Alabama Ferry, E bank of Trinity River, 12.1 km (7.5 mi) WSW of Porter Springs, Houston Co., Texas. Locality 24.—TBEG locality 145-T-58, Cook Mountain Forma- tion, Hurricane Lentil, Flat Branch, 0.6 km (0.4 mi) from entrance gate on Middleton—Guys Store Co. road, Leon Co., Texas. Locality 25.—TBEG locality 145-T-52, Cook Mountain Forma- tion, Hurricane Lentil, Two Mile Creek, 8.5 km (5.3 mi) SW of Leona, Leon Co., Texas. Locality 26.—Toulmin locality ACI-4, Gosport Sand, Little Stave Creek, 5.6 km (3.5 mi) N of Jackson and W of U. S. Highway 43, a westward-flowing tributary of Stave Creek, in secs. 19 and 20, T. 7N., R. 2 E., Clarke Co., Alabama. Locality 27.—Toulmin locality AMo-4, Gosport Sand, Claiborne Bluff on the left bank of the Alabama River at E end of bridge on U. S. Highway 84 and extending S for about 1.6 km (1.0 mi), NE, sec. 30, T. 7 N., R. 6 E. and sec. 25, T. 7 N., R. 5 E., Monroe Co., Alabama. Locality 28.—Toulmin locality AMo-6, Gosport Sand, Rattle- snake Bluff on the left bank of the Alabama River 3.2 km (2.0 mi) below Gosport Landing in SEY, sec. 31, T. 7 N., R. 5 E. at mi. 69.8, Monroe Co., Alabama. Locality 29.—Toulmin locality MCI-1, Moodys Branch Forma- tion, Garland Creek, in S bluff of Garland Creek, 7.7 km (4.8 mi) NE of Shubuta, NW¥,, sec 28, T. 1 N., R. 16 E., Clarke Co., Mis- sissippi. Locality 30.—Toulmin locality MHi-1, Moodys Branch Forma- tion, gully or steephead east of swimming pool in Riverside Park, in S\4, sec. 25 or N\4, sec. 36, T. 6 N., R. 1 E., Jackson, Hinds Co., Mississippi. Locality 31.—Moodys Branch Formation, Jackson, Hinds Co., Mississippi. !! Locality 32.—Moodys Branch Formation, Montgomery (Creola) Landing near the town of Montgomery on the east side of the Red River, SEY, sec. 25, T. 8 N., R. 5 W., Grant Parish, Louisiana. ’ Locality 17, normally under the water of the Little Brazos River, can be collected only during periods of extremely low water level. '° Numerous individuals have searched for this locality, including Hodgkinson and Garvie. To our knowledge no one has been able to find Cook Mountain sediments at this locality. '! This may be same locality as that listed immediately above. BULLETIN 341 Locality 33.—Yazoo Formation, Miss Lite Aggregate clay pit, SEY,SWY,, sec. 25, T. 7 N., R. 1. W., Cynthia, Hinds Co., Mississippi. Locality 34.—USGS locality 5264, Red Bluff Clay (Oligocene), type locality, Red Bluff, 1.6 km (1.0 mi) SW of Hiwannee on E side of the Chickasawhay River, sec. 28, T. 10 N., R. 7 W., Wayne Co., Mississippi. Locality 35.—Vicksburg Group (early Oligocene), Vicksburg, Warren Co., Mississippi. Locality 36.—USGS locality 7671, Vicksburg Group, Mint Spring | Formation, Brown’s Cave, E bank of Leaf River, 0.8 km (0.5 mi) above the bridge on Bay Springs—Raleigh road in sec. 13, T. 2 N., | R. 8 E., Smith Co., Mississippi. Locality 37.—Toulmin locality AWa-3. Yazoo Formation and © Vicksburg Group, Bucatunna Formation, St. Stevens Quarry on the right bank of the Tombigbee River E of St. Stephens, sec. 33, T. 7 N., R. 1 W., Washington Co., Alabama. Locality 38.—USGS locality 6454 and MGS locality 102, Vicks- burg Group, Byram Formation, type locality. From beneath indu- rated ledge at low water level, Pearl River, just upstream from bridge at Byram, NWY,SWY,NW'4, sec. 19, T. 4 N., R. 1 E., Hinds Co., Mississippi. Locality 39.— Vicksburg Group, Byram Formation, Big Black Riy- er, near Edwards, Hinds Co., Mississippi. Locality 40.—MGS locality 112c, Vicksburg Group, Byram For- mation, Mississippi Valley Portland Cement quarry, north of Red- — wood on Highway 3, NW‘, sec. 26, T. 18 N., R. 4 E., Warren Co., Mississippi. Locality 41.—Exxon Corporation #1 R. H. Strain well, East Baton Rouge Parish, Louisiana. Locality 42.—Exxon Corporation #1 Baker well, East Baton Rouge Parish, Louisiana. Locality 43.—Exxon Corporation #1 Labokay well (Houston Riy- er Prospect), Calcasieu Parish, Louisiana. Locality 44.—Exxon Corporation #1 State Lease 12770 well, Cam- eron Parish, Louisiana. Locality 45.—Amoco-Imperial #A-1 Puffin B-90 well, 44°30'N, 53°30'W, Nova Scotian shelf, offshore Eastern Canada. Locality 46.—Amoco Imperial #A-1 Heron H-73 well, 44°10'N, | 52°15'W, Nova Scotian shelf, offshore Eastern Canada. Locality 47.—Mobil Sable Island #1 F-67 well, 44°00'N, 59°45'W, Nova Scotian shelf, offshore Eastern Canada. Locality 48.—Amoco-Imperial #A-1 Bittern M-62 well, 44°50’N, 51°00'W, Nova Scotian shelf, offshore Eastern Canada. Locality 49.—Amoco-Imperial #A-1 Kittiwake P-11 well, 44°50'N, 53°30'W, Nova Scotian shelf, offshore Eastern Canada. Locality 50.—Amoco-Imperial #A-1 Petrel A-62 well, 45°00'N, 52°45'W, Nova Scotian shelf, offshore Eastern Canada. Locality 51.—Amoco-Imperial #A-1 Murre G-67 well, 46°10'N, 49°00'W, Nova Scotian shelf, offshore Eastern Canada. Locality 52.—Amoco-Imperial-Skelly #A-1 Spoonbill D-30 well, 45°50'N, 49°00’'W, Nova Scotian shelf, offshore Eastern Canada. Locality 53.—Amoco-Imperial #A-1 Gannet O-54 well, 45°10'N, 52°30'W, Nova Scotian shelf, offshore Eastern Canada. Locality 54.—Amoco-Imperial #A-1 Shearwater J-20 well, 44°30'N, 52°45'W, Nova Scotian shelf, offshore Eastern Canada. Locality 55.—Amoco-Imperial-Skelly #A-1 Mallard M-45 well, 44°20'N, 52°00'W, Nova Scotian shelf, offshore Eastern Canada. Locality 56.—Amoco-Imperial-Skelly #A-1 Osprey G-84 well, 44°50’ N, 49°00’ W, Nova Scotian shelf, offshore eastern Canada. REFERENCES CITED Abbott, R. T. 1974. American seashells. Van Nostrand Reinhold Co., New York, 663 pp., 24 color plates. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 39 Abildgaard, P. C. 1791. Nyere efterretning om de skaldyr fra middelhavet, form Forskal har beskrevet under navn of Anomia tridentata. Skrivter af Naturhistorie-Selskskabet, Copenhagen, I (a): pp. 171-175. Aldrich, T. H. 1887. Notes on Tertiary fossils, with descriptions of new species. Cincinnati Society of Natural History, Journal, vol. 10, pp. 78-83, | fig. 1895. New or little known Tertiary Mollusca from Alabama and Texas. Bulletins of American Paleontology, vol. 1, No. 2, 30 pp., 5 pls. Almogi-Labin, A. 1982. Stratigraphic and paleoceanographic significance of late Quaternary pteropods from deep-sea cores in the Gulf of Aqaba (Elat) and northernmost Red Sea. Marine Micro- paleontology, vol. 7, No. 1, pp. 53-72. Almogi-Labin, A., and Reiss, Z. 1977. Quaternary pteropods from Israel. Revista Espanola de Micropaleontologia, vol. 9, No. 1, pp. 5-48. Andrews, J. 1971. Seashells of the Texas coast. The Elma Dill Russel Spencer Foundation Series No. 5, University of Texas Press, Aus- tin and London, 297 pp. Aynimelech, M. 1945. Revision of fossil Pteropoda from Southern Anatolia, Syria and Palestine. Journal of Paleontology, vol. 19, pp. 637- 647. Be, A. W. H., Damuth, J. E., Lott, L., and Free, R. 1976. Late Quaternary climatic record in western equatorial At- lantic sediment. Geological Society of America, Memoir 14, pp. 165-200. Be, A. W. H., and Gilmer, R. W. 1977. A zoogeographic and taxonomic review of euthecosomatous Pteropoda, in Ramsay, A. T. S. [ed.], Oceanic Micropa- leontology, vol. 1, Chapter 6, pp. 733-808, Academic Press, London. Be, A. W. H., MacClintock, C., and Chew-Currie, D. 1972. Helical shell structure and growth of the pteropod Cuvierina columnella (Rang) (Mollusca. Gastropoda). Biominerali- zation Research Reports, vol. 4, pp. 47-79. Berger, W. H. 1978. Deep-sea carbonate. Pteropod distribution and the arago- nite compensation depth. Deep Sea Research, vol. 25, No. 5, pp. 447-452. Berggren, W. A., Kent, D. V., Flynn, J. J., and Van Couvering, J. A. 1985. Cenozoic geochronology. Geological Society of America, Bulletin, vol. 96, pp. 1407-1418. Blainville, H.-M. D. de 1816-1830. Vers et Zoophytes, in Dictionnaire des sciences na- turelles, ... etc. Pt. 2. Regne organise. Paris and Stras- bourg, 60 volumes and atlas of 12 plates. Blanckenhorn, M. 1889. Pteropodenreste aus der oberen Kreide Nordsyriens und aus dem hessischen Oligocan. Zeitschrift der Deutschen Geo- logischen Gesellschaft, vol. 41, pp. 593-602. Boas, J. E. V. 1886. Spolia Atlantica. Bidrag til pteropodernes. Morfologi og systematik samt til kundskaben om deres geografiske udbredlse. Kongelige Danske Videnskabernes Selskkabs Skrifter. Copenhagen, 6 Raekke, naturvidenskabernes ma- tematikk, Afd. 4, pp. 1-231. Boltoyskoy, D. 1974. Study of surface-shell features in Thecosomata (Pteropoda: Mollusca) by means of scanning electron microscopy. Ma- rine Biology, vol. 27, pp. 165-172. Bonelli, S. 1872. in Bellardi, L., J Molluschi dei terreni Terziari(i) del Pie- monte e della Liguria descritti da L. Bellardi. Torino. Bonnevie, K. 1913. Pteropoda from the Michael Sars North Atlantic Deep-Sea Expedition. Report of Scientific Research, ‘‘Michael Sars” North Atlantic Deep-Sea Expedition 1910, vol. 3, pp. 1- 69. Bosc, L. A. G. 1816-1817. Nouveau Dictionnaire d'Histoire Naturelle. Deter- ville, Paris, vol. 2, 592 pp.; vol. 5, 614 pp.; vol. 7, 586 pp.; vol. 15, 550 pp. Brann, D. C., and Kent, L. S. 1960. Catalogue of the type and figured specimens in the Pale- ontological Research Institution. Bulletins of American Paleontology, vol. 40, No. 184, 996 pp., 1 pl. Burton, E. St. J. 1933. Faunal horizons of the Barton Beds in Hampshire. Geo- logical Association of London, Proceedings, vol. 44, pp. 131-167. Carpenter, P. P. 1858-1859. First steps towards a monograph of the Caecidae, a family of the rostriferous Gastropoda. Zoological Society of London, Proceedings for 1858, part 26, pp. 413-444. Chen, C., and Be, A. W. H. 1964a. Seasonal distribution of euthecosomatous pteropods in the surface waters of five stations in the western North Atlantic. Marine Science of the Gulf and Caribbean, Bulletin, vol. 14, pp. 185-220. 1964b. Distribution of pteropods in western North Atlantic sed- iments. American Association of Petroleum Geologists, Bulletin, vol. 48, No. 4, pp. 520, 521 [abstract]. Collins, R. E. L. 1934. A monograph of the American Tertiary pteropod mollusks. The Johns Hopkins University Studies in Geology, No. 11, pp. 137-234, pls. 7-14. Conrad, T. A. 1833. Fossil shells of the Tertiary formations of North America, illustrated by figures drawn on stone by T. A. Conrad. vol. 1, No. 4, pp. 39-46 (G. D. Harris reprint 1893, pp. 63- 74; Paleontological Research Institution, reprint 1963, Ithaca, New York). 1865. Catalogue of the Eocene and Oligocene Testacea of the United States. American Journal of Conchology, vol. 1, pp. 1-35, corrections, p. 190 (+ two unnumbered pages). 1866. Check list of invertebrate fossils of North America. Eocene and Oligocene. Smithsonian Miscellaneous Collections, vol. 7, pp. 1-41. Cossmann, A. E. M. 1893. Notes complémentaires sur la faune Eocénique de |'Ala- bama. Annuaire Géologique Universal, Revue de Géo- logie et Paléontologie, livr. 12, 51 pp., 2 pls. 1912. Essais de paléoconchologie comparée. Paris, livr. 9, 215 pp., 10 pls. 1913. Catalogue illustré des coquilles fossiles, etc. Appendix 5. Société Royal de Malacologie Belgique, Annales, vol. 49, pp. 19-238. Cox, L. R. 1960. Gastropoda, General characteristics of gastropoda, in Moore, R. C. [ed.], Treatise on Invertebrate Paleontology, pt. I, Mollusca 1. Geological Society of America and Uni- versity of Kansas Press. Lawrence, Kansas, pp. 184-1169. 40 BULLETIN 341 Curry, D. 1965. The English Paleogene pteropods. Malacological Society of London, vol. 36, pp. 357-371. 1981. Pteropodes Eocénes de la Tuilerie de Gan (Pyrenees-At- lantiques) et de quelques autres localites du SW de la France. Cahiers de Micropaleontologie, vol. 4, pp. 35-44, pl. 1. Curry, D., and Rampal, J. 1979. Shell microstructure in fossil thecosome pteropods. Malacologia, vol. 18, pp. 23-25, 1 fig. Cuvier, G. 1797. Tableau élémentaire de l'histoire naturelle des animaux. xvi + 710 pp., 14 pls., Paris. 1804. Concernantl‘animal de l'Hyale, un nouveau genre de moll- usques nus intermédiaire entre |"Hyale et le Clio et l’éta- blissement d’un nouvel ordre dans la classe des mollusques. Muséum National d’Histoire Naturelle, Annales, Paris, vol. 4, pp. 223-234, pl. 59. 1817. Le Régne Animal distribué d’aprés son organisation. Paris, vol. 2, xvili + 532 pp. Dall, W. H. 1892. Tertiary fauna of Florida. Wagner Free Institute of Sci- ence, Philadelphia, Transactions, vol. 3, pp. 201—473, pls. 13-22. 1921. Summary of the Marine shell-bearing mollusks of the northwestern coast of America, from San Diego, California, to the Polar sea, mostly contained in the collections of the United States National Museum with Illustrations of hith- erto unfigured species. United States National Museum, Bulletin 112, pp. 1-217, 22 pls. Defrance, M. J. L. 1804-1845. Dictionnaire Universel des Sciences Naturelles. Paris and Strasbourg. Deshayes, G. P. 1856-1865. Description des Animaux sans Vertébres Découverts dans le Bassin de Paris pour servir de supplemént a la description des coquilles fossiles des environs de Paris, com- prenant une revue générale de toutes les espéces actuelle- ment de Paris, comprenant une revue générale de toutes les espéces actuellement connues. Paris, vol. 2, pp. 433- 640, pls. 27-39. Diester-Haass, L., and Spoel, S. van der 1978. Late Pleistocene pteropod-rich sediment layer in the North- east Atlantic and protoconch variation of Clio pyramidata Linné, 1767. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 24, pp. 85-109. Dockery, D. T., III 1977. Mollusca of the Moodys Branch Formation, Mississippi. Mississippi Geological Survey, Bulletin 120, 212 p., 28 pls. 1986. Punctuated succession of Paleogene mollusks in the north- ern Gulf Coastal Plain. Society of Economic Paleontolo- gists and Mineralogists, Research Reports, pp. 582-589. Dockery, D. T., III, and Zumwalt, G. S. 1986. Pteropods (Mollusca, Gastrooda) from the upper Yazoo Formation (Eocene) at Cynthia, Mississippi. Mississippi Geology, vol. 6, No. 4, pp. 9-13, pls. 1, 2. Fairbridge, R. W. [ed.] 1966. The encyclopedia of oceanography. Encyclopedia of earth sciences, vol. 1, Reinhold Publishing Corp., New York, 1,021 pp. Fischer, P. 1880-1887. Manuel de Conchyliologie et de Paleontologie con- chyliologique. F. Savy, Paris, xxi + 1,369 pp., 33 pls., Paris. Fol, H. 1875. Réponse a une reclamation de M. E. Ray-Lankester. Ar- chives de Zoologie Expérimentale et Générale, vol. 4, 214 pp., 10 pls. Furnestin, M. 1979. Planktonic mollusks as hydrological and ecological indi- cators, in Spoel, S. van der, et al. [eds.], Pathways in Mal- acology. Bohn, Scheltema, and Holkema, Utrecht der W. Junk, b. v., The Hague, pp. 175-194. Gardner, J. A. 1927. New species of mollusks from the Eocene of Texas. Wash- ington Academy of Science, Journal, vol. 17, pp. 362-383, figs. 1-44. 1951. Two new guide fossils from the Tallahatta Formation of the southeastern states. Washington Academy of Science, Journal, vol. 41, pp. 8-12. Gilmer, R. W. 1974. Onsome aspects of feeding in thecosomatous pterood mol- /uscs. Biologie et ecologie Méditerranéenne, Aix-en-Prov- ence, Journal, vol. 15, pp. 127-144. Godwin-Austen, H. H. 1882. Land and freshwater Mollusca of India, including South Arabia, Beluchistan, Afganistan, Kashmir, Nepal, Burma, Pequ, Tenasserim, Malay Peninsular, Ceylon, and other Islands of the Indian Ocean. Supplementary to Messrs. Theobald and Hanley’s Conchologia Indica. vol. 1, col- ored plates, London. Gray, J. E. 1840. Synopsis of the contents of the British Museum. 42nd Edi- tion, 370 pp. British Museum, London. 1847. A list of the genera of Recent Mollusca, their synonyms and types. Zoological Society of London, Proceedings, pt. 15, pp. 129-219. 1850. Systematic arrangement of the figures, in Gray, M. E., Figures of molluscous animals, vol. 4, pp. 63-206, Lon- don. de Gregorio, A. 1890. Monographie de la Faune-Eocénique de l'Alabama et sour- tout de celle de Claiborne de |’Etage Parisien (Horizon a Venericardia planicosta Lamk. Annales de géologie et de paléontologie, livr. 7 and 8, 316 pp., 46 pls. Harris, G. D. 1895. Claiborne fossils. Bulletins of American Paleontology, vol. 1, No. 1, 52 pp., 1 pl. 1899. The Lignitic stage, Part II, Scaphopoda, Gastropoda, Pter- opoda, and Cephalopoda. Bulletins of American Paleon- tology, vol. 3, 128 pp., 12 pls. Harris, G. D., and Palmer, K. E. H. V. W. 1946-1947. The Mollusca of the Jackson Eocene of the Missis- sippi embayment (Sabine River to the Alabama River). Bulletins of American Paleontology, vol. 30, No. 117, 564 pp., 65 pls.; part I, Bivalves and bibliography for parts I and II, G. D. Harris, 1946, 206 pp., 25 pls.; part I, Uni- valves and index, K. V. W. Palmer, 1947, pp. 207-563, pls. 25, 26, 62-64; pls. 57-61 by G. D. Harris. Harris, G. F. 1894. On the discovery of a pteropod in British Eocene strata, with a description of a new species. Proceedings of the Malacological Society of London, vol. 1, pp. 60-61. Henderson, J. 1935. Fossil non-marine Mollusca of North America. Geological Society of America, Special Paper 3, 313 pp. NortTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 41 Herman, Y. 1971. Vertical and horizontal distribution of pteropods in Qua- ternary sequences, in Funnell, B. M., and Riedel, W. R. [eds.], The Micropaleontology of Oceans. Cambridge Uni- versity Press, London, pp. 463-486. 1973. Preliminary pteropod results from the Mediterranean Sea. Initial Reports of the Deep-Sea Drilling Project, vol. 13, United States Government Printing Office, Washington, DC, pp. 993-1001, pls. 1, 2. 1978. Pteropods, in Haq, B. U., and Boersma, A. [eds.], /ntro- duction to Marine Micropaleontology. Elsevier, pp. 151— 159. Herman, Y., and Rosenberg, P. E. 1969. Pteropods as Bathymetric Indicators. Marine Geology, vol. 7, pp. 169-173. Hodgkinson, K. A. 1974. Stone City and Cook Mountain (Middle Eocene) scapho- pods from southeast Texas. University of Kansas Pale- ontological Contributions, Paper 70, 25 pp., 8 pls. Janssen, A. W. 1990. Long distance correlation of Cainozoic deposits by means of planktonic gastropods (‘‘pteropods’’); some examples of future possibilities. Tertiary Research, vol. 7, pp. 65-72. Janssen, A. W., and King, C. 1988. Planktonic molluscs (pteropods), in Vinken, R. et al. [eds.], The Northwest European Tertiary Basin. Results of the International Geological Correlation Programme Project No. 124. Geologisches Jahrbuch, Reihe A, Heft 100, pp. 356-368, figs. 188-207. Jeffreys, J. G. 1869. British Conchology. J. van Voorst, London, vol. 5, pp. 1- 258, pls. 1-102. 1877. New and peculiar Mollusca of the Eulimidae and other families of Gastropoda, as well as of the Pteropoda, pro- cured in the Valorous Expedition. Annals and Magazine of Natural History, vol. 19, ser. 4, pp. 317-339. Jung, P. 1973. Pleistocene Pteropods — Leg 15, site 147, Deep-Sea Drill- ing Project, in Edgar, N. T., and Saunders, J. T. et al., Initial Reports of the Deep-Sea Drilling Project. vol. 15, U. S. Government Printing Office, Washington, DC, pp. 753-767, pls. 1-5. Keen, A. M. 1971. Sea shells of tropical west America, Marine mollusks from Baja to Peru. Second edition, Stanford University Press, Stanford, California, 22 color pls. Korobkoy, I. A. 1966. Krynologie (Mollusca Pteropoda) paleogenovikh otlojenii juga SSSR. Voprosy Paleontologii, vol. 5, pp. 71-92, 4 pls. Korobkoy, I. A., and Makarova, R. K. 1962. A new pteropod mollusk from the upper Eocene deposits in the USSR. Paleontologischeskii Zhurnal, vol. 4, pp. 83- 87. Lalli, C. M., and Wells, F. E., Jr. 1978. Reproduction in the genus Limacina (Opisthobranchia: Thecosomata). Journal of Zoology, Proceedings of the Zoological Society of London, vol. 186, pp. 1345-1348. Lamarck, J. B. P. A. de M. de 1804. Mémoires sur les fossiles des environs de Paris, comprenant la détermination des espéces qui appartiennent aux ani- maux marine sans vertébres, et dont la plupart sont figurés dans la collection des vélins du Muséum. Muséum National d’Histoire Naturelle, Annales, Paris, vol. 5. Laubriere, L. P. de 1881. Description d’espéces nouvelles du Bassin de Paris. Bulletin de la Société Géologique de France, Paris, vol. 3, pp. 377— 384. Lea, H. C. 1849. Catalogue of the Tertiary Testacea of the United States. Academy of Natural Sciences, Philadelphia, Proceedings, 1848, vol. 4, pp. 95-107. Lea, I. 1833. Contributions to geology. Philadelphia, 227 pp., 6 pls. Linnaeus, C. 1758. Systema naturae per regna tria naturae. Editio Decima, Reformata. Stockholm, vol. 1, Regnum animale, 824 pp. 1767. Systema naturae per regna tria naturae, “‘Vermes Testa- cea’. Editio duodecima, Reformata, Stockholm, pp. 533— 1327 + register. Ludwig, R. 1864. Pteropoden aus dem Devon in Hessen und Nassau, sowie aus dem Tertidr-Ton des Mainzer Beckens. Palaeontogra- phica, vol. 11, pp. 311-323. MacNeil, F. S. 1944. Oligocene stratigraphy of southeastern United States. American Association of Petroleum Geologists, Bulletin, vol. 28, pp. 1313-1354. MacNeil, F. S., and Dockery, D. T., III 1984. Lower Oligocene Gastropoda, Scaphopoda, and Cephalo- poda of The Vicksburg Group in Mississippi. Mississippi Department of Natural Resources, Bureau of Geology, 415 pp., 72 pls. Mancini, EF. A. 1979. Eocene-Oligocene boundary in southwest Alabama. Gulf Coast Association of Geological Societies, Transactions, vol. 11, pp. 282-289, pls. 1-3. Massy, A. L. 1932. Mollusca: Gastropoda. Thecosomata and Gymnosomata. Discovery Reports, vol. 3, pp. 267-296. McGowan, J. A. 1960. The systematics, distribution, and abundance of the Eu- thecosomata of the North Pacific. Ph.D. dissertation, Uni- versity of California, San Diego, 197 pp. 1968. The Thecosomata and Gymnosomata of California. The Veliger, vol. 3 (Supplement), pp. 103-107, pls. 12-20. 1971. Oceanic biogeography of the Pacific, in Funnell, B. M., and Riedel, W. R. [eds.], The Micropaleontology of Oceans. Cambridge University Press, London, pp. 3-74. Meisenheimer, J. 1905. Pteropoda. Wissenschaftliche Ergebnis. Tiefsee Expedi- tion “Valdivia”, vol. 9, pp. 1-314. 1906a. Die tiergeographischen Regionen des Pelagials, auf grund der Verbreitung der Pteropoden. Zoologische Anzeiger, vol. 28, pp. 155-163. 1906b. Die Pteropoden der deutschen Sud-polar Expedition 1901— 1903. Deutschen Sud-polar Expedition 1901-1903, IX (Zool.), vol. 1, pp. 92-152. Meyer, O. 1884. Notes on Tertiary shells. Academy of Natural Sciences, Philadelphia, Proceedings, 1884, vol. 36, pp. 104-112, 3 text-figs. 1886. Part II. Contributions to the Eocene Paleontology of Al- abama and Mississippi. Part 2, in Smith, E. A., Geology of Alabama, Geological Survey of Alabama, Bulletin 1, pp. 61-85 pls. 1-3. 1887. Beitrag zur Kenntnis der Fauna des Alttertiars von Mis- sissippi und Alabama. Senckenbergische Naturforschende Gesellschaft in Frankfurt a. M., 22 pp., 2 pls. 42 BULLETIN 341 Milne-Edwards, H. 1848. Note sur la classification naturelle des mollusques gastér- opodes. Annales des Sciences Naturelles, Zoologie, ser. 3, vol. 9, pp. 102-112. Morton, J. E. 1954. The biology of Limacina retroversa. Journal of the Marine Biological Association of the United Kingdom, Plymouth, vol. 33, pp. 297-312. Nelms, K. C. 1979. Sedimentary and faunal analysis of a marginal marine section, the Stone City Member (Middle Eocene), Crockett Formation, Burleson County, Texas. Unpublished M. S. thesis, Texas A. and M. University, 189 pp. d’Orbigny, A. D. 1836. Voyage dans l’Amerique méridionale. Mollusques, exécute pendant les années 1826-1833. Bertrand, Paris, vol. 5, part 3, pp. 49-184. Palmer, K. E. H. V. W. 1937. The Claibornian Scaphopoda, Gastropoda, and dibran- chiate Cephalopoda of the southern United States. Bulletins of American Paleontology, vol. 7, No. 32, 548 pp., 90 pls. Palmer, K. E. H. V. W., and Brann, D. C. 1965-1966. Catalogue of the Paleocene and Eocene Mollusca of the southern and eastern United States. Bulletins of Amer- ican Paleontology, vol. 48, No. 218, pt. 1 (1965), Pele- cypoda, Amphineura, Pteropoda, Scaphopoda, and Ce- phalopoda, pp. 1-466, pls. 1-3. pt. 2 (1966), Gastropoda, pp. 467-1057, pls. 4, 5. Pelseneer, P. 1888a. Report on the Pteropoda collected by the H. M. S. Chal- lenger during the years 1873-1876. II. The Thecosomata. Report of the Scientific Results of the Voyage of H. M. S. “Challenger” during the years 1873-1876, Zoology, vol. 23, pp. 1-132. 1888b. Report on the Pteropoda collected by the H. M. S. Chal- lenger during the years 1873-1876. III. Anatomy. Reports of the Scientific Results of the Voyage of H. M. S. “Chal- lenger’”’ during the years 1873-1876, Zoology, vol. 23, p. 1-97. Phipps, C. J. 1774. A voyage towards the North Pole undertaken by His Ma- Jesty’s command... . 1773. London, pp. i-viii, 11 pls., 3 maps. Potiez, v. L. V., and Michaud, A. L. G. 1838. Galerie des Mollusques ... de Dauai. vol. 1, Paris. Pruvot-Fol, A. 1954. Mollusques opisthobranches. Faune de France, Paris, Lechevalier, vol. 58, 460 pp., 1 pl., 173 figs. Rampal, J. 1968. Les ptéropodes thécosomes en Méditerranée. Comission Internationale pour l’Exploration Scientifique de la Mer Méditerranée, Monaco, pp. 1-142. 1973. Phylogenie des Ptéropodes Thécosomes d'apreés la structure de la coquille et la morphologie du manteau. Comptes Rendus d l’Academie Scientifique de Paris, vol. 77, pp. 1345-1348. 1974. Structure de la coquille des Ptéropodes au microscope a balayage. Rapports et Procés-Verbaux des Réunions, Commission Internationale pour l’Exploration Scienti- fique de la mer Mediterranée, vol. 22, No. 9, pp. 133, 134. 1975. Les Thécosomes (Mollusques pélagiques). Systématique et évolution, ecologie et biogéographie Méditerranées. Thése Doctorat d’Etat, Université de Provence, Marseille, 485 pp. Rang, P. K. S. L. 1827. Description de deux genres nouveaux (Cuvieria et Euribia) appartenant a la classe de Ptéropodes. Annales des Sci- | ences Naturelles, vol. 12, pp. 320-329, pl. 45. 1828. Notice sur quelques mollusques nouveaux apartenant au — genre Cleodore, et etablissement et monographie du sous- genre Creseis. Annales des Sciences Naturelles, vol. 13, pp. 302-319, pls. 17, 18. 1834. [title unknown]. Magasin de Zoologie, Lequien, Paris. Richter, G. 1976. Zur Frage der Verwandtschaftsbeziehungen von Limacin- idae und Cavolinidae (Pteropoda: Thecosomata). Archiv fir Molluskenkunde Frankfurt am Main, vol. 107, pp. 137-144. Rottman, M. L. 1980. Net tow and surface sediment distributions of pteropods in the South China Sea region: comparison and oceanograph- ic implications. Marine Micropaleontology, vol. 5, No. 1. pp. 71-110. Sarnthein, M. 1971. Oberflachensedimente im Persischen Golf und Golf von Oman. II. Quantitative Komponentenanalyse der Gross- fraction. “Meteor” Forschungs Ergebnisse. vol. C, No. 5, pp. 1-113. Schiemenz, P. 1906. Die Pteropoden der Plankton-Expedition. Ergebnisse der Nord-Atlantic Plankton-Expedition der Humboldtstif- tung, Kiel und Leipzig, vol. 2, pp. 1-37. Scott, A. J. 1963. Interpretation of Eocene depositional environments, Little Brazos River Valley, Texas. University of Texas Geolog- ical Society and Baylor Geological Society, Field trip guide book. 29 pp. Shimer, H. W., and Shrock, R. R. 1944. Index fossils of North America. New York and London, John Wiley and Sons, Inc., 837 pp., 303 pls. Spengel, J. W. 1881. Die Geruchsorgane und das Nervensystem der Mollusken. Zeitschrift fir wissenschaftlichen Zoologie, Leipzig, vol. 35, pp. 313-383, pls. 17-19. Spoel, S. van der 1967. Euthecosomata, a group with remarkable developmental stages (Gastropoda, Pteropoda). J. Noorduyn en Zoon. N. V., Gorinchem, 375 pp. 1972. Pteropoda. Thecosomata. Conseil International pour l’Ex- ploration de la Mer, Zooplankton Sheet 140-142, 12 pp. Spoel, S. van der, and Pierrot-Bults, A. C. [eds.] 1979. Zoogeography and diversity of plankton. Bunge Scientific Publishers, Utrecht, 410 pp. Squires, R. L. 1989. Pteropods (Mollusca: Gastropoda) from Tertiary forma- tions of Washington and Oregon. Journal of Paleontology, vol. 63, No. 4, p. 443-448, 2 figs. Stenzel, H. B. 1953. The geology of Henrys Chapel Quadrangle, northeastern Cherokee County, Texas. University of Texas Publication No. 5305, 119 pp. Stenzel, H. B, Krause, E. K., and Twining, J. T. 1957. Pelecypoda from the type locality of the Stone City Beds (Middle Eocene) of Texas. University of Texas Publication No. 5704, 237 pp., 22 pls. Stepien, J. C. 1980. The occurrence of chaetognaths, pteropods and euphausiids in relation to deep flow reversals in the Straits of Florida. Deep Sea Research, vol. 27, pp. 987-1011. NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 43 Stubbings, H. G. 1938. Pteropoda. The John Murray Expedition. 1933-1934. Sci- ence Reports, vol. 5, pp. 3-33. Sverdrup, H. U., Johnson, M. W., and Fleming, R. H. 1942. The oceans, their physics, chemistry, and general biology. Prentice-Hall, Englewood Cliffs, New Jersey, 1,087 pp. Tesch, J. J. 1904. The Thecosomata and Gymnosomata of the Siboga Ex- pedition. Siboga Report, vol. 52, pp. 1-92. 1913. Pteropoda in Das Tierreich, R. Friedlander and Sons, Ber- lin, vol. 36, pp. 1-154, 108 figs. 1946. The thecosomatous pteropods. I. The Atlantic. Dana Re- port, vol. 5, No. 28, pp. 1-82, pls. 1-8, text-figs. 1-34, Copenhagen, Denmark. 1948. The thecosomatous pteropods. II. The Indo-Pacific. Dana Report, vol. 5, No. 30, pp. 1-45. pls. 1-3, text-figs. 1-34, Copenhagen, Denmark. Toulmin, L. D. 1977. Stratigraphic distribution of Paleocene and Eocene fossils in the eastern Gulf Coast region. Geological Survey of Alabama Monograph 13, 601 pp. (vol. 1), 20 maps, charts, and tables (vol. 2). Vayssiere, A. 1915. Mollusques eupteropodes (ptéropodes thécosomes) proy- enant des campagnes des yachts Hirondelle et Princesse Alice (1885-1913). Resultats des Campagnes Scientifiques accomplies sur son yacht par Albert ler, Prince souverain de Monaco, vol. 47, pp. 3-226. Venables, E. M. 1963. The London Clay of Bognor Regis. Proceedings of the Geological Association of London, vol. 78, pp. 245-271. Watelet, A., and Lefevre, T. 1885. Note sur les pteropodes du genre Spirialis decouverts dans le Bassin de Paris. Société Royal de Malacologie Belgigue, vol. 15, pp. 100-103. Wenz, W. 1923. Zur Systematik tertiarer Land- und Stisswassergastropo- den. Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft Frankfurt-am-Main. vol. 7, pp. 116-117. Wormuth, J. H. 1981. Vertical distributions and diel migrations of Euthecoso- mata in the northwest Sargasso Sea. Deep-Sea Research, vol. 284, No. 12, pp. 1493-1515. Wrigley, A. G. 1934. Lutetian fauna at Southampton Docks. Proceedings of the Geological Society of London, vol. 45, pp. 1-16. Zilch, A. 1959. Handbuch der Palaozoologie. Band 6. Gastropoda. Teil 2, Lfg. 1. Euthyneura. Gebriider Borntrager, Berlin, 200 pp., 701 figs. PLATES Note: Specimens described as “‘lost”’ in the following plates were lost or destroyed during the preparation of scanning electron micrographs [SEM]. Some images were obtained using a light microscope [LM]. 44 12 shee 6-9. 10-15. BULLETIN 341 EXPLANATION OF PLATE | Page Altaspiratella: bearnensis (Curry; 1981) a ncs. ee ccccces.is din n8 0.0 testes e ese a ate Gioia ss aie eevee ehcuere «eke ousieleysle aie a eect are ee eee eee 13 Weches Formation. 1. Locality 8, hypotype (USNM 180480), apertural view, showing showing sinus at base of the aperture, x 33 [SEM]. 2. Locality 7, hypotype (USNM 360382) showing sinuous columella, x71 [SEM]. . Altaspiratella elongatoidea (AlGrICh), :<...... 0. <.<.s:sis.<0:3¢2, 5, s11dore-0/: 4 «0: aiayere ahoiae Breleis see eRe ee eee OS eee 14 Locality 1, Wilcox Group, Bashi Member. Holotype (USNM 638862), apertural view, x17 [LM]. : Altaspiratella gracilens Hodgkinson, NEW'SPECIES oo: . 1.0% 6 ste ase wine ay= wreeie ie ofa eels eintors RIS oore eters telelsyele cis loe Ts te ere eee 14 Weches Formation. 4. Locality 8, holotype (USNM 180481), apertural view, x27 [SEM]. 5. Locality 7, paratype (USNM 180482), apertural view, x29 [SEM]. Limacina adornata/ Hodgkinson, new Species: «<< -.-.-)-)2).-.00 0252 «See ciieiewis Hee sae eee eee eee Eee Eee ee EEE EEE Cee nnere 14 Locality 18, Cook Mountain Formation, Wheelock Member. 6-8. Holotype (USNM 180483). 6, apertural view, x 28 [SEM]; 7, dorsal view, x 33 [SEM]; 8, ventral view, x33 [SEM]. 9. Paratype (USNM 180484), apertural view, x41 [SEM]. Limacina aegis Hodgkinson; new Species: 2.<2.4,<.0:0)2 2:1 6 << ato es rs Ae eH eee sale Sera lee ee eee ae Ee eC IETS 15 10-12. Well locality 53 (2,940 ft), Eocene (cuttings). Holotype (USNM 180485). 10, apertural view, x 27 [SEM]; 11, dorsal view, x27 [SEM]; 12, ventral view, x27 [SEM]. 13-15. Well locality 45 (7,780 ft: recovered from cuttings in a Cretaceous interval, but probably from ‘“‘caved-in’’ Eocene sediments). Paratype (USNM 180486). 13, apertural view, x16 [SEM]; 14, dorsal view, x15 [SEM]; 15, ventral view, x16 [SEM]. ————— PLATE | BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 103 PLATE 2 BULLETINS OF AMERICAN PALEONTOLOGY, VOLUME 103 Figure 1-3. 8-10. 11-14. 15-18. . Limacina canadaensis Hodgkinson, new species . Limacina choctavensis (Aldrich) NorTH AMERICAN EOCENE PTEROPODS: HODGKINSON, GARVIE, AND BE 45 EXPLANATION OF PLATE 2 Limacina augustana Gardner Locality 5, Tallahatta Formation. Holotype (USNM 560589). 1. Apertural view, x 16 [LM]. 2. Dorsal view, x16 [LM]. 3. Ventral view, x15 [LM]. Well locality 49. Holotype (USNM 180487). 4. Apertural view, x38 [SEM]. 5. Dorsal view, x35 [SEM]. 6. Ventral view, x35 [SEM]. Locality 1, Wilcox Group, Hatchetigbee Formation, Bashi Member. Syntype (USNM 638860), apertural view, juvenile whorls missing, x18. Limacina convolutus Hodgkinson, new SpeCieS ...... 2.2.6... tne nnn teen e ete e eee e eee teens 16 Locality 12, Cook Mountain Formation, Wheelock Member. Holotype (USNM 180488). 8. Dorsal view, x51 [SEM]. 9. Ventral view, x54 [SEM]. 10. Apertural view, x51 [SEM]. Limacina davidi Hodgkinson, new specieS ......... 2-22 eee eee eee etn eee e nsec net e eect e sete eenee ence eens 17 Well locality 42, Wilcox Formation. Holotype (USNM 180489). 11. Dorsal view, x16 [LM]. 12. Apertural view, x17 [LM]. 13. Ventral view, x17 [LM]. 14. Apertural view, x 32 [SEM]. Limacina heatherae Hodgkinson, new Species: .......... 222.2 e ee nce tenet esc e nee erect ee entete se seesteeretenes 17 Well locality 42, Lower Wilcox Formation (cuttings). Holotype (USNM 180490). 15. Apertural view, x51 [SEM]. 16. Dorsal view, x 36 [LM]. 17. Apertural view, x 36 [LM]. 18. Ventral view, x 36 [LM]. 46 Figure 1-5. 6-8. 11-13. 14, 15. BULLETIN 341 EXPLANATION OF PLATE 3 Limacina helikos Hodgkinson; new: species) <. .«.c:csera.5 016 = Golliers Renny srccse.ctvecesssese ce weceess torte sccaree eee eee eT Gollins {1193 4) tetera eee GColoradoiRiven?.cccc..s1eses eesene eee columnella, Cuvierina GConradi (1833) gestae serceteeee eee Gonradi(USGS)) seccec cst ee awoke ohare neat sence ane aes ORO Conrad (US GG) Rese eccec cher as eres ca teeee ae oeReee oe eee eee Conus (Lithoconus) sauridens Conrad, 1833 ........0...0.0cc0ec0eeeee 7 CONVOLULUS TETINACITIA eos se stene sue senesneseoeeee Dies Rooke. GoW thes :esccccciss sesso cee a eae a caes eee ee 27 corpulenta, GaecUum (MCIOCENAS) ocd ccc sarce nie tees s obec A enaete ence 26 (Gleodoral( Greseis)ctaccssk ese vec eee ee 26 GHIGN(Gresets)ie cc eceoreh oh ce ocean a ee 26 CU OSCIS ee chvsa sc cos ceaaetesyanetTaeei ws eat este SUV OL! si cecsnez eaecex sector eee Cossmann (1893) »24, Gossmann (912) nice tcccascaces cae actencwon cued nee este ester ee 24-26 Cossmann (1913) (COSSINANNI SKADLONON sae. merere steer eee 23 Cox (1960) Creseis Rang, 1828 aciculaRang 828) sae. cc-scncssessesueseeee ee 7,28 corpulenta (Meyer, 1887) 7,10,26,27 cylindrica Hodgkinson, n. sp. ............... Soe: 5,10,27,32,35 elbaideiGregoro, 1890). c.ccsecsccecseosanesececee eee ee 6,7 hastata (Meyer, 1886) .................+ OM ed 7,10,24,26,27,28 spch | Ga hastatai(Meyers 1'886)) seecsssetescecceee ee eee 7,28 nimbas de Gregorio’ l'890) 2.ccorescecc reece ote soe eee 6,7 simplex (Meyer, 1886) ..................- One 7,10-12,25,28,29 SPA nes ae es see nace Maen oet ee ese Renn ae ee A Ree 5,28,29 sp: of Aldrich (1'895))\ <2.cst..cc-cessoeeseeete nee 28 SPD eect aoe: virgula Rang, 1828 cretacea, Praehyalocylis @rockett Formation. :. 2: :c.sc:c0s-cossstesce soe one soe ee Stone:Gity Member <.. 2: :s.~ 1 ae 5,10,14,18 ira ya (USA O) eset sees coves cacnaeecn sce cochderen sats vocaneot sees set scaseaeseeee 31 UGTA (USAT) Wee cred. oes ceases oe o esa eee ase e a cates SEE RY 6,12,13 CGray A (USS 0) ee see ce see seca aes ccc ore oe cee esses Paber enc ceee nee ese ee 6,12,24 exGregorios (S90) ere ce oe esese thes = cote obs cance revee eae eae 6,22,27 de Gregorio Collection [University of Palermo, Palermo, Sicily, tall yi) Steet cerca ace ces ccna ce sates Se cec ete toe vac os tlemnsaa tenn cctemonectee’s 7 RGrITIN PE Cie bce ses ce ree coaeni oe atic we eee oe eee nee eUR ee ee Te 11 CGO FLO LMI CKICON a, Sec nec asics tree CMe coo we ROC N Caer SEES One RRO NS 5 PULL GUVICTINGN I Mace ccacs seocte sae teneesascaeireneeesee 1 eee 5,10,32 lneveo by (Gee) DS ORFS) eae ecespohaccacenacan esses concede unee RessBoundocaaane 22 EPATIISS Grd A (1899) ieee aneeetcaeee esc tace nosenoceeceen cost tnene ae 14,16 Harris, G: D:, and Palmer (1946-1947) .......:.2.0:ecsses.s+-00. 24-28 Lari SCT ME: V8 94 eee ane tessa seeeeecaairaset es ooantcienuntchece cose? 32 hastata, God Or ai Greseis) Passer rerio EO 27 ELION(GEreSeis) Panacea sos men cae ne eae tenon aoe nao e ee 27 CLOSES Mr eee eee eee een ces Oyen 7,10,24,26,27,28 ISVOWHCIIO® cathe anne es POR COCR CACC ER ECER a eter are acor Ree roe eae et acancnce 27 hastata (cf.), GlCOd OFA Gresels) aocsesics scene ta eee e ee Re 28 GL OSCIS) 2c coaSckiae tae Shanes Sova ed dee tedeaWaisicevesncewasaceentaawreaeeee 7,28 NEQUEr Ae MIINACING accuses cess ore eee Dc thes 5,10,17 NELICINGMICIIMACING, cx.staserescascesad ve cone eri seeete coon ee ate e 14,21 helicOides; TEMACING Seas occae sco ete oke SOM Se OR OE e one ener 6 helikos, Limacina Henderson (1935) Herman (1971) 6 Herman (1973) 6 Herman (1978) 6 Herman and Rosenberg (1969) 9 Hodgkinsoni(li974)) Sf ieccsccewses oscecea ctescooneecre. ta caceace tas Oncseeneers 6 Hodgkinson; /Erlene) ..<..c2<:s00j.c0.c0evessecsne toners ener e es eraaeeeeee 11 Homalaxis'spyoBurtoni(li933))casecsceusectesce te sseeeeseeteasece eee 22 FROOVEDMPetemiRe sasascacsecicavctesedondeusspecceaeateaduade mmueanataneese eee 11 FLUTTICANE BAY Olly ceceseasewac tosses seswaise acetone snc ces earn cet eee ene 38 FA yalocplisueol Si Si esnsseccesee seo see cea se eetseaceseceateee 6,12,24,29,30 SPA See rec ake: ar aha yseesec Sees eee are 9). 5,10,12,29 istriata(Rangei828)) casos scencsnetecesesece- tered sense ener ene eee 29,30 Indian Ocean iiisecccc cca ceec sca cusscdenc state desea covessdoversscesosseoteese 5,6 inflata, GQUvleninassniedicocsene vanes sass Poesia a se seawedeeauseces caaea usta demesonenteenns 33 9 [tally sceeeu oe. dest 0sotievas sete sa esowiaectonwaetenaesatouces deouan cesseuls deo soeeere 33 JACKSONUGIOUP Masees des sew core coc evacedesovosekasenoevesuk weeen Coe eeane ees Janssen G90)k eketsncestoncc tease ecsewaee asecd echeeos cate ecaenee teres Janssen and King (1988) .... on = ite ¥ Teftreysi@l S69) ees scoct saree ons caso re ee aera a onac ater Jefireysi (87:7) hx.csseesuesecvosde owns woke cases sae ceonoeeantewedaseesdeeeense Jung (UOT 3) Ae. 9. a eesesse we awteispoceeu seaweeeucne sue nenses seaeae es cuswee force set Neen Ql GFA) ds.ccecs te seccsaeaunecedete sccdssnaseeaeenveursdossrtasere Knight; Mr-de Misi Jim 75. .0.-0-.