ae = palicncmer. Watareherabeper ate letne ramp pas “ Path ela Cet on thn FE BH pd . Set Pin ete aie oir 4p 1 ean eX POMONA OES POE pepiiegeethiy eee 40 - HARVARD UNIVERSITY Lis LIBRARY OF THE Museum of Comparative Zoology : The Library Museum of Comparative Zoology ~. Harvard University DEEL EINS OF AMERICAN PAL eCIN MOBIC Ne * WOE. JEN IU * 1970 - 1971 MUS. COMP. ZOOL. LIBRARY FEB 16 1971 HARVARD UNIVERSITY IN MEMORIAM THERON WaASSON 1887-1970 Sremon W. MULLER 1900-1970 E. LAURENCE PALMER 1888-1970 CONTENTS OF VOLUME LVIII Bulletin No. Pages 257. The Reotaformidae, a New Family of Upper Cretaceous Nessellariina (Radiolaria) from the Great Valley Sequence, California Coast Ranges. By Emile A. Pessagno, Jr. , 1-34 258. Analysis of Some American Upper Cretaceous Larger Foraminifera. By W. Storrs Cole and Esther R. Applin 35-80 259. Silicoflagellates from Central North Pacific Core Sediments. By Hsin-Yi Ling 81-120 260. Revision cf the North American Pleurocysti- tidae (Rhombifera-Cystoidea). By Ronald ly Parsley” ....2:...0:..:0.- 131-213 261. Morphology and Taxonomy of Cyclonema Hall (Gastropoda) Upper Ordovician, Cincinnatian Province. By Esther H. Thompson _..... 214-284 262. New Vasum Species of the Subgenus Hystri- vasum. By S. C. Hollister 285-304 Plates 1-9 10-17 18-20 21-30 31-35 36-39 INDEX No separate index is included in the volume. Each number is indexed separately. Contents of the volume are listed in the begin- ning of the volume. er MUS. COMP. ZOOL. LIBRARY JUL 6 1970 BULLETINS = enversir OF AMERICAN PALEONTOLOGY Vol. 58 No. 257 \ THE ROTAFORMIDAE, A NEW FAMILY OF UPPER ™. CRETACEOUS NASSELLARIINA (RADIOLARIA) FROM THE GREAT VALLEY SEQUENCE, CALIFORNIA COAST RANGES By EMILE A. PESSAGNO, JR. 1970 Paleontological Research Institv * Ithaca, New York Wemsueae PALEONTOLOGICAL RESEARCH INSTITUTION 1969 - 1970 PRESIDENT cc 8 eo ee Dace ecacas ieee ee ee WILLIAM B. HEROY VICE 1970 Paleontological Research Institution Ithaca, New York Wis GS Ae Library of Congress Card Number: 72-120354 Printed in the United States of America Arnold Printing Company CONTENTS Page AND EREPEU CE eT EN oe en ee ee 5 ra tary dr 6110 ra eee hate we cece k Oe tee Meee er ES ee, Seca aoe ct eevee cece e ees ea sess rasa 5 ENGL AIBC ER TGCS 25 eR ace ee ee ee 5 BTM estar OO oye eee ees ome eet 9h E a Be oeucnes a endnote orl Cree St ents esses 7 Wrethodmotestidyaetns .< eae mek wwe 6. omen ON Rupe eee ee Lele eee Se Ob Pod 8 Mo callityend ESCrAptlOl sie. ese ee ens ee eee ee ce ee eer See Be 8 Wing Hes tall caer tO Tame ted S Srey Coal tan CoN pes cree a cee oe eee ene a eee 11 Systematicmed esGniptiOnsye ees ceo. ee Ua ee a eee ee 11 FER U iy aR Ce eANA CO TTT Clea year Ach TN Ses ae ene ed eee 13 (Gremursye OL f.O 1-710 ca am nV © ET eee ne ecn eeee e e 15 (GeEMUseS QL Ut OMIT G:, OU ne SOM) ees ce eee en eee ee WA 1 PCE RFRN OV GL SS) UE a A a el ee 20 TEMAS) | zsbakes ee en Me leh A ale ie ek pe ie PaaS n eh ee eee: 23 x > Sans = «jt e =< a : . | . = Areata ' : S _ « ; ; ee ¥ nt 44, oa | 1) eine je ~ : : '} Pw a Si bars a § piap’ ; tts ad ——a| wee 7 THE ROTAFORMIDAE, A NEW FAMILY OF UPPER CRETACEOUS NASSELLARIINA (RADIOLARIA) FROM TA SGREAT VALLEY SEQUENCE, CALIFORNIA COAST RANGES EMILE A. PESSAGNO, JR. ABSTRACT The Rotaformidae Pessagno, n. fam., are a bizarre group of dicyrtid Nassellariina with cartwheel-shaped tests and nine cephalic skeletal elements identical to those of the Neosciadiocapsidae Pessagno. It is postulated that the Neosciadiocapsidae gave rise to the Rotaformidae through (1) the rotation of the cephalis and upper thorax into the plane of the thoracic skirt and (2) the loss of the thoracic skirt and the subsequent development of a thoracic ring. Two new genera and seven new species of Rotaformidae are described from the Upper Cretaceous portion of the Great Valley Sequence, California Coast Ranges. INTRODUCTION This is the second (first, Pessagno, 1969b) in a series of re- ports dealing with the Upper Cretaceous Radiolaria of the Great Valley Sequence, California Coast Ranges (Text-figure 1). Sam- ples collected from the Upper Cretaceous portion of the Great Valley Sequence contain a rich, endlessly diverse radiolarian as- semblage which is for the most part undescribed. It is apparent from the writer’s investigations of the California Upper Cretaceous as well as those during JOIDES Leg I that Radio- laria can serve as useful biostratigraphic indices not only to the geologist interested in unravelling the complex stratigraphy of orogenic belts such as the Cordilleran Mobile Belt, but also to the oceanographer attempting to interpret the stratigraphy of the oceanic crust. The Rotaformidae Pessagno, n. fam., like the Neo- sciadiocapsidae Pessagno, is one of the numerous families of Mesozoic Radiolaria that show great potential for developing de- tailed systems of zonation. ACKNOWLEDGMENTS This work was supported by grants from the National Science Foundation: GP—4043 to the University of California, Davis, California, and GP—1224 to the Southwest Center for Advanced Studies, Dallas, Texas, and by the general NASA grant (NGL—44- 004-001) to the Southwest Center for Advanced Studies. The writer wishes to thank Mr. Verne Harlan for his assistance in the field; to Mr. Walter Brown and Mrs. Sheila Moiola for their care in taking the scanning electron micrographs and preparing the il- lustrations; and to Miss Maria Bilelo for her help in the laboratory. Numerous megafossils were kindly identified for the writer by Dr. David L. Jones, Paleontology and Stratigraphy Branch, U.S. Geo- logical Survey, Menlo Park, California. Contribution No. 115 Geosciences Division, University of Texas at Dallas, P. O. Box 30365, Dallas, Texas 75230 95 6 BULLETIN 257 TERTIARY- QUATERNARY [V3] TERTIARY SEDIMENTS VOLCANICS GREAT FRANCISCAN JURASSIC - VALLEY “5,5 CRETACEOUS | ROCKS vev| CRE SEQUENCE PLUTONICS (J-UK) NEVADIAN METAMORPHICS TEXT - FIGURE 1: INDEX MAP. After Ojakangas, 1968, p.975 CRETACEOUS RADIOLARIA: PESSAGNO ~I TERMINOLOGY 1. Cephalic skeletal elements. As with Neosciadiocapsidae Pessagno. Include apical bar, vertical bar, median bar, dorsal bar, primary right lateral bar, primary left lateral bar, secondary right lateral bar, secondary left lateral bar, and axial spine. Use of terms bar and spine conform to Goll (1968, p. 1413). (See Pl. 2, figs. 1, 2; Pl. 4, fig. 4A-B.) 2. Anterior. Side of test corresponding to juncture of dorsal bar with cephalic wall. 3. Posterior. Side of test corresponding to juncture of vertical bar with cephalic wall. 4. Right and left. Defined in the sense of Goll (1968, p. 1413). With specimens viewed from anterior end (“front”) —“the right side and left side are the same as the viewer’s right side and left side.” 5. Radius (i).* Rodlike structure (s) connecting thorax or central cephalo-thoracic body with thoracic ring. Radii in Saturniforma possess canals that connect thorax with thoracic ring. (See Pl. 1, fie. 1). a. Oral radii.* Radii situated to either side of thoracic mouth. b. Aboral radii.* Remainder of radii exclusive of oral radii. (Seer PIS Ih fig> I-) 6. Thoracic ring.* Ring structure connected to thorax by radii. (SeerPl> Ietig.-1.) 7. Thoracic fringe.* Coarse polygonal meshwork on the margin of the thoracic ring. Only known on Rotaforma, n. gen. (See Pl. 1, fig. 1.) 8. Interradial area.* Space framed by two given radii, thoracic ring, andy thorax: “(See Pl) fie. 1) 9. Apical in direction. Toward cephalis. 10. Abapical in direction. Away from cephalis. Toward thoracic mouth. 11. Porta(ae). Paired large round to elliptical openings situated be- tween aboral radii. Porta (Latin, F.) = gate or door. (See PI. 5, figss 2,3.) 12. Pseudoporta(ae).* Large pores situated at juncture of radii with thorax. Not situated between radii as in case of portae. Only occurring with Rotaforma, n. gen. (See Pl. 1, fig. 3.) 8 BULLETIN 257 9 13. Cephalo-thoracic body.* Principal portion of test exclusive of radii and thoracic ring. 14. Cephalopyle. Tubular structure occurring at base of cephalis at point of juncture of vertical bar with cephalic wall: «(See Bla 3; fig. 2.) * — new term. METHOD OF STUDY During the course of this investigation a JSM-1 scanning elec- tron microscope equipped with a goniometer stage was used as the primary means of illustrating and studying rotaformid mor- phology (cf. Honjo and Berggren, 1967, pp. 393-404, pls. 1-4; Hay and Sandberg, 1967, pp. 407-418, pls. 1, 2). Specimens under study were shadow casted with gold palladium for SEM analysis. It has been found that gold palladium can be removed from specimens in a matter of seconds with a drop of aqua regia. Once this is done specimens can be mounted in hyrax or other suitable mounting media for optical analysis with transmitted light. The number of air bubbles in the mounting medium or for that matter in the speci- mens can be appreciably reduced by degasing the hyrax under vacuum. LOCALITY DESCRIPTIONS All from California NSF 291-B. Yolo Formation [upper part of type Yolo at Cache Creek, (north bank) Yolo County]. Limestone nodules interbedded with dark gray calcareous mudstones and siltstones; 140 feet below the contact of the Yolo Formation with the overlying Sites Forma- tion. USGS Glascock Mountain Quad. (7.5’); T12N; R4W; Sec- tion 2; 0.15 miles downstream from northwest end of Rt. 16 bridge over Cache Creek. An ammonite collected from this locality by the writer and identified by D. L. Jones (USGS, Menlo Park, Calif.) as “Kossmaticeras aff. K. japonicum” indicates (fide Jones) that NSF 291-B is Coniacian in age. NSF 350, Limestone nodules from the lower portion of the “Ante- lope Shale’’/“Fiske Creek Formation” cropping out along the north bank of Cache Creek, Yolo County, California. USGS Glascock Mountain Quad. (7.5’); T12N; R4W; Section 4; 0.13 miles $35°W of Rayhouse Road crossing of Cache Creek at “Low Water Bridge’. CRETACEOUS RADIOLARIA: PESSAGNO 9 NSF 350 occurs 542 feet above a horizon containing common Prae- globotruncana stephani (Gandolfi) and 658 feet below beds con- taining Rotalipora greenhornensis (Morrow) and Rotalipora ap- penninica (O. Renz). NSF 350 likewise occurs 1,047 feet below beds containing Calycoceras sp. (late Cenomanian form) , Rotali- pora cushmani (Morrow) , Rotalipora appenninica (O. Renz), and Hedbergella brittonensis Loeblich and Tappan. (Planktonic fora- miniferal identifications are the writer’s; ammonite identification by D. L. Jones, U.S. Geological Survey, Menlo Park, California.) The planktonic foraminiferal data indicate that NSF 350 is definite- ly of Cenomanian age. In that NSF 350 appears to occur below the R. cushmani (Morrow) datum point (first appearance) it is most likely correlative with the Rotalipora evoluta Subzone of Pessagno, 1967, 1969a. Data presented by Renz, Luterbacher, and Schneider (1963, 1073-1116) indicate that R. cushmani makes its first appearance within the upper part of the Mantelliceras man- telli Zone (early Cenomanian) of the Neuenburger Jura. NSF 405. Limestone nodules from the late Cenomanian portion of “Antelope Shale’ /“Fiske Creek Formation”; 0.6 miles southwest of Monticello Dam on Route 128; USGS Monticello Dam Quad. (7.5’). T8N; R2W; Section 29, Napa County, California. Am- monites identified for the writer from this locality by D. L. Jones (U.S. Geol. Survey, Menlo Park, Calif.) include Acanthoceras sp. and Puzosia sp. A preliminary report by Jones indicated that the ammonites are of late Cenomanian age. NSF 498-B. “Antelope Shale’’/‘Fiske Creek Formation’. Limestone nodules associated with gray siltstones, mudstones, and sandstones. USGS Monticello Dam Quad. (7.5’). T8N; R2W; Section 29, Napa County, California; 0.31 miles southwest of NSF 405 on Rt. 128; locality occurs along strike with respect to NSF 405. See megafossil data presented for NSF 405. NSF 568-B. “Marsh Creek Formation”. Samples from limestone nodules interbedded with dark gray siliceous to calcareous mud- stones. Antioch South Quad. (7.5’). TIN; R2E; Sect. 32 South bank of Marsh Creek, Deer Valley Road Crossing of Marsh Creek, Con- tra Costa County, California. NSF 568-B by bridge. Associated planktonic Foraminifera present at this horizon include Globo- 207 LLETIN Bu 0 l ees) = =a ae ee cS Se5) ees eee PE eee ees @€-89S 4iSN upiupbdwp7 $S94D| slg 49949 Yss0W,, -V1lidod JAILV 1494 “Apnys uDIDDIUO x SIONVA sapun ji!4s sajdwos Aupw ‘sajdwos jo iaquinu a- 16@ 4SN payiwiy 2, uDiuDWOUa> w4S 1SVOD edojajuy, wy 4921 ays, VINYOSITVD NYFHLYON JDNANOAS AAITIVA LVAYD JO NOILYOd SNOID Ydddn QNV Ni 3avVaiIwaod JINAYINIIO vlo¥ JO JDNVGNNSV Gy coal Nab eon D ‘suawideds ¢-¢ jo siskjpup ‘ds -u ‘puiiBasad ‘ds‘u ‘puoio> ‘ds ‘u ‘winijsajapo ‘ds ‘u ‘sisuasauoliq ‘ds -u ‘winijspqp ‘ds ‘u ‘ds-‘u *suawioads a10W 410 9 ‘stjiqpaiw “issay Aipuiwijaid Dp uo pasng DWIOJIUIN}DS DWJIOJIUIN}DS DWIOJIUINJDS DWJOJIUINYDS DWJIOJIUINYDS DWJOJDJOY DWJOJDJOY :yuDpuNngYy uoWWO CRETACEOUS RADIOLARIA: PESSAGNO 11 truncana churchi Martin, Globotruncana arca (Cushman) and Gublerina ornatissima (Cushman and Church). Biostratigraphic data from the Putah Creek, Pleasants Valley, and Tesla areas indi- cate that the radiolarian assemblage present at NSF 568-B is as- signable to the upper part of the G. calcarata Zonule of Pessagno (1967, 1969a) . CRITERIA FOR CLASSIFICATION (See ‘Text-figure 3) The multiple criteria used for the classification of the Rota- formidae are summarized in Text-figure 3. The relative importance of most of these criteria is difficult to assess at the present time. Most investigators who have studied “Cyrtoid’” Nassellariina in recent years [e.g., Foreman (1968); Goll (1968); Pessagno (1969b) ; Petrushevskaya (1964, 1965); and Riedel (1958; 1967; ms.] have stressed cephalic structure and in particular the struc- ture of the cephalic skeletal elements in classification. It is gen- erally agreed that an emphasis on cephalic skeletal structure will lead to a more phylogenetic classification — a classification which in all probability will transgress Haeckelian classification. Riedel’s (1967 and ms.) recent classification is an excellent example of a more phylogenetic classification based on this criterion. As noted by Pessagno (1969b) , cephalic structure is likely to be more useful in classification at the superfamily level than at the family level. The investigator’s study of the Neosciadiocapsidae (Pessagno, ibid.) together with his study of the Rotaformidae, n. fam., indicates that both families possess identical cephalic skeletal elements and hence, should be placed within the same superfamily. SYSTEMATIC DESCRIPTIONS Phylum PROTOZOA Subphylum SARCODINA Class ACTINOPODEA Subclass RADIOLARIA Order POLYCYSTIDA Remarks. — Riedel (1967, p. 291) emended the Polycystida Ehrenberg to include only those Radiolaria having a skeleton com- prised of opaline silica and lacking admixed organic compounds. BULLETIN 257 9 | ‘Buis 21201044 JO UOly “Buls 21901044 —Djuawoujo pun edous puod !!ipos ul sjouns JO @2U9SQD 10 e2UaesSaig "$0910 =|DIpossaju yO adpoys pun saquinn ‘yynow D12DIOYZ YO 494901045 “Buis 21301044 yo a@Bulsy uo saiod jo ‘aBulsy = 1901044 adoys pun uodljnqgisysig yO @2UaSqGD 10 aduUasald “Buls = d19010Y4 ‘Apoq 21901044 ‘apyiod PUBS HPO Pos sues ed -ojpyde> uo saiod jo JO @2UasqD 10 aduasaild adoys pud uoljyngisssig ‘S4aquDYyds jo JequNnn "(| DIIAeA "uolyIaS 40 |DdIdD) susoy Asowiid ‘(adoys jaeyM4ssidd ssO12 ul tIpds yo ednys yO @2UesSqd 10 a@DUeseld “B:ea) 48a, yo Asjpowoasd ‘ajAdojnyded ‘SJUSWA/a |D4a/aS ‘1IpDs yo sequinw yO @2UaSQGD 10 aUaesaig 21jDyda> jo 4a;IDIDYD 13A41 DidID3dS 13A41 olden VSIA) A Wived “QOPIWAOJOJOY FO UOlPODIFISSO]2 4O¥ Klayig :€ IWYNOI4-1X3IL CRETACEOUS RADIOLARIA: PESSAGNO 13 Suborder NASSELLARIINA Family ROTAFORMIDAE Pessagno, n. fam. Type genus. — Rotaforma Pessagno, n. gen. Description. — Dicyrtid, cartwheel-shaped Nassellariina with nine cephalic skeletal elements (vertical bar, primary right lateral bar, primary left lateral bar, median bar, axial spine, secondary right lateral bar, secondary left lateral bar, dorsal bar, and apical bar) dividing base of cephalis into six collar pores (PI. 2, figs. 1, 2). All cephalic skeletal bars trifurcating at juncture with wall of cephalis. Median bar almost normal to plane of thoracic ring. Central portion of test comprising cephalis and part of thorax con- nected by radii to circular or subcircular thoracic ring. Remarks. The Rotaformidae, n. fam., are undoubtedly one of the most bizarre groups of Nassellariina either in the Mesozoic or Cenozoic. Their peculiar cartwheel-shaped tests are unlike those of any other “Cyrtoid” nassellariinid family group. In spite of the unusual shape and symmetry of the rotaformid test, it can be established that the Rotaformidae are closely related to the Neosciadiocapsidae Pessagno. Both families display the same type and number of cephalic skeletal elements and collar pores. The cephalic skeletal bars of the Rotaformidae like those of the Neosciadiocapsidae trifurcate at their point of juncture with the wall of the cephalis. The data at hand suggest that the Rota- formidae evolved from the Neosciadiocapsidae (1) by the rotation of the cephalis and upper portion of the thorax nearly into the plane of the thoracic skirt and (2) by the loss of the thoracic skirt and the development of a thoracic ring (Text-figure 4) . Neosciadiocapsidae showing strong rotation of the cephalis and the proximal part of the thorax towards the plane of the thor- acic skirt are common in the Cenomanian (PI. 8, figs. 1-4; compare Pl. 8, fig. 1, with Pl. 3, fig. 3). It is likewise possible in Cenomanian strata to observe neosciadiocapsids displaying a tendency to lose their thoracic skirts and to develop thoracic rings with intercon- necting radii (Pl. 8, figs. 5, 6). These latter forms, however, seem to show little rotation of the cephalis and proximal portion of the thorax towards the plane of the thoracic ring. With the rotation of the cephalis and proximal portion of the thorax into plane (or near- 14 BULLETIN 257 CAMPANIAN > Rotaformidae Neosciadiocapsidae SANTONIAN GRETAGCEOQUS VIPIPEIR TURONIAN CENOMAN- IAN pe ° ALBIAN — Text-figure #.—Diagram depicting phylogenetic relationship of Neo- sciadiocapsidae and Rotaformidae and probable phylogenetic relationship of rotaformid genera. Swelling of life line indicates times of greatest abundance, diversity, and speciation; life line of Rotaformidae exaggerated by 3X to allow space to show relationship of Rotaforma to Saturniforma. Hypothetical ancestor linking Neosciadiocapsidae and Rotaformidae depicts a form having thoracic ring and thoracic fringe and partial rotation of cephalis and upper thorax toward plane of thoracic ring. hypothetical ancestral. form CRETACEOUS RADIOLARIA: PESSAGNO 15 ly so) of the thoracic ring, the median bar of the rotaformid test is situated approximately at right angles to the plane of the thor- acic ring. With most Neosciadiocapsidae the median bar is parallel to the plane of the thoracic skirt. Although the precise time that the Neosciadiocapsidae gave rise to the Rotaformidae is not docu- mented at present, it is probable that this evolutionary event oc- curred during the Albian or the early Cenomanian (Text-figure 4). Rotaforma, n. gen., is regarded as the most primitive genus of Rotaformidae. Unlike Saturniforma, n. gen., it still shows a cepha- lopyle and a rudimentary apical horn (PI. 3, figs. 2, 5, 6), and coarse polygonal meshwork on portions of its thorax (PI. 1, fig. 6). It is likely that Rotaforma gave rise to Saturniforma, n. gen, through the loss of the cephalopyle and apical horn, reduction in the size of the thoracic mouth and the cephalis, by the addition of portae between each of the secondary radii, and by the addition of canals in the radii and thoracic ring. Range. —Cenomanian to latest Campanian. Range zone may extend into Albian. Albian not extensively sampled during this study. Occurrence. — Great Valley Sequence of the California Coast Ranges. Genus ROTAFORMA Pessagno, n. gen. Type species. — Rotaforma mirabilis Pessagno, n. sp. Description. — Test microgranular, dicyrtid, wheel-shaped. Cephalis small, hemispherical with rudimentary apical horn. Prominent cephalopyle situated posteriorly (PI. 3, fig. 2). Cephalic skeletal elements and collar pores as for family. Thorax large, gross- ly funnel-shaped; inflated anteriorly; flaring in an abapical direc- tion to form a tunnel-like structure (PI. 1, figs. 2, 4); flattened posteriorly. Epithecal layer extending from cephalis onto thorax, masking medium-sized polygonal pore frames of thorax (PI. 1, fig. 6). Thoracic ring attached by radii to posterior margin of thorax. Radii and thoracic ring lack central canals (PI. 9, figs. 1, 2) . Pseudo- portae situated at juncture of radii with thorax. Thoracic ring on well-preserved specimens with thoracic fringe of coarsely polygonal meshwork. Remarks. — Rotaforma Pessagno, n. gen., differs from Saturni- forma Pessagno, n. gen., by possessing a cephalopyle, an apical horn, 16 BULLETIN 257 a large, distinct thoracic mouth, a thoracic fringe, by lacking portae, and central canals. Rota (Latin, F.) = a wheel + forma (Latin, F.) = form, shape. Range.— Early to late Cenomanian. Range may extend into Albian. Albian not extensively sampled during the course of this investigation. Occurrence. — Great Valley Sequence, California Coast Ranges. Rotaforma hessi Pessagno, n. sp. Pl. 3, figs. 4-6; Pl. 4 figs. 1-4 Description. — As with genus except as follows: Cephalis pro- jecting in an apical direction always between two aboral radii (PI. 3, figs. 4-6). Collar structure moderately well developed. Radii six in number; triradiate in cross section. ‘Thoracic fringe relatively wide; better developed abapically than apically. Pore frames sub- rectangular to elliptical. Remarks. — R. hessi, n. sp., differs from R. mirabilis, n. sp., by having six rather than seven radii; by having radii which are proportionately shorter and triradiate in cross-section; by having a wider thoracic fringe. In addition, the cephalis of R. hesst always projects between two aboral radii whereas that of R. mirabilis oc- curs directly over an aboral radius. This species is named for the late Dr. Harry H. Hess, Depart- ment of Geology, Princeton University, in honor of his many con- tributions to geology and oceanography. Type locality. — NSF 350. See Locality Descriptions. Deposition of types. — Holotype = USNM 165478; paratypes — USNM 165479 — 165480 and Pessagno Collection, University of Texas at Dallas. Range. — Early to late Cenomanian. Range may extend to Al- bian. Albian not extensively sampled during present study. Occurrence. — See Text-figure 2 and Locality Descriptions. Rotaforma mirabilis Pessagno, n. sp. Pl. 1, figs. 1-6; Pl. 2, figs. 1,2; Pl. 3, figs. 1-3; Pl.9; figss2 Description. — As with genus, with the following exceptions: Cephalis projecting directly over an aboral radius. Collar stricture moderately well developed. Radii seven in number, quadraradiate in cross-section with four furrows situated between four ridges. Fringe on thoracic ring comprised of elliptical to subcircular pore CRETACEOUS RADIOLARIA: PESSAGNO 17 frames; thoracic fringe better developed abapically than apically. Remarks. — Rotaforma mirabilis, n. sp., differs from R. hessz, n. sp. by having seven quadraradiate rather than six triradiate radii; by having a narrower thoracic fringe; and by having a cepha- lis which projects over one of the aboral radii. Mirabilis (Latin, F. or M.) = unusual or extraordinary. Type locality. — NSF 350. See Locality Descriptions. Deposition of types. — Holotype = USNM 165481. Paratypes — USNM 165482 — 165484 and Pessagno Collection, University of Texas at Dallas. Range. — Early to late Cenomanian. Range may extend to Al- bian. Occurrence. — See Text-figure 2 and Locality Descriptions. Genus SATURNIFORMA Pessagno, n. gen. Type species. — Saturniforma caelestium Pessagno, n. sp. Description. — Test microgranular, dicyrtid, wheel-shaped. Cephalis small, indistinct; lacking cephalopyle and apical horn; col- lar stricture absent. Cephalic skeletal elements as with family; usual- ly difficult to see in their entirety. Cephalo-thoracic body large disclike mass, more convex anteriorly than posteriorly, connected to thoracic ring by variable number of radii; oral radii flanking small thoracic mouth (PI. 5, fig. 5). Two portae situated between each of aboral radii (PI. 6, fig. 1). Thorax perforate; distribution and number of pores varying with species; pores usually circular. Thoracic ring attached by radii near posterior margin of thorax. Thoracic ring smooth to spinose lacking thoracic fringe. Remarks. — Saturniforma Pessagno, n. gen., differs from Rota- forma Pessagno, n. gen., by lacking a cephalopyle and an apical horn; by having a smaller, less distinct thoracic mouth, a disclike cephalo-thoracic central body, central canals in its radii and thor- acic ring, and two circular to elliptical portae between each of the aboral radii. Saturniforma most likely arose from Rotaforma (1) through the reduction in the size of the cephalis; (2) through the reduction in the size of the thoracic mouth; (3) through the loss of a cephalopyle and apical horn; (4) by the addition of portae between aboral radii, by the addition of canals in its radii and thoracic rings, and (6) through the loss of a thoracic fringe. The precise time of this evolutionary event cannot be documented at 18 BULLETIN 257 present. However, it probably occurred during Albian or early Cenomanian times (cf. Text-figure 4). Saturnus (Latin, M.) = planet Saturn + forma (Latin, F.) = shape, form. Range. — Early Cenomanian to latest Campanian. Range may extend into Albian. Albian not extensively sampled during this study. Occurrence. — Great Valley Sequence, California Coast Ranges. Saturniforma abastrum Pessagno, n. sp. Pl. 5, figs. 1-4 Description. —Test as with genus; having ten short, massive radii, a circular thoracic ring with a spinose perimeter, and a double row of prominent rounded pores encircling the periphery of the cephalo-thoracic body both anteriorly and posteriorly. Remarks.—S. abastrum, n. sp., differs from S. caelestiwm, n. sp., by having a spinose rather than smooth thoracic ring; by having ten rather than nine radii; by having shorter radii; and by having smaller interradial areas. ab (Latin, prep.) = from + astrum (Latin, N.) = a constella- tion, a star. Type locality. — NSF 291-B. See locality Descriptions. Deposition of types. — Holotype = USNM 165485. Paratypes — USNM_ 165486 — 165488, and Pessagno Collection, University of Texas at Dallas. Range and occurrence.—‘Yo date this species has only been found at its type locality in strata of Coniacian age. See Text-figure 2 and Locality Descriptions. Saturniforma brionesensis Pessagno, n. sp. IPI (35 sales, (99 IRL, |7/, aie, il Description. —'Test as with genus, but having ten short radii, a smooth, circular thoracic ring, and prominent circular pores evenly distributed anteriorly and posteriorly over all of the cephalo- thoracic body. Remarks. —S. brionesensis, n. sp., appears closely related to S. caelestium, n. sp. It can be distinguished from the latter species by possessing ten rather than nine radii which are shorter and more massive, by possessing circular pores which are evenly distributed anteriorly and posteriorly over the entire cephalo-thoracic body, and by having a more circular thoracic ring. Like S. caelestium, S. CRETACEOUS RADIOLARIA: PESSAGNO 19 brionesensis possesses a smooth thoracic ring as opposed to the spinose thoracic ring of S. abastrum, n. sp., S. peregrina, n. sp., and S. corona, nN. sp. S. brionesensis is named for the Briones Valley, near its type lo- cality. Type locality. — NSF 568-B. See Locality Descriptions. Deposition of types. — Holotype = USNM 165489. Paratypes = USNM 165490 and Pessagno Collection, University of Texas at Dallas. Range and occurrence.—'Yo date S. brionesensis, n. sp. has only been found at its type locality in strata of latest Campanian age. See Locality Descriptions and Text-figure 2. Saturniforma caelestium Pessagno, n. sp. PAL, iy, safes, L639 IIL (Op sales, 124 Description. — Test as with genus, but having nine radu, a smooth subcircular thoracic ring, and an irregular row of pores encircling the periphery of the disclike cephalo-thoracic body both anteriorly and posteriorly. Remarks. —S. caelestium, n. sp., differs from S$. brionesensis, n. sp., by having nine rather than ten radii, by having a subcircular thoracic ring, and by having pores that are restricted to an irregular row which encircles the disclike cephalo-thoracic body. Caelestium (Latin, N.) = a heavenly body. Type locality. — NSF 291-B. See Locality Descriptions. Deposition of types. — Holotype == USNM 165491. Paratypes = USNM_ 165492 — 165493 and Pessagno Collection, University of Texas at Dallas. Range and occurrence.—'Yo date this species has only been found at its type locality in strata of Coniacian age. See Text-figure 2 and Locality Descriptions. Saturniforma corona Pessagno, Nn. sp. Biiaties 2-6 Description. — Test as with genus, but having eleven radii, a thoracic ring with a spinose periphery, and prominent circular pores evenly distributed both anteriorly and posteriorly over all but the central portion of the cephalo-thoracic body. Remarks. —S. corona, n. sp., is most likely related to S. abas- ium, nm. sp., and S, peregrina, n: sp. All three species'’ possess spinose thoracic rings and similarly shaped interradial areas. S. 20 BULLETIN 257 corona differs from S. abastrum by having eleven rather than ten radii and by the character and distribution of pores on its cephalo- thoracic body. It differs from S. peregrina by having a far less lobu- late thoracic ring, in the distribution and character of the pores on its cephalo-thoracic body, and by having eleven rather than ten radii. Corona (Latin, F.) = crown halo. Type locality. — NSF 568-B. See Locality Descriptions. Deposition of types. — Holotype = USNM 165494. Paratypes = USNM 165495 and Pessagno, Collection, University of ‘Texas at Dallas. Range of occurrence.—To date this species has only been found at its type locality in strata of latest Campanian age. Saturniforma peregrina Pessagno, n sp. Pl. 6. figs. 3-5 Description. —'Test as with genus, but having ten long slender, radii, a lobulate, spinose thoracic ring, and pores which are irregu- larly dispersed both posteriorly and anteriorly on the cephalo- thoracic body; pores tending to be larger toward periphery and smaller and more widely spaced toward its center. Remarks. — S. peregrina, n. sp., differs from S. abastrum, n. sp., by having longer radii, a more lobulate periphery, and in the dis- tribution of pores on its cephalo-thoracic body. S. peregrina differs from S. corona, n. sp., by having a more lobulate periphery, propor- tionately larger interradial areas, and eleven radii which are pro- portionately longer. Peregrina us, a, um (Latin) == foreign, strange. Type locality. — NSF 350. Holotype = USNM 165496. Para- types = USNM 165497 — 165498. Range. — Early Cenomanian to late Cenomanian. Range zone may extend into Albian. Albian not extensively sampled during this study. Ocurrence. — See 'Text-figure 2 and Locality Descriptions. CRETACEOUS RADIOLARIA: PESSAGNO 2] REFERENCES CITED Foreman, Helen P. 1968. Upper Maestrichtian Radiolaria of California. Spec. Papers in Paleontology, No. 3, pp. iv-v; 1-82, pls. 1-8. Goll, R. M. 1968. Classification and phylogeny of Cenozoic Trissocyclidae (Radio- laria) in the Pacific and Caribbean Basins. Part I. Jour. Pal., vol. 42, No. 6, pp. 1409 — 1432, pls. 173 — 176. Hay, W. W., and Sandberg, P. A. 1967. The scanning electron microscope, a major break through for micropaleontology. Micropaleontology, vol. 13, No. 4, pp. 407 — 418, pls. 1,2. Honjo S., and Berggren, W. A. 1967. Scanning electron microscope studies of planktonic Foraminifera. Micropaleontology, vol. 13, No. 4, pp. 393 — 406, pls. 1-4. Ojakangas, R. W. 1968. Cretaceous sedimentation Sacramento Valley, California. Geol. Soc. Amer., Bull., vol. 79, pp. 973-1008, 11 figs., 5 pis. Pessagno, E. A., Jr. 1967. Upper Cretaceous planktonic Foraminifera from the Western Gulf Coastal Plain. Palaeont. Americana, vol. 5, No. 37, pp. 245-445; pls. 48-101, text-figures 1-63. 1969a. Upper Cretaceous stratigraphy of the Western Gulf Coast Area of Mexico, Texas, and Arkansas. Geol. Soc. Amer., Mem. 111, pp. 1-139, pls. 1-60. 1969b. The Neosciadiocapsidac, a new family of Upper Cretaceous Radiolaria. Bull. Amer. Paleont., vol. 56, No. 253, pp. 373 —439, pls. 23-38; text-figs. 1-4. Petrushevskaya, M. G. 1964. On homologies in the elements of the inner skeleton of some Nas- sellaria. Zool. Zhur., vol. 48(8), pp. 1121—1128. (In Russian) 1965. Peculiarities of the construction of the skeleton of Botryoids (Order Nessellaria). Trudy Zool. Inst. Leningr., vol. 35, pp. 79-118 (In Russian). Renz, O., Luterbacher, H., and Schneider, A. 1963. Stratigraphisch — paldontologische Untersuchungen im Albien und Cénomanien des Neuenburger Jura. Eclogae Geol. Helv., vol. 56, No. 2, pp. 1074 — 1114 pls. 1-9. Riedel, W. R. 1968. Radiolaria in Antarctic sediments. B.A.N.Z. Antarctic Research Exped. Repts., ser. b, vol. 6, pt 10, pls. 1-4, 13 text-figs. Systematic classification of Polycystine Radiolaria. SCOR sym- posium on Micropaleontology of Marine Bottom Sediments. MS., Cambridge, September 1967, pp. 1-47 (in press). mate 4. a ; Se re ele te an eee yy |" Te ae nak se Lae ea eh Oe ett ; ah 7 7 » ’ - ry AM - v oo PLATES 24 BULLETIN 257 EXPLANATION OF PLATE 1 All figures scanning electron micrographs. Figure Page 1-4. Rotaforma mirabilis Pessagno, n. Sp. .............-:c.00--ca Holotype (USNM 165481). NSF 350. “Fiske Creek Forma- tion’/“Antelope shale.’ Cenomanian. Fig. 1: View of an- terior side of test. 4 = thoracic ring; B — thoracic fringe; G = oral radii; D = aboral radius; & = interradial area; marker = 50 microns. Fig. 2: Marker = 50 microns. Fig. 3: F = pseudoporta; marker — 50 microns. Fig. 4: View into thoracic mouth; cephalic skeletal elements barely visible; note diatom in lower right; marker = 25 microns. 5. Rotaforma mirabilis Pessagno, mn: Sp: <:..4..2....4.-.0-.2.0 eee NSF 350. Cenomanian portion of “Fiske Creek Formation’’/ “Antelope Shale.” Paratype (USNM 165482). Marker = 50 test; thoracic fringe largely broken away; marker — 50 microns. 6. Rotaforma mirabilis Pessagno, n. Sp. ...............0.00:cccceeeeee NSF 350. Cenomanian portion of “Fiske Creek Formation’’/ “Antelope Shale.” Paratvpe (USNM 165483). Marker = 50 microns. 16 16 BULL. AMER. PALEONT., PLATE 1 BULL. AMER. PALEONT., VOL. 58 PLATE 2 5 Ort CRETACEOUS RADIOLARIA: PESSAGNO 2! EXPLANATION OF PLATE 2 All figures scanning electron micrographs. Figure Page 1. Rotaforma mirabilis Pessagno, n. sp... ~=616 Paratype (Pessagno Collection). NSF 350. “Fiske Creek For- mation”’/‘“Antelope Shale.’”’ Cenomanian. Cephalic skeletal elements. Vertical bar broken away. Marker — 10 microns. 2. Rotaforma mirabilis Pessagno, n. Sp. .........00...0......0000cs, 16 NSF 350. “Fiske Creek Formation”/‘“Antelope Shale.’ Paratype (Pessagno Collection). Cephalic skeletal elements. Marker = 10 microns. Ko 26 BULLETIN 257 EXPLANATION OF PLATE 3 All figures except figure 1 are scanning electron micrographs. Figure Page 1... Rotaforma.mirabilis’ Pessagno, mn. “Sp. ee...) ee Paratypes (USNM 165484). NSF 350. Cenomanian portion of “Fiske Creek Formation’’/‘‘Antelope Shale.” Dark lines vis- ible in middle of radii represent grooves, not canals; light photomicrograph of specimen mounted in hyrax. Marker —= 50 microns. 2. Rotaforma mirabilis Pessagno, n. Sp. 20.20.00... Paratype (Pessagno Collection). NSF 350. Cenomanian portion of “Fiske Creek Formation”/“Antelope Shale.” Note well- developed cephalopyle. Marker — 10 microns. 3. Rotaforma mirabilis Pessagno, NwSPeres kc eee Topotype; view of anterior side. NSF 350. Cenomanian por- tion of “Fiske Creek Formation’/‘“Antelope Shale.” Marker —= 50 microns. 4.5: -Rotaforma hessi PesSagno, Ne Sp: <2.....¢kecccg-ccn-<21 pee Holotype (USNM 165478). NSF 350. Cenomanian portion of “Fiske Creek Formation”/“Antelope Shale.” Figure 4: Pos- terior side; marker — 50 microns. Figure 5: Arrows point to cephalopyle (left) and apical horn (right). Marker = 10 microns. 6. Rotaforma hessi Pessagno, n. Sp. .........eeeccceceececeeeeeeeeeeeeeeeees Paratype (USNM 165479). NSF 350. Cenomanian portion of “Fiske Creek Formation’ /“Antelope Shale.’ Posterior side; arrow points to apical horn; cephalopyle obscured by matrix; marker — 25 microns. 16 16 16 16 3 PLATE VOL. 58 ’ BuLL. AMER. PALEONT. BULL. AMER. PALEONT., VOL. 58 PLATE 4) 5 ~I CRETACEOUS RADIOLARIA: PESSAGNO 9 EXPLANATION OF PLATE 4 All figures scanning electron micrographs. Figure Page 1,4A-B. Rotaforma hessi Pessagno, n. sp. ae 16 Topotype. Specimen destroyed in mounting. “NSF 350. Ceno- manian portion of “Fiske Creek Formation’/‘Antelope Shale.” Fig. 1: Marker = 50 microns. Fig. 4A-B: Stereo- pair of cephalic skeletal elements. Marker — 10 microns. 2. Rotaforma hessi Pessagno, Nn. Sp... ee 6 Paratype (USNM 165480). Cenomanian portion of “Fiske Creek Formation’/‘“Antelope Shale.” Marker — 50 microns. 3. Rotaforma hessi PesSsagno, n. SDP. ................::cccceeeeeeeeeeeeeeeeteeneees 16 Paratype (USNM 165479). Cenomanian portion of “Fiske Creek Formation’/‘““Antelope Shale.” Same specimen as in Pl. 3, fig. 6. Marker = 50 microns. = 28 BULLETIN 257 EXPLANATION OF PLATE 5 All figures scanning electron micrographs. Figure Page 1-3. Saturniforma abastrum Pessagno, Nl. SP. ..............0.cccccceeee Holotype (USNM 165485). NSF 291-B. Coniacian portion of the type Yolo Formation. Figs. 1,2: Arrow in figure 2 points to a porta; markers — 50 microns. Fig. 3: Marker = 25 microns. 4. Saturniforma abastrum Pessagno, n. Sp. 2.0. NSF 291-B. Coniacian portion of type Yolo Formation. Para- type (USNM 165486). Arrow points to a cephalic skeletal element. Marker — 25 microns, 5,6. Saturniforma caelestium Pessagno, N. Sp. ooo... Holotype (USNM 165491). NSF 291-B. Coniacian portion of type Yolo Formation. Fig. 5: Arrow points to thoracic mouth; marker — 50 microns. Fig. 6: Marker = 50 microns. 18 19 ULL. AMER. PALEONT., VOL. 58 PLATE 5 BULL. AMER. PALEONT., VOL. 58 CRETACEOUS RADIOLARIA: PESSAGNO 29 EXPLANATION OF PLATE 6 All figures except figure 6 are scanning electron micrographs. Figure Page 1,2. Saturniforma caelestium Pessagno, n. sp. 19 Paratype (USNM 165492). NSF 291-B. Coniacian portion of type Yolo Formation. Marker — 50 microns. 3. Saturniforma peregrina Pessagno, Nn. SP. 2.000... 20 Holotype (USNM 165496). NSF 350. Cenomanian portion of “Fiske Creek Formation”/“Antelope Shale.” Marker = 50 microns. 4,5. Saturniforma peregrina Pessagno, n. sp. .............. 20 Paratypes (USNM 165497-165498). NSF 350. Cenomanian por- tion of “Fiske Creek Formation’/‘“Antelope Shale.’ Markers = 25 microns and 50 microns respectively. 6. Saturniforma brionesensis Pessagno, n. Sp. ................00ccceeeee 18 Holotype (USNM 165489). NSF 568-B. Latest Campanian por- tion of the “Marsh Creek Formation.’ Light photomicro- graph. Marker — 50 microns. 30 BULLETIN 257 EXPLANATION OF PLATE 7 All figures scanning electron micrographs. Figure Page 1. Saturniforma brionesensis Pessagno, n. sp. ........ ee, Paratype Pessagno Collection. NSF 568-B. Latest Campanian portion of “Marsh Creek Formation.’ Marker — 50 microns. 2-4. Saturniforma corona Pessagno, N. SDP. ........ eee Holotype (USNM 165494). NSF 568-B. Latest Campanian portion of “Marsh Creek Formation.” Figs. 2-3: Marker = 50 microns. Fig. +: Marker = 10 microns. 5,6. Saturniforma corona Pessagno, n. Sp. ........ ee oes Paratype (USNM 165495). NSF 568-B. Latest Campanian por- tion of “Marsh Creek Formation.” Fig. 5: Marker = 50 microns. Fig. 6: Note canal in thoracic ring; marker = 10 microns. 19 BuLL. AMER. PALEONT., VOL. 58 PLATE 7 PLATE 8 58 VOL. > BuLL. AMER. PALEONT. CRETACEOUS RADIOLARIA: PESSAGNO 3] EXPLANATION OF PLATE 8 All figures scanning electron micrographs.* *NorTe: All of the unnamed neosciadiocapsid species figured were found after the writer presented his paper on the Neosciadiocapsidae for publica- tion (Pessagno, 1969b). Figure Page 1-3. Unnamed Neosciadiocapsid from Cenomanian portion of “Fiske Creek Formation”/“Antelope Shale’ (NSF 350). Note archlike or tunnellike thoracic velum (4 in fig. 1) and position of ceph- alo pyle and apical horn (B and C respectively in fig. 2). Fig. 1: Marker = 50 microns. Fig. 2: Marker = 10 microns. Biss Marker — 50) microns, 2 Proeen See IE OB EY noe SESE dh 13 4. Unnamed Neosciadiocapsid from Cenomanian portion of “Fiske Creek Formation’’/“Antelope Shale” (NSF 350). Cephalis and upper part of thorax are rotated towards upper left. Arrow PoINtsstoycephalopyles Mianker = — 50))micnonsy ee 13 5. Unnamed Neosciadiocapsid from Cenomanian portion of “Fiske Creek Formation”/“Antelope Shale” (NSF 350). Shows de- velopment of ring structure but no rotation of cephalis and upper part of thorax into plane of ring. Marker = 25 microns. 13 6. Unnamed Neosciadiocapsid from Cenomanian portion of ‘Fiske Creek Formation’/“Antelope Shale’ (NSF 350). Shows de- velopment of multiple ring structures but no rotation of ce- phalis and upper part of thorax. Marker = 25 microns. ............ 13 ~ 32 BULLETIN 257 EXPLANATION OF PLATE 9 All figures scanning electron micrographs. Figure Page 1. Rotaforma mirabilis Pessagno, n. sp. .....................cccccceeees 16 Topotype. NSF 350. Juncture of radius with thoracic ring. A = radius; B = thoracic ring. Note lack of central canal in thoracic ring. Marker — 5 microns. 2. Rotaforma mirabilis Pessagnos ny Sp: ene. eee eee 16 Topotype. NSF 350. A = quadraradiate radius lacking central canal. Marker = 5 microns. Note: Light face t to plate numbers. A abastrum, Saturnifcrma soo Acanthoceras sp. Antelope Shale . appenninica, Rotalipora Ce arca, Globotruncana B brionesensis, Saturniforma brittonensis, Hedbergella 67 Cache Creek caelestium, Saturniforma . calcarata, Globotruncana Calycoceras sp. Campanian Cenomanian ......... : churchi, Globotruncana 2, Contra Costa County, California Cordilleran Mobile el tee on one ae corona, Saturniforma 7/ cushmani, Rotalipora “Cyrtoid”’ Nassellariina 5,6 E evoluta, Rotalipora Fiske Creek Formation Globotruncana _ Great Valley Sequence _ greenhorensis, Rotalipora Gublerina INDEX 10, 18-20 9 8, 9 9 11 10, 18, 19 9 8 10, 17-19 11 10, 19, 20 9 11 58) ype refers to page numbers. Bold face type refers H Hedbergella 9 hessi, Rotaforma 3,4 10, 16, 17 M mantelli, Mantelliceras __. 9 Mantelliceras 9 Marsh Creek Formation 9,10 mirabilis, Rotaforma _ 1-3,9 10, 15-17 Monticello Dam 9 Napa County, California 9 Nassellariina 5,13 Neosciadiocapsid (unnamed)... 8 13 Neuenburger Jura 9 Oo ornatissima, Gublerina ._.. 101 P peregrina, Saturniforma 6 10, 19, 20 Polycystida Ehrenberg el Praeglobotruncana 9 RUZOSTAaNSpy eee 9 R Rotaformar... 10, 13-16 Rotaliporar>.. 9 S Saturniforma 10, 14, 15, 17-19 Saturnus 18 stephani, Praeglobotruncana 9 \¢ Yolo County... 8 Yolo Formation .___. 8, 10 a) W 7 vy oui afd aw 7 ? sat gitrred: . > oes. F ca * se - y @ : : 7 7 _ BULL. AMER. PALEONT., VOL. 58 PLATE 9 MUS. COMP. ZOOL. LIBRARY JUL 28 1970 HARVARD BULLETINS | unwersiry OF AMERICAN PAeEONTOLOGY Vol. 58 No. 258 ANALYSIS OF SOME AMERICAN UPPER CRETACEOUS LARGER FORAMINIFERA By W. Storrs CoLe AND EstTHER R. APPLIN 1970 Paleontological Research Institution Ithaca, New York UsrS Ae PALEONTOLOGICAL RESEARCH INSTITUTION 1969 - 1970 PRESTO) Ee NT oo oo a ea ae ac ED WILLIAM B. HERoy VICE-PRESIDENT? (102 Brine) ee ee Pe 2k ee eee ee DANIEL B. SAss SSE GRIT AR 9 sa goc coco ceo cee ree nee ae ne ee oe a ee REBECCA S. HArRIS DIRECTOR; “EP REASURER, 2) 200) 22 Se ea eer, Oe KATHERINE V. W. PALMER COUN SE) Saree et eee ee oS E e oe e ARMAND L, ADAMS ees eee SAE Ne UA ti iN eee ee DAvw NICOL Trustees REBECCA S. Harris (Life) DANIEL B. Sass (1965-1971) AxeL A. Oxsson (Life) KENNETH E. CASTER (1966-1972) KATHERINE V. W. PALMER (Life) DONALD W. FISHER (1967-1973) W. Storrs CoLe (1964-1970) WiuiaM B. Heroy (1968-1974) VirciL D. WINKLER (1969-1975) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PALMer, Editor Mrs. Fay Briccs, Secretary Advisory Board KENNETH E. CASTER HANS KUGLER A. Myra KEEN Jay GLENN Marks AXEL A. OLsson Complete titles and price list of separate available numbers may be had on application. For reprint, Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., New York, N.Y. 10017 U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Cor- poration, 111 Fifth Ave., New York, N. Y. 10003 U.S.A. Subscription may be entered at any time by volume or year, with average price of $18.00 per volume for Bulletins. Numbers of Palaeontographica Ameri- cana invoiced per issue. Purchases in U.S.A. for professional purposes are de- ductible from income tax. For sale by Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. Pee E PINS OF AMERICAN PEE ONTOLOGY (Founded 1895) Vol. 58 No. 258 ANALYSIS OF SOME AMERICAN UPPER CRETACEOUS LARGER FORAMINIFERA By W. Storrs Cote AND EsTHER R. APPLIN July 22, 1970 Paleontological Research Institution Ithaca, New York 14850, U.S.A. Library of Congress Card Number: 76-120355 Printed in the United States of America Arnold Printing Corporation CONTENTS ENOVSTRTR EOTech EE ee I oa A An eee 39 TimitiA@ a WCC ee eee ee NE i ie a eee eee ee 39 Ihe aha «A oee ee he Fk ee ce eRe Ri Se Oe ec 40 SaTPA Mpa Hn CRC OMSL ENyatl OLS pers Ss ee ce ee a ce ene 45 WeseniptlOne OleSDeClESi m= emma e. ote aA eae cee BSc) Bic poet Se 48 IMehenences: (ClCed i: vn es en eee Be ica Pee a eee Srp oko aerials RE 65 69 TEUBII@S cecencemd es tS 7 san eal ies me Sd AE a Alec a ene PERE. See so kt, © ase aa eS er ; Aa oe roe) . ean 7 _ a ° a > io 7*. : ; a os “ : é e - Pr ek foam ' ek ae ; te beet vag i ra i > aoe nn 1 a eat r . fi Mi ge arte 4, : . ‘Ti ‘i}yi 4 F i lam i AS Bevis \ he nm kee ¢ SP OS “4 . ie . ' . a ray < i vr J %, ad A aS ent CRETACEOUS FORAMINIFERA: COLE AND APPLIN 71 EXPLANATION OF PLATE 11 Figure Page All figures, x 40, except 1, 2, 7, X 12.5; 6, X 20 1-8. Chubbina macgillavryi Robinson .............................. . 48 1. Slightly oblique axial section of a micro- spheric specimen. 2. Part of the thin section of limestone in which the specimen, fig. 1, was em- bedded to illustrate the marginal con- tinuation of this specimen (lower part) and two megalospheric specimens. 3,4, 7,8. Axial sections of megalospheric specimens. 5. Transverse section of a megalospheric specimen. 6. Part of transverse section of the flange of a microspheric specimen. 1-8. Loc. 2A — Collier Corporation well No. 1 (Florida). See text for exact locality description. 72 BuLLETIN 258 EXPLANATION OF PLATE 12 Figure Page All figures, X 40 1-12. Sulcorbitoides pardoi BroOnnimann ................................... 57 1-8,10. Transverse sections to illustrate the vari- able development of the lateral cham- bers. 9,11,12. Median sections. 1, 2,4-10. Loc. 3-Gulf Coast Realties well No. 2 (Florida). HP se ZyD): 45 53C; Sy Os sivaly (Sy SDS hy SDE 3,11,12. Loc. +B-Gulf Coast Realties well No. 12 (Florida). See text for exact locality descriptions. Butt. AMER. PALEONT., VOL. 58 PLATE 12 3ULL. AMER. PALEONT., VOL. 58 PLATE} CRETACEOUS FORAMINIFERA: COLE AND APPLIN 73 EXPLANATION OF PLATE 13 Figure Page All figures, x 40 1-4,5, 7,10. Waughanina cubensis D. K. Palmer ...... 62 1. Vertical section of a topotype from Cuba. 2. Vertical section which should be compared with figure 2, plate 21 (Cole, 1944). 3,4. Same vertical section. 3, by transmitted light; 4, by reflected light. Compare with figure 6, plate 1 (Bronnimann, 1958). 5, 7,10. Equatorial sections. 5. Microspheric speci- men. 7, 10. Megalospheric specimens. 7. Compare with figures 4, 5, plate 1 (Bronnimann, 1958). 10. Compare with figures 1, 2, plate 16 (Brénnimann, 1954b). 6,8. Pseudorbitoides israelskii Vaughan and Cole peed) Vertical sections. 9. Sulcorbitoides pardoi Bronnimann ................ Ohl ease Re 57 Median section; note the similarity to the equatorial sections of Vaughanina cubensis, figs. 5, 7, 10, this plate, except the periembryonic coil is longer and approaches the periphery of the test and the radial plates are less distinct. 1. Loc. 10-Habana Province, Cuba. 2,5,9,10. Loc. 3-Gulf Coast Realties well No. 2 (Florida). 0. 3A. Oar «3IC: A 7. Loc. 4B-Gulf Coast Realties well No. 12 (Florida). 6. Loc. 8-Welch well No. 1 (Louisiana). 8. Loc. 9-Plumly well No. 1 (Texas). See text for exact locality descriptions. 74 BULLETIN 258 EXPLANATION OF PLATE 14 Figure Page All figures, X 40, except 3, 6, X 210 1-7. Pseudorbitoides israelskii Vaughan and Cole ............ 35, See 9 1,2,4. Vertical sections. 3. Distal part of the equatorial layer of the specimen illustrated as fig. 4, this plate, enlarged to show details. 5. Equatorial section parallel to, but slightly above the equatorial plane to illustrate the top part of the embryonic apparatus (center) surrounded by lateral chambers beyond which is the zone of radial plates. 6. Enlargement of the embryonic apparatus of the microspheric specimen, fig. 7, this plate. Equatorial section of a microspheric specimen. ba | 1,2, 5-7. Loc. 7-Johnson well No. 1 (Mississippi). 3,4. Loc. 8-Welch well No. 1 (Louisiana). See text for exact locality descriptions. BuLL. AMER. PALEONT., VOL. 58 PLATE 14 BuLL. AMER. PALEONT., VOL. 58 Mm I me Py ers n * ” Pine NS OSx ue pe gine’ y ~S pe iy CRETACEOUS FORAMINIFERA: COLE AND APPLIN 75 EXPLANATION OF PLATE 15 Figure Page All figures, x 40, except 9, X 20 1-9. Pseudorbitoides trechmanni H. Douvillé 60 1-3, 5,7. Vertical sections of megalospheric speci- mens. 2, 7. Specimens formerly identified as Lepidorbitoides nortoni (Vaughan) by Cole (Florida Geol. Sur., Bull. 19, p. 40, 1941). 4+,6,8,9. Equatorial sections of megalospheric specimens. 4. Specimen formerly identi- fied as Lepidorbitoides nortoni (Vaughan) by Cole (Florida Geol. Sur., Bull. 19, p. 40, 1941). 4, 6, 9. Sections slightly oblique, but exposing the embry- onic apparatus, equatorial chambers and some of the lateral chambers; note radial plates which show indistinctly in fig. 6 (lower right) and fig. 9 (bottom). 8. Section slightly above equatorial layer, exposing embryonic apparatus and lateral chambers; note radial plates in the lower part. 9. For enlargement, see ier, 33, LPL, 15). 1, 3,5, 6,8,9. Loc. 3-Gulf Coast Realties well No. 2 (Florida). iL, S¥a\, By OG. Sibi. yO) BCE 2,4,7. Loc. 6-Cory well No. 1 (Florida). See text for exact locality descriptions. 76 BULLETIN 258 EXPLANATION OF PLATE 16 Figure Page All figures, * 40, except figure 1, x 20 1,4,5. Chubbina macgillavry Robinson 0... i... 1. Part of a thin section of limestone with two transverse sections of megalospheric specimens of this species and several unoriented sections of Sulcoperculina dickersoni (D. K. Palmer). 4. Axial section of a megalospheric specimen. 5. Transverse section of a megalospheric specimen. 2,3,6,7. Pseudorbitoides trechmanni H. Douvillé ate 2,6. Sections parallel to, but slightly above the equatorial plane. 6. Section exposes mainly the lateral chambers and the top of the embryonic apparatus (center). 3. Enlargement of part of the specimen illus- trated as fig. 9, Plate 14; note faint radial plates over equatorial chambers. Equatorial section just at the top of the equatorial layer with the embryonic ap- paratus completely exposed, a few lat- eral chambers (left center) and well- developed radial plates. “I 1,4,5. Loc. 2-Collier Corporation well No. 1 (Florida). ile Ale 4,5. 2A. 2,3,6,7. Loc. 3-Gulf Coast Realties well No. 2 (Florida). Dis 03. si, Si(Ce See text for exact locality descriptions. 48 60 PLATE 16 BuLL. AMER. PALEONT., VOL. 58 bat. vo Pe . RP isc = 4 Ram DO: nS 5 a, = ea en 0 iE: - % of x 7 tT ee yy BULL. AMER. PALEONT., VOL. 58 CRETACEOUS FORAMINIFERA: COLE AND APPLIN EXPLANATION OF PLATE 17 77 Figure Page All figures, & 40, except 6, 7, X 100 1. Pseudorbitoides trechmanni H. Douvillé ........................ Vertical section of a large megalospheric specimen. 2, 3, 5-7. Lepidorbitoides (Orbitocyclina) minima H. Douvillé 2,3. Central parts of vertical sections. 2. Speci- men formerly identified as L. rutteni Thiadens (Cole, 1942, pl. 9, fig. 1). 3. Compressed specimen; compare with figure 2, plate 9 (Cole, 1942). 5-7. Parts of equatorial sections. 6. Enlarge- ment of the central part of the specimen illustrated as figure 5, this plate. 6, 7. Note arcuate chambers in the zone surrounding the embryonic apparatus and short spatulate chambers beyond. Compare these illustrations with figures 3, 4, plate 22 (L. minima) and figure 1, plate 22 (Vaughan, 1929) (identified as Orbitocyclina nortoni) and figure 2, plate 2 (M. G. Rutten, 1941) [identified as L. (Orbitocyclina) macgillavryi]. 4. Sulcorbitoides pardoi Bronnimann .......................... Median section. 1. Loc. 3B-Gulf Coast Realties well No. 2 (Florida). 2,3, 5-7. Loc. 11-Matanzas Province, Cuba. 4. Loc. 4B-Gulf Coast Realties well No. 12 (Florida). See text for exact locality descriptions. 60 50 57 INDEX Note: Light face type refers to page numbers. Bold face type refers to plate numbers. A aguayoi, Asterorbis .Lepidorbitoides americana, Pseudorbitella Anacacho Limestone.. angulata, Sulco- perculina apiculata, Orbi- LOIOCS Het ee armata, Lepidorbi- toides Asterorbis Ayalaina barkeri, Vaughanina.. Barrettia bed Basses Plaines Formation Borelis Camerina Campanian cardenasensis, IBOTCMISI oe ee PC OUD Dita eee , Polylepidina ...... Cedar Keys, Florida .. Chiapas, Mexico chubbi, Pseudor- bitoides .. Chubbina Coastal Petroleum Company Collier Corporation cosdeni, Sulcoper- culina . cruysi, Smoutina ....10 Cuba Loe cubensis, Camerina , Sulcoperculina 43 43 59, 61 46-48, 58 55-57 44, 54, 64 43, 45, 54, 55 39, 42, 45, 47, 48, 60, 62 48, 52 48, 52 50, 52 45, 47 46-48, 53 97, 58 39, 46, 48, 49, 52 62 46, 48, 49 45, 46, 55 39, 45, 49 39-41, 46, 47, 51, 58, 64 04, 55 54, 56 , Vaughanina 13 cubensis globosa, Vaughanina cubensis minor, Vaughanina diazi, Sulcoper- culina dickersoni, Camerina , Miscellanea , Sulcoperculina ..10 E estrellae, Lepidorbi- toides! .2. 5 eee F Oni aye eee floridensis, Lepidor- bitoides gansseri, Globo- truncana , Rugotruncana Glades County, Florida globosa, Sulcoper- culina , Vaughanina Globotruncana Green Island, Jamaica Guatemala guatemalensis, Vaughanina Gulf Coast Realties 78 39, 43-47, 34, 56, 57, 62-64 46, 62-64 47, 62-64 55 43, 45, 54, 50 39, 40, 43, 45, 46, 49, 51, 54, 58, 64 54-58 46, 62-64 63 46, 48, 49, 54. 58, 62 H Hanzawa, Pseudor- bitella Hilliard Turpentin (CO), eee ne a Historbitoides Humble Oil and Refining Co. ............ israelskii, Pseudor- bitoides INDEX 59 43, 45 39, 57, 59, 60 40, 54, 58 Brame 13, 14 39, 42-44, 47, 53, 57-60, 62 63 J jamaicensis Chubbina 48 5 1M OUNOEY Socasonencaseeac 46 jordanae, Vaughanina ......... 45, 62-64 K Ratn ay fe ec 46 Kinney County, Texas Dil kozaryi, Historbi- WOVDES seach hota octecke 57, 59, 60 L Lawson Limestone .... 44-46, 49 Lepidorbitoides .......... 39, 41-43, 45-47, 49, 50, 59-62 linneiana, Globo- truncana ...... 47 Kouisiana ........ 41-43, 47 M Maastrichtian 39, 44-48, 54, 60, 62 macgillavryi, Chubbina ..... 11,16 39, 46, 48, 49 , Lepidorbitoides .... 50-52 , Orbitocyclina ........ 51 macroporous, Omphalocyelus ...... 53 Matanzas, Cuba .......... 53 mayaroensis, Globotruncana ...... 44, 54 McCord Oil Company 40, 54 Meandropsina 52, 54 media, Orbitoides 44 45, 54, 64 Mexico 47 52, 64 minima, Lepidorbi- COLES ese esa 17 39, 41, 43, 47, 50, 51, 59, 62 , Orbitocyclina ....17 47, 50, 52, 53, 62, 63 , sulcoperculina ...... 55, 56 minor, Vaughanina .... 47, 62-64 Miscellanea .... 43,55 Mississippi ....... 41, 42, 47, 59 nortoni, Lepidorbi- tO1deSie eee es 39, 46, 59-61 , Orbitocyclina ........ 41, 43, 50-52, 59 Nuevo beds ... 53 Oo obesa, Sulcoperculina 55-57 Omphalocyelus _........... 39, 53, 54, 56, 64 Orbitocyclina .. 41-43, 47, 50-53, 59, 62, 63 Orbitoides .................... 43-45, 53, 54, 57, 58, 64, 65 P palmeri, Lepidorbi- toldesa 2ey.ce 50-52 _Orhitoides 43-45 pardoi, Sulcoperculina 58 , Sulcorbi- toides ..10,12, 13,17 39 40, 46-48, 57, 58 Peninsular Oil and Refining Cone... 40 Piedra Parada beds .. 47, 53 planasi, Lepidorbi- COIdES te ee 43, 50, 51 Polylepidina ................ 50, 52 Pseudorbitella ........... 59, 61 Pseudorbitoides .......... 39, 42-47, 52-54, 57-63, 65 R rooki, Asterorbis ...... 42, 43 , Lepidorbitoides . 43 Rugotruncana ............ 44, 47 (i rutteni, Ayalaina _ Lepidorbitoides .... , Meandropsina ...... , Orbitocyclina , Pseudorbitoides rutteni armata., Lepidorbitoides S San Louis Con- glomerate San Miguel Formation Smoutina socialis, Orbitolites .... Sulcoperculina ............. Sulcorbitoides Sun Oil Co. Texas tissoti, Orbitoides ...... INDEX 53, 54, 58-60, 65 50 47, 53 47 39, 44, 45, 49 50 39, 44-47, 49, 54-58 .. 39, 40, 47, 48, 57, 58 44 .. 40-42 47, 48, 50 44, 45, 58 80 torrei, Omphalo- CY CLUSH ee 10 39, 53, 54 Se LOEGelnaweres 10 39, 46-48. 53, 54 Torreina? #25544. 39, 46-48, 53, 54 torreina, Torreina .... 54 trechmanni, Pseudor- bitoides .......... 15-17 39, 46, 52, 53, 59-61 tschoppi, Lepidorbi- tOIGES Mr At ae 50 U Upper Campanian ..... 46, 47 Upper Cretaceous ...... 39-41, 43 Upper Lawson Mimestonew 49 Upper Santonian ........ 42,47 WpsoniClaya. 47 Vv Vaughanina ................ 39, 42-46. 54, 56, 57, 62-64 Venezuelaye see 64 vermunti, Camerina .. 45, 55, 56 , Suleoperculina ...... 54, 56, 57 mus. COMP. ZOOL LIBRARY AUG 26 {970 D BULLETINS invers OF AMERICAN Pee ON TOLOGY Vol. 58 No. 259 SILICOFLAGELLATES FROM CENTRAL NORTH PACIFIC CORE SEDIMENTS By Hs1n-Y1 LING 1970 Paleontological Research Institution Ithaca, New York WarSaAs PALEONTOLOGICAL RESEARCH INSTITUTION 1969 - 1970 DEPRESSED ga ec gare eee WILLIAM B. HEROY VICE = PRESIDENT oo oocn cea sees iete norte hear ae se rate nae stn = seen te eee nane ete ent cee DANIEL B. SAss ST Te Ne ee roe ee eee REBECCA S. HArris POTRECTOR, | TREASURER ooo nace sccate cece ee reereenerey KATHERINE V. W. PALMER COPS 0. F214 yea a ee OP RE a pene ere ARMAND L. ADAMS REPRESENTATIVE AAAS: COUNCIL | 2r.0:::<--.--sencoscceqcesseeseatwaraccncsneeneanuveaneeaaena Davw NICOL Trustees Resecca S. Harris (Life) DANIEL B. Sass (1965-1971) Axe. A. OLsson (Life) KENNETH E. CASTER (1966-1972) KATHERINE V. W. PALMER (Life) DonaLp W. FIsHER (1967-1973) W. Srorrs CoLe (1964-1970) WILLIAM B. Heroy (1968-1974) Vircit D. WINKLER (1969-1975) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PALMER, Editor Mrs. Fay Briccs, Secretary Advisory Board KENNETH E. CASTER HANS KUGLER A. Myra KEEN Jay GLENN Marks AXEL A. OLSSON Complete titles and price list of separate available numbers may be had on application. For reprint, Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., New York, N.Y. 10017 U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Cor- poration, 111 Fifth Ave., New York, N. Y. 10003 U.S.A. Subscription may be entered at any time by volume or year, with average price of $18.00 per volume for Bulletins. Numbers of Palaeontographica Ameri- cana invoiced per issue. Purchases in U.S.A. for professional purposes are de- ductible from income tax. For sale by Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. PW VUNS OF AMERICAN PvieEON TOLOGY (Founded 1895) Vol. 58 No. 259 SILICOFLAGELLATES FROM CENTRAL NORTH PACIFIC CORE SEDIMENTS By HsIn-Y1 LING August 7, 1970 Paleontological Research Institution Ithaca, New York LW), Bs Ns Library of Congress Card Number: 77-123873 Printed in the United States of America Arnold Printing Corporation CONTENTS P PENLYS CpG ape ce Wea ne eR Fe ood et cect ccbain. Sead. uusestocence: ss Se a er eee ee intro ductionmrandseA chm owed Gents) eo eee esa ee nee cee eee eee cee BAYS COM) ah Camly cll COMO @ Syne en. meserres sas een eee en eR eS eh ee eee Agee) (COGS TISSTCG TEEN 10) 9 eae por we cae tel a a. Miocene silicoflagellate assemblage in the T128-25 core ~...............-.. b. Quarternary occurrence of Mesocena cf. elliptica .0........2..0.2022000000000---- TRG RTI@IPCIINGOS LS I ENE a ae eee ment eR ee Oe ee pate meen we es tea ae eee a ee in A ee Ne A mt as aE TEXT-FIGURE 1. Track and core positions of RV Thomas G. Thompson Cruise 28 (TOURS ie eh ees aes a Re, i A ee ain Ee OP ea te ee Oe en ieee Pe 2. Schematic diagram of silicofiagellate showing the measurements (ineIMTerONs) emia d eminiatiniswp a peters e e ee eee 3. Miocene portion (from 365 to 499 cm) of a core [28-25 and dis- ERD UMOnmO fest veoh) alee aitemetasxccae eee are ees ee ee eee 4+. Distribution of silicoflagellates in the central north Pacific deep-sea SC GUITIG1) Semer ee eee ee eee Ree ener ede at eh sik) eae A sg, BA ee eee tema ee 5. Distribution of silicoflagellates in the central north Pacific deep-sea SE CLTIT 11S mune ENS Lote hata en en ee pant 7 Fo ee eee Se eee TABLES Hee Centralmnonrthmlyacitie CORES. eek ie Si eee Se aes eee oece ae enw eee cares ere 2. Silicoflagellate occurrences in the south Atlantic Ocean —...-.......022.0.20...... 3. Stratigraphic succession in Hokuriku region, Japan ...................-.---.----------- 4+. Silicoflagellate occurrences in Hokuriku region, Japan —_........-...--..........---- 7 , 1” ae ws Pe ee | 7 q } 7 ° 1" t i. _ gut oS Ly A ie . ? ms a" a manta Ud ; ; y+ 4 2} Ue ite i. Ps Li’ 7. se rt awa ee hog a r ' ; —- i : 7 ‘ | oe > eee » ; “foal « f = he - : ’ Aloe q ri ‘ yn “ > 5 JY os vidi MMe ky aade: Sle eked Z 5 o,f i | iy aes Ms : ‘ fajash4, SA TS i , . ae t 4 oy i . e ’ ; : a x ‘ey a Ny re ,. -« ‘ a _ | i ' ‘ : es 4 : a" 4 ; n rt J . ae q ¢ } 2 j t _ ‘ = 7 4 ) 7 ‘ ® = : ys 9 - J =? om, hy ae SS Mee ©. bf i : ' -* ks i ap My -_ (Fi 8 - Su re ; ‘ : ; = ; = a" & ve » = . SILICOFLAGELLATES FROM CENTRAL NORTH PACIFIC CORE SEDIMENTS* Hs1n-Y1 L1ING Department of Oceanography University of Washington ABSTRACT Silicoflagellates are siliceous planktonic microorganisms which have never been a significant constituent of pelagic sediments. Their importance as guide fossils has been recognized only during the last few decades. From the central north Pacific deep-sea sediments collected during 28th cruise of RV Thomas G. Thompson, 11 silicoflagellate taxa with one new species, Dictyocha subarctios, were recovered. The lower lithological unit of TI28-25 core is identified as Miocene after a comparison of the faunal composition with the known Tertiary land records. Quaternary occurrences of Mesocena cf. elliptica are discussed, and its most recent extinction together with the latest appearance of Dictyocha cf. ausonia and D. subarctios may suggest a biostratigraphic datum for the middle latitude of the north Pacific deep-sea sediments. INTRODUCTION AND ACKNOWLEDGMENTS Although silicoflagellates are marine planktonic microorgan- isms, they have never been a significant contributor to siliceous pelagic sediments (Riedel, 1963; Kozlova and Mukhina, 1967; Saito and Bé, 1967) ; consequently, only limited investigations have been made on these microorganisms from deep-sea deposits. During cruise 28, 1968, of the research vessel Thomas G. Thompson (YT-28) of the University of Washington, deep-sea core sediments were collected from the central north Pacific Ocean GWiext-fic. <1, Table 1). The purposes of this present paper are threefold: first, to docu- ment the occurrence of silicoflagellates from north Pacific deep-sea sediments; second, to discuss a Miocene assemblage found in a core 25 (T128-25) ; and third, to evaluate critically the Quaternary oc- currence of Mesocena cf. elliptica Ehrenberg. It is a privilege to acknowledge members of the scientific party and Captain Vernon H. Wyatt and the crew of the RV Thomas G. Thompson tor their enthusiastic cooperation during the cruise when the author served as chief scientist. The author is grateful to Dr. York T. Mandra, San Francisco State College, for his kind discussion and criticism of the paper; to Dr. James D. Hays, Mr. Lloyd H. Burckle, and Mrs. Jessie Donahue of Lamont-Doherty Geological Observatory, Columbia University, for their providing reference samples of RV Robert D. Conrad (RC) cruises; to Dr. Catherine Nigrini, Kanata, Ontario, Canada, for her unpublished manuscript, Dr. Dora P. Henry for discussion on taxonomy, and to *Contribution No. 521, Department of Oceanography, University of Washington. 86 BULLETIN 259 ivy 180° 175° 170° 165° ALEUTIAN ISLANDS woe aa ADAK “MIDWAY 220 te) HONOLULU 15 165°E 170° 175° 180° 175° 170° 165° 160° 155°W Text-figure 1.— Track and sediment core positions of RV Thomas G. Thompson cruise 28 (TT-28) : m —deep-sea cores in which silicoflagellates were recovered; ® —location of RV Robert D. Conrad (RC) 10-202 core sample. Mrs. Carol J. Stadum and Mrs, Shirley J. Patterson for their tech- nical assistance during the preparation of the manuscript. The research was sponsored by National Science Foundation (grant GA-1443, and -11308) and the Office of Naval Research [contract Nonr 477 (37), project NR 083 012]. The ship operation of the cruise was also made possible through the financial support of the above two agencies. NorTH PAciFic SILICOFLAGELLITES: LING 87 TABLE 1. CENTRAL NORTH PACIFIC CORES Water Depth Core (m) Length Core Number Latitude Longitude (corrected) (cm) TT28-01 PC' 23°03’ N 156°06’ W 4260 783 TT28-02 PC 26°10’ N Sel Sev 5257 756 TT28-03 PC 27°29’ N 154°57’ W 5551 861 TT28-04 PC 30°19’ N 154°57' W 5709 1077 TT28-05 PC 32°24’ N 154°31’ W 5601 880 TT28-06 PC SS mI SLaN 154°42' W 5577 694 28-07 AC 38°09’ N 156°25' W 5548 208 mn28-08) PC 7/51? IN| 160°17' W 5072 1048 TT28-09 PC SHEEN 163°27' W 5302 1033 TT28-10 PC 34°52’ N 169°09’ W 5753 859 TT28-11 PC 33°01’ N 174°00’ W 5495 1045 TT28-12 GC* 30°25’ N 175°41' W §145 170 TT28-13 PC 31°50’ N 177°04' E 5307 132 TT28-14 PC 33°26’ N U7ShasiSe E: 5079 1027 TT28-15 AC 35 22/0N 1692530: 5452 183 TT28-16 PC SOM SaaIN 174°31' E 5182 206 e28=17 EC 38°59’ N 177°05’ E 5264 234 TT28-18 GC 36°08’ N WAP SP 1 3871 127 m2 8=19 GE 35°49’ N 179°56’ W 4582 493 TT28-20 GC BB) IN| 177°07' W 5314 173 TT28-21 GC 37°59’ N 171°49’ W 5479 541 Mee 8-22) GC 39°59’ N 174°29' W 5917 530 TT28-23 GC 42°36’ N 174°25' W 597 568 TT28-24 GC 45°00’ N 176°00’ W 5721 632 TT28-25 GC 46°00’ N 167°30’ W 5412 499 TT28-26 GC 47°57’ N 163°04’ W 5014 212 TT28-27 GC 47°56’ N 154°06’ W 5120 294 = piston core; 2—auxiliary (trigger) core; 3 = gravity core SYS PEMATIC PALEONTOLOGY The methods used for the preparation of the samples and for the location of the specimens illustrated in the paper have already been described elsewhere (Stadum and Ling, 1969). Throughout the present study additional slides for sediments of finer fraction (less than 74 y) are also examined for each sample. Terminology applied by Tynan (1957), Mandra (1968) and Loeblich, II, e¢ al. (1968) has been adopted here. Text-figure 2 illustrates the measurements (A, B, C, D) made on the specimens. One holotype and two paratypes of the new species, Dictyocha subarctios, will be deposited in the U.S. National Museum, Washington, D.C., and the USNM numbers assigned here- in are from their Cenozoic Catalogue No. 132. All the other slides used for the present study will be deposited permanently in the 88 BULLETIN 259 micropaleontology collection of the Department of Oceanography, University of Washington, Seattle, Washington. —_————— C B Text-figure 2. — Schematic diagram of silicoflagellate showing the measure- ments (in microns) made in this paper. A—length of basal body ring without radial spines. B = width of basal body ring without radial spines. C = length of radial spine in major axis. D —length of radial spine in minor axis. Genus DICTYOCHA Ehrenberg, 1839 Dictyocha cf. ausonia Deflandre Pl. 18, figs. 1-3 Dictyocha fibula Ehrenberg, 1854 (part), Ehrenberg, Mikrogeol., pl. 22, fig. 42b (not others). Dictyocha fibula var. brevispina Lemmermann, 1901 (part), Deutsch. Bot. Ges., Ber., vol. 19, pp. 260-261. Dictyocha fibula Ehrenberg, Carnevale, 1908, R. Ist. Veneto Sci. Let. Arti, Mem., vol. 28, No. 3, p. 35, pl. 4, fig. 29. Dictyocha ausonia Deflandre, 1941 (part), C. R. Acad. Sci. Paris, vol. 212, p. 101, figs. 8, 13 (only). Dictyocha ausonia Deflandre, Deflandre, 1950, Microscopie, vol. 2, pp. 67, 68, figs. 194, 199, 200(?), 201, 202(?) (only). Dictyocha ausonia Deflandre, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 249, fig. 38. NorTH PACIFIC SILICOFLAGELLITES: LING 89 MEASUREMENTS IN MICRONS Sample A B (oy meyiD) TT28-19 490- 493 L-2 (D45/0) 42 36 4 Z (Pl. 18, fig.1) x500 TT28-14 850- 853 R-2 (G17/0) 40 36 4+ 3 (Pl. 18, fig.2) x500 TT28-14 1000-1003 R-1 (E31/0) 49 34 4 3 (Pl. 18, fig. 3) x500 Observed range 30-49 28-38 4-6 2-5 based on 20 specimens Taxonomic notes. — It is considered that the orientation of an apical bar that is in the minor axis or perpendicular to the major axis 1s one of the diagnostic features for the present species (com- pare with Bachmann, 1967). Among such forms, only D. fibula Svarecaspera ta. rhombica Schulz (1928, p. 253, fig. 37) = D. f. fa. rhombica Schulz (Gemeinhardt, 1930, p. 50, fig. 40 a-c) was re- ported for modern occurrences from the Atlantic Ocean by Schulz and Gemeinhardt and from Kii Channel, Osaka Bay, by Yanagisawa (1943, fide Tsumura, 1963). However, as will be discussed later the size of D. forma rhombica, according to Schulz, ranges from 78 to 112 », which is approximately twice as large as that of the present species. Admittedly the present form is most closely related to D. ausonia; however, in the present paper it is not considered as con- specific because: 1. D. ausonia was originally reported from the Miocene sedi- ments of Caltanissetta, Sicily (Sarmatian) ; Bergonzano (Helvetian) , and Marmorito (middle Miocene undifferentiated) , Italy. Tynan (1957) described the present species as D. mutabilis from the Mio- cene Calvert Formation of Maryland, and Mandra (1968) found it rarely (less than 1 percent) and only from diatomite at Sharktooth Hill of Relizian stage in his California work. In the present study, the species was not found in the lower lithologic unit of core TT28- 25 which is considered as Miocene (see discussion) but only in Quaternary sediments. The geological range of D. ausonia needs to be determined. 2. In his description of the species, Deflandre stated (1950, p. 67) : “ornementation indiscernable dans les conditions normales.” I have found specimens whose basal body ring ornamentation under ordinary transmitted light ranges from entirely smooth to irregu- larly granulated; therefore, it may be advisable to broaden the 90 BULLETIN 259 definition of the present species to encompass such an intraspecific variation. In connection with this, several samples were examined from the Calvert Formation in the reference collection which were kindly sent by Dr. Lincoln Dryden, Bryn Mawr College, Bryn Mawr, Pennsylvania. Unfortunately only one sample, from ap- proximately 3.4 miles north of Scientist’s Cliff (7.5 min. quad. Prince Frederick) , Maryland, contained any of the present species and only few; therefore, no conclusion on the range of variation was reached. 3. Furthermore, the specimens recovered from Quaternary sediments demonstrate a limited range of variation in size and shape, and I failed to observe a complete series of morphologic variation as illustrated by Deflandre. Therefore, further study of specimens from both Miocene and Quaternary sediments is needed before the north Pacific form can be positively identified as con- specific with that of Miocene form. 4. By determining the range of intraspecific variation, the taxonomic validity of Dictyocha regularis Carnevale could also be determined. Undoubtedly, at least a part of Lemmermann’s D. fibula var. brevispina (1901, pp. 261-262) seems to belong to the present species. Lemmermann referred to Ehrenberg’s three figures as the illustrations for the proposed variety. A figure of Ehrenberg (1854, pl. 22, fig. 42b) was referred to by Deflandre for D. ausonia under discussion. ‘The other two illustrations, particularly of plate 21, figure 42b, are different from those of the present species. Occurrence. — Despite the taxonomic uncertainty for the present species, its upper limit seems to coincide with that of Mesocena cf. elliptica and Dictyocha subarctios, n. sp., and thus it may become one of the stratigraphically useful forms, at least in the middle latitudes of the north Pacific deep-sea sediments. Dictyocha fibula Ehrenberg Pl. 18, figs. 4-10 Taxonomic notes. —'The present species has been well reviewed recently by Mandra (1968); therefore, no attempt will be made to repeat it here. The species shows an enormous variation even at the intra- or infraspecific rank. For example, a specimen illustrated here (PI. 18, fig. 6) is closely related to the D. fibula forma constricta C Schulz (1928, p. 253, fig. 35), and I consider that Schulz’s form is NortH PActiric SILICOFLAGELLITES: LING | at the extreme of such variation. Another variation found in the north Pacific samples is that the specimen possesses a short apical bar (Pl. 18, fig. 8), and perhaps it is the intermediate form of the present species to D. staurodon Ehrenberg (1844, p. 71; 1854, pl. 18, fig. 58; Mandra, 1968, p. 253, fig. 63) but without an apical accessory spine. Also included under the present species is D. f. var. pentagona Schulz (op. cit., p. 255, fig. 41) because the “variety” was found only sparsely during the present study. MEASUREMENTS IN MICRONS Sample A B (1) TT28-16 204-207 R-2 (S38/4) 50 45 10 7 (Pl. 18, fig.4) x540 TT28-17 196-199 R-1 (L20/3) 304936. 8a. 8 (Pl 18 fie's) x540 eh 28-23) 3170-373 R-1 (K21/4) 40 Siy) ES 315) (Pl. 18, fig. 6) x520 TT28-25 390-393 R-1 (06/4) 52 47 9 9 (Pl. 18, fig. 7) x540 TT28-25 390-393 R-2 (H15/0) 56 47 10 8 (RSS tis2)8)) x5 00 TT28-25 390-393 R-1 (M24/3) 28 a 3 — (Pl. 18, fig.9) x500 TT28-25 390-393 R-2 (Q14/0) Zh — i = \(PIET8; fig. 10) x500 Occurrence. — The species are found in almost all the samples studied, with their more frequent occurrence in sediments of Quaternary age. Dictyocha fibula ‘var.’ aculeata Lemmermann Pl. 18, figs. 11-13 Dictyocha fibula var. aculeata Lemmermann, 1901, Deutsch. Bot. Ges., Ber., woll, IG), jo, Aa, oll 10, aatece I, We Dictyocha fibula var. aculeata Lemmermann, Gemeinhardt, 1930, in Krypto- gamen-Flora, vol. 10, pt. 2, p. 55, fig. 43a, b. Dictyocha fibula var. aculeata Lemmermann, Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 68, figs. 25, 26(?). Dictyocha fibula var. aculeata Lemmermann, Gemeinhardt, 1934, Deutsch. At- lantischen Exped., Wiss. Ergebn., vol. 12, pt. 1, No. 3, p. 301, figs. 122, 124, Dictyocha fibula var. aculeata Lemmermann, Hovasse, 1940, Soc. Zool. France, Bull., vol. 64, No. 6, p. 323. Taxonomic notes. —Lemmermann (1901) — described _ this “variety” from a sample of Challenger Expedition (exact nature and type of sample as well as locality were not given) , and Gemein- hardt (1930, p. 55) regarded the form as of a warm-water habitat. The form illustrated as D. epiodon by Ehrenberg (1844, pp. 70, 79 1854, pl. 35B, B, 4, fig. 10 (only)) from the north Atlantic at 94°17’ N, 22°33’-W, depth 12,000 ft may be conspecific with the present form; however, future work on north Atlantic samples is necessary to clarify this point. 92 BULLETIN 259 MEASUREMENTS IN MICRONS Sample A B Cae) TT28-19 31- 34 R-2 (023/4) 36 32 10 8 (PI. 18, figs. 11,12)x500 TT28-19 490-493 R-1 (L6/4) 35 30 Sito (Pl. 18, fig. 13)x500 Diced range 28-40 26-37 4-12 4-8 based on 20 specimens Occurrence. — This species (‘‘var.’’) was found frequently in the Quaternary sediments. Dictyocha fibula “var.’’ messanensis (Haeckel) Pl. 18, fig. 14 Dictyocha messanensis Haeckel, 1861, K. Preuss. Akad. Wiss. Berlin, Monats- ber., Jahr 1860, pp. 799-800. Dictyocha messanensis Haeckel, 1862, Monogr. d. Radiol., p. 272, pl. 12, figs. 3-6. Dictyocha fibula Hertwig (not Ehrenberg), 1879, Der Organismus der Radio- larien, p. 89, pl. 9, fig. 5. Dictyocha messanensis Haeckel, Haeckel, 1887, Rept. Voy. Challenger, Zool., vol. 18, p. 1561. Dictyocha fibula var. messanensis (Haeckel), Lemmermann, 1901, Deutsch. Bot. Ges., Ber., vol. 19, p. 261. Dictyocha fibula var. messanensis (Haeckel), Gemeinhardt, 1930 in Krypto- gamen-Flora, vol. 10, pt. 2, p. 51, fig. 41a-c. Dictyocha fibula var. messanensis (Haeckel), Zanon, 1934, Acta Pont. Acad. Sci. Noy. Lincei, vol. 87, pp. 67-68, fig. 19. Dictyocha fibula var. messanensis (Haeckel), Gemeinhardt, 1934, Deutsch. Atlantischen Exped., Wiss. Ergebn., vol. 12, pt. 1, No. 3, p. 290, pl. 7, figs. 3-7. Taxonomic notes. — The critical examination of the previous records by earlier workers reveals that the following forms have been referred to the present species: (a) with neither basal nor apical accessory spines (Haeckel, 1861, 1862, 1887; Hertwig, 1879 (part) ; Lemmermann, 1901); (b) with basal accessory spines only (Hert- wig, 1879 (part); Gemeinhardt, 1930, figs. 41a, b; 1934, figs. 3-6; Zanon, 1934, fig. 19); (c) with apical accessory spines only (Hert- wig, 1879 (part) ); (d) with both basal and apical accessory spines (Gemeinhardt, 1930, fig. 41c; as fa. spinosa) . In view of the fact that such variations can be found in the same sample, as Gemeinhardt (1930) illustrated from his Meteor station 49, emendation for the present species will be necessary to include all the forms discussed. This will make the present species more meaningful in the study of deep-sea sediments and applicable for future stratigraphic purposes. NortuH PAciFic SILICOFLAGELLITES: LING 93 The form described by Frenguelli (1935, fide Loeblich, II, et al., 1968) as D. fibula f. mesocenoidea from Argentina seems similar to the present species except that the size is approximately 1/3 larger than that of the specimens found from the north Pacific, and yet it can be still considered as an ecological modification of the species. However, so far I have not found a specimen from the Southern Hemisphere to verify this point, and, therefore, Fren- guelli’s forma is excluded, at least at present, from the above synonymy list. MEASUREMENTS IN MICRONS Sample A B CED TT28-17 4-7 R-2 (0O10/0) 46 44 106 10 (PI. 18, fig. 14) x450 Observed range 40-50 38-48 6-12 6-12 based on 20 specimens Occurrence. — The present species (“var.”) are found only in sediments of the Quaternary age. Dictyocha fibula “forma” rhombica Schulz JPL ls}, ase, Dictyocha fibula Ehrenberg, 1854 (part), Mikrogeol., pl. 22, fig. 42a (only). Dictyocha fibula var. aspera forma rhombica Schulz, 1928, Bot. Archiv, vol. Bil ING 7, 10, BOS sites See Dictyocha fibula forma rhombica Schulz, Gemeinhardt, 1930, im Krypto- gamen-Flora, vol. 10, pt. 2, p. 50, figs. 40a-c. Dictyocha fibula forma rhombica Schulz, Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 67, fig. 13. Dictyocha rhombica Deflandre, 1941 (part) (not Lemmermann or Schulz), C. R. Acad. Sci., vol. 212, p. 101, figs. 1-2(?) (only). Dictyocha mutabilis Deflandre, 1950 (part), Microscopie, vol. 2, figs. 203, 204, 210 (only). Dictyocha fibula forma rhombica Schulz, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 252, fig. 72. MEASUREMENTS IN MICRONS Sample A B CAPD) TT28-25 Nose R-2 (G23)/0) 73 59 10 7 (PI. 18, fig.15) x450 Taxonomic notes. — When Schulz named the present forma, he described the basal body ring as “stark granuliert” and the size as 78-112 » in major axis. Gemeinhardt (1930) then combined the 04 BULLETIN 259 forms of smooth as well as granulate basal body rings into Schulz’s forma, and by doing so he also included Ehrenberg’s specimens (1854, pl. 22, figs. 42a, b) from Caltanisetta, Sicily. The figure 42b of Ehrenberg’s was already referred to by Deflandre (1950) as D. ausonia, and it is agreed with Deflandre judging from the size of Ehrenberg’s figure. During the study, the present “forma” was found sparsely and was limited in occurrence to the lower lithologic unit of TT28-25 core; however, the surface ornamentation does vary from granulate to smooth, and therefore, Gemeinhardt’s opinion is followed. Deflandre (1941) illustrated forms similar to the present species as D. rhombica, and in 1950 he proposed a new name as D. mutabilis. Unfortunately, he did not refer or compare the new species with that of Schulz. However, judging from his illustration and particularly from his three figures (1950, figs. 203, 204, 210), which he considered as type for the new species, it is apparent that at least a part of D. mutabilis seems to be conspecific with that of Schulz. However, as D. ausonia, he also illustrated a series of varia- tions (1941, figs. 3-7; 1950, figs. 205-209) for D. mutabilis. It is felt that until further study is made, it is premature to conclude that the present form is identical with that of Deflandre. In this connection it is also necessary to examine the two species proposed by Deflandre because there is an apparent confusion of name applied by later workers. In establishing D. mutabilis, Deflandre stated (1950, p. 70), “D. mutabilis est exactement du méme type morphologique que D. ausonia, dont il deffére toutefois trés nettement, tant das ses proportions générales que par ses dimensions et son ornamentation superficielle. Les variations sont superposables a celles de D. ausonia, mais les spécimens du type géniteur sont beaucoup plus rares, proportionnellement, que dans l’espéce italienne.” ‘The size comparisons, according to Deflandre’s original descrip- tion, for the two species are: D. ausonia D. mutabilis total 50-54 pw 87-100 1 range 42-56 without radial spine 32-47 64-68 pw NortH PAciFic SILICOFLAGELLITES: LING Oo Or If the size difference is followed strictly, then Tynan’s specimen ol D. mutabilis (1957, pl. 1, fig. 9) should be considered as D. ausonia, while Stradner’s D. ausonia (1961, pl. 2, fig. 67 (only) ) as D. muta- bilis, and Bachmann's D. ausonia (1963, pl. 18, figs. 40-44) and D. mutabilis (pl. 18, figs. 38, 39, 45) should be transposed. Occurrence. — The present “forma” is found rarely; therefore, it is not shown in Text-figure 3 and only in the lower unit of TT28- 25 which is considered as Miocene in the present study (see dis- cussion) . Dictyocha subarctios Ling, n. sp. Pl. 18, figs. 16-18; Pl. 19, figs. 1-4 Description. — Basal body ring, circular or nearly circular in apical and antapical view; four short radial spines of similar length located at approximately 90° apart extended horizontally; apical structure moderately arched from the basal plane; apical bar straight; its length 1/2 to 2/3 of the diameter; basal accessory spines, short, and projected obliquely down and inward in edge view; apical accessory spine absent. MEASUREMENTS IN MICRONS Sample A,B C,D TT28-24 510-513 R-2 (E16/0) 32 2 (EG SRS. ies, 1G) x500 (S24/0) 35 2 (Pl. 18, figs. 17,18) x500 R-4 (K40/0) 37 2 et 19, fig. 1) x500 paratype (U46/2) 34 2 (PI. 19, fig. 2) x500 paratype R-5 (K10/0) 32 2 ( sae fig. 3) x500 holotype (D38/1) 38 2 3 .19, fig. 4) x500 Observed range 30-40 2-4 based on 20 specimens Remarks. — The new species superficially resembles D. fibula fa. rotundata Schulz (1928, p. 255, fig. 42) from Kuznetsk, Russia (Paleocene, fide Loeblich, III, et al., 1968, p. 18) and D. rotundata Jousé (Jousé, 1955, fide Loeblich, III. et al., op.cit., p. 111, pl. 21, figs. 6-9) but differs from them definitely By possessing four radial spines instead of two, and it is larger (30-40 » vs. 20 or 22-28 y). The forms illustrated by Bachmann as D. fibula fa. rotwndata Schulz ioasep: 149) pl. 17, figs, 34-37) from “Badener Tegel” of Frat- tingsdorf, Austria, are also similar to the new species but differ in that Bachmann’s Austrian species clearly shows that two opposite radial spines are much longer than the other two, and the apical bar 6 BULLETIN 259 is on a minor axis, therefore showing the tendency of approaching D. cf. ausonia, as seen in his figure 37. It should be mentioned here also that apparently Bachmann erred in referring his specimen to that of Schulz. Occurrence. — In three cores, T'T28-17, 22, and 23, the upper limit of the present species coincides approximately with that of Mesocena cf. elliptica, while in another core, 24, it continues up to slightly higher than this horizon. The occurrence of the present species in the above four cores may suggest that it had confined biogeographic distribution. Genus DISTEPHANUS Stohr, 1880 Distephanus crux (Ehrenberg) Pl. 19, figs. 5, 6 Taxonomic notes. — The present species has been reviewed and an extensive synonymy list was prepared recently by Bachmann (1967) and Mandra (1968). MEASUREMENTS IN MICRONS Sample A B (CD) [128-25 367-370 R-1 (G9/4 41 40 20 18 (PI. 19, fig.5) x500 ['T28-25 473-476 R-2 (U28/3) 39 16 14 (PI.19, fig. 6) x500 Observed range 30-41 28-40 8-20 10-18 based on 10 specimens Occurrence. — The species occurs sparsely and only in the Miocene interval of the TT28-25 core (see discussion) and a sample of RC 10-202 (45°37’ N, 173°00’ W; water depth approxi- mately 5700 m) at 997-1000 cm. The somewhat abnormal form is here illustrated (Plate 19, fig. 6) in which the basal body ring is not completely closed. Although the species has been reported abundant to common from the sediments of Oligocene and Miocene age (see discussion) , its range has been extended from Upper Cretaceous (Klement, 1965) to Recent deep-sea Atlantic sediments (Schulz, 1928, p. 256). ’ Distephanus crux cf. “var.” stauracanthus (Ehrenberg) PI. 19, figs. 7, 8 Dictyocha stauracanthus Ehrenberg, 1845, K. Preuss. Akad. Wiss. Berlin, Ber., p. 76. Dictyocha stauracanthu; Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 33, No. 15, fig. 10. NorTH PActFic SILICOFLAGELLITES: LING 97 Distephanus stauracanthus (Ehrenberg), Haeckel, 1887, Rept. Voy. Challenger, Zool., vol. 18, p. 1564. Distephanus crux var. stauracanthus (Ehrenberg), Lemmermann, 1901, Deutsch. Bot. Ges., Ber., vol. 19, p. 263. Distephanus crux var. stauracanthus (Ehrenberg), Schulz, 1928, Bot. Arch., vol, 21, No. 2, p. 260, fig. 48 (only). Distephanus crux var. stauracanthus (Ehrenberg), Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 60, fig. 52. Taxonomic notes. —'The “variety” was originally described by Ehrenberg from Hollisk Cliff, Virginia, and Norwich, Connecticut. Schulz later added Santa Monica, California, as the third locality for its occurrence but still used Ehrenherg’s figure. It should be noted here that all the occurrences so far are from Miocene sedi- ments and only within North America. Apparently, as Schulz noticed (op. cit., p. 260), the “variety” occurrs only sparsely be- cause both Tynan (1957) in his study of the Calvert Formation and Mandra (1968) from California failed to find the present “variety.” Recently, Dumitrica (1967) proposed a_ phylogenic lineage of Dictyocha crux-D. stauracantha-D. bachmanni. His D. stauracantha, illustrated in figure 1 and plate 2, figure 10(?), 11- 14, definitely possess two longer basal radial spines on major axis and, therefore, it is different from the original Ehrenberg’s form. MEASUREMENTS IN MICRONS Sample A Bs (CID) TT28-14 490-493 R-2 (L18/2) 2 ie Ry, (PI. 19, figs. 7,8) x470 Observed range 30-36 30-36 2-3 based on 10 specimens Occurrence. — The “‘variety” is found sparsely in the present samples studied and only from sediments of Quaternary age. Distephanus octangulatus Wailes Pl. 19, figs. 9, 10 Distephanus speculum var. octonarius Ehrenberg forma, Wailes, 1928, Van- couver Mus. Notes, vol. 3, Nos. 3,4, p. 14, pl. 12, fig. 33. Distephanus octangulatus Wailes, 1932, Canadian Biol. and Fish., Contr., vol. 7, No. 17, p. 216, fig. 3. Distephanus octangulatus Wailes, Wailes, 1939, Canadian Pac. Fauna, 1. Protozoa, 1 e. Mastigophora, p. 10, fig. 22. Taxonomic notes. — This is the first reported occurrence for the present species from deep-sea sediments, and the previous records by Wailes (1928, 1932, and 1939) were all in pilchards caught off the west coast of Vancouver Island. Beyond any doubt the speci- 98 BULLETIN 259 mens recovered here agree well with those of Wailes. The intra- specific variation observed during the present study are: (1) apical accessory spines from clearly present to almost indiscernible, and (2) the size of apical ring from two-thirds to one-half of that of basal body ring. MEASUREMENTS IN MICRONS Sample A,B TT28-24 210-213 L-2 (G19/0) 36 (Pl. 19, figs. 9, 10) x500 Occurrence. — The species was found sparsely in central north Pacific samples studied, and it was never found from the surface sediments of the core. There is some indication that the species occurs stratigraphically after the extinction level of Dictyocha cf. ausonia, D. subarctios, and M. cf. elliptica and possibly also after the D. crux cf. “var.” stauracanthus. Further study is needed to sup- port this conclusion. Distephanus speculum (Ehrenberg) Pl. 19, figs. 11-20 Taxonomic notes. —Under the present species here included are the several “‘varieties,’’ or forma, as proposed by various workers according to the number of radial spines. Therefore, the reader can refer to the earlier works, such as Lemmermann (1901) and Schulz (1928) for the synonymy of these forms. From the north Pacific deep-sea sediments, the number of radial spines ranges from five to nine. MEASUREMENTS IN MICRONS Sample A ‘S TT28-25 390-393 R-2 (Q8/1) 24 13 (PI. 19, fig. 11) x500 496-499 R-2 (R24/3) 20 14 (Pl. 19, fig. 12) x500 451-454 R-1 (J20/4) 24 18 (PI. 19, fig. 14) x500 R-2, (Ji17/0) 24 18 (PI. 19, fig. 15) x500 496-499 R-2 (Y32/3) 22 11 (PI. 19, fig. 13) x500 451-454 R-2 (W30/1) 28 14 (PI. 19, figs. 16,17) x500 TT28-23 370-373 R-1 (M33/0) 48 20 (Pl. 19, figs. 18,19) x330 TT28-24 510-513 R-2 (P21/3) 28 8 (PI. 19, fig. 20) x430 Occurrence. —The species was found in most of the Miocene and Quaternary samples studied. NortTH PACIFIC SILICOFLAGELLITES: LING 99 Genus CANNOPILUS Haeckel, 1887 Cannopilus hemisphaericus (Ehrenberg) Pl. 20, figs. 1-7 Taxonomic notes.— The present species has been reviewed extensively by Bachmann (1967), and Mandra (1968). Loeblich, III, et al., (1968) recently indicated that the generic name is super- seded by Halicalyptra Ehrenberg. However, the name, Halicalyptra, was first proposed for a polycystine (Radiolaria) genus (Ehren- berg, 1847, in table opposite to p. 54) in his study of materials from Barbados. It is true that H. virginica, illustrated by Ehrenberg (1854, pl. 18, fig. 110) , shows a hemispheric or convex outline with numerous openings in edge (or side) view, and with a straight spine at the top of the structure (Campbell, 1954, p. D118). Still the exact nature of the specimen is obscure, and only further examination of samples from Barbados and Richmond, Virginia, where the species was reported would clarify the above taxonomic problem. Meanwhile, the generic name Cannopilus is adopted in the present paper. From the samples studied, the number of apical windows in the specimens varies from three to eight and it is regarded as an intra- specific variation of the species. In all cases they show a hemispheric outline in edge view (see Pl. 20, figs. 5, 6). However, from the present north Pacific samples no specimen was found with two apical windows that would be referable to Dictyocha binoculus (Ehrenberg) Lemmermann (1901, pp. 266-267, pl. 11, fig. 22) or at least as part of Distephanus speculum “var.” cannopiloides (Pr.- Lavr.) Gleser (1966, fide Bachmann, 1967, pp. 159-161). It should be mentioned here that in the reference collection from the Ant- arctic region where Distephanus speculum is common, the author did find specimens with two apical windows and in such cases, the apical structure is truncated and parallel to the plane of basal body ring in edge view similar to that of Distephanus speculum illustrated by Deflandre (1950, fig. 7), Tynan (1957, text-fig. 2), and Mandra (1968, fig. 2). 100 BULLETIN 259 MEASUREMENTS IN MICRONS Sample A B (e D TT28-25 367-370 R-1 (U18/2) 46 32 20 (PI. 20, fig. 2) x450 420-423 R-1 (U7/2) AD S34 Pree (Pl. 20, fig. 1) x500 420-423. -R-2 (R31/3) 42 30 (Pl. 20, fig. 3) x500 473-476 R-1 (V20/0) VR G0). 2A (Pl. 20, fig. 4+) x400 473-476 R-1 (Y7/0) 42'* 234 220) 2 aki, (Pl. 20, fig. 5) x450 496-499 R-2 (X52/4) 42° 33 15. 10 (PI. 20, fig. 6) x450 RC10-202 997-1000 R-1 (G4/1) She GRO = (Pl. 20, fig. 7) x450 Occurrence. — The species is found only from the sediments of lower lithologic unit (365-499 cm) of a TT28-25 core and a sample of RC10-202 at 997-1000 cm. Genus MESOCENA Ehrenberg, 1843 Mesocena cf. elliptica Ehrenberg Pl. 20, figs. 8-14 Dictyocha triangula Ehrenberg, 1839, K. Akad. Wiss. Berlin, Abh., Jahrg. 1838, p. 129. Dictyocha (Mesocena) triangula Ehrenberg, Ehrenberg, 1840, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., p. 208. Dictyocha (Mesocena) elliptica Ehrenberg, 1840, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., p. 308. Mesocena triangula Ehrenberg, 1844, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, p. 71, p. 84. Mesocena elliptica Ehrenberg, Ehrenberg, 1844, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., p. 71, p. 84. Dictyocha diodon Ehrenberg, 1844, Verh. K. Preuss. Akad. Wiss. Berlin, Ber, Pp. 71) ps o4- Mesocena triangula Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 20, fig. 41. Mesocena elliptica Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 20, fig. 44. Dictyocha diodon Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 33, No. 15, fig. 18. Mesocena quadranguia Ehrenberg, 1873, K. Akad. Wiss. Berlin, Abh., Jahrg. 1872, p. 273, nom. nud. Mesocena quadrangula Ehrenberg ex Haeckel, 1887, Rept. Voy. Challenger, Zool., vol. 18, p. 1556. Mesocena polymorpha var. quadrangula Ehrenberg, Lemmerman, 1901, Deutsch. Bot. Ges., Ber., vol. 19, p. 256, pl. 10, figs. 5-7. Taxonomic notes. —'Vhe above synonymy list is prepared only for those directly related to the following discussion. For the other later references the reader may refer to the recent work by Mandra (1968) under Mesocena crenulata and its “varieties” and M. poly- “ce morpha “var.” quadrangula. The name Mesocena and the species belonging to this genus are discussed extensively by Deflandre (1932, particularly pp. 494- 498), and it is agreed that the name M. crenulata proposed by NortTH PAcIFIC SILICOFLAGELLITES: LING 101 Lemmermann (1901, p. 255) is invalid (Deflandre, 1932; Loeblich, Pilset al., 1968; p. 54). There is an inclination to choose M. elliptica for these forma because this name, used by Ehrenberg, does not imply a definite number of radial spines and it agrees with iconographic priority as Deflandre suggested (1932, p. 498). This is invalid though as the name Dictyocha triangula = Mesocena triangula was earlier proposed by Ehrenberg which has apparent priority over M. elliptica and legally stands as valid (Stoll, et al., 1961, ICZN art. I) From the lower lithologic unit of TT28-25 core samples and a sample of RC10-202 at 997-1000 cm depth, specimens were found with two, three, and four radial spines, which have been referred to previously as M. crenulata and its “varieties.” Although the form with three radial spines is rare compared with the other two forms, both two and four spine forms are also found in the samples, and therefore, they should be considered as an intraspecific variation. In six other cores, TT28-14, 17, 19, 22, 23 and 24, another form of Mesocena was observed. The absence of other Miocene silicoflagellates and its close association with modern forms in these sediments strongly suggests that this form is of Quaternary age (see discussion). These younger specimens are rectangular rather than elliptical (compare PI. 20, figs. 13, 14 with 11, 12) and the basal body ring is generally smoother and somewhat irregularly granulate in contrast to that cf a definite crenulate pattern found in Miocene samples and larger in size (maximum diameter of basal body ring along the major axis, 56-78 y» vs. 54-61 ,). This latter form seems to agree with those described previously as M. quad- rangula Ehrenberg ex Haeckel (1887, p. 1556) and illustrated as M. polymorpha “var.” quadrangula Lemmermann (1901, p. 256, pl. 10, figs. 5-7; 1903, p. 26;fig. 89). As Loeblich, III, e¢ al. (1968, p. 55) has pointed out, Lemmermann’s name is again invalid. On the basis of only the deep-sea core samples from the present central north Pacific, it may be possible to separate these two forms. However, taxonomic problems for the present species are compli- cated because these two forms have been reported from another geologic age by previous workers. For example, the so-called M. elliptica or M. crenulata “varieties” have been reported from Mio- 102 BULLETIN 259 cene sediments (see discussion). Mukhina (1963) illustrated the form from station 3802 of the central Pacific and Hays et al. (1969) reported it from the eastern Pacific of tropical regions. Through the courtesy of Hays and his colleagues a sample, RCI1- 208 (05°21’N, 139°58’W; water depth 4720 m) at 880 cm depth from the top of the core, was examined. From this sample, which is of Pleistocene age (Hays, personal communication) , specimens of Mesocena, referable to Lemmermann’s, are also found. It is the conclusion, therefore, that judging from the data of V (Vema) 24- 58 and -59, which were located nearby the reference sample studied, a part of M. elliptica of Hays et al. is that of Lemmermann’s M. polymorpha “var.” quadrangula. On the other hand, a form similar to M. polymorpha “var.” quadrangula, which was described from the North Atlantic by Haeckel (1887), has been reported in its fossil counterpart by Lemmermann (1901), Bachmann and Ichikawa (1962, pl. 9, figs. 1-3, 5, 6 only), Mandra (1968, fig. 24), and Zanon (1934, fig. 4). Furthermore, these two different forms “ec of Mesocena were reported in the same work by the above Bach- mann and Ichikawa, and Mandra. Apparently Tsumura faced the same difficulty because he stated (1963, pp. 34, 35): “This variety (M. crenulata var. elliptica (Ehr.) Lemmermann) sometimes can not be distinguished distinct- ly from M. polymorpha var. quadrangula when the basal ring is angular and resembles rhomboid a little. That the basal ring of M. crenulata is elliptical and M. polymorpha varieties are angular, are the main different points. These different points in M. crenulata var. elliptica are very obscure. Although the figure illustrated in the original description by Schulz is the typical shape of M. crenu- lata var. elliptica, the figure, illustrated in “Kryptogamen-Flora” by Gemeinhardt resembles M. polymorpha var. quadrangula. If the variety called M. crenulata var. elliptica did not exist at all, we could distinguish distinctly M. crenulata from M. polymorpha, for the basal ring is elliptical and this is angular. We can hardly assent that M. crenulata and M. polymorpha are quite different species, because of the existence of M. crenulata var. elliptica.” Thus, although there are some apparent differences, not enough characteristic features have been found that can be con- sidered as diagnostic to separate these two forms. Therefore, these NortuH PaActric SILICOFLAGELLITES: LING 103 two forms have been combined only provisionally in the present paper. Undoubtedly a further critical examination of Miocene as well as Quaternary specimens from many parts of the world is urgently needed to resolve this taxonomic problem. MEASUREMENTS IN MICRONS Sample A B C D TT28-25 496- 499 R-1 (S5/3) 50 42 8 (Pl. 20, fig. 8) x500 RC10-202 997-1000 R-2 (F20/4) 50 48 eZ, (Pl. 20, fig. 9) x450 TT28-25 Nose R-2 (V20/0) 50 44 8 £5 (PI. 20, fig. 10) x500 TT28-25 496- 499 R-2 (D12/1) 52 50 6 4 (PI. 20, fig. 11) x500 TT28-25 496- 499 R-2 (X14/1) 56 50 8 5 (PI. 20, fig. 12) x590 Observed ranges 44-61 44-52 5-10 TT28-17 231- 234 R-2 (R26/0) 58 50 8 8 (PI. 20, fig. 13) x500 TT28-22 380- 383 R-2 (K12/0) 72 66 10 7 (PI. 20, fig. 14) x500 AGE CONSIDERATION A comprehensive study on silicoflagellates from deep-sea sedi- ments was begun by Haeckel (1887), although Ehrenberg (1873) described a few forms from bottom sediments. In the following dis- cussion, the names of taxa as used by various authors in their articles are followed. In his work on Radiolaria from the Challenger deep-sea samples, Haeckel documented 30 species of silicoflagellates, includ- ing some fossil forms known by previous workers. Not only are some of the Challenger samples, such as those from stations 225, 266, 268 and 272, now considered as of Tertiary age (Riedel, 1954, 1959, MS; Riedel and Funnell, 1964; Funnell, MS (1967), MS (1968)), but some species Haeckel described have only _pre- Quaternary geologic range. Gemeinhardt (1934) reported (Table 2) the presence of silicoflagellates from 14 south Atlantic bottom samples collected during the Meteor Expedition. Except for Distephanus speculum “var.” brevispina and D. spec. “var.” pentagonus, Distephanus crux is the only silicoflagellate not found in plankton samples, and whose geologic occurrence is so far known only in the Tertiary period (see below). Gemeinhardt (1934, pp. 300-301) was indeed puzzled by the presence of D. crux in his Meteor sediments and its complete absence in the plankton samples. By finding and illustrating Dic- 104 "Meteor" Station Table Sample plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments plankton sediments 5 BULLETIN 259 Silicoflagellate Taxa Dictyocha fibula var. aculeata D. fibula var. messanensis D. speculum var. pentagonia D. speculum var. septenarius D. fibula var. stapedia Distephanus crux +|D. speculum var. regularis x +} D. speculum x present abundant but not listed individually absent a one Xe EX eK abundant but not listed individually absent abundant but not listed individually absent only as Dictyocha spp. x only as Distephanus spp. absent not studied absent only as Distephanus spp. absent Xx x D. speculum fa. brevispina 2. — Silicoflagellate occurrences in the South Atlantic Ocean. (Data from Gemeinhardt, 1934). NortTuH PAcIFIC SILIGCOFLAGELLITES: LING 105 tyocha fibula “var.” aculeata, he suggested the possibility of a transitional bioseries of Dictyocha fibula- D. fibula D. crux. Apparently both Haeckel and Gemeinhardt were unaware of the possibility of reworking or actual outcrops of Tertiary sedi- ments in the modern deep-sea bottom at that time. In the attempt to document various silicoflagellate species from the deep-sea sediments of the central north Pacific, the follow- ing interesting occurrences of these microfossils were noticed; they are (a) Miocene silicoflagellate assemblage in the interval of 365 to 499 cm of the core 25 (IT128-25), and (b) Quaternary occur- rence of Mesocena cf. elliptica. (a) Miocene silicoflagellate assemblage in the core TT 28-25. The gravity core 1128-25 is 499 cm in total length. A labora- tory examination revealed that two basic lithologic units are recog- nized from the core sediments. The upper 0-365 cm is fairly homo- genous, pale brown (10YR 5/2) (according to the rock-color chart distributed by the Geological Society of America, Inc., 1963) Holo- cene clay, while the lower unit, 365-499 cm, bottom of the core, is generally, except for an interval of 455-465 cm, which is dark yel- lowish brown (I10YR 4/2), a grayish yellow (5Y 8/4) siliceous ooze consisting chiefly of diatoms, silicoflagellates, and a few Radiolaria and ebrids. Thus the contact between the two layers is “ec var.” aculeata- sharp and clearly indicated by a color change as well as by textural differences (Text-fig. 3). The faunal composition of the silicoflagel- late assemblage in the lower layer seems to indicate that the sedi- ment is Miocene. This age assignment is reached after the following consideration. Because the above mentioned works by Haeckel and Gemein- hardt were the only extensive references for silicoflagellate occur- rences from ocean bottom samples, a comparison of the silicoflagel- late microfauna found in the lower unit of the TT28-25 core with the following known Tertiary occurrences on land is appropriate here. Martin (1904) illustrated three species of Miocene silico- flagellates from the Calvert Formation of Maryland in his article on Radiolaria. Although he did not describe nor illustrate any forms other than Distephanus crux and Dictyocha fibula?, a reexamination of his original slides, currently at the U.S. National Museum and 106 BULLETIN 259 WIZZ "ZZ 272 (1) MLZZZZZ (2) MM LZZZZZZZA "LZ WALLA LL LLL 50% Text-figure 3.— Miocene portion (from 365 to 499 cm) of core TT28-25 and distribution of silicoflagellate taxa. + —less than 2%. For Mesocena cf. elliptica ; \Wilililiilll! —2 radial spine forms (= M. diodon); O—3 radial spine forms (—M. triangula) ; ////// — 4 radial spine forms (= M. elliptica). Less than 2% of 2 radial spine forms (1) and 3 radial spine forms (2) are noticed in the sample. NortuH PAciFic SILICOFLAGELLITES: LING 107 carried out in connection with a radiolarian study (Ling and Anikouchine, 1967), indicated that at least a few other forms, Distephanus speculum, Dictyocha bachmanni and Corbisema tria- cantha, are found in Martin’s slides. Tynan (1957) studied the Miocene Calvert Formation of Mary- land and presented (op. cit., text-fig. 3) the stratigraphic ranges of 11 hitherto known genera of silicoflagellates. He stated (op cit., pp. 134-136) that “The Miocene is characterized by the occurrence of the genera Mesocena and Cannopilus, which are limited to that age... Within the Miocene, the genus Nothyocha is limited to the middle only. The silicoflagellates reached their maximum develop- ment during the Miocene. At the close of the Miocene, seven of the eight genera presented in the Miocene disappeared, leaving only Dictyocha to continue to the present time.” The faunal composition of Calvert sediments, according to Tynan, is as follows: Dictyocha crux, 90%, D. speculum, 10%, and both D. mutabilis and Corbisema trigona, less than 1%. The occurrence of silicoflagellates in Tertiary marine sediments from California was summarized by Mandra (1960, 1968). Among his stratigraphic conclusions (1968, p. 243), Mandra stated: “Six statistically valid species (Cannopilus calyptra, C. hemisphaericus, C. sphericus, Distephanus crux, D. speculum var. brevispinus, Meso- cena crenulata var. diodon) appear to be confined to two or more California Miocene stages,” and furthermore, “Hanna (1931, pp. 198-201) and this study confirm the presence of Mesocena in Eocene strata. Hence the recorded restriction of Mesocena to the Miocene as reported by Tynan (1957, pp. 133-134) must be modified.” In Europe, Stradner (1961) suggested the possible stratigraphic value of silicoflagellates in petroleum exploration. He illustrated 106 figures of 20 species and gave their geological ranges. Bachmann (1963) analyzed Miocene silicoflagellate fauna in “Badener Tegel” near Frattingsdorf, northern Austria. His fauna consist of five Dictyocha, two Mesocena, one Corbisema, and three Cannopilus species. Of special interest in Bachmann’s microfauna is the fact that Dictyocha crux represents approximately 50% of his assemblage (302 out of 700 total counted specimens). Bachmann and Papp (1968) summarized the stratigraphic distribution of silico- flagellates from upper Oligocene through Miocene from Austria. 108 BULLETIN 259 Jerkovic (1965) illustrated several new silicoflagellate fauna from Miocene (lower) Sarmation diatomite of Yugoslavia. Dumitrica (1968) found silicate microfossil assemblage from the “Horizon des Schistes a Radiolares” of Miocene (Tortonian) deposits in Rumania. Besides listing and illustrating Radiolaria and discoasters, he reported 28 silicoflagellates and ebridians. From Asia, Ichikawa (1956), Bachmann and Ichikawa (1962), and Bachmann (1964, 1967) examined silicoflagellates from three Miocene diatomaceous deposits of Japan. These studies were not based on_ stratigraphically spaced samples from the respective diatomites. Bachmann’s findings on silicoflagellate occurrences are important, because these three diatomites are not only in succession from late middle to late Miocene age but they also represent Mio- cene assemblage from the Japan Sea side. According to Fuji and Bachmann (1968), the three diatomites in the sedimentary column are shown in the following Table 3, and occurrences of the silico- flagellates in these three diatomites can be summarized as in Table 4. Undoubtedly an investigation on silicoflagellates from samples of closer stratigraphic intervals will ascertain the exact time range of the silicoflagellate species discussed by Bachmann. The silicoflagellate fauna recovered from the lower lithologic unit, interval between 365 and 499 cm depth, of the T7T28-25 core sediments present a somewhat different faunal composition from the known Miocene assemblages reviewed above. There is a com- plete absence of Cannopilus sphericus and C, picassoi; less abundant occurrence of Distephanus spp.; a complete absence of triradiate forms, such as genus Corbisema; and, finally, the silicoflagellate population consists of a monotonous assemblage throughout the interval (see Text-fig. 3). However, the occurrence of the species recovered here undoubtedly leads to the conclusion that the micro- fossils are Miocene in age and probably middle to late Miocene and not of the early Miocene. The author does admit, though, that it is still a dangerous exercise to place such an age determination upon this sedimentary unit, and only further detailed abundant strati- graphic occurrences of silicoflagellates from deep-sea sediments, particularly in the north Pacific, would confirm this conclusion. A sample from the Lamont-Doherty core collection, RC10-202 at 997-1000 cm depth from the top of the core, was studied for NortuH PAciFic SILICOFLAGELLITES: LING 109 Geologic Age Wakura-Notojima Area Pliocene ; Kojima sandstone Akasaki mudstone Upper Wakura (4) lizuka (3) diatomaceous mudstone diatomaceous mudstone glauconite sandstone glauconite sandstone Nanao lida (2) calcareous : sandstone diatomaceous mudstone Hojuji (1) Akaura diatomaceous mudstone sandstone Higashiinnai Nanahara alternation mudstone TTT TTT TT TT Anamizu Lower group Table 3.— Stratigraphic succession in Hokuriku region, Japan (modified after Fuji and Bachmann, 1968). Silicoflagellate occurrence reported: (1) Bachmann (1964), (2) Bachmann (1967), (3) Ichikawa (1956), (4) Ichikawa (1956), Bachmann and Ichikawa (1962). Miocene 110 BULLETIN 259 Upper Middle Diatomaceous mudstone and Wakura | Tida jul date of publication (1962) | (1967) Silicoflagellate taxa Mesocena elliptica Dictyocha crux D. fibula D. speculum C orhisema triacantha fa. minor C annopilus schulzi cx oe e- Dictyocha crux parva tetraceros sphaericus ernestinae a a lo a a a D. crux fa. trigona D. speculum cannopiloides D. speculum fa. minuta C annopilus iidaensis C. hemisphaericus Dictyocha formosa D. ausonia D. Mesocena apiculata schauinslandi M. oamaruensis C annopilus jouseae C. ichikawai CG. latifenestratas Table 4.—Silicoflagellate occurrences in Hokuriku region, Japan (Data after Bachmann, 1964, 1967; Bachmann and Ichikawa, 1962). Nortu PAciric SILICOFLAGELLITES: LING 11] comparison. The lithology of the sediments, according to Mrs. Jessie Donohue (personal communication) , is similar to the lower sedimentary unit of the TT28-25 core here discussed, and the micro- scopic examination of the sample further reveals that the sediment contains approximately a similar assemblage. (b) Quaternary occurrence of Mesocena cf. elliptica. In six of TT-28 cores studied, Nos. 14, 17, 19, 22, 23, and 24, an occurrence of M. cf. elliptica (Text-figs. 4, 5) was noticed. The complete absence of known Miocene forms and the association with modern assemblages in these cores seems to suggest that M. cf. elliptica did occur during Quaternary time. Such an observation seems to agree with the result of recent work on Radiolaria from the north Pacific (Hays, MS), because in the core sediments studied (1) only a few Eucyrtidium calvertense are found at the basal part of cores 14 and 22 and no specimen of E. matwyama Hays is found. The last appearance of latter form approximates the base of the Jaramillo Event (0.95 m.y. B.P.) (Hays, op. cit.) and (2) Drup- patructus acquilonarius Hays is found in the lower part of cores 17, 22, and 23. As discussed in systematic paleontology, there are some differences in the species at least in superficial appearance and in size between the Miocene specimen Mesocena cf. elliptica and those of Quaternary. It should be noted here that the last extinction for the M. cf. elliptica seems to coincide with those of Dictyocha cf. ausonia and D. subarctios Ling, n. sp. Such an unusual Quaternary occurrence agrees with the find- ings of Hays et al. (1969) and that of Mukhina (1963, 1966), al- though they found M. elliptica at two different levels within Pleisto- cene deep-sea sediments from the equatorial Pacific region. Be- cause the stratigraphic position of these M. elliptica has been dis- cussed in connection with other biogenic relics and the results of paleomagnetic polarity time scale, the present finding in the Quaternary deposits deserves a close examination here. In 1963, Mukhina reported M. elliptica from the core sediments at station 3802 (03°01.5’S, 172°52.4’W; water depth, 5329 m) of Vityaz’ 1957 Cruise 26. She stated that M. elliptica was found in sediment of the upper part of the core in the interval of 12 to 50 cm and that the species was known previously only from Tertiary sediments. The finding of M. elliptica in the samples studied indi- BULLETIN 259 9 11 nt ' o Nu - i icoflagellates in the central north Pacific il istribution of si ure 4.— D fig ext- T sea sediments. p- e de 113 LING PACIFIC SILICOFLAGELLITES: NorTH TT28-20 TT28-24 TT28-23 TT28-22 Pacific in the central north Text-figure 5.— Distribution of silicoflagellates iments. deep-sea sed 114 BULLETIN 259 cates a contemporary existence of the present form. Occurrence of this species is not shown in her figure 2 of floral composition but it is illustrated in her plate 3, figure 26, as an exotic form. In 1966, Mukhina studied the Swedish Deep-Sea Expedition (SDSE) core No. 62, as a part of her further investigation of diatom flora from deep-sea sediments of the equatorial Pacific which particularly aimed towards stratigraphic correlation and paleoclimatic implica- tion. Although it is not indicated in her figure 5 of the floral composition, occurrence of the present species at 1062 cm depth in this core was mentioned (1966, p. 109). Mukhina (fide Funnell, MS (1968) ) generally recognizes seven (I-VII) Quaternary horizons based on diatom and silicoflagellate assemblages from the region with Horizon I as Post-Glacial or Holocene Epoch. The criteria and her horizons which are relevant to the discussion of the present paper are as follow: Horizon IV is similar to Horizon If and is said to correspond to glacial conditions; it is distinguished by the presence of the silicoflagellate Mesocena elliptica and by the ex- tinction of the diatom Rhizosolenia praebergonii just above the base. Horizon V is similar to Horizons I and III and is said to cor- respond to interglacial conditions; it is distinguished by the maximum abundance of Rhizosolenia praebergonir and by the extinction of Thalassiosira convexa about half- way through the horizon. [Hays et al. (1969) indicated that R. praebergonii first appears usually above the Mam- moth Event of Gauss Normal Epoch and extends to above the Olduvai Event. Recently Koizumi (1968) found this species from the upper part of upper Miocene Funakawa Formation (Sample AK86). Though he showed a figure of the species (plate 34, figure 20 a, b) from Pliocene Wakimoto Formation (Sample AK115), it is not listed in his Chart I nor mentioned in his floral references (p. ZU). Horizon VI is similar to Horizons If and IV and is said to cor- respond to glacial conditions; it is distinguished by the entry of Rhizosolenia praebergonit part way through the horizon, by abundant Thalassiosira convexa and by the NortuH PAcIFIC SILICOFLAGELLITES: LING 115 presence of Nitzschia praemarina which became extinct at the end of the horizon. [Hays et al. (1969) indicated that the upper limit of T. convexa is below the Olduvai Event. | In applying these criteria, Mukhina then recognized Horizons I to V from the SDSE core 62 as follows: Horizon I, 9-90 cm; Hori- zon II, 90-380 cm; Horizon III, 380-740 cm; Horizon IV, 740-1230 cm; and Horizon V, 1230-1480 cm, the bottom of the core. She also recognized Horizons I through VI (fide Funnell, MS (1968) ) from a core 5100 (07°08.0’S, 140°13.0’W; water depth, 4076 m) of Vityaz’ 1961 Cruise 34. Ushakova (1966) found four stratigraphic horizons from the core 5100 based on nannoplankton assemblages. They are: Horizon I, 0-19 cm; Horizon II, 19-140 cm; Horizon III, 140-220 cm; and Horizon IV, 220-240 cm. It is in Horizon III, and particularly starting from 170 cm downward, that the number of discoasters in- creased sharply. Funnell (MS (1968) ), therefore, considered that Ushakova’s Horizon I corresponds approximately to Mukhina’s Horizon I; her Horizon II approximately to Mukhina’s II through IV, her Horizon III approximately to Mukhina’s Horizon V, and her Horizon IV to Mukhina’s Horizon VI. Furthermore, the presence of abundant discoasters (including forms recorded as D. brouwert and D. tribrachiatus) in the lower part of the core (below 180 cm) suggests that it, and by implication of Mukhina’s Horizons V (part) and VI, may be Pliocene in age. As for SDSE core 62, Ushakova indicated that discoasters are found between 1060 and 1230 cm and become dominant between 1230 and 1430 cm, the bottom of the core. Ushakova concluded (op. cit., p. 116) that “the boundary for the complete disappearance of discoasters from the sediments in core 62 should be raised at least to 1060 cm.” The radiolarian analysis of Nigrini (MS) on the SDSE core 62 reveals the following zonal sequences: Zone 1 (uppermost Quater- nary) , 0-200 cm; Zone 2, 218-460 cm; Zone 3, 508-810 cm; Zone 4 (lowermost Quaternary) , 868-1170 cm; Pliocene, 1170-1470 cm. It should be noted also that the Plio-Pleistocene boundary on the same core was indicated previously by Arrhenius (1952) between 1230- 1300 cm and this was generally agreed to by Riedel et al. (1963). Recently Hays et al. (op. cit.) studied numerous deep-sea cores from the equatorial Pacific and indicated that the occurrence 116 BULLETIN 259 of M. elliptica will bracket the Jaramillo Event (0.89-0.95 m.y.) (Cox, 1969) of the Matuyama Reversed Epoch. ‘The diatom micro- floral succession they found in the area seems to agree in general with that of Mukhina’s work. However, assuming that the Plio- Pleistocene boundary is at approximately 2 m.y., B.P., which is within (by Cox) or base (by Hays, et al.) of the Olduvai Events of Matuyama Reversed Epoch, this then implies that M. elliptica, according to the data (by Hays, et al.) , occurs approximately half- way through the Quaternary. Furthermore, there is approximately a 0.5 m.y. gap after the disappearance of Fragilariopsis antarctica and Rhizosolenia praebergonii and the reappearance of M. elliptica. As discussed earlier, these are more or less in successive sequence, according to Mukhina’s work, or, judging from the stratigraphic position in SDSE core 62, the occurrence of M. elliptica is within lower to lowest Quaternary according to (Zone 4) Nigrini (MS), Arrehenius (1952) and Riedel, et al. (1963). According to Hays, et al. (op. cit.) the upper limit of occur- rence of M. elliptica in cores V24-58, 59, 60, and 62 is near the Bruhnes-Matuyama paleomagnetic polarity epoch boundary. From their work, assuming 0.75 m.y. as the approximate position for the upper extinction in the core, the sedimentation rate (mm per 1000 years) calculated for the TT-28 cores are: 10 mm for the core 14, 2.3 mm for core 17, 5.5 mm for core 19, 5.1 mm for core 22, 7.4 mm for core 23, and 7.8 mm for core 24.The figures thus calculated are generally in good agreement with the recent results of paleomag- netic work by Opdyke and Foster (MS). Naturally, numerous fac- tors need to be considered, particularly: (1) rate of sedimentation was constant during the deposition of the entire core length, (2) despite the different type of coring apparatus, the core sediments are mutually comparable and no appreciable compaction or stretch- ing occurred during and after core recovery or after core recovery and (3) disappearance of M. cf. elliptica is geologically isochronous at low and middle latitudes of the north Pacific. It is concluded here that silicoflagellates could be a useful tool for deep-sea biostratigraphy. Furthermore, the problem formu- lated from the limited presence of M. cf. elliptica in the Quaternary deposits from equatorial and central north Pacific and its complete NortTuH PACIFIC SILICOFLAGELLITES: LING 1 7/ absence in the Pliocene, and possibly also in the early Pleistocene Epoch, still remains unsolved. REFERENCES Arrhenius, G. 1952. Sediment cores from the East Pacific. Swed. Deep-Sea Exped. Rept., vol. 5, fasc. 1, pp. 1-227. Bachmann, A. 1963. Silicoflagellidae. In Bachmann, A., et al., Mikropalaontologische Studien im “Badener Tegel” von Frattingsdorf N. O. Mitt. Geol. Ges., Wien, vol. 56, No. 1, pp. 145-155, pls. 16-22, figs. 1-2. 1964. Part II. Silicoflagellidae und Archaeomonadaceae. In Ichikawa, W.., et al., Fossil diatoms, pollen grains and spores, silicoflagellates and archaeomonads in the Miocene Hojuji diatomaceous mudstone, Noto Peninsula, Central Japan. 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BULLETIN 259 Explanation of Plate 18 All figures x500 unless otherwise indicated. Dictyocha cf. ausonia Deflandre ...:..2).2.420:5:50 5 ee 88 1. TT28-19, 490-493 em, L-2 (D45/0); 2. TT28-14, 850-853 cm, R-2 (G17/0); 3. TT28-14, 1000-1003, R-1 (E31/0). Dictyocha fibula Ehrenberg. ...:...::...044.0005-..0. eee 90 4. TT28-16, 204-207 cm, R-2 (S38/4), x540; 5. T1T28-17, 196-199 cm, R-1 (L20/3), x540; 6. TT28-23, 370-373 cm, R-1 (K21/4), x520; 7. TT-28-25, 390-393 cm, R-1 (06/4), x540; 8. TT28-25, 390-393 em, R-2 (H15/0); 9. TT28-25, 390-393 cm, R-1 (M24/3); 10. TT28-25, 390-393, R-2 (Q14/0). Dictyocha fibula ‘var.’ aculeata Lemmermann .......................... 91 11, 12. Different focus levels, TT28-19, 31-34 cm, R-2 (023/4); 13. TT28-19, 490-493 cm, R-1 (L6/4). Dictyocha fibula ‘“‘var.’”’ messanensis (Haeckel) |... 92 14. TT28-17, 4-7 cm, R-2 (010/0), x450. Dictyocha fibula forma rhombica Schulz nn. 93 15. T'T28-25 nose, R-2 (G23/0), x450. Dictyocha subarctios Ling) nxsp) (500... oc once ee 95 16. T1T28-24, 510-513 cm, R-2 (E16/0) ; 17, 18. Different focus levels, TT28-24, 510-513, R-2 (S24/0). BULL. AMER. PALEONT., VOL. 58 PLATE 18 BULL. AMER. PALEONT., VOL. 58 NorTH PACIFIC SILICOFLAGELLITES: LING 125 Explanation of Plate 19 All figures x500 unless otherwise indicated. Figure Page 1-4. Dictyocha subarctios Ling, n. sp. 95 1. Paratype, USNM No. 651557, TT28- 24, 510- 513 cm, te 4 “(K40/0) : 2. Paratype, USNM No. 651558, TT28-24, 510- 513 cm, R-4 (U46/2); 3. Holotype, USNM No. 651559, T128-24, 510-513, R-5 (K10/0); 4. Oblique abapicai view, TT28-24, 510-513, R-5 (D38/1). 5,6. Distephanus crux (Ehrenberg) ...................0.cccccccccccccsceceeeeeeeee: 96 5. T1T28-25, 367-370, R-1 (G9/4); 6. TT28-25, 473-476 cm, R2 U28/3). 7,8. Distephanus crux cf. “var.” stauracanthus (Ehrenberg) .............. 96 7, 8. Different focus ee x470, TT28-14, 490-493 cm, R-2 (L18/2). 9,10. Distephanus octangulatus Wailes 0c. 97 9, 10. Different focus levels, TT28-24, 210-213 cm, ie 2 (G19/0). 11-20. Distephanus speculum (Ehrenberg) 2200s. 98 11. T1T28-25, 390-393 cm, R-2 (Q8/1); fig. 12, TT28-25, 496-499, R-2 (R24/3); fig. 13, T28-25, 496-499 cm, R-2 (Y32/3); fig. 14, TT 28-25, 451-454 cm, R-1 (J20/4); fig. 15, T'T28-25, 451-454 cm, R-2 (J17/0); figs. 16, 17 TT 28-25, 451-454 cm, R-2 (W30/1); figs. 18, 19, TT28-23, 370-373 cm, R-1 (M33/0), x330; fig. 20, TT28-24, 510-513, R-2( P21/3), x430. 126 BULLETIN 259 Explanation of Plate 20 All figures x500 unless otherwise indicated. Figure Page 1-7. Cannopilus hemisphaericus (Ehrenberg) ...................0....0.cccccccee 99 1. TT28-25, 420-423 cm, R-1 (U7/2); 2. TT28-25, 367-370 cm, R-1 (U18/2), x450; 3. TT 28-25, 420-423 cm, R-2 (R31/3); 4. TT28-25 473-476 cm, R-1 (V20/0), x400; 5. edge view, TT'28-25, 473-476 cm, R-1 (Y7/0), x450; 6. oblique apical view, TT28-25, 496- 499 cm, R-2 (X52/4), x450; 7. RC10-202, 997-1000 cm, R-1 (G4/1), x450. 8-14. Mesocena cf. elliptica Ehrenberg (2.0... o eee 100 8. TT28-25, 496-499 cm, R-1 (S5/3); 9. RC10-202, 997-1000 cm, R-2 (F20/4), x450; 10. TT28-25, nose, R-2 (V20/4); 11. TT28-25, 496-499 cm, R-2 (D12/1) ; 12. TT28-25, 396-499 cm R-2 (X14/1) ; 13. T'128-17, 231-234 cm, R-2 (F26/0); 14. TT28-22, 380-383 cm, R-2 (K12/0). BULL. AMER. PALEONT., VOL. 58 PLATE 20 INDEX Note: Light face figures refer to the page number. Bold face figures refer to the plate number. A acquilonarius, Druppatructus ...... 111 var. aculeata, Dictyocha fibula .... 91 “var.” aculeata Dictyocha fibula 18 91, 105 antartica, Fragilariopsis ........ 116 PMLATNG Ciro: ot cocn cose: 89, 91, 102, 103 ausonia Dictyochay =... 88, 89, 90, 94, 95 cf. ausonia, Dictyocha .......... 18 88, 96, 98, 111 B bachmanni, Dictyocha ......... 97, 107 “Badener Tegel,” Frattingsdorf, PRUISGEIAY 9. eek 95, 107 IBTA ONC KOKS saabancecoasesoseeee 99 Bergonzano, Italy ...... 89 binoculus, Dietyocha 2... 99 var. brevispina, Dictyocha fibula . 88, 90 “var.” brevispina, Distephanus Speculums 103 var. brevispinus, Distephanus Speculum 107 brouweri, Discoaster 115 Bruhnes-Matuyana paleomagnetic polarity epoch boundary ............ 116 Caltanissetta, SC i eee , 94 Calvert Formation 89, 90, 97, 105, 107 calvertense, Eucyrtidium ...... 111 calyptra, Cannopilus ............ 107 “var.” cannopiloides, Distephanus Speculum) ............... 99 Cannopilus ................ 99, 107 Challenger ............... 91, 103 forma constricta, Dictyocha fibula 90 convexa, Thalassiosira 114,115 Corbisema .... 107, 108 crenulata, Mesocena 100, 101, 102 crux, Dictyocha ... 97, 105, 107 crux, Distephanus 19 96, 103, 105, 107 D Dictyocha ......... ae 88, 107 diodon, Dictyocha 100 var. diodon, Mesocena crenulata eee 107 Distephanus ........ 96, 108 E elliptica, Dictyocha (Mesocena) ............ 100 100, 101, 102, 111, 114, 116 elliptica, Mesocena .. cf. elliptica, Mesocena .......... 20 85, 90, 96, 98, 100, 105, 111, 116 var. elliptica, Mesocena crenulata cers ees 102 epiodon, Dictyocha .. 91 F fibula, Dictyocha 18 88, 90, 92, aoe 105 Funakawa Formation .............. 114 G Gauss Normal Epoch 114 H Halicalyptral = 99 Helyetianue 89 hemisphaericus, Cannopilus ....... 20 99, 107 Hollisk Cliff, Wircinaee ee 97 “Horizon des Schistes a Radiolares,” Rumania 108 127 INDEX J Jaramillo Event 111, 116 K Kii Channel, Osaka Bay 89 M Mammoth Event 114 Marmorita, Italy ...... 89 matuyama, Eucyrtidium 111 Matuyama Reversed Epoch 116 Mesocena 100, 101, 102, 107 forma mesocenoidea, Dictyocha fibula 93 messanensis, Dictyocha : 92 var. messanensis, Dictyocha fibula .... 92 “var.’’? messanensis, Dictyocha fibula : 18 92 Meteor ee 92, 103 mutabilis, Dictyocha 89, 93, 94, 95, 107 N Norwich, Connecticut 97 Nothyocha ...... 107 oO octangulatus, Distephanus 19 97 var. octonarius, Distephanus speculum 97 Olduvai Event 114, 115, 116 P Pacific 85, 87, 90, 91, 93, 98, 99, 101, 102, 108, 111, 115, 116 var. pentagona, Dictyocha fibula 91 “var.” pentagonus, Distephanus speculum 103 picassoi, Cannopilus 108 polymorpha, Mesocenal-= 102 praebergonii, Rhizosolenia .......... 114, 116 praemarina, INItZSChiaee eee 115 Q quadrangula, Mesocena ............... 100, 101 var. quadrangula, Mesocena polymorpha .......... 100, 102 “var.” quadrangula, Mesocena polymorpha .......... 100, 101, 102 R regularis, Dictyocha 90 Re zane eee 89 rhombica, Dictyocha 93, 94 forma rhombica, Dictyocha fibula .... 89, 93 “forma” rhombica, Dictyocha IDIDUUAY sanceccdnnonenes< 18 93 forma rhombica, Dictyocha fibula var. aspera ............ 89, 93 Richmond, Virginia 99 Robert D. Conrad (RC), research vessel (RV) .......... 85, 86, 96, 100, 101, 102, 108 rotundata, Dictyocha 95 forma rotundata, Dictyocha fibula .... 95 S Santa Monica, Californiay eee 97 Sarmatianiessee 89, 108 Scientist’s Cliff, Maryland i. 90 Sharktooth Hill, Californias 89 speculum, Distephanus ....... 19 98, 99, 107 sphericus, Cannopilus 107, 108 forma spinosa, Dictyocha fivula var. messanensis .. 92 INDEX stauracantha, Dictyocha ........ a. 97 stauracanthus, Dictyocha .......... 96 stauracanthus, Distephanus ....... : 97 var. stauracanthus, Distephanus crux 97 ef. “var.” stauracanthus, Distephanus Gib. Gee 19 96, 98 staurodon, Dictyocha 91 subarctios, Dictyocha ....18,19 87,90, 95, 98, i001 Swedish Deep-Sea Expedition (SDSE) 114, 115, 116 T Thomas G. Thompson (TT), research vessel (EN). 2 eer 85, 86, 89, 94, 95, 96, 100, 105, 108, 111 triacantha, Corbisema triangula, Dictyocha triangula, Dictyocha (Mesocena) triangula, Mesocena tribrachiatus, Discoaster trigona, Corbisema Tortonian Vv Vancouver Island ... Vema (V), research vessel virginica, Halicalyptra Vityaz WwW Wakimoto Formation 100, 100, ULI 107 101 100 101 115 107 108 97 102 99 115 114 @ or ey, © Ay) a Ree ie eh i ' . es ; ie TAs 4h ns 7 e- S* Sau ys rn ha - ORE Hus. i 4% a ee PaaS +) MUS. COMP. ZOOL LIBRARY BULLETINS ie ey OF UNIVERSITY; AMERICAN PaALnONTOLOGY (Founded 1895) Vol. 58 No. 260 REVISION OF THE NORTH AMERICAN PLEUROCYSTITIDAE (RHOMBIFERA-CYSTOIDEA) by RONALD L, PARSLEY October 30, 1970 Paleontological Research Institution Ithaca, New York 14850 U. S. A. PALEONTOLOGICAL RESEARCH INSTITUTION 1970 - 71 PRESIDENT! 2.5.2 ooo sc cocked secs ak toast csc canoe nna eae eee eee WILLIAM B. 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For reprint, Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., New York, N.Y. 10017 U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Cor- poration, 111 Fifth Ave., New York, N. Y. 10003 U.S.A. Subscription may be entered at any time by volume or year, with average price of $18.00 per volume for Bulletins. Numbers of Palaeontographica Ameri- cana invoiced per issue. Purchases in U.S.A. for professional purposes are de- ductible from income tax. For sale by Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. Bese lie TINS OF AMERICAN Peron | OLOGY (Founded 1895) Vol. 58 No. 260 REVISION OF THE NORTH AMERICAN PLEUROCYSTITIDAE (RHOMBIFERA-CYSTOIDEA) by RONALD L. PARSLEY October 30, 1970 Paleontological Research Institution Ithaca, New York 14850 U. S. A. Library of Congress Card Number: 70-123874 Printed in the United States of America Arnold Printing Corporation CONTENTS ENORUIHEGE” Aino ce eet sence ac ae Seer a Corea a ee ea a ne 135 REI IUO Te tt ee tee ene as PSs Pine vet OF oe Se 135 Acknowledgments ....................-.-.- ee Pa REA Dery te a nes lee Sd 137 SeIRER TEI ALIGS) Merete eee ewe eas eee re: HON RO Ae dee Oi yell ene 8 tse 137 ISTEP CESTAS TIS Ea Rs naar A = RS en ne eo A LL See 1377, LENGE AGVAMIGHET GOALS 0 PY Sopa ero Se ED er 141 REMADE TIGU SITES mT PEN gq eh ore cen eR ee als ON ee 183 Pinter cust ESO TIChiiy ANG KR Ky, Soest ec eo ee th ed 187 58 SNP STR SS Si a RA a ada ah, MSA eae Pe er ie Nan See Parle EE 196 Eales eeeee ene ene Ra bees “rhomb-shaped elevation (with the long axis oblique to the suture) .” Unfortunately, neither author presented adequate photo- graphic evidence. If they are right, the structure must be prone to destruction. The arcuate hydropore is generally similar to that in other cystoids or other ‘‘Pelmatozoa.” The column is externally typical of an advanced glyptocystitid. There is an expanded proximal region similar to the tetramerous proximal stele of many “carpoids’’ with alternate, expanded seg- ments that, according to Bather’s (1913, p. 459, figs. 63, 64) figures partly override the intervening ossicles and suture in a dove-tail fashion with them. Distally the segments do not imbricate or suture in a dove-tail manner. Here the ossicles are more elongate than those in the proximal column and (in North American species) bear a medial annulus or ridge. The column is gently tapering, circular in cross-section, and often showing evidence of the distal portion having a counter- clockwise planispiral curvature or spiral (also seen in Amecystis) . The lumen is proximally large, analogous to that of “carpoids,” and distally it is small. At the distal end there is no evidence of any sort of holdfast. Mode of life and orientation. — Life orientation has been dis- cussed by various authors but in the greatest detail by Kirk (1911), Bather (1913), and Paul (1967a). Kirk (1911, pp. 20,21) recognized the basic life orientation as visualized by most workers: an unattached, eleutherozoic cystoid with the convex rhomb face upwards and the flattened anal face adjacent to the substrate. He also noted that the distal end of the column was “somewhat coiled” and without a holdfast. Bather (1913, pp. 509,510) did not recognize the eleutherozoic potential of this genus. He was convinced that the rhomb face rested on the substrate, supported by the umbones of /L2, L2 and L3, thus allowing the unobstructed use of the pectinirhombs on the under- side, and the likewise unobstructed “‘sanitary’” use of the anus on the upper face. Bather assumed that the substrate was hard enough so that the theca would not sink in deep enough to foul the rhombs. The distally coiled column was postulated to have served as a loose attachment about some upright object. Bather seems to have been overly concerned about the sanitation problems of this genus which NortTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 159 overshadowed other compelling reasons for the ventral position of the anal face, e.g., hydrodynamics of the theca, fouling potential of pectinirhombs. Paul (1967a, pp. 113-118) pointed out the drawbacks of Bather’s arguments and has extensively elaborated on the life orien- tation and economy of the genus. He is in general agreement with Kirk and most subsequent students, including the author, in orienting the rhomb surface uppermost and in noting its apparent eleutherozoic habits. He further postulated that water currents flowing through the dichopores of the pectinirhombs (see above) flowed in an admedial direction across the theca. If the organism was rheotaxially oriented, according to Paul, deoxygenated water would have flowed over rhomb B2/IL2. The inferred inefficiency of circulating deoxygenated water would thus render this rhomb of little use. In accordance with Dollo’s Law the rhomb would tend to be reduced or disappear, as it often does in younger species. It is possible that the currents may have flowed in the opposite direc- tion, 2.e., abmedially, thereby moving particulate matter both through and over the rhombs to the lateral and proximal margins. This would have helped in keeping the upper surface clean of fouling substrate. Paul also noted that the loss of the B2/IL2 rhomb is usually associated with the presence of an antirectal lobe. He interpreted such forms, e.g., Pleurocystites sp. Breimer, to have been more vagile than those with the B2/IL2 rhomb and no antirectal lobe. The latter type, e.g., P. squamosus, was postulated by him as being slow moving, with the theca always against the substrate. While Pauls’ analysis is comprehensive, some additional comments are needed. The convexoplanate theca probably served as a hydrofoil so that bottom currents exerted a certain amount of lift. This lift, together with the displacement volume of the theca and possibly some muscular aid from the proximal column, may have been suf- ficient to have maintained the theca parallel to, but off of, the sub- strate. In the absence of currents the theca would almost certainly rest on the sea floor. The raising of the theca would have facili- tated the more efficient use of the ventral hydropore, gonopore and anus, but would not have totally obstructed their use if it did 160 BULLETIN 260 not. The depression or emargination on the proximal end of the rectal lobe probably would have allowed fairly efficient voiding of fecal matter into the milieu if the theca was resting on the sub- strate. If water were pumped through the gut and voided by aid of muscular contractions of the periproct against the walls of the gut, this would be especially true. The hydropore and gonopore could function and not become clogged if the apertures were small enough but would have functioned more efficiently if above the substrate. The lack of ventrally extended marginals produced as “runners” (as in many anomalocystitids) or as knobs (as in many of the Cornuta) , or the lack of a concave lower face, seems to indicate that the ventral polyplated periproct, which was probably slightly convex in life, was, however, generally not in contact with the substrate. From the Middle to the Upper Ordovician there is a general trend toward the enlargement of the periproct, manifested by the narrowing of the marginals and the relative broadening of the theca. The periproctials, in keeping with this trend, become smaller, more evenly hexagonal and thinner. There is also a concomitant tendency for the pectinirhombs to become slightly diminished in size and probably, as evidenced in P. beckeri, become less efficient. It seems unlikely that these trends are unrelated. The decrease in size of the rhombs may be directly related to the increased and ?more efficient respiration by increased flowage of water through the gut. This increase can be explained by (probable) rhythmic flexing of the (progressively more flexible) periproct which was effected by peristaltic pumping of the digestive system. The pectinirhombs, being always close to the sediment, prob- ably had some clogging problems. While elevated callus-like rims are common in Pleurocystites which would tend to deflect a certain amount of sediment, the problem would still exist. (See also dis- cussion by Paul, 1967a, pp. 110, 111.) It is possible that their pectini- rhombs were not efficient enough, considering their habitus orienta- tion, and progressive respiratory demands were made on other organs, é.g., the gut. Possibly, in accordance with Dollo’s Law, the rhombs were thereby diminished. Pleurocystites was a detrital feeder by nature of its flexible, elongate, exothecal arms. The lateral position of the grooves facili- tated the gathering of organic particles from and near to the sub- NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 161 strate. Food was probably aided toward the peristome by entangle- ment in strings of mucus, propelled by cilia and ?water currents produced by periproctial-intestinal pumping. The column is generally distally coiled or curved into a semi- circle. ‘This curvature would aid in stabilizing the animal on the sea floor. ‘The column was also a locomotor organ, probably not as efficient as the heterostele in “carpoids” due to its greater rigidity (it has no gliding planes and the dove-tail suturing is not overly flexible) and its greater length. It did, however, allow wriggling over the substrate. The proximal column, which is somewhat ana- logous in form and function to the heterostele in “carpoids,” is a conservative holdover from more primitive pentaradial glyptocy- stitids. The long, terete distal column in adult specimens probably was sufficiently heavy to preclude actual swimming. Juvenile speci- mens tend to have a more flagelliform column and may have had some swimming ability. In North America Pleurocystites are found in shaly limestones to dark limy shales or, in some cases, in recrystallized limestones. The limy mud environment, where the waters were well aerated and were rich in organic detritus, seems to have been the most common living environment. Usually this genus is found in association with numerous other organisms: cystoids, crinoids, brachipods, or their fragments. Pleurocystites squamosus Billings, 1854 PI. 21, figs. 1-5; Pl. 22, figs. 1-9; Pl. 23, figs. 1-6; Pl. 24, figs. 3-5, 8, 9; Pl. 26, figs. 6-9; Text figs. 14 1854. Pleurocystites squamosus Billings, Canadian Jour., vol. 2, pp. 251-252, figs. 9-12. 1854. Pleurocystites robustus Billings, ibid., p. 252, fig. 15. 1857. Pleurocystites squamosus Billings, Billings, Canada Geol. Sur., Report of Progress for the Years 1853-54-55-56, p. 286. 1858. Pleurocystites squamosus Billings, Billings, Canadian Organic Remains, Dec. III, Canada Geol. Sur., p. 49, pl. 1, figs. la-d. 1858. Pleurocystites robustus Billings, Billings, ibid., pp. 49,50, pl. 1, fig. 2a. 1895. [?] Pleurocystites mercerensis Miller and Gurley, Illinois State Mus. Nat. Hist., Bull. No. 6, pp. 60,61, pl. 5, figs. 25-26. 1896. Pleurocystis squamosus Billings, Haeckel, Die Amphorideen und Cystoi- deen, Fest. v. C. Gegenbaur, Bd. 1, pp. 37-44. 1899. Pleurocystites squamosus Billings, Jaekel, Stammesgeschichte der Pelma- tozoen, Thecoidea und Cystoidea, Bd. 1, p. 234. 1899. Pleurocystites squamosus var. robustus Billings, Jaekel, ibid., p. 234. 1899. non Pleurocystites squamosus var. anticostiensis Billings, Jaekel, ibid., p. 234. 162 BULLETIN 260 1913. Pleurocystis squamosus Billings, Bather, Roy. Soc. Edinburgh, Trans., vol. 49, pt. 2 (No. 6), p. 464, p. 459, figs. 63,64, p. 463, fig. 65. 1913. Pleurocystis squamosus var. robusta Billings, Bather, ibid., pp. 465, 463, fig. 66. 1916. Pleurocystites squamosus mut. matutina Billings, Ruedemann, New York State Mus., Bull. 189, pp. 27-29, pl. 5, figs. 1-4. 1928. Pleurocystites squamosus Billings, Hussey, Univ. Michigan, Contrib. Mus. Paleont., vol. 3, No. 4, pp. 77-78, pl. 1, figs. 1-3,6. 1946. Pleurocystites squamosus Billings, Wilson, Canada Dept. Mines, Res., Geol. Sur., Bull. 4, p. 12, pl. 2, figs. 5-6. 1946. Pleurocystites robustus Billings, Wilson, ibid., pp. 13,14, pl. 4, fig. 4. 1967a. Pleurocystites squamosus Billings, Paul, Zool. Soc. London, Symp. No. 20, p. 120. Diagnosis. — Theca variable in outline and rhomb face proso- pon, rectal lobe common but usually not greatly produced. Three well-developed pectinirhombs, diamond-shaped to oval in outline. Periproct covered with ca. 500 platelets that are usually hexagonal in outline. Range. — Middle Ordovician of Ontario, Quebec, Michigan, New York ?Kentucky, and ?Virignia. Description. — Pleurocystites squamosus varies considerably in form, especially in outline of the theca and configuration of the pectinirhomb rims or calluses, as well as in the prosopon on the rhomb surface. Aside from minor variations in outline and size of the rectal lobe, the outline of the lateral margins shows consider- able variations They may be evenly curved (PI. 23, fig. 3) or may be nearly straight-sided with pronounced “shoulders” or angula- tion at the distal rhombs (Pl. 23, fig. 4). These variations occur in all ontogenetic stages except that the pronounced “shoulders” are usually found on larger specimens but are never as well de- veloped as in P. beckert. The theca in Pleuwrocystites squamosus, like other species of Pleurocystites, and other pleurocystitids) , bears superficial resem- blance to the “carpoid” orders Mitrata and to the North American representatives of the Soluta. These similarities as discussed above, e.g., flattened convexo-planate theca, geniculation of plates to form “marginals,” and the relative enlargement of some abmarginals to form prominent “somatic plates,” are simply convergent features due to the adaptation of the benthonic-vagile mode of life. The secondarily derived bilateral symmetry which is especially evident in the plate outlines on the rhomb face is also similar to NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 163 many of the “carpoidea.” With the exception of JL2 and “O3” which are axial in position, all of the plates on this face are essentially symmetrically paired. On the anal face bilateral symmetry is primarily manifest in the basal and lateral series. The “marginal” plates form a border of even width about the periproctial area. It is characteristically made up of B2, B3, IL4, IL5, IL1, 1L3, L1 and L4. The basals B2, B3 form most of the ven- tral proximal girdle. In the anal lobe of many specimens JL4 extends proximally for some distance. Plates LJ and IL3 form only small triangular facets on the anal face. They rarely attain the inner margin of the border, and geniculate onto the rhomb face where they are prominent “marginals.’’ Enclosing the largest part of the periproctial area are the “marginal” laterals LJ and L4 which suture medially. This suture is commonly short, but L1/L4 are never completely separated by the intercalation of distal plate elements. The disposition of the plates on the upper or rhomb surface is uniform, although there occurs some variation in plate outline. Basals B2 and B3 meet sagittally and form a broad, squat “Y.” They are subequal and differ mainly in that B2 shares a pectini- rhomb with JL2. Across the proximal ends of these basals (at the base of the “Y”) is a low, rounded transverse ridge against which abuts the proximal end of the column. Basals BJ and B4 complete the attachment base on the anal surface and extend onto the dorsal face, occupying proximal positions lateral to B2 and B3. Bf is somewhat larger than Bl and comprises much of the rectal lobe area located at the (habitus) left proximal margin. Infralaterals JL4 and IL5 are subequal and subquadrate plates which lie proximally-laterally to JL3 and ILI respectively. IL4 is usually slightly larger than JL5 due to its proximal extension to form the proximal lateral corner of the rectal lobe. JLJ and IL3 are also subequal, usually heptagonal on the rhomb face and, while they are prominent “marginals” on this face, they become sharply reduced laterally and are manifest on the anal face as small, trian- gular facets. Infralateral JL2 is median in position and is analogous in position to the median adoral plate in many Mitrata. It is the largest thecal plate, hexagonal in outline, and shares a pectinirhomb with B2. 164 BULLETIN 260 There are four pectinirhomb-bearing lateral plates, LI-L4. Lateral L5 is presumed to be missing, although Paul (1967a) homo- logized it with what is herein called “O6”. The non-marginal or “somatic” laterals (L2 and L3) are subequal in size and outline. L2 is slightly smaller than L3 and pentagonal in outline, while L3 is elongately, irregularly hexagonal. The adjacent “marginal” laterals (LI and L#) are steeply sloping, elongate, usually penta- gonal plates on the rhomb face. The half-pectinirhombs on LI and L4 are larger than those on the “somatic” laterals, not only in the length of the dichopores, but in the surrounding callus area. In some specimens the margins of these plates are quite convex. Distal to L2 and L3 are two hexagonal radials, R2 and R3. R2 is larger and more sagittal than R3 which is shifted, relative to the axial plane, to the left. Radials R/, R# and Rd have become in- corporated into the apical area which also includes orals and in- cluded arm plates. The apical area has been discussed above and is typical for the genus. The arms and column are likewise typical. Pectinirhombs, which are often diagnostic in Pleurocystites, show considerable individual and ontogenetic variation in this species. Both the lamellar folds and the calluses, or rims, are af- fected. Pectinirhomb L3/L4 is always the largest, occupying most of the suture’s length; L1/L2 is smaller and occupies usually less than half the length of the dividing suture; I[L2/B2, while usually slightly smaller than rhomb L//L2, often occupies a greater portion of the suture. Many juvenile specimens tend to have narrow, steeply elevated rims about the folds, while mature forms commonly have broader and relatively less steep-sided rims. As a rule, the absutural ends of the rims on the lateral plates of adult specimens are some- what pointed and elongated, especially the admarginal ones on L/ and L4. The rim around JL2/B2 is generally uniformly oval with little absutural thickening. Prosopon on the rhomb face is highly variable. Most specimens are relatively smooth but with low, radial ridges extending from near to, or from, the center of each plate to each plate corner. This is especially prevalent on R2, R3, L2, L3, ILI, IL2 and IL3. Fre- quently the ridges on these plates coalesce with those on adjacent NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY ne f3} aaeat Text-fig. 4.— Pleurocystites squamosus Billings. A par- tial reconstruction of a rhomb or dorsal surface (Pl. 22, fie 9) en this specimen the radial elements of the prosopon are well develop- ed. In specimens of this type the rims or calluses around the rhombs are sometimes not so well developed as in the smoother forms (Text- fig. 1) 165 166 BULLETIN 260 plates. In some specimens the concentric growth lines are also present and are produced into low ridges, which results in a can- cellate effect. Other specimens have transverse, fine to coarse, crenulations across the sutures of the rhomb surface plates that are bounded by radial ridges and are superficially similar to conjunct pore rhombs; otherwise the plates are smooth. Finally, in some specimens the plates are smooth except for slight faceting or flat- tening of the plate surfaces between the radial ridges. Discussion. — It is apparent that this species, as recognized in this work, shows considerable variation in thecal outline, pectinirhomb rims and prosopon. Variation in P. squwamosus is not, however, so extensive as to be unwieldy, nor is it a catch-all for a group of similar but distinct species. Several morphological types, when viewed separately, may seem distinct enough to warrant the estab- lishing of a new species or subspecies; however, “intermediate” forms between these and other types would indicate that such splitting would be arbitrary. Jaekel (1899, p. 234) and Bather (1913, p. 465) both placed the monotypic P. robustus Billings (Pl. 21, fig. 2) in the better known species P. squamosus. Pleurocystites robustus is conspecific with P. squamosus and is known only as a distal end of a theca bearing rather coarse prosopon. Pleurocystites Miller and Gurley, 1895, has never been reported other than from the lower Lexington Limestone, Curdsville Limestone Member of Mercer County, Ken- tucky. It seems to be a preservational (silicified) variation, and there is no apparent morphological basis to separate it from P. squamosus. Ruedemann (1916, pp. 27-29) added the “variety” (“mutation” as used by him) P. squamosus mut. matutina for some lower Tren- tonian specimens from New York. The specific assignment of these specimens is probably correct. Ruedemann (op. cit., p. 29) also noted that P. anticostiensis sillings, placed in synonymy with P. squamosus by Jaekel (1899, p. 234), is not Middle Ordovician in age as supposed by Billings (1857, p. 288) but is found in late Ordovician or (?) early Silurian beds. A small fragment of a specimen from these beds examined at the Geological Survey of Canada in Ottawa indicates that these pleurocystitids were dorsally convex and with a periproct bearing NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 167 small platelets. When more specimens from these beds are known they probably will be closer akin to P. beckeri than to P. squamosus. Pleurocystites filitextus Billings Ply24. figs, 6) 7: Pl. 255 figs, 1-8 1854. Pleurocystites filitextus Billings, Canadian Journal, vol. 2, p. 252, figs. 13,14. 1857. Pleurocystites filitextus Billings, Billings, Canada Geol. Sur., Report of Progress for the Years 1853-54-55-56, p. 286. 1857. Pleurocystites elegans Billings, ibid., p. 287. 1857. [?]Pleurocystites exornatus Billings, ibid., p. 287. 1858. Pleurocystites filitextus Billings, Billings, Canadian Organic Remains, Dec. III, Canada Geol. Sur., pp. 50-51, pl. 2, figs. 1a,1b. 1858. Pleurocystites elegans Billings, Billings, ibid., pp. 51,52, pl. 2, figs. 2a-d. 1858. [?] Pleurocystites exornatus Billings, Billings, ibid., p. 52. 1859. Pleurocystites filitextus var. P. elegans Billings, Chapman, Canadian Journal n. s., vol. 4, p. 45. 1881. Pleurocystites filitextus Billings, Billings, Ottawa Field Naturalists Club, Trans., No. 2, p. 34. 1896. Pleurocystites filitexta Billings, Haeckel, Amphorideen und Cystoideen, Fest. v. C. Gegenbaur, Bd. 1, pp. 44,45, pl. 2, figs. 15,16. 1899. Pleurocystites filitextus Billings, Jaekel, Stammesgeschichte der Pelma- tozoen, Thecoidea und Cystoidea, Bd. 1, p. 234. 1900. Pleurocystis filitextus Billings, Bather, Treatise on Zoology, Pt. 3, p. 65, fig. 34. 1913. Pleurocystis filitextus Billings, Bather, Roy. Soc. Edinburgh, Trans. vol. 49, pt. 2, (No. 6), pp. 465,466; p. 453, figs. 60,61; p. 454, fig. 62; p. 463, fig. 68. 1913. Pleurocystis elegans Billings, Bather, ibid., pp. 466,467; p. 463, fig. 67. 1913. [?] Pleurocystis cxornata Billings, Bather, tbid., p. 467. 1916. Pleurocystites filitextus Billings, Ruedemann, New York State Mus., Bull., No. 189, p. 28. 1946. Pleurocystites filitextus Billings, Wilson, Canada Dept. Mines, Res., Geol. Sur-eBulls Nos 4.) p. 13) ple stics 4: 1946. Pleurocystites elegans Billings, Wilson, ibid., p. 13, pl. 3, fig. 3. 1948. Pleurocystites cf. filitextus Billings, Sinclair, Jour. Paleont. vol. 22, No. 3, pp. 303-305, pl. 42, figs. 1-4,10. 1948. Pleurocystites elegans Billings, Sinclair, ibid., pp. 303-305. Diagnosis. — Pectinirhomb L3/L4 lanceolate, usually extending length of suture in mature specimens, its bisecting suture fre- quently lateral, parallel to subparallel to rhomb surface. L1/L2 usually subrhombic in outline. Periproct covered with 30-70 irregu- lar, polygonal plates. Range.— This species is found in the Middle Ordovician (Trentonian) Hull beds and Sherman Fall beds of the Ottawa Formation, Ontario and Quebec. Sinclair (1948, p. 305) stated that Wilson (1946, p. 2) was probably in error placing this species from the “Cystid beds” of Raymond in overlying Cobourg beds. Description. — The outlines of the theca and pectinirhombs are 168 BULLETIN 260 somewhat variable, and this is the reason why Billings (1854) and others recognized P. elegans as a separate species. Pleurocystites fili- textus has commonly been described as an elongate, narrow shoul- dered form, and P. elegans, with an outline similar to P. sguamosus but essentially without the rectal lobe, was considered a different species.* In P. filitextus, as now or previously recognized, the rectal lobe is usually not well developed, although one of the syntypes (Bill- ings, 1858, pl. 2, figs. la-b) does display a prominent one. This may be due largely to preservation. The thecal plates in P. filitextus are similar to those in P. squamosus except that they are relatively longer. The distal plates, however, are relatively similar in scale. One of the most distinct differences between these two species is that in many specimens of P. filitextus the “marginal” laterals LJ and L¢ are absent from the dorsal face. In such specimens the pectinirhombs, especially L3/L4, are elongated and essentially marginal. (Pl. 24, fig. 1.) Other specimens have greater expression of the “marginal” laterals on the dorsal surface, and these specimens usually have a broader theca with diamond-shaped, rather narrow rimmed pectinirhombs. Previously such specimens were frequently referred to as P. elegans. Intermediate forms are known, however, where a specimen will ex- hibit characteristics of P. filitextus and of “P. elegans.” (Pl. 25, figs. 1, 3, 5, for comparisons.) In specimens where pectinirhombs L3/L4 is marginal it is usually lanceolate in outline and extends the entire length of the suture. In “P. elegans” this rhomb is elongately quadrate to oval and slightly shorter (in adult forms) than the suture. Rhomb L1/L2 generally is intermediate between being wholly marginal or dorsal. In outline it is diamond-shaped and does not extend the length of the suture. Pectinirhomb B2/IL2 is not markedly distinc- tive. 4 Bather (1913, p. 467) noted that when Billings’ (1858) specimen, in plate 2, fig. 2d, was removed from P. elegans and placed in P. filitextus by W. R. Billings (1881, p. 34) no difficulty existed in telling the two species apart. Also, Bather, ibid., noted the only significant difference between P. squamosus var. robustus and P. elegans was the nature of the pectinirhombs, as he had no information about the periproctials of the latter species. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 169 One of the principal species taxobases is the size and number of the periproctials. P. filitexius has 30-70 irregular platelets. It can now be demonstrated, as was correctly presumed by Bather (1913, p. 466), that “P. elegans” also shares this feature. As in P. squa- mosus, there is some indication that the peripheral platelets tend to be smaller than those toward the center of the area, thus sup- porting the hypothesis of peripheral addition of new platelets. So far as is known, the periproctials bear no prosopon. The anal pyramid is composed of eight, or more commonly nine, wedge-shaped plates, with several thin, tapered plates vari- ously intercalated between them. As in P. squamosus, the adjacent periproctials are reduced in size and appear to be tightly sutured. The arms and column are not so well known as in P. squa- mosus but do not seem to be significantly different. Prosopon on the dorsal surface consists primarily of ridges radiating from the center, or umbones, to the plate corners, as well as numerous, pseudo-conjunct pore rhomblike, interangle ridges. The interangle ridges are frequently more pronounced than those on P. squamosus and are nearly as large as the primary radiating ridges. In “P. elegans”-like specimens the ridges are all prominent and unbroken; in “P. filitextus’-like specimens the primary radiat- ing ridges are relatively prominent and unbroken, but the inter- angle ridges are reduced and beaded. The beading is often more pronounced on the more proximal thecal plates. Discussion. — The differences between P. filitextus and P. ele- gans have been examined and variously dealt with by divers au- thors. Billings (1858, pl. 2) noted, while commenting on figure 2d of that plate: “. . . The crushed condition of this, and indeed of all specimens, renders it most difficult to decide when the species are so closely allied.”” Chapman (1859, p. 45) in a review of Billings (1858) expressed the opinion that P. elegans “may prove . . . mere variety of P. filitextus.” W. R. Billings (1881, p. 45), on the other hand, removed the specimen in question (cf. Billings, 1858, pl. 2, fig. 2d) from P. elegans and placed it in P. filitextus, maintaining that the two species were distinct. Jaekel (1899, p. 234) placed P. elegans in the species P. filitextus; however, he did not state the criteria by which this conclusion was derived. If he were in pos- session of “P. elegans” which showed the large periproctials, or 170 BULLETIN 260 specimens which showed “transitional” traits, they were not men- tioned in his work. Jaekel (cbid.) also included P. exornatus Billings, 1957, as a “variety” of P. filitextus. Unfortunately, P. exornatus was never figured, and no specimen bearing this name is to be found in the collections of the Geological Survey of Canada. In his original de- scription, Billings, (1857, p. 257) described P. exornatus as having strong, radially arranged ridges on the plates of the dorsal face and large periproctials like those of P. filitextus. The pectinirhombs were described as being similar to P. robustus (=P. squamosus here- in). It is possible that this essentially unknown species was similar to “P. elegans” and, hence, conspecific with P. filitextus. Subsequent to Bather (1900, 1913), authors generally recog- nized P. filitextus and P. elegans as separate species. Wilson (1946) partially redescribed these two species and photographically fig- ured some of the type material. Her descriptions, like those of Bill- ings (1854, 1857, 1858), are based on the general nature of the rhombs and the plate sculpture. Sinclair (1948, pp. 303-305) discussed the nomenclature of both “species” at length and recognized the wide variation mani- fest in them. While he recognized the distinct possibility that P. elegans was conspecific with P. filitextus, he did not formally place them in synonymy. Differences between Pleurocystites filitextus and “P. elegans” are gradational in outline and on the rhomb surface as evidenced by intermediate and intermixed traits on various specimens. To some degree the differences may be ontological. Many small specimens tend to be “P. elegans” types while large specimens are frequently undoubtedly P. filitextus. However, small P. filitextus specimens and large “P. elegans” specimens are known. It is possible that when more specimens are available and can be statistically analyzed we may be dealing with sibling speciation. Some specimens of Pleurocystites squamosus are remarkably homeomorphic with “P. elegans” (PI. 22, fig. 6; Pl. 23, fig. 2). Thecal outline, prosopon, are often similar. In some cases only the periproctial area is diagnostic, especially if the pectinirhombs are eroded or if the specimen is a juvenile. The paleoecology of P. filitextus varies from that of other NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 171 forms in this genus. It is usually found in dark, organic shales, which indicates that it lived in quiet, and probably deeper, waters than other coeval species of Pleurocystites. Pleurocystites watkinsi Strimple Pl 24 fide Pl 20, 11S asc: Text-figure 5 1948. Pleurocystites watkinsi, Strimple, American Jour. Sci., vol. 246, pp. 761- 764, pl. 1, figs. 1-3. 1967a. Praepleurocystites watkinsi (Strimple), Paul, Zool. Soc. London, Sym. No. 20, p. 120. Diagnosis. —Theca nearly bilaterally symmetrical in outline; anal surface with broad “marginal” plates; periproctial area re- duced; rectal lobe only slightly extended; plate “O7” present; IL/ and /L3 transversely attain periproctial margin; dorsal surface markedly convex, with three oval, elevated, “disjunct” pectini- rhombs. Range.— This species is represented by two specimens: the holotype from the Bromide Formation (Trentonian) at Rock Crossing, Criner Hills, southwest of Ardmore, Oklahoma, and a closely related specimen from the Lincolnshire Formation (Black- riverian) , Luttrell, Tennessee. Plewrocystites watkinst, with the pos- sible exception of P. bassleri from China, may be the oldest known species in the genus. Description. — The theca is subtriangular in outline and _ is nearly bilaterally symmetrical. Rectal and abrectal lobes are not well developed on the anal surface but are manifest as alate (sym- metrical) , parts of the theca when viewed dorsally. In transverse profile the theca has a narrow, alate margin from which arises the nearly hemispherically convex dorsal surface. Each side of the nearly planate ventral surface slopes gently dorsally toward the axial plane. The “marginal” plates that comprise the periproctial girdle are unusually broad, especially at the proximal angles and at the distal ends of LJ and L4. On the dorsal surface the relative sizes and shapes of the plates are usually different from the same plates on other species. The basals B2 and B3 together form a broad “V”; distally these plates atypically suture with the “somatic” laterals L2 and L3 re- spectively. The suture between B2/IL2 typically has a_pectini- 172 BULLETIN 260 rhomb, but the suture itself is slightly sigmoidal. Basals BJ and B4 are typically lateral to B2 and B3 on the dorsal face and usually are subquadrate in outline. On the anal face of P. cf. watkinsi B1 and B# are narrow, arched, subrectangular plates against which the column abuts. These ventral basals do not attain the periproct margin, but are contained in an embayment in the medially ex- tended infralaterals JL4 and IL5 which join sagittally (see Pl. 24, fig. 2). The holotype is more typical in that basals B2 and B3 form the adcolumnal margin on the anal face and infralaterals JL4 and IL5 are not produced toward the sagittal plane. The infralateral series is especially atypical in size and plate outline. Most pleurocystitids have an evenly hexagonal JL2 plate, but in P. watkinsi it is irregular along the 1L2/B2 pectinirhomb suture, and the overall outline is subquadrate. 12, which normally is in contact with JL/ and JL3, is completely separated or barely in contact, due to the suturing of B2 and B3 with L2 and L3, respec- tively. LJ and JL3 are irregular in outline on the dorsal face. On the ventral face they taper slightly and then medially flare toward the periproct margin. The greatest length attained by ILI and IL3 on the periproctial margin is in this species. Infralaterals JL4 and IL5 are subquadrate and occupy the proximal angles on the dorsal surface. Ventrally they also occupy the proximal angles and in P. cf. watkinsi extend adaxially to form the entire proximal margin of the periproct: their common suture is at the axial plane and is aligned with the suture between B/ and B#. The “somatic” lateral plates L2 and L3 are as large or larger than JL2 which is usually the largest plate on the pleurocystitid dorsal surface. ‘These laterals lack the normal pentagonal outline of other species and are irregular, with gently curved sutures. The “marginal” laterals LJ and L¢ are essentially lateral on the dorsal surface and when viewed in profile are subhemispherical in outline on the dorsal face. On the anal face they are the largest and widest plates of the periproctial girdle. They attain their greatest width distally adjacent to the smaller “distal” plates. The suture joining LI and L4 is relatively the longest of any pleurocystitid, whereas in most species these laterals are adaxially attenuate and join with a short suture. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 173 The “somatic” radials R2 and R3 are relatively larger than in most species but are similar in outline and position. “Marginal” radial R# on the ventral face is typical in size, shape, and position, as is R5 on the dorsal face. R/ is unusually long, pentagonal in- stead of being subquadrate and is abnormally wide on the ventral face. On the dorsal face it is of normal width and shape. Text-fig. 5.— Plate outlines of the distal ventral face of Pleurocystites watkinsi Strimple, based on the holotype specimen (PI. 28, fig. 8). Note the position of the hydropore slit between O1/“O6”. For explanation of plate terminology see Table 1. 174 BULLETIN 260 Pleurocystites watkinsi has an extra element in its ventral distal ‘‘somatic’’ plates, t.e., “06”. This is most likely a retention of the third element of the O/ triad, or O1, O6, O7 grouping, which is present in most glyptocystitids. The subquadrate “O6” plate is unique in that it shares the hydropore and gonopore with OJ in- stead of the usual O//“O7” condition. Plate “O6” is located to the (morphological) right (habitus, left) of the sagittal “O7” and is in contact with, in clockwise order, L4, “O7”’, Ol, D3, and R5. The proximal portion of “O7” partly intercalates between the distal adaxial ends of L/ and L#. Due to the unusual shortening of Ol, the pentagonal “O7” plate atypically sutures with “RI”. The abbreviated O/ plate is unevenly pentagonal in outline and uniquely does not suture with LJ. On the dorsal face the op- posed oral to O/, “O3”, is also relatively reduced in size but is typical in outline (pentagonal) and position. The incorporated arm plates on both faces are typical in posi- tion and outline but tend to be wider than in other species. On the dorsal surface there are three well-developed, elevated, oval, and disjunct pectinirhombs. The rhombs, especially those on the lateral plates, are surrounded by a massive rim or callus, which is generally larger on the admarginal half-rhombs. Each _pectini- rhomb is bisected by a wide ridge which is parallel to, and split by, the common suture between the two lamellar fields. This ridge is topographically the most protuberant feature of each rhomb. The ridge is probably added in the late juvenile or early adult stage of development, perhaps indicating a change in economy or respiration requirements. If unidirectional circulation occurred along the folded lamellae, as suggested by Paul (1967a) , and passed under the ridge, it seems likely that the current would have entered the dorsal half-rhombs (on the somatic laterals L2, L3, and IL2) and exited on the opposing ventral half-rhombs. It has not been es- tablished, however, that the lamellar folds do, in fact, extend under the transverse ridge, and it is possible that water circulation was limited to each half-rhomb. The abmarginal ends of the rhombs extend above the thecal surface as small, vertical, stabilizer-like projections. The prosopon of the dorsal surface is highly distinctive, al- though it does bear some resemblance to that of Coopericystis, n.gen. NorRTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 175 The principal radiating ridges extend from the umbones of L2, L3 and JL2. On the laterals this position essentially coincides with the abmarginal apex of the pectinirhomb rim. Lesser foci for these ridges are found marginally on JL/ and JL3, and their ridges merge with others on [L2, L2 and L3. Concentric prosopon on each plate is manifest as sharp, steep-sided ridges which, under normal light- ing, dominate over the radial variety, except at the distal end of the theca where prosopon is not well developed. In most cases the radial and concentric ridges, paralleling the plate margins, are rela- tively straight, but the irregularities in outlines have resulted in slightly sinuate ridges in some places. Prosopon on the anal sur- face is absent, or limited to low pustules on the periproctial “mar- ginals.” The nature of the periproct is not well known; only a few small areas are preserved. The entire periproct area is probably covered by ca. 200 small, hexagonal and pentagonal platelets which tend to be elongate and trapezoidal along the periphery. The maximum dimension for the platelets is ca. 0.5 - 0.7 mm. The small size of the periproct, relative to the total ventral area, apparently is a primitive holdover. ‘This seems especially evident when it is com- pared to the relatively larger periprocts in younger species, ¢.g., P. beckeri of the Upper Ordovician. The anal pyramid is unknown. On the non-holotype specimen the proximal portions of the arms are preserved. Extrapolating their length from the taper of the better of the preserved arms, the total length exceeded that of the theca, as it does in P. squamosus. No specific difference in arm morphology is evident. The column is also similar to that of P. squamosus, except that the inflated columnals of the proximal column are either markedly, longitudinally ridged, or are beaded. Distally the prosopon is not so well developed. Discussion. — Pleurocystites watkinst has several distinct mor- phological features which might be considered sufficient by some, e.g., Paul (1967a), to place it in a separate genus. Features such as “disjunct’”’ pectinirhombs, unusual prosopon, marked thecal con- vexity, greater width of the periproctial “marginals,” variation in (some) plate outlines and contacts, are typical and/or accentuated. Nevertheless, the species is here considered to be compatible with 176 BULLETIN 260 the generic, typified by P. squamosus. Some of these and other dif- fering aspects should be discussed further. As has been pointed out by Breimer (1963, p. 299, 300) the presence of “O7” (=plate 13 of Bather and others) is known in only two species, viz., P. watkinsi and Pleurocystites sp. Breimer.) Breimer further stated that in his species (taken from a glacial erratic of apparent Caradocian age) : .... Plates 13 [“O7’] and 18 [“O6”] occupy the same topographic position as plate 18 does in specimens where plate 13 is not individualized. Plates 13 and 18 are considered topographical homologues of plate 18 in other specimens. We conclude that plate 13 if not individualized has fused with plate 18. In his species the hydropore and gonopore are typically shared between OJ and “O7” instead of the unique O1/“O6” position which is seen in P. watkinst. If Breimer is correct in assuming that “O6” and “O7” are normally fused, the displacement of the pores to include “O6” instead of “O7” is less enigmatic. The Breimer hypothesis, for reasons expressed below, is preferable to Bather’s (1913, p. 455) idea that L4 and “O7” have fused, for which there is no evidence; or to Carpenter’s (1891, pp. 11, 12) which holds that “O7” has been lost to the periproctials; or to Kirk’s (1911, p. 21) which stated that “O7” has been crowded out. Sinclair (1948, op. cit.) recognized that Ol and “O7” were parts of the typical Ol triad, as first recognized by him, but he did not have knowledge of either species where “O6” is present. “O6” is, therefore, probably the third element which has been retained in a few aberrant species. The equating of Bather’s plate 13 to “O7” and Bather’s plate 17 to “O6” is topographically correct when both plates are present, but the implied homology is incorrect. The plate alternating be- tween L/ and L4 is homologously the same in all species, t.e., “O7”. When the so-called plate 13 (=L5 of others) is present, plate 18 is assumed to be the adjacent plate occupying part of the normal position for plate 18 (“O7”) in other species. This so-called plate 18 (“Oo”) is, therefore, not assignable in Bather’s system, but is a rare, primitive holdover of the OJ triad, or Ol, O06, O7 grouping. In profile and outline there are similarities between this species and Coopericystis pyriformis. Both forms are markedly con- vexiplanate and have thin, alate, proximal angles which give the respective thecae a horizantally stabilized, hydrofoil configuration. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 177 The theca, if facing into a current, would have to exert little effort to keep its ventral surface above and parallel to the substrate. This could have been aided by the dorsal flexture of the proxi- mal column. Stable anchorage would have been provided by the distal column. Stabilization of the theca was probably enhanced by the protruding dorsal ends and sides of the distal pectinirhombs, in addition to the alate margins and proximal angles. In addition to their subvective duties, the arms also must have aided in orientat- ing the animal. Pleurocystites distans Bolton Pl. 26, figs. 1-3 1970. Pleurocystites distans Bolton, Geol. Sur. Canada, Bull. 187, p. 61, pl. 11, fig. 1. Diagnosis. — Theca subpentagonal, proximal angles nearly at right angles, rhomb surface nearly devoid of prosopon. Range. — The holotype is from the Farr Formation, Middle Ordovician [late Barneveld], “Shipyards” quarry, between New Liskeard and Haileybury, Ontario. It is also known from the Decorah Formation, Middle Ordovician [Fustspira bed], Hader, Minnesota. Description.— ‘The theca is pentagonal in outline and rela- tively broader than other North American species. Laterally the margins are straight or gently curved and parallel to subparallel to each other. Distal to the infralaterals the margins sharply curve toward the distal apex which is not preserved intact in any of the extant material. In profile the theca is more depressed than most pleurocystitids. On the rhomb surface prosopon is virtually absent, only faint ridges extend from the plate centers to the plate corners. The column embayment formed by the basals (B1-B4) and found in most Middle Ordovician pleurocystitids is essentially absent or reduced. Jn most other respects the basals are fairly typical. Infralaterals JL4 and IL5, which form the proximal corners of the theca, are usually rhomboid in outline; JLJ and IL3 are typical except for their greater width and their unusually straight outer (marginal) edge. The centrally positioned, hexagonal IL2 plate is unusually wide, having a width:height ratio of ca. 1.25; 178 BULLETIN 260 this being a rare case where such “biometrics” have relevance in this genus. The laterals, especially L/ and L4, are broader than in other species but appear to be relatively (slightly) longer. The distal pectinirhombs are broadly oval with thin rims on the inside plates (L2 and L3), but on the marginal laterals (LJ and L4) the rims taper to the margin as raised, subtriangular fields. The pectini- rhombs (and their rims) are similar to those on the Upper Ordo- vician species P. beckert. The L3/L4 pectinirhomb is unusually long, intermediate in length between those of P. filitextus and P. squamosus. Dichopores are numerous, with ca. 22 in the L3/L4 rhomb. The B2/IL2 rhomb is somewhat variable in the material we have at hand, extending from 60 percent to 30 percent of the total suture length. Apparently, this rhomb becomes relatively wider in ontogeny, and to some degree this may also be true for the distal rhombs. The rim around 62/2 is thin, with only slight extension into a triangular field on the B2 portion. Little is known of the periproctial face. The periproct margin is thin and of even width. Predictably, the periproctials are general- ly hexagonal, more evenly so near the center of the periproct, and near the margins they tend to be elongated. In a small (juvenile?) specimen, where periproctials are preserved, it is estimated that there are ca. 250 platelets. Discussion. — This species is still imperfectly known with only several incomplete specimens available. In a number of features this species is morphologically advanced for a Middle Ordovician form. The narrow periproctial rim, sharply converging sides of the distal theca, and the small periproctials are more typical of Upper Ordo- vician species. Some specimens of the Middle Ordovician species P. squamosus (see Pl. 23, figs. 1,2) are similar in outline but show marked differences in the relative dimensions of the thecal plates, especially IL2. Pleurocystites beckeri Foerste Pl. 26, fig. 4; Pl. 27, figs. 1-7; Text-fig. 6 1924. Pleurocystites beckeri Foerste, in Slocum and Foerste, Iowa Geol. Sur., Ann. Rep. 1919,1920, vol. 29, pp. 359-362: pl. 31, fig. 12; pl. 33, figs. 1,6; pl. 34, figs. la-d. 1924. Pleurocystites multistriatus Ulrich and Kirk, in Slocum and Foerste, ibid., pp. 366-369, pl. 33, figs. 2,3; pl. 34, figs. 2a-c. NortTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 179 1924. Pleurocystites slocomi Foerste, in Slocum and Foerste, ibid., pp. 362,363, pl. 33, fig. 5; pl. 34, figs. Sa-d. 1924. Pleurocystites sp. Foerste, iz Slocum and Foerste, zbid., pp. 365-366, pl. 34, 1924. pseeetee clermontensis Foerste, in Slocum and Foerste, ibid., pp. 363-365, pl. 33, fig. 7; pl. 34, figs. 7a-d. Diagnosis. —Theca with markedly angulate shoulders; periproc- tial area large; distal thecal plates reduced in size; R# and R5 fused, three well-developed pectinirhombs; rims on L/ and L4 half- rhombs elongated and terminate at shoulder angle. Range. — This species is found in the lower and middle Ma- quoketa Formation (Upper Ordovician, Cincinnatian) in the vicinity of Clermont, Fayette County, Iowa. Description. — The theca tends to be pentagonal in outline; the abruptly rounded shoulders, proximal angles and the reduced dis- tal end of the theca sharply contrast with the straight margins of the rest of the theca. In longitudinal profile the periproctial face of the theca is gently, transversely arched, the axis traversing the infralaterals JL/, IL2 and IL3. With the exception of the marginal, sharply angulate LJ and I4, the plates on the dorsal surface between the basals and proxi- mal radials are generally similar in outline to those of P. squamosus. At the distal end of the rhomb face, plates D/ and D2 tend to converge on “O3”. Plates RI and R# also converge distally, with their admedial longitudinal suture being essentially parallel to the adjacent outside margin. This distal convergence does not, however, result in reduction in the size of the arm bases. The distal end of “O3” is substantially reduced in width. As in all pleurocystitids, the pectinirhombs are unequal in (transverse) length, with the marginal or outer half-rhomb being longer. In P. beckeri this inequality is accentuated so that the LI half-rhomb may be up to twice as long as the L2 half rhomb; the the B2 half-rhombs may be ca. 40 percent longer than the [2 half- rhomb and L4 may exceed two-thirds the total length of the rhomb. In P. squamosus L4 rarely exceeds L3 by such a ratio. In P. beckeri the rims on half-rhombs LJ and L¢4 are more elongated and both terminate in acute angles (50°-60°) at the shoulder angles. The rims of the half-rhombs on L2, L3 and B2/IL2 are similar to those of P. squamosus. 180 BULLETIN 260 The exposed dichopore fields are unusual in that they have one or two pairs of narrow septa which are parallel to the dividing suture (Foerste, 1924, p. 34; Pl. 27,. fig. '4)). hese septaare symmetrical relative to the dividing suture but are spaced relative to the ratio of length inequality between adjacent half-rhombs. In some specimens the marginal half-rhombs may have an azygous, older (absutural) septum. A counterpart in such cases could be present under the absutural callus of the opposite half-rhomb. The function of these septa is unkown; perhaps they represent seasonal “still stands’ in growth or periodic, environmentally induced, growth aberrations. The depth to which these septa extend into the folds is not positively known, but they probably extend all the way through them. ‘The efficiency and circulatory or circulatory pat- terns in the rhombs were probably modified relative to other genera. Prosopon on the dorsal surface is generally consistent on all except the distalmost plates which tend to be essentially smooth. The primary radial ridges extending from the umbones to the plate angles are usually well developed but are not significantly larger than the inter-angle, “pseudorhomb”’ ridges that are con- fluent between adjacent plates. Concentric growth lines are not evident. While the prosopon pattern is not markedly different from some specimens of P. squamosus, the ridges are generally more rugose. The periproctial area is large, subpentagonal, and has approxi- mately the same outline as the theca. It is bounded by the usual “marginal” plates which are relatively narrow on this face. The enlarged periproct is a trait common to contemporary (Upper Ordovician) British species. The rectal lobe is moderately produced and is squarely trun- cated; usually it is not so extensively produced as in some con- temporary British species. The anal embayment of the periproct onto the rectal lobe is prominent, but the anal pyramid and sur- rounding platelets are unknown. The distal plates on this face are poorly known, and neither of the two specimens displaying these plates is distally complete or adequately preserved. As on the dorsal face, the distal plates, relative to other species, are reduced in size, and the entire area << NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 181 seems to be so protuberant. The sutures of these plates seem to be unusually straight and all of the known plates are somewhat atypical in outline and position. The outline drawing of this distal plate area (Text-fig. 6) is partly interpretation, due to inadequate preservation. The commonly paired radials “R#” and “R5” are fused into a single plate which, contrary to the general trend, is enlarged on this face, partly at the expense of “O7”. Plate OJ is abnormal in that it intercalates between L1 and L#4 instead of “O7” which usually occupies this position. There is no evidence of the hydro- pore or gonopore between O/ and “O7” or anywhere else. Text-fig. 6.— Plate outlines of the ventral distal plates of Pleurocystites beckeri Foerste. The drawing is based on the holotype (PI. 27, fig. 7). 182 BULLETIN 260 Little is known of the periproctial platelets, except that they are mostly hexagonal. According to Foerste (1924, p. 361) they aver- aged 0.8 mm. in diameter, and on the holotype were estimated to number ca. 800. The single, known specimen with an arm (PI. 27, fig. 2) does not exhibit any differences in that structure from those of other species of Pleurocystites. Likewise, the column is typical except that the proximal, inflated portion is shorter than usual. Discussion. — Foerste (1924) and Ulrich and Kirk (in Foerste, 1924) described a number of similar, mostly monotypic, coeval species of Plewrocystites from the Maquoketa Formation of Fay- ette County, Iowa. Incorporated in these descriptions were such taxobases as thecal ratios, shoulder angles and, to a minor degree, prosopon. The unreliability of these traits in closely related species has been previously discussed. Other taxobases, such as thecal out- line, disposition of plates, and the nature of the pectinirhombs, vary less in these several species than in the type species, P. squa- mosus. Pleurocystites multistriatus, P. slocomi, P. clermontensis, and Pleurocystites sp. Foerste are herein all considered conspecific with P. beckeri (Pls. 26, 27). Pleurocystites beckeri, as now recognized, exhibits a number of traits common to the essentially contemporaneous (Ashgillian) species from Scotland, e.g., P. gibba, P. quadrata and P. foriolus, all of Bather (1913). The angular theca, extended rectal lobe, ex- panded periproctial area, smaller periproctial platelets, and the rela- tively wider proximal theca are all such traits. Characteristics of the prosopon and the general morphology of the pectinirhombs in P. beckeri are, however, more conservative and resemble Middle Ordo- vician North American forms, é.g., P. squamosus. Foerste (1924, p. 358) and others have pointed out that the pleurocystitids are most likely North American in origin. Following their widespread distribution in the Middle Ordovician, pleuro- cystitids are known from few localities in the Upper Ordovician in the New World: viz., P. anticostiensis from the English Head Limestone on Anticosti Island, P. beckeri from the Maquoketa Formation in Iowa, and fragmental specimens closely related to P. beckeri from the Canadian Rockies in British Columbia (per- sonal communication with B. Norford, and personal examination) . NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 183 Most Upper Ordovician species of Plewrocystites are found in Great Britain. COOPERICYSTIS, n. gen. Pl. 28, figs. 1, 2; Text-fig. 7 Type species, Coopericystis pyriformis, n.sp. Diagnosis.—‘Theca pyriform in outline; one small pectini- rhomb, L3/L4 present; JL4 and JL5 reduced to thin, marginal plates on the dorsal face. Periproctial face unknown. Range. — Blackriverian; Benbolt Formation, three-fourths of a mile southwest of Mt. Eager Church, in Hogskin Valley (Powder Springs Quadrangle) , Tennessee. This is the only known location of this rare genus. Description. —'The theca outline is subpyriform; the width is almost equal to the length. At present only the dorsal surface is known. The plates of the dorsal surface are easily homologized with those of Pleurocystites. As in P. watkinsi, there is an elevated cen- tral portion on this face and transversely thin marginal areas of unequal and varying widths. At the proximal angles the marginal area is essentially absent. Juxtaposed basals B2 and B3 form a broad “Y’, as they do in Pleurocystites. The laterally placed basals BJ and B4 are subquad- rate on this face and are restricted to the adcolumnal area of the proximal margin. Adjacent to B/ and B4 on the proximal margin are infralaterals IL4 and IL5 that consist of narrow, subrectangular plates which extend to and include the proximal angles of the theca. Infralaterals JLJ, IL2 and IL3 are, consequently, relatively large and form a complete transverse series. JL3 and ILI are distal to IL4 and IL5, respectively, and occupy most of the extended, ob- tuse proximal angles. Both are regular (subpentagonal) in outline. Between JL/ and JL3 is the large, transversely elongated, hexagonal infralateral IL2. The lateral plates, while similar to their homologues in Pleuro- cystites, are relatively narrower due to the constriction of the distal theca. L3 is irregularly hexagonal and L2 is pentagonal to hexa- gonal. L/ and L# are generally subrectangular and are part of the 184 BULLETIN 260 steeply sloping, distal lateral margins. L2 and L3 are predominantly restricted to the raised portion of the theca. Laterals L3/L4 bear a small, oval pectinirhomb which occupies less than 40 percent of the common suture. This simple rhomb on the theca of Coopericystis is predominantly rim material which en- closes approximately six dichopores. The reduced size and large amount of rim material in this pectinirhomb would tend to indi- cate that it is a vestigial structure. In approximately the same position as the pectinirhomb, there is a strong, trans-sutural rib on the laterals L//L2 which imparts added rigidity between these two plates and hydrodynamically balances the L3/L4 pectinirhomb. As in Pleurocystites, there are four radial plates. Radial R2, which is irregularly pentagonal in outline, and R3, which is un- evenly hexagonal, are predominantly located on the raised portion of the theca. Both are medially thickened by prosopon ridges. In admarginal contact with R2 and R3 are R1 and R¢4, respectively. They are subrectangular in outline and are somewhat elongated, relative to their homologues in Pleurocystites. Plates RI and R# are part of the marginal band and do not extend to the elevated portion of the theca. The three terminal distal plates, D/, “O3”, D2, are similar in outline to their homologues in Pleurocystites. The most marked difference is manifest in the sharply distally tapering, narrow “O3” plate. Arm base plates D/ and D2 are similar to those of Pleuro- cystites. The arms are not well known; their length and plate make-up is assumed to be essentially the same as in Pleurocystites. The proximal column and several segments of the distal column are known, and both are similar to those of Plewrocystites. An outstanding feature of Coopericystis is the prosopon. It is especially well developed on the raised ‘central’ portion of the distal thecal surface and on the abmarginal edges of the horizontal to gently sloping thecal margins. The larger thecal plates of the central area have radiating ridges (either single or double) extend- ing from the center of the plate to the corners and to the mid- points of the edges. This is especially noticeable on JL/, IL2, IL3, NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 185 Text-fig. 7.— Coopericystis pyriformis, n. gen. and n. sp. Partial reconstruction of the rhomb face based on the holotype (see Pl. 28, fig. 1). The single, reduced L3/L4¢ pectinirhomb is countered by a vertical rib on the oppos- ing laterals L1/Z2. 186 BULLETIN 260 L2, L3, R2 and R3. Sharply raised and closely spaced concentric growth lines are also prevalent on most dorsal plates. Ridges extending both proximally, between the inner and outer basals from near the margins of JL/J or JL3, and distally, over the inner laterals (L2, L3) but close to the suture with the outer laterals (L1, L4), mark the sharp demarcation between the marginal band and the raised “central” theca. These ridges also extend over the radials R2 and R3 but not onto the more distal thecal plates. At the lateral and distal extremities of the theca these two areas merge. Discussion. —"To what degree the unusual dorsal surface pro- file and its prosopon played in the economy of the animal is con- jectural. If we are correct in assuming that pleurocystitids lived in a “carpoid”’-like manner and faced into the bottom currents, then it may be assumed that the upper surface had a hydrodynamic func- tion. The longitudinal and transverse profiles indicate that the convexi-planate theca functioned as hydrofoil. Its maximum thick- ness occurred transversely across the pectinirhomb. It is possible that the marginal ridge opposite the pectinirhomb had a hydro- dynamic balancing function, countering the rhomb. As has been postulated above, the hydrofoil shape aided in keeping the theca slightly above, and parallel to, the sea floor, especially when the animal was in motion. Coopericystis bears a remarkable resemblance to Regulaecystis Dehm [ (1932) , 1953] from the Lower Devonian, Hunsruckschiefer of Germany. Both forms have only one pectinirhomb (L3/L4) and are similar in thecal outline. Regulaecystis does not have a raised “central area’ on the dorsal face, as does Coopericystis, nor is there a great deal of similarity in plate outlines and positions. However, one might interpret the raised tripartite ridge on the dorsal surface of Regulaecystis as a remnant of the raised “central” theca. [See Kesling, 1968, (1967) p. S197, fig. 98, la, c, d, f.] The arms in Coop- ericystis diverge only slightly from the longitudinal axis, while in Regulaecystis they are divergent nearly at right angles to it. (Dehm, 195s wabals 62, dosnt, Oy) It is possible that these heterochronus homeomorphs are in- dependently derived from within the glyptocystitid lineage, with Coopericystis, being more closely related to Plewrocystites, and NorRTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 187 Regulaecystis being derived from some other stock, perhaps ??Cheirocrinus. Coopericystic pyriformis, n. sp. Diagnosis. — Species diagnosis and description are, for the present, the same as that for the genus. Range. — The same as that for the genus. AMECYSTIS Ulrich and Kirk, 1921 Type species, Pleurocystites laevis Raymond, 1921. Middle Ordovician, Trentonian, Kirkfield Formation, Kirkfield, Ontario. Synonymy. — The generic synonymy is the same as that for the type species, A. laevis. Diagnosis. — Pleurocystitid with evenly sagittate theca, dorsal face without pectinirhomb (s) or sutural pores, R2 axially located, R3 deflected to left, marginal. Range. — Middle Ordovician, Blackriverian; Shippensberg Lime- stone, Pennsylvania; Decorah Shale, Minnesota: Trentonian; Hull Limestone, Ontario; Curdsville Limestone, Kentucky; Trenton Limestone, Michigan. Description. —'The theca is evenly though roundly sagittate in outline and possesses a high degree of plate bisymmetry. This is especially true in the proximal portion where the anal and abanal lobes are equal in size and shape. All of the thecal plates can be directly homologized with those of Pleurocystites, although the shapes and positions of some may vary. On the dorsal face, basals B2 and B3 together form a broad “Vv” and are, in this respect, similar to those of Plewrocystites. Likewise, the configuration of basals BJ and B# and the mode of column insertion is also similar. Infralaterals JL4 and IL5 are positioned so that they have near- ly equal marginal area on both proximal and lateral sides of the theca. In outline they are subrhombic to subtriangular. Infralaterals ILI and JIL3 are wholly marginal on their (thecal) marginal edges and do not extend onto the lower face as narrow, triangular inserts into the periproctial marginals, as in Pleurocystites. They are irregularly hexagonal or heptagonal in outline. [L2 is typically hexagonal, but in some specimens it is proportionally larger than in other pleurocystitids. BULLETIN 260 Text-fig. 8.— Partial recon- struction of Amecystis laevis Ulrich and Kirk (PI. 29, fig. 5). There is some indication that large specimens such as this may divide the JL2 or “central dorsal” plate into two subequal pentagonal plates. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 189 Both the laterals and radials tend to be relatively smaller than in Pleurocystites, and due to the lack of pectinirhombs they are more regular in outline. The axial laterals (L2, L3) are usually pentagonal in outline, while the outer or marginal laterals (LJ, I4) are elongated and tend to be subrectangular or pentagonal. Lateral L# is distally shortened due to the marginal position of R3. Radial R2 is evenly pentagonal to hexagonal (except for an embay- ment to receive “O3” in some specimens) and is axially located. Radial R3 is marginal and shifted to the left, relative to its homo- logue in Pleurocystites. Its increased size, along with the admarginal shifting, has displaced R# from the dorsal face. It is probably missing altogether. From our sketchy knowledge of the ventral face, R3 seems to extend onto the face, displacing R5 as well. The re- maining radial “R/” is elongated and subrectangular in outline. It is to some degree the symmetrical counterpart of R3, although it is somewhat smaller. The distal plates of the dorsal surface (DJ, “O3” and D2) are similar to those of Pleurocystites except that they are relatively smaller. Few examples of the ventral or anal face are known and our knowledge must be pieced together from several poorly preserved specimens. The proximal margin of the ventral face is similar to Pleurocystites. Along the lateral edges JLJ and JL3 are major mar- ginal plates on this face, not merely triangular insets as they are in Pleurocystites. As a consequence, the marginal laterals (L1, L4) are relatively shorter. At the distal end of the theca several diagnostic differences in the marginal plates appear. Radial plate R3, which seems to have displaced R# and R5, extends almost to the sagittal axis, as does “R1” on the opposite side. Distal plate “O7” apparently intercalates between these two plates (“R/”, R3) and uniquely may form a small portion of the periproctial girdle. The largest of the ventral distal oral plates is OJ which is typically elongated and shares the hydropore slit with “O7”. No gonopore has been observed. Distal plates D1’, D2’ and D3’ are nearly identical with their homologues in Pleurocystites. The periproctial surface is paved with generally evenly to slightly elongated hexagonal platelets. Larger specimens of Ame- 190 BULLETIN 260 cystis have platelets with a maximum diameter of ca. 1.5 mm and average ca. 0.8 mm. The total number of platelets or periproctials is estimated to be over 200 in the type species, A. laevis. The column is similar in size and make-up to that of Pleuro- cystites and Coopericystis. All of the specimens examined show that the proximal column is smooth, without prosopon, as are the crests of the alternating, raised segments of the distal column. The arms of Amecystis, so far as known, are morphologically similar to those of Pleurocystites except that they emerge nearer the distal apex, due to the reduction in size of the distal (thecal) series, and they are relatively thinner. In Pleurocystites the longi- tudinal plane, which bisects the food groove, is essentially horizon- tal, z.e., it lies parallel to the plane of extension or is rotated slightly inward. The longitudinal planes in the arms of Amecystis, at least proximally, are rotated inward so that they are inclined approximately 60 degrees with the horizontal. Discussion. —The striking similarity between Amecystis and Pleurocystites bespeaks a close genetic relationship despite the absence of pectinirhombs (indeed a major factor), the apparent absence of radials R4 and R5, and some differences in plate position in the former genus. Sinclair (1951, p. 177) also pointed out that, at least in one occurrence, Port Rouge, County Portneuf, Quebec, both genera are found on the same bedding plane in equal num- bers. To some this might be suggestive that Amecystis and Pleuro- cystites are displaying sexual dimorphism. This phenotypic phe- nomena is not well developed in echinoderms and does not explain the fact that in other localities they are apparently mutually ex- clusive. Most likely we are dealing with a case of isochronous homeomorphy in which these two genera have evolved from the same, or a similar, glyptocystitid ancestor. If this premise is accepted, it then becomes difficult to concur with Ulrich and Kirk (1921, p. 148) who postulated a common rhombless ancestor for both Pleurocystites and Amecystis. Virtually all primitive glyptocystitids have pectinirhombs. While it is true that Amecystis is generally in older strata than most species of Pleurocystites, it does not neces- sarily follow, with reference to Ulrich and Kirk, ibid., that it repre- sents an older or more primitive stock. There is evidence that the opposite may be a more correct explanation. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 191 Within the pleurocystitids there seems to be a general trend for species to become more symmetrical in thecal outline (except in some cases for the anal lobe) and more regular in plate outline. This occurs in progressively younger species and in species or in species which have lost all or some of their pectinirhombs, or where the pectinirhombs are markedly reduced. Coupled with this loss or reduction of pectinirhombs, the periproctials on the ventral face tend to become progressively smaller, especially in Pleurocystites. This trend is, however, somewhat tempered in older forms, e.g., Amecystis, where, despite the loss of pectinirhombs, the periproctials are still relatively large. If the trend for the reduction of pectini- rhombs is applied to Amecystis, we can visualize an early loss (Upper Cambrian-Lower Ordovician) of rhombs in the rhomb- bearing ancestor. This is, however, a recurrent theme in the glypto- cystitids. It probably has occurred independently several times in the pleurocystitid lineage and would account for the heterochronous parallelism of Plewrocystites, Coopericystis, and possibly Regulae- cystis. With the loss of rhombs, Amecystis probably was much more plastic in attaining regularity of plate outline and would have rapidly adjusted to its nearly bisymmetrical plate arrangement. The paleoecological habits of Amecystis seem to be similar to those of Pleurocystites. Both genera appear to be probable rheo- taxial organisms that faced into prevailing bottom currents. They apparently favored lime to lime mud substrates on which they lightly rested or were slightly raised above but remained parallel to it. These genera were probably wrigglers, capable of movement across the sea floor and were possibly capable, especially in juveniles, of swimming short distances. The similar morphology of the arm in pleurocystitid genera reflects a similar mode of subvection. The lateral to slightly in- clined food grooves in the arms of Pleurocystites probably served the same function as the steeply inclined grooves of Amecystis, namely, the superficial sweeping of the substrate by the arms. Sub- vection below the surface of the substrate is possible but unlikely. If such a mode of feeding were common in these animals, there would have been little use for such long, gently tapering arms. Some feeding above the substrate may also have been possible, 7.e., 192 BULLETIN 260 directly from the sea water, but extensive practice of such feeding probably would have selectively produced arms with the food grooves in a dorsal or near dorsal position and not in the lateral to ventro-lateral position as they are found. Dehm (1934) concurred with Ulrich and Kirk in deriving Pleurocystites from Amecystis and went on to state that the mor- phologic resemblance between Amecystis and some solutan “car- poids,” e.g., Jowacystis, was not simply due to convergence but ac- tually represented close generic relationship. Various authors, notably Gill and Caster, 1960, Parsley and Caster, 1965, and Caster, 1968 (1967) , clearly demonstrated the distinct nature of the Soluta from that of the Rhombifera. This remarkable convergence seems to be due only to similar modes of life. Ulrich and Kirk (ibid., pp. 147, 148) listed other localities from which specimens of Amecystis are known and treated them as unnamed species. ‘Those specimens from the Curdsville Limestone, Mercer County, Kentucky, and from the Decorah Shale, Minne- apolis, Minnesota, are herein included in the type species. The latter form, while bearing a distinct pustulose prosopon, shows no other significant variation. Specimens from the Shippensberg Lime- stone from Pennsylvania are of a new species, A. raymondi, n.sp. and are described below. Amecystis laevis Ulrich and Kirk, 1921 Pl. 26, fig. 5; Pl. 29, figs. 1-5; Pl. 30, figs. 5, 6; Text-fig. 8 1921. Pleurocystites laevis, Raymond, Canada Dept. Mines, Geol. Sur., Mus. Bull. No. 31) pp: 2,55 ple2) ties. 9-3, 1921. Amecystis (laevis), Ulrich and Kirk, Biol. Soc. Washington, Proc., vol. 34, pp. 147,148. Diagnosis. — Amecystis with flattened, evenly sagittate theca; thecal plates thin, smooth or with pustulose prosopon. Range. — Middle Ordovician (Blackriverian) , Decorah Shale, Minneapolis, Minnesota: (Trentonian) , Kirkfield Formation, Kirk- field, Ontario; Lower Trenton, Pont Rouge, Portneuf Co., Quebec; Curdsville Limestone, High Bridge area, Mercer County, Kentucky. Description. — The theca is evenly sagittate in outline, with the equidimensional proximal lobes not being greatly developed. The lateral margins smoothly curve between the proximal angles and the NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 193 distal oral plates. Unlike Pleurocystites, the dorsal face is gently and evenly arched, resulting in a much flatter profile. The admedial basals (B2, B3) are elevated above the abmedial basals (BJ, B4) in the same manner as they are in Coopericystts. The general observed condition of a flattened proximal area seems to be primarily due to preservation. The basals are slightly elon- gated, relative to their homologues in Plewrocystites, as are the infra- laterals JL1, IL3 and, to a lesser degree, IL2. Conversely, both the laterals and radials are shorter than their homologues in Pleurocystites. Thus, the two proximal series of plates make up more than half of the thecal length, as opposed to Pleurocystites where the two distal series, plus the distal plates, make up more than half of the thecal length. This redistribution of area covered by the various series of plates is most likely due to thecal adjustments related to the ancestral loss of pectinirhombs. In general, the thickness of the thecal plates in A. laevis is less than in coeval, similar-sized specimens of Pleurocystites, and this frequently results in poorer preservation. The general description of the theca, arms and column, and their interrelationships for this species, have been discussed above under the generic heading. Discusston. — Heretofore the only photograph and line drawing of the plate pattern in Amecystis used in the literature has been that of the type specimen as illustrated in Raymond (1921, pl. 2, figs. 1-3). Subsequent authors used Raymond’s line drawing with- out comment. It has been pointed out to the author by Dr. G. W. Sinclair of the Canadian Geological Survey, and subsequently sub- stantiated, that the type specimen exhibits the remarkable state of preservation in having two nearly identically sized individuals superimposed one on top of the other (PI. 29, fig. 1). The upper specimen has been partly eroded, exposing part of the lower speci- men. This resulted in the misinterpretation of plate and thecal out- lines. It is the apparent non-recognition of this fact by Raymond (ibid.) which resulted in a somewhat erroneous interpretation of the dorsal thecal plate pattern. One might speculate that here is preserved some form of sexual activity. The usual mode of occurrence for this species is much the same as that for many specimens of Pleurocystites: dorsal (morpho- 194 BULLETIN 260 logically anterior) face upwards in a fine-grained matrix which before diagenesis and recrystallization seems to have been a soft, lime mud or limy silt. Current action probably was gentle to moderate. Associated thin-shelled brachiopods are rarely broken and show little evidence of wear. Amecystis raymondi, n. sp. Pl. 30, figs. 1-4 Diagnosis. — Amecystis with extended, somewhat angulate proxi- mal lobes; lateral margins of theca along infralaterals nearly straight; strong bordering ridge on lobes and _ lateral thecal margins; strong, radiating prosopon on thecal plates. Range. — Blackriverian, Shippensberg Limestone, known from one locality three and one-half miles north of Greencastle, Pennsyl- vania. Also known from ?Benbolt Limestone, .35 mi. ENE of Fair- view School in a roadcut on ‘Tennessee Hwy. 131, Granger County (Swan Island Quadrangle), Tennessee. Some questionable frag- ments are known from Speers Ferry, Virginia, and Luttrell, ‘Tennes- see. Description.—In outline the theca is more angular in this species than in A. laevis, having straight-sided lobes and _ lateral edges where formed by the infralateral plates. A close resemblance in proximal thecal outline exists between this species and Pleuro- cystites rugert (cf. Bather, 1913, pl. 5, figs. 57, 60). In both cases the lobes are “squarely” truncated. The distal margin in 4. raymondi is more broadly rounded than that of the type species. Most of the sutures between the plates are gently curved, perhaps due to the smoothly arched dorsal surface, as opposed to the relatively straight sutures in the dorsal theca of A. laevis. As pointed out by Ulrich and Kirk (1921, p. 148) this form has thicker plates than specimens belonging to A. laevis. The admedial basals (B2, B3) typically form a wide “V”. They are wider than their homologues in the type species, as are the admarginal basals (B/, B4). The latter are also enlarged and are subrectangular in outline. Infralaterals JL4 and IL5 are located at the proximal angles of the theca and are reduced in size. They are subrhomboid in out- line and display well-curved sutures. The infralaterals JLJ and IL3 are similar, although narrower than those in A. laevis. The out- NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 195 side edges of these four marginal-occurring infralaterals are unusual- ly straight, resulting in characteristic lateral margins of the same nature. JL2 occupies the center of the theca and is typically hexa- gonal. The lateral series is not clearly discernible in the specimens available. They seem to have the same general outlines as their homologues in A. laevis, but they are smaller, relative to the amount of thecal area they occupy. The proximal ends of the laterals do not extend as far as the proximal half of the theca. Conversely, laterals LJ and L# extend abnormally far forward on this surface, giving the effect of crowding the radials R2 and R3. The radials, which are preserved only in the holotype, are relatively smaller and more irregular than their homologues in A. laevis; R2 is hexagonal, R3 is pentagonal. “RJ” is also reduced and subpentagonal instead of subrectangular in outline as seen in the type species. With the exception of part of “O3” preserved on the holotype, none of the distal plates is known. The elements of the prosopon on the dorsal face of the theca are similar to those of Pleurocystites. These include: 1) Pseudo- rhomb-like ridges aligned across plate sutures, 2) Radiating ridges from the center or outside margin of plates to the plate corners. 3) Fine, but distinct, concentric growth lines. Pustulose serrations found on all ridges are due to concentric growth and are a feature common in Coopericystis. These ridges are low and narrow but distinct. There are also strong marginal ridges extending from the proximal ends of the column embayment to the distal ends of the admarginal laterals LJ and L#. A second pair of prominent ridges extends from the proximal ends of the marginal ridges obliquely across the theca. They broaden and flatten distally toward the mid (thecal) margins of JL/J and JL3, where they terminate. Both these and the marginal ridges bear six or more lesser, pustulose ridges which are similar to, but more massive than, those making up the normal prosopon pattern. The ventral periproct surface is unknown on this species, However, in the region of JL3 on the holotype specimen sufficient weathering has taken place to expose what seem to be the impres- 196 BULLETIN 260 sions of hexagonal periproctial platelets. Their diameter is ca. 0.5 mm, but they are probably larger toward the middle of the peri- proct area. They would seem to be considerably smaller than those of A. laevis and are estimated to number approximately 1,000 over the entire surface. This number is in keeping with the proposed relationship between platelet size and the loss of pectinirhombs. No remains of arms are known, but there is some evidence of the column. Scattered over the holotype slab are some columnals which most likely belong to this species. They indicate that the col- umn is a normal glyptocystitid structure having prominent longi- tudinal crenulations on both the proximal and distal portions. Discussion. — The similarities between this and other pleurocy- stitids have been noted above. The available material is sparse, but it is assumed that both arms and column are of the same relative dimensions as those of A. laevis. REFERENCES Bassler, R. S., and Moody, M. W. 1943. 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Echinodermata from the Ordovician (Pleurocystites, Cremacrinus) and Silurian (Hemicystites, Protaxocrinus, Macnamaratylus) of Lake Timiskaming region, Ontario and Quebec. Geol. Sur. Canada, Bull 187, pp. 59-66, pls. 11-13. Breimer, A. 1963. On a specimen of Pleurocystites (Cystoidea) from an erratic boulder near Westerhoar (Netherlands). K. Nederl. Akad. v. Wetenschappen-Amsterdam, Proc., Ser. B, vol. 66, No. 5, pp. 296- 302, pls. 1,2, text-fig. 1. NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 197 von Buch, L. 1846. Notice of a new family of crinoid animals called Cystidea. Quart. Jour., Geol. Soc. London, vol. 2, pp. 11-12. 1846. On the Cystidea (a new family of radiated animals), introduced by an account of the Caryocrinus ornatus, Say. Quart. Jour., Geol. Soc. London, vol. 2, (Translations and Notices of Geological Memoirs) pp. 20-42, pls. 3,4. Carpenter, P. H. 1891. On certain points in the morphology of the Cystidea. Linn. Soc. Jour., vol. 24, Zoology, No. 149,150, pp. 1-52, pl. 1 Caster, K. E. 1968 (1967). Homotostelea, in Treatise on Invertebrate Paleontology. Part S, Geol. Soc. America, pp. 581-627, figs. 372-395. Chapman, E. J. 1857. Cystideans. Canadian Jour. Sci. Lit. Hist., n.s., vol. 2, pp. 302-304. Dehm, R. 1932(1933). Cystoideen aus dem rheinischen Unterdevon. Neues Jahr- buch fiir Min. Geol. u. Paleont., Beil-Bd. 69, Abt. B, pp. 63-93, pl. 2, text figs. 1-13, tab. 1-5. 1934. Untersuchungen an Cystoideen des rheinischen, Unterdevons. Acad. Wiss. 3. Munchen, Sitzb. mat.-naturw. Abt., 1934, pp. 19-43, pls. 1,2, 6 text-figs. Delpey ,G. 1942. Organes spéciaux d’Echinoderms primitifs: les pectinirhombs, Soc. Geol. France, Bull. (5), vol. 11, (1941), pp. 207-217. Foerste, A. G. 1942. New echinoderms from the Maquoketa beds of Fayette County, Iowa, Part II. Iowa Geoi. Sur., Ann. Reports, 1919, 1920, vol. 29, pp. 345-383, 1 text fig., pls. 29-34. Gill, E. D., and Caster, K. E. 1960. Carpoid echinoderms from the Silurian and Devonian of Aus- tralia. Bull. Amer. Paleont., vol. 41, No. 185, pp. 5-71, pls. 1-11, text figs. 1-12. Grant, J. A. 1880. Cystidean life. Ottawa Field Nat. Club, Trans., No. 1, pp. 26-31, pl. 1: Haeckel, E. 1896(1895). Die cambrische Stammgruppe der Echinodermen. Jena. Zeit. f. naturw, Bd. 30, pp. 393-404. 1896a. Die Amphorideen und Cystoideen, Beitrage zur Morphologie und Phylogenie der Echinodermen. Festschr. z. 70 Geburtstage von Carl Gegenbaur, vol. 1, pp. 1-179, pls. 1-5, text-figs. 1-25. Leipzig. Hussey, R. C. 1928. Cystotds from the Trenton rocks of Michigan. Univ. Michigan, Contrib. Mus. Paleont., vol. 3, No. 4, pp. 77-79, pl. 1. Jaekel, O. 1899. Stammesgeschichte der Pelmatozoen 1. Thecoidea und Cystoidea, Berlin (Springer), pp. i-ix, 1-442, pls. 1-18, 88 text-figs. 1918(1921). Phylogenie und System der Pelmatozoen, Pal. Zeit., vol. 3 pp. 1-128, text-figs. 1-114. Kesling, R. V. 1961. A new Glyptocystites from Middle Ordovician strata of Michigan. Univ. Mich., Contrib. Mus. Paleont., vol. 17, No. 2, pp. 59-86, pls. 1-3, figs. 1-4. 1963. Key for classification of cystoids. Univ. Mich. Contrib. Mus. Paleont., vol. 18, No. 6, pp. 101-116. 198 BULLETIN 260 1968(1967). Cystoids, Treatise on Invertebrate Paleontology, Part S, Geol. Soc. America, pp. 86-267, figs. 32-157. Kirk, E. 1911. The structure and relationships of certain eleutherozoic Pelma- tozoa. United States Nat. Mus., Proc., vol. 41, pp. 1-137, pls. 1-11. Miller, S. A. 1889. North American geology and paleontology. Cincinnati, Ohio, pp. 1-718. Miller, S. A., and Gurley, Wm. F. E. 1895. Desoiphon of some new species of Paleozoic Echinodermata. Illinois State Mus. Nat. Hist., Bull. No. 6, pp. 5-62, pls. 1-5. Parsley, R. L., and Caster, K. E. 1965. North American Soluta (Carpoidea, Echinodermata). Bull. Amer. Paleont., vol. 49, No. 221, pp. 109-174, pls. 16-18, text figs. 1-11. Paul, C: Ra ¢: 1967. The British Silurian cystoids, British Mus. (Nat. Hist.) Bull., Geology, vol. 13, No. 6, pp. 297-355, pls. 1-10, text figs. 1-44. 1967a. The functional morphology and mode of life of the cystoid Pleurocystites, E. Billings, 1854, Echinoderm biology. Zool. Soc. London, Symp. No. 20, pp. 105-123, figs. 1-22. Raymond, P. E. 1921. A contribution to the description of the fauna of the Trenton Group. Canada Dept. Mines, Mus. Bull. No. 31, pp. 1-64, pls. 1-9. Regnell, G. 1945. Non-crinoid Pelmatozoa from the Paleozoic of Sweden. Medd. from Geol. Min. Inst. 108, pp. viii + 255, pls. 1-15, 30 text-figs. 1951. Revision of the Caradocian-Ashgillian cystoid fauna of Belgium with notes on isolated pelmatozoan stem fragments. Inst. Roy. Sci. Nat. Belgique, Mem., No. 120, pp. 3-47, pls. 1-6. 1960. The Lower Palaeozoic echinoderm faunas of the British Isles and Balto-Scandia, Palaeontology, vol. 2, Pt. 2, pp. 161-179. Ruedemann, R. 1916. Account of some new or little-known species of fossils, mostly from Paleozoic rocks of New York, New York State Mus., Bull. No. 189, I, pp. 7-112, pls. 1-32, figs. 1-39. Sinclair, G. W. 1948. Three notes on Ordovician cystids. Jour. Paleont., vol. 22, No. 3, pp. 301-314, pls. 42-44, text figs. 1-6. 1951. The occurrence of cystids in the Ordovician of Ontario and Quebec, Canadian Field Naturalist, vol. 65, No. 5, pp. 176-179. Sirimple, H. L. 1948. Pleurocystites watkinsi n. sp. from the Bromide Formation of Oklahoma, American Jour. Sci., vol. 246, No. 12, pp. 761-764, pl. 1. Ulrich, E. O., and Kirk, E. 1921. Amecystis, a new genus of Ordovician Cystidea. Biol. Soc. Wash- ington, Proc., vol. 34, pp. 147-148. Wilson, A. E. 1946. Echinodermata of the Ottawa Formation of the Ottawa-St. Lawr- ence Lowland. Canada Dept. of Mines and Res., Geol. Sur. Bull., No. 4, pp. 1-61, pls. 1-6. Zittel, K. A. 1879. Handbuch der Palacontologie, Palaeozoologie. { Band, I. Abthei- lung., Echinodermata, pp. 308-560, Munchen & Leipzig (Olden- bourg). PLATES The cost of the reproduction of the text figures and plates has been met by a grant from the Graduate School of the University of Cincinnati. Explanation of the letter prefixes on the specimen numbers: FMNH Field Museum of Natural History FMNH(UC) Field Museum of Natural History, Walker Museum Collection GSC Geological Survey of Canada NYSM New York State Museum ROM Royal Ontario Museum UCM University of Cincinnati Museum UCM (K) University of Cincinnati Museum, Kopf Collection UMMP University of Michigan Museum of Paleontology USNM United States National Museum USNM(S) United States National Museum, Springer Collection 200 BULLETIN 260 Explanation of Plate 21 Figure Page 1-5. Pleurocystites squamosus Billings ..00...0...c ees 161 All specimens are from unspecified localities in the Cobourg For- mation, Ottawa, Ontario. According to Dr. G. W. Sinclair most of these specimens came from quarries at or near Carling Street and Booth Street, the present site of the Geological Survey of Canada buildings. Trentonian. 1. Rhomb surface of the theca with part of the theca attached. This specimen is a syntype of P. elegans = P. filitextus herein, but its pectinirhombs indicate that this homeomorph is P. sguamosus. GSC 1382; X 2. 2. Distal end of the rhomb surface. This specimen is the holotype Pleuro- cystites robustus Billings which is herein included in P. sguamosus. GSC 1384; X 2. 3. Rhomb surface of the theca with the proximal portions of the arms and column present. Syntype. GSC 1381; X 2. 4. Detail of two nearly complete arms. The interlocking aspect of the alternating covering plates is clearly evident. Syn- type. GSC 1381a; X 3. 5. Rhomb surface of the theca with parts of the arms and column preserved. Syntype. GSC 1381b; X 1.5 PLATE 21 BULL. AMER. PALEONT., VOL. 58 a mwa STP ean TA | PLATE 22. | BULL. AMER. PALEONT., VOL. 58 | NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 201 Explanation of Plate 22 Figure Page 1-9. Pleurocystites squamosus Billings ............ Fae, stl tee 12g Mea aw .. 161 1. Rhomb surface of the theca with part of the proximal column. Kirkfield Formation, Kirkfield, Ontario. Trentonian. USNM(S) 4235; X 1.5. 2,3. Periproct and rhomb surfaces, respectively, of an incomplete silicified theca. Curdsville Formation, Curdsville, Mercer County, Kentucky. Trentonian. USNM 42198; X 2. 4. Rhomb surface with part of the column. Note the rounded outline, especially in the proximal portion of the theca. See figure 5, Plate 24. Kirkfield Formation, Kirkfield, Ontario. Tren- tonian. USNM(S) 4235; X 1.5. 5. Rhomb surface with its distal end partly reconstructed. Silicified. This is the holotype of Pleurocystites mercerensis Miller and Gurley which is herein included in P. squamosus. Curdsville Formation, Curdsville, Mercer County, Kentucky. Trentonian. FMNH(UC) 6047; X 2. 6, 7. Rhomb and periproct surfaces, respectively, of a “P. elegans” type. The small periproctials definitely place this specimen in P. squamosus. Hull Formation, Hull, Quebec. Trentonian. ROM 104T; X 2. 8. Rhomb surface with parts of the arms and column attached. Note the numerous radiating ridges and the reduced rims or calluses about the rhombs on this specimen and on figure 9. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM (K) 39537; X 2. 9. Rhomb surface with portions of the arms and column present. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM(K) 39538; X 2.5. 202 BULLETIN 260 Explanation of Plate 23 Figure Page 1-6. Pleurocystites squamosus Billings .....0.000000000cceees: 161 1. Rhomb surface with part of the column. Note the inflated segments with the median annulus on the distal column. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM(K) 39539; X 1.5. 2. Rhomb surface with prominent “P. elegans’-type ribbing. ?Hull Formation, Chaudiere Falls, Hull, Quebec. Trentonian. USNM(S) 4246; X 3. 3. Rhomb surface with an unusually rounded outline. Hull Formation. Beaver Meadow near Hull, Quebec. Trentonian. ROM 18875; X 2. 4. Portion of a rhomb surface. Note the numerous radiating ridges and the well- developed rhomb calluses or rims. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM(K) 39540; X 1.5. 5. Distal end of a rhomb face showing plate and proximal arm plate outlines. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM(K) 35943; & 2.5. 6. Rhomb surface with most of the arms intact. Cobourg Formation, Ottawa, Ontario. Trentonian. GSC 1381c; XG" BuLu. AMER. PALEONT., VOL. 58 PLATE 23 | BuLL. AMER. PALEONT., VOL. 58 PLATE 24 tt) { —e wt NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 203 Explanation of Plate 24 Figure Page 1,6,7. Pleurocystites filitextus Billings .. et eokit 167 1.Two rhomb surfaces and a periproctial face, respectively. The elongated rhombs and large periproctials are typical. Co- bourg Formation, Ottawa, Ontario. Trentonian. USNM 93437; xX 2: 2. Pleurocystites cf. watkinsi Strimple ................. olga 2s Periproctia] surface with most of the column and part of an arm intact. Lincolnshire Limestone, Luttrell, Tennessee. Black- riverian. USNM 93442; X 2. 3-5, 8,9. Pleurocystites squamosus Billings ........... | Ap TEER fie 1B 3. Distal end of the periproctial face. Note the numerous hexa- gonal periproctials. Cobourg Formation, south end of Lebreton St., Ottawa, Ontario. Trentonian. GSC 9064. X 1.5. 4. Peri- proctial face with the anal pyramid well preserved. The proxi- mal ends of the arms and column are attached. Kirkfield For- mation, Kirkfield, Ontario. Trentonian. UCM 39541; X 1.5 5. Periproctial face of figure 4 on Plate 22. 8. Distal end of a periproctial face. The hydropore slit is well developed. Kirk- field Formation, Kirkfield, Ontario. Trentonian. USNM(S) 4242; X 2. 9. Periproctial face with portions of the arms and column intact. Kirkfield Formation, Kirkfield, Ontario. Tren- tonian. UCM 39542; X 1.5. 204 BULLETIN 260 Explanation of Plate 25 Figure Page 1-7. Plevracystites filitextus Billings =425000.. 22 4 eee ee 167 All specimens are from unspecified localities in the Cobourg Forma- tion, Ottawa, Ontario. See the explanation for Plate 21. Tren- tonian, All X 2. 1, 2. Rhomb and periproctial faces, respectively. Note the differences in the two upper rhombs. USNM 42197. 3, 4. Portions of rhomb and periproctial faces, respectively. The peri- proctials are typical (figure 4) for this species. Holotype. GSC 1400. 5. Rhomb surface of a theca. This specimen is a syntype of P. elegans Billings = P. filitextus. GSC 1382b. 6. Rhomb surface with most of the arms intact. This specimen is a syntype of P. elegans Billings = P. filitextus. GSC 1382c. 7. Rhomb surface with a considerable amount of the arms present. The prosopon is typical of “P. elegans.’ GSC 1382a. 8: [Pleurocystites: filitextus Billings. ))5...2..50. eee 167 Rhomb surface with parts of the arms and column. Note the unusual aspect of the upper left rhomb and the long relative length of | the complete arm. Sherman Fall Formation, Peterborough, On- | tario. Trentonian. GSC 17696; X 2. BuLL. AMER. PALEONT., VOL. 58 PLATE 25 BuLL. AMER. PALEONT., VOL. 58 PLATE 26 | NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 205 Explanation of Plate 26 Figure Page 1-3. Pleurocystites, distanms Bolton ...0.00000000ccccccocceceeccee cette 17 (7 1, 2. Incomplete rhomb and periproctial face, respectively. The proximal angles formed by JL4 and JL5 are close to right angles. Note the narrow periproctial margin which is typical of Upper Ordovician species and Amecystis. Galena Formation, Fusispira beds, (?Stewartville Dolomite), Hader, Minnesota. Trentonian. USNM 42141; X 1.66. 3. Incomplete rhomb surface with part of the proximal column attached. Same locality. USNM 42141; XOIG6: 4. Pleurocystites, beckeri Foerste 000000... 178 Incomplete rhomb surface with part of the proximal column. This specimen is the holotype of P. clermontensis Foerste = P. beckeri herein. Lower Maquoketa Formation. Clermont, Iowa. Cincinnatian. FMNH 16858; X 2. 5. Amecystis laevis Ulrich and Kirk 0... 192 Periproctial face with part of the column and with hexagonal peri- proctials 0.5-1 mm in diameter. Note the narrow periproctial margin and the high degree of symmetry. Kirkfield Formation, Ontario. Trentonian. USNM(S) 4247; X 2. 6-9. Pleurocystites squamosus (Billings) mut. matutina Ruedemann 161 All specimens of this “subspecies” are from the Glens Falls Lime- stone, Glens Falls, New York. Trentonian. 6. Incomplete peri- proctial face with some of the periproctials intact, part of the proximal column and arm impressions are also preserved. Para- type. NYSM 7382; X 2. 7. Incomplete and distorted rhomb face with parts of the distal arms and proximal column _ intact. Several periproctial plates are visible. Paratype. NYSM 7384; X 2. 8. Distorted and incomplete rhomb face. Holotype. NYSM 7381; X 2. 9. Partially disarticulated rhomb face with one nearly complete arm. Paratype. NYSM 7383; X 1.5. 206 Figure 1-7. Pleurocystites beckeri Foerste BULLETIN 260 Explanation of Plate 27 All specimens are from the Maquoketa Formation, Iowa. Cin- cinnatian. All X 2 except for figure 4. 1. Rhomb surface of the theca. Photograph is of a plaster cast of the original. This specimen is the holotype of P. slocomi Foerste = P. beckeri herein. Lower Maquoketa, Clermont, Iowa. FMNH 16858. 2. Rhomb surface with a portion of a single arm intact. Lower Maquoketa, Clermont, Iowa. Paratype. FMNH 16884. 3. Rhomb surface of an incomplete theca. This specimen is the holotype of P. multistriatus Ulrich and Kirk in Foerste = P. beckeri herein. From two miles northwest of Clermont, Iowa. Lower Maquoketa. USNM 93441. 4. Detail of the upper right rhomb of figure 3. The bars across the fold lamellae are probably due to “still stands” in growth; X 4. 5, Periproctial face with part of the column attached. Dover Township in Fayette County, Jowa. Middle Maquoketa. FMNH no number. 6, 7. Rhomb and peri- proctial faces, respectively, of a nearly complete theca. Lower Maquoketa, Clermont, Iowa. Holotype. FMNH 16884. BuLL. AMER. PALEONT., VOL. 58 PLATE 27 BULL. AMER. PALEONT., VOL. 58 NorTH AMERICAN PLEUROCYSTITIDAE: PARSLEY 207 Explanation of Plate 28 Figure Page 1,2. Coopericystis pyriformis, n. gen., n. sp. ee. 183 Rhomb surfaces of the holotype and paratype specimens, respec- tively, each with part of the column intact. Note the presence of a single pectinirhomb counter-balanced by a ridge on the opposite side of the theca. Benbolt Formation, three-quarters of a mile southwest of Mt. Eager Church, Hogskin Valley (Powder Springs Quadrangle), Tennessee. Blackriverian. USNM 114198; xX 3. 3-8. Pleurocystites watkinsi Strimple ........... 171 The specimen is from the Bromide Formation at Rock Crossing in the Criner Hills southwest of Ardmore, Oklahoma, Black- riverian. Holotype. USNM(S) 4640; X 2. 3, 4. Lateral views of the right and left side, respectively. The “disjunct” pectini- rhombs in the pleurocystitids are known only in this species. 5, 6. Distal transverse and proximal transverse views, respec- tively, of the theca. 7, 8. Rhomb and periproctial surfaces, respec- tively, of the theca. Note the wide marginal area and reduced periproct in figure 8. 208 Figure BULLETIN 260 Explanation of Plate 29 15. Amecysti$ laevis Ulrich: and. Kirk «:..siqiotie eee oe ees 1. Rhomb or dorsal face with proximal portions of the arms intact. The unusual appearance is due to the superposition of one specimen over another. Kirkfield Formation at Kirkfield liftlock, Ontario. Trentonian. Holotype. GSC 7936; X 2. 2. Distally in- complete rhomb surface with part of the proximal column attached. Kirkfield Formation, Kirkfield, Ontario. Trentonian. UCM(K) 39543; X 1. 3. Rhomb surface with part of the proxi- mal column intact. Kirkfield Formation, Kirkfield, Ontario. Tren- tonian. USNM(S) 4248; X 1.5. 4. Partially preserved rhomb surface with one arm and a portion of the proximal column intact. The pustulose prosopon is unknown in other specimens. Decorah Shale, Rhinidictya bed, Minneapolis, Minnesota. Black- riverian. USNM 93446; X 2. 5. Rhomb surface with the proximal portions of the arms and much of the column intact. The double IL2 plate may be due to fractionation of a larger plate or fortui- tous fracturing. Lower Trenton Formation, West Neebish, Michigan. Trentonian. USNM 93444; X 2. BuLL. AMER. PALEONT., VOL. 58 PLATE 29 BuLL. AMER. PALEONT., VOL. 58 PLATE 30 | NortTH AMERICAN PLEUROGCYSTITIDAE: PARSLEY 209 Explanation of Plate 30 Figure Page PE ANTIGCUSTIS FAYIMNGOMGL, TSI. .u...2:)0scc0.cccsestese ec cuscscnnsectseeseateodaecivaccotecs 194 Three rhomb or dorsal faces of the holotype and two paratypes, respectively. All specimens are from the Shippensberg Limestone, three and one-half miles north of Greencastle, Pennsylvania. Blackriverian. USNM 93447; X 2. AMPAINIGCYSTIS aAVINIONGIy Ms SPs on, ce tees terres rece ceccien ces ete ee 194 Rhomb surface of a juvenile specimen. ?Benbolt Formation, .35 mile ENE of Fairview School in a roadcut on Tennessee High- way 131, Granger County (Swan Island Quadrangle), Tennes- see. To be placed in the Sedgwick Museum; X 3.5. 5,6. Amecystis laevis Ulrich and Kirk .0..00000000....occcceccceeeeceee 192 5. Incomplete rhomb surface with a discontinuous arm and most of the column intact. ?Trenton Limestone, found on a rock pile at the south end of West Neebish channel, Chippewa County, Michigan. UMMP 56240; X 1.5. 6. Portion of the distal rhomb surface and part of the proximal rhomb surface with some of the proximal column attached. The specimen is silicified and has been etched from the matrix. Curdsville Limestone, three and one- half mile south of High Bridge, Kentucky, along the Cincinnati Southern Railroad. Trentonian. USNM 93448; X 1. INDEX Note: Light face type refers to page numbers. Bold face type refers to plate number. A eas ve 138, 149, 187 TENG et. ei aera 135, 136, 137, incinnati, aa 139, 141, 147, University of .......... 135, 137 158, 187-192 Cincinnatian ................ 179 anatiformis, Clermont, Iowa .......... 179 Cheirocrinus .......... 149 clermontensis, Anomalocystida .......... 141 Pleurocystites ....26 182 Anomalocystites ........ 141 Cobourg beds .............. 167 Anticosti Island ........ 136, 143,182 Coopericystis .............. 135, 136, 137, anticostiensis, 138, 139, 174, Pleurocystites........ 135, 136, 466, 183-187, 7 Ardmore, Oklahoma .. 171° ‘Cornuta»....... See ea 160 Ashpillian) 200.002 145, 182 Caneeen Pond in : ‘ 147 « County Portwneur 2 i= Lee aie Criner Hills ........... 171 B Curdsville Baltic! Repion ....e 145 it Limestone | auuaie cnet 166, 187, 192 Barneveld ...........ccc000: 177 cystid beds” .............. 167 : Cystoideasmett eee 137 bassleri, rid 135 Pleurocystites ........ IS6, 171 Py ke fos Tn Bather oF Awe 2 ters. 135, 138, 140, D 141, 143, 148, 153, 158,166, Dalvé, E. R. Mrs. ........ 137 168, 169,170, Decorah Shale ............ 177, 187, 192 176,194", ‘Dehm, Ry -3.-) eee 138, 140, 141, beckeri, 192 Pleurocystites 26,27 135, 143,148, Delpey, G. ...........0.... 139 175, 178-183. Devonian, Lower ........ 138, 184 Belsiumye 143 = distans, Belli gBh Mi, -oe ke eee 137 Pleurocystites ...26 135, 145, 159, Benbolt Limestone .... 183, 194 177-178 Billings, 2B) (ees 141, 143.166, Dollo’sLaw? =... 159 168, 170 Billings* Waka ee 168, 169 |= Blackriverian .............. 171, 183,187, elegans, 194 Pleurocystites 21,25 168, 169 Boltons Lehi ee 137 English Head Breimer, vA... nes 143, 147, 148, Limestone ................ 182 153,157, 176 ““Borepe se eee 138 British Columbia ...... 143,182 exornatus, Bromide Formation .... 171 Pleurocystites ........ 170 Cc F Cambrian, Upper ........ 191 Fairview School ........ 194 Canadian Rockies ...... 182 Farr Formation .......... Lin Caradocian, 143, 144,145, Fayette County, 146, 176 TOWall1....:-...eeee 179, 182 Carpenter, Pigs... 140,153,176 Field Museum of “Carpoidea” Skene 140 Natural History ..... 137 Carpoldsine ee 141,158,161, filitextus, 192 Pleurocystites 24,25 135, 142, 143, Caster iss Wa 2.5.38052 137, 192 145, 147, 148, Ceratocystis ................ 141 156, 167-171, Chapman bids. 169 178 210 ——S Foerste, A. foriolus, Pleurocystites fusispira bed Geological Survey of Canada ....:.!......... Germany gibba, Pleurocystis Gill, E. D. & Casters Ke hy Girvan Glyptocystitida ........... glyptocystitid radical Grange County, Tennessee reat Britain 2... Greencastle, Pennsylvania Hader, Minnesota Praeckeh Wy po... ...c.0:..0.5 Haileybury, Ontario .. High Bridge, Kentucky Hogskin Valley, Tennessee Hull Limestone ...... Hunsruckschiefer ...... Efunt, Al M.. .......:..... l Indiana, University TIowacystis ..........0.000... LEGGE Ys Ree PEK CIRIOEE Foo once ee. cec: Kentucky mesling, KR. V. ........... ETE a Ce rs TTI 9) De Kirkfield Formation .. Kirkfield, Ontario ...... INDEX 135, 138, 143, 180, 182 Lae 136, 166, 170, 193 186 182 192 135 137, 138 138 194 138, 183 194 . 140, 141, 143, 149, 153, 157, 166, 169, 170 143, 162, 187 . 137, 149, 186 137 158, 159, 176 187, 192 187, 192 Kopf Collection, University of Cincinnati LE laevis, Museum 137 Amecystis ..... 29,30 135, 190, 192- laevis, Pleurocystites Lexington Limestone .............. Lincolnshire Kormiation) -—— Llanvirn Luttrell, Tennessee .... M Macurda, D. B. .......... Maquoketa Formation .............. Mercer County, Kentucky Michigan Michigan, University of ........ Maller Ss. Ae eae Miller, S. A. & Gurley, W. F. E. Minneapolis, Minnesota Minnesota Mitrata Mitrocystites Monteithssds)-2ee ee Mt. Eager Church multistriatus, Pleurocystites New Liskeard, Ontario New Orleans, Louisiana IN@WaeOln Kare New York State Museum New World ................ Niteckis M. Hy 22... INOELORGS ba North America Oklahoma Ontario 211 194, 196 187 166 171 138 171, 194 137 182 166, 192 142, 143, 162, 187 177 1 135, 138, 161 143 142, 143, 162, 167, 187 Ordovician Ordovician, Lower Ordovician, Middle Ordovician, Upper Ottawa Parsley, Mrs. Palo Parsley, R. L. & Caster: Ke EB: PaulSiC ans Cae “Pelmatozoa”’ Pennsylvania Bhelane 22 aes Pleurocystida Pleurocystis Pleurocystites Pleurocystites Sp. Breimer .2..20 Pleurocystites sp. Foerste Pleurocystites, synopsis of morphology Pont Rouge, Quebec Portneuf County, Quebec . Powder Springs Quadrangle, Tennessee pyriformis, Coopericystis quadrata, Pleurocystites INDEX 137, 166 191 135, 136, 138, 142, 143, 160, 162, 166, 167, 177, 178, 182, 187, 192 135, 136, 138, 143, 160, 175, 178, 179, 182, 183 137, 166 137 192 135, 137, 138, 140, 143, 145, 148, 149, 151, 152, 153, 154, 157, 158, 159, 160, 174, 175 135, 137, 141- 161, 182, 183, 184, 187, 189, 190, 191, 192, 193 147, 152, 153, 154, 159, 176 182 152-158 190, 192 192 183 Quebec 444.2 ee 142, 143, 162, 167 R Raymond se hee 135, 167, 193 raymondi, Amecystis) 5.2... 30 135, 192,194- 196 Regnell, ‘Gio: See 140, 153 Regulaecystis .............. 137, 138, re 9 Hhombifera ).3..-25 137, 138, 192 Richardson, E. S. ........ 137 robustus, Pleurocystites ....21 166, 170 Rock Crossing (OKA) pt eee 171 Royal Ontario Museums. eee 137 Ruedemann, R. .......... 166 rugeri, Pleurocystites ........ 147, 194 S Scotland \;..2..4 35 135, 143, 182 Sherman Fall beds .... 167 Shippensberg Limestone ................ 187, 192, 194 Silurian’: eee 166 Sinclair, G. W. ........... 135, 138, 140, 143, 148, 149, 15125 153) 155, 156, 170, 176, 190, 193 slocomi, Pleurocystites ... 27 182 Smithsonian Institution 137 Solutae 2-0 eee 140, 162, 192 Speers Ferry, WATSinT ae eee 194 squamosus, Pleurocystites 21,22, 23,24,26 135, 141, 143, 143, 145, 148, 150, 151, 156, 157, 159, 161- 167, 170, 175, 176, 178, 179, 182 squamosus var. robustus, Pleurocystites ....21 168 Strimple, \He. ..setcnnc 153 SUN NC ee 138 Swan Island Quadrangle, Tennessee ............... 194 INDEX T Vv Tennessee .................... 143 ~«=~*VVirginia ........... 143, 162 Trenton Limestone .... 187 Y MMeENtOMIAM ...:-...266-.:-- 146, fee mt Yunnan Province, : a Chinay ee 138 Trochocystites ............ 141 Tulane University WwW Dept. of Geology ... USO Wialeshee: hess. cs ovoleve, 143 watkinsi, U Pleurocystites 24,28 135, 137, 152 Ulrich, E. O. & 153, 154, 171 1iG ty a4 ORR cae 135, 182, 190, 177, 183 G4 eWilSOnwAce Ee 167, 170 213 yee nee re Minas re eels } ve i habetl! neural iis aT) (ae an. anh i $ i 1 @ 4 4 ’ ; ni ‘ eal in 7 , " in Aen ray spe % ri rie ae ta PHOT i t ; Bbt lige a wven Nh + ie ry espe ch ¥ RR esses, Bld Peale iff = @ fr bee? ior OMSL ORL beh yy ny in ii at 5 0 ‘ = ~ ay ’ ery U / iis ib x \ ‘ Nie ; Sh Teuir’ -) entree ati say. “2 ’ 4, i ot 1 matey ie hyPaeied Gut TTL pe 7] Pyrayts! yw Sie ey, we an ih. ¥ 4 ® i Habiy, leant. ne a ae : : 2a ah ‘ ) , bai = svt hi LY 1 Uae i ray P\- (D MUS, COMP. zoo”: LIBRARY JAN 8 197] BULLETINS HARVARD UNIVERSITY, OE AMERICAN EALEONTOLOGY (Founded 1895) Vol. 58 No. 261 MORPHOLOGY AND TAXONOMY OF CYCLONEMA HALL (GASTROPODA), UPPER ORDOVICIAN CINCINNATIAN PROVINCE By EsTHER H. ‘THOMPSON 1970 Paleontological Research Institution Ithaca, New York U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION 1970 - 71 PRESIDENT 9s 2c ook ee ee ee AR eee WILLIAM B. HEROYy VICE-PRESIDENT 62s onsen ee a a 2 DANIEL B. Sass SECRETARY: 5.505 eet 2S ere ieee he eh eat ee REBECCA S. HARRIS DIRECTOR, “TREASURERS 22h oe ee ee ee ee KATHERINE V. W. PALMER COUNSEL | co 2365 es er ses ae ee) ee ARMAND L, ADAMS REPRESENTATIVE AVAVA'S: COUNCID (oti ee ee Davw NICOL Trustees Repecca S. Harris (Life) DoNnaALD W. FIsHER (1967-1973) AXEL A. OLsson (Life) MERRILL W. HAAs (1970-1973) KATHERINE V.W. PALMER (Life) PuHILip C. WAKELEY (1970-1973) DANIEL B. Sass (1965-1971) WILLIAM B. HERoy (1968-1974) KENNETH E. CASTER (1966-1972) - Vircit D. WINKLER (1969-1975) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PaLMer, Editor Mrs. Fay Briccs, Secretary Advisory Board KENNETH E. CASTER HANS KUGLER A. MyrA KEEN Jay GLENN MARKS AXEL A. OLSSON Complete titles and price list of separate available numbers may be had on application. For reprint, Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., New York, N.Y. 10017 U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Cor- poration, 111 Fifth Ave., New York, N. Y. 10003 U.S.A. Subscription may be entered at any time by volume or year, with average price of $18.00 per volume for Bulletins. Numbers of Palaeontographica Ameri- cana invoiced per issue. Purchases in U.S.A. for professional purposes are de- ductible from income tax. For sale by Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. mine TINS OF AMERICAN PxbkON TOLOGY (Founded 1895) Vol. 58 No. 261 MORPHOLOGY AND TAXONOMY OF CYCLONEMA HALL (GASTROPODA), UPPER ORDOVICIAN CINCINNATIAN PROVINCE By EsTHER H. THOMPSON December 10, 1970 Paleontological Research Institution Ithaca, New York U.S.A. Library of Congress Card Number: 79-139408 Printed in the United States of America Arnold Printing Corporation CONTENTS Page SUBSUSDGTR © codices icateon didn a Sete Ase as Ea ee ne 219 eeUCTIO TG teenee. Peter RRM RT ES oes car sw? ae cal ee ee eae pe 219 BTRCA SUT Ne LOIN GES enero cee eer, oO ese cee ts a ee ee ee 220 Collections and materials studied __... nok ge: Bad 2 as) hogs ae ahaa 221 PCPETPLD OS. RTGS eet ret ee cel ae lee ORR RN eden chin 221 UMTS CH UNG Ciec eee terre ea, ene neem ©: Seren aa ee 222 ALeOECOl Ol vara NGA ssOClatlons|e esse ee 224 IMI@TDINOUOES? accuses, SOI Ee Per aR ne ae pen CLE ety en YN Oe 225 Baysorenyrot Gy cloneriamer PE seek. At wie Set Le ee Ree 230 CIT eats lst Cait Orn pm eea eee ete ae ae EN 2 Ee Ly ei cc sae wi 231 SVStelIa tl CmGeSCHIPtlonspmerese ssi ate Shietwes halos 2. Ee ee eee 234 Cyclonema from outside the Cincinnatian Province ~....................20.:.2-0eseeees--- 255 TEBE CIENT fe RA SSI SS Eo re eS eo LTA rc cab ace ee re 269 IRGHRENGSS Sate. ae er a Dex Sen eee eR noes pment 6 Freee t Dipl EAC S meee me Biel lermnie Sete A NI Ain As OA ek ak ae ee dae eee Rens ote 275 ern ory “pts o an AeVaTROT Sy vpn? ry} , qT >a 7 7 ips *9 . = » Canavan “rar@ Guha % eS see sy 1 A é ; 7 Re: 7 ya _ \ © moat (oa ‘i - toilte ini : - a = iL = - a iJ % - aia . 7 * ro Sal 1 _ wa = ie i evele ov velunulad ait h ye 1 =~ — < < i Aiiee fer =! Amos a} ie oy 199) a MORPHOLOGY AND TAXONOMY OF CYCLONEMA HALL (GASTROPODA), UPPER ORDOVICIAN, CINCINNATIAN PROVINCE EsTHER H. THOMPSON* ABSTRACT Cyclonema Hall is a common gastropod in Upper Ordovician rocks of the Cincinnati area. It is unique among Cincinnatian gastropods in that its shell is fully preserved and presumably was composed originally of calcite. Juvenile whorls generally are destroyed unless protected by bryozoans. Mature whorls appear to consist of three layers of original calcite. Cyclonema is an early member of the family Platyceratidae which includes Paleozoic gastropods which were coprophagous upon crinoids and cystoids. Specimens of Cyclonema occasionally are found attached to Glyptocrinus deca- dactylus Hall, but their association was probably temporary. Most species of Cyclonema were probably detrital feeders and ill-adapted to a sedentary mode of life. Cyclonema occurs in shaly limestones of varying thickness, associated with crinoid debris and bryozoans. It would seem that Cyclonema inhabited normal marine waters with a firm substrata, free of muddy sediment which would clog the gills. Species of Cyclonema are differentiated on shell shape, aperture shape, and ornament. Shell shape varies from high-spired to low-spired, with whorl profile ranging from concave to straight to convex among various species. The shape of the aperture is of little taxonomic value because it is influenced by the surface of attachment. Nonetheless, most species of Cyclonema have dis- tinctive apertures: either polygonal or circular or auriform. Ornament is the most diagnostic characteristic. All species of Cyclonema have collabral growth lirae. Collabral growth wrinkles, formed by thickened growth lirae, are char- acteristic of Cyclonema. All but two species have spiral lines cancelling the lirae. Spiral ornament may be of one to three orders: cords, costae, and threads in descending order of prominence. Cyclonema seems to have been derived from Holopea, a high-spired gas- tropod with a smooth, polished surface ornamented only by collabral growth lirae. Cyclonema was probably the ancestor of typical uncoiled, sedentary platyceratids. Many Cyclonema-like forms of Ordovician to Devonian age from New York, Ontario, and Quebec have been called Cyclonema, although properly they should be referred to other, unrelated genera. In this paper only those species which oc- cur in the Upper Ordovician rocks of the Cincinnati area are described in detail. Thirteen species and two subspecies are redescribed from type material. INTRODUCTION The present study is concerned with the taxonomy, paleo- ecology, morphology, and phylogeny of the gastropod Cyclonema Hall. Only those species which occur in the Upper Ordovician rocks of the Cincinnati area are described in detail. These are the classic species of Cyclonema as described by Conrad (1842) and Hall (1852). Many Cyclonema-like forms of Ordovician to Devonian age from New York, Ontario, and Quebec have been called Cyclo- nema, although properly they should be referred to other, unrelat- ed genera. Those species provisionally placed in the genus are de- * Esther H. Thompson Cornell. 220 BULLETIN 261 scribed briefly and rejected species are excluded to present a clearer discussion of Cyclonema. Thirteen species and two subspecies of Cyclonema are rede- scribed from type materials. As many species as possible are illus- trated by photographs of their type specimens. Individuals of Cyclonema sometimes are found attached to the tegmen of crinoids. Thus, the genus is classified (Knight, et al., 1960) with other Paleozoic coprophagous gastropods in the Platy- ceratidae. Most species of Cyclonema do not seem to have been coprophagous; they were probably detrital feeders. Derivation of Cyclonema from both Gyronema and Holopea is discussed, based upon morphologic affinities. Recent ecologic evidence (Bowsher, 1955) indicates that Cyclonema was a _ primi- tive platyceratid from which Dyeria and others developed. Cyclonema is unique among Cincinnatian gastropods in that its shell characteristically is fully preserved, but juvenile whorls are missing. Presumably a septa was formed between the proto- conch and teleoconch, and the protoconch was broken off. The work of Bassler (1915) has been of invaluable assistance in compiling synonymies for species of Cyclonema. Most earlier bibliographic work is taken from his index. References used in synonymy and not mentioned in the text of this paper are not listed under references. ACKNOWLEDGMENTS The present paper was written in partial fulfillment for the degree of Master of Science at Miami University, Oxford, Ohio. The author extends appreciation to John K. Pope under whose direction and advice the paper was prepared. Thanks are also due Roy Reinhart for his help in collecting specimens and for edi- torial reading. The author is indebted to Ellis L. Yochelson of the United States Geological survey for his invaluable assistance at the United States National Museum and for critical review of the manuscript. His continued support and enthusiasm are deeply appreciated. John Pojeta of the United States Geological Survey also ad- vised the author at the United States National Museum. Harold B. Rollins of the University of Pittsburgh offered valuable data on shell structure from his work with gastropods. CINCINNATIAN CYCLONEMA: THOMPSON 221 Particular thanks go to the following persons who generously lent specimens in their charge for study: Roger L. Batten, Ameri- can Museum of Natural History; Frederick Collier, United States National Museum; Donald W. Fisher, New York State Museum; Matthew H. Nitecki, Field Museum of Natural History; Joseph Marak, Miami University; and Kenneth Beem, University of Cin- cinnati Museum. Copeland MacClintock, Yale University, and David M. Raup, University of Rochester, gave advice by letter. Much of the field work was aided by a Grant-in-Aid of Re- search from The Society of the Sigma Xi. COLLECTIONS AND MATERIALS STUDIED Ulrich (in Ulrich & Scofield, 1897) named most of the species of Cyclonema; therefore, his type collections from the United States National Museum (USNM) were relied upon heavily in writing this paper. Specimens from the James, Faber, and Billings Collec- tions were obtained from the Field Museum of Natural History (FMNH) in Chicago. The American Museum of Natural History (AMNH) and the New York State Museum (NYSM) also lent type materials; most of these are of species questionably assigned to the genus or rejected from it. In addition to type specimens, the author examined numer- ous Cyclonema specimens from the Shideler Collections of Miami University (MU) and from the University of Cincinnati Museum (UCM). PREVIOUS STUDIES Paleozoic gastropods in the family Platyceratidae, particularly Platyceras (Platyceras), have long been a fossil curiosity because of their common association with crinoids. This was a form of commensalism which significantly influenced the morphology of the gastropods. During the last half of the nineteenth century Platyceras was described repeatedly in an interesting series of papers. An association between crinoids and these molluscs was first noted by Austin and Austin (1843, p. 73), who believed the crin- oids to be carnivorous; they had died in the act of feeding upon a gastropod. At that time, the aperture on the tegmen was thought 999 BULLETIN 261 —— to be the mouth; thus, the Austins’ explanation was accepted for 20 years. In 1866, Meek and Worthen (p. 384) first suggested that the crinoids were not carnivores because the line of contact be- tween the gastropod and crinoid indicated that the association was more than transient. Trautschold (1867, p. 41) described a gastro- pod attached to the anal plate of a crinoid, indicating that perhaps the snail fed upon the excrement of the crinoid or was in some way dependent upon it for its food. Meek and Worthen (1868, p. 340) described additional occurrences of attached specimens and proposed that each crinoid had attached to it a particular species of Platyceras. Two years later Billings (1870, p. 235) suggested that the gastropod was carnivorous upon the crinoid and was crushed in its arms while feeding upon the crinoid. Further discussions by Meek and Worthen (1873, pp. 334-339), Trautschold (1879, p. 119), Hinde (1885, p. 172), and Keyes (1888a, 1888b) established the fact that the gastropods were sedentary upon the crinoid teg- mens, feeding at least in part upon the excrement of the host crin- oid, Clark (1908, p. 22) was the first to note the occurrence of Cyclonema on crinoids, especially Glyptocrinus. In addition, he cited the association of Platyceras and crinoids as the oldest ex- ample, Upper Ordovician, of parasitism in the geologic record. Bowsher (1955) reviewed and restudied the adaptation of the platyceratids to a coprophagous mode of life. Several of his con- clusions will be discussed later. MODE OF LIFE By current definition (Knight, et al., 1960) the family Platy- ceratidae includes all Paleozoic gastropods which were copropha- gous on crinoids and cystoids. All were sedentary to some degree and appear to have fed on the crinoid fecal matter, as indicated by the position of the gastropod over the anal opening of the crinoid. The coprophagous habit was most fully developed in Platy- ceras, whose apertural margin conforms to the tegmen surface of the host crinoid. Re-entrants on the margin of Platyceras coincide with the radiating ridges of the crinoid tegmen, indicating that the gastropod remained in this position for most of its life. The shape CINCINNATIAN CYCLONEMA: THOMPSON 223 of the aperture is determined by the surface of attachment and is of little taxonomic value. Clarke (1921, p. 67) described examples of Cyclonema bilix (Con- rad associated with Glyptocrinus decadactylus Hall. The tegmen of Glyptocrinus is relatively smooth and correspondingly, the aper- tural margin of Cyclonema is nearly smooth. Irregularities do exist on the margins of attached specimens, but they are too minute to permit identification of a Cyclonema specimen with the correspond- ing tegmen ridges of a Glyptocrinus specimen (Bowsher, 1955, p. 7). Gently undulating growth wrinkles, characteristic of many species of Cyclonema, are also indicative of a sedentary life. Unlike the geologically younger Platyceras, the aperture of Cyclonema was not fixed in a particular orientation with respect to the anal opening on the tegmen. Thus, it would seem that Cyclonema was less dependent upon crinoids for its nourishment and less adapted to the sedentary habit (Clarke, 1921, p. 67). The gastropod may have been attracted to the temporary food supply provided by the crinoid, but it was more mobile than Platyceras and probably had a broader diet. Bowsher (1955, p. 6) reported that nothing is known of the fecal waste of extinct crinoids. He noted studies of living coma- tulid crinoids whose wastes consist of undigested food particles held together in pellet forms by a jelly-like substance. The pellets contained a mixture of organic detritus, “such as threads of algae, macerated leaves, and other plant remains, diatoms, peridinians, crustacean larvae, copopods, ostracodes, fragments of hydroid col- onies and myzostomids—all more or less digested —as well as some living infusorians’” (Bowsher, 1955, p. 6). Few specimens of Cyclonema are found preserved in the arms of crinoids, compared to the abundance of Platyceras thus _pre- served. The abundance of unattached specimens of Cyclonema would indicate that they had a supplementary diet with the means to obtain it. Probably Cyclonema, along with most Archaeogastro- poda, was microphagous; that is, it ate minute algae and other detrital material. This food “is either raked up from the sub- stratum by radular action or picked up by tentaculiform appen- dages’” (Graham, 1955, p. 146). “All the Archaeogastropoda ex- cept the limpets have a rhipidoglossan radula’’ (Knight, e¢ al., 224 BULLETIN 261 1960, p. 1104). Thus, Cyclonema could have been an _ herbivore scraping the surface layer of mud or algae for detritus, or a filter- feeder on plankton. The former diet seems more probable when compared to liv- ing gastropods. Hipponix australis (Lamarck) is a sedentary living gastropod which feeds on the feces of Turbo sp., while another species, H. antiquatus (Linnaeus) eats algal detritus (Graham, 1955, p. 150). In the same way, various species of Cyclonema may have had differing diets. Clarke (1908, p. 151) termed the copro- phagous habit an “individual adjustment” which did not affect all individuals of the genus. Furthermore, an individual may not have remained coprophagous throughout its life. Another alternative is suggested by Frankenberg and Smith (1967). Their studies of living coprophagous gastropods show that generally the snails ingest several kinds of feces, including their own, and thus obtain a substantial fraction of the organic ma- terial required for their metabolism. Cyclonema may have con- sumed feces of other organisms, in addition to those of Glypto- crinus. Cyclonema was coprophagous upon crinoids but probably sup- plemented this diet with other fecal matter or scraped algal detritus. Diets may have differed among species or during the ontogeny of an individual. This conclusion is supported by the relatively few specimens of Cyclonema found preserved on crinoid tegmens, the random orientation of those attached specimens over the anus, and comparison of living Archaeogastropoda. Clarke (1908, 1921) and other early workers described the as- sociation of gastropods and crinoids as parasitism. However, the excrement of attached gastropods apparently did not foul the crinoid’s necessary oxygenated sea water, nor was Cyclonema abso- lutely dependent upon the vital functions of the crinoid host. Therefore, the relationship is better termed commensalism. PALEOECOLOGY AND ASSOCIATIONS Cyclonema is an archaeogastropod belonging to the suborder Trochina (Cox in Knight, et al., 1960). Trochinoids are presumed to possess a monobranchiate gill structure with a pocket between the ctenidial membranes and the left wall of the mantle cavity. This is a delicate gill structure because the pocket is readily CINCINNATIAN CYCLONEMA: THOMPSON 225 blocked with sediment. For this reason, the trochinoids are found on a firm substrata relatively clear of sediment. They inhabit the intertidal and nearshore zones, but “do not invade muddy areas” (Yonge in Knight, et al., 1960, p. 116) . Cyclonema often occurs in limestones of varying thickness in the Richmond Group of Ohio. The limestone may be shaly, but is rarely sandy. Cyclonema is found associated with almost every Cincinnatian organism, making ecologic generalizations difficult. However, Cyclonema most commonly is found in crinoid hash and encrusted by bryozoans. Coprophagous individuals obviously shared the environment of crinoids. According to Imbrie (in Imbrie & Newell, eds., 1964, p. 421) crinoids and bryozoans are associated in Permian strata with Derbyia, clams, and subulitid snails. Newell identified the paleo- ecology of the environment as “shallow, prodelta, nutrient-rich waters overlying a marl bottom.” In the Ordovician, different genera but a similar community occurs with Cyclonema: brachiopods, other gastropods, pelecypods, trilobites, echinoderms, and bryozoans. Thus it would seem that Cyclonema inhabited nutrient-rich marine waters of normal salinity. The substrata was firm and the overlying water free of muddy sediment to prevent clogging of the gills. Cyclonema’s occurrence with echinoderms and bryozoans sug- gests that the water was clear and warm, but not necessarily near- shore. In thin section, the interior of individuals of Cyclonema is filled by sparry calcite and micrite. Coarse, crystalline calcite is concen- trated in the spire; micrite is found in the body whorl. ‘The charac- ter of the internal preservation suggests that the interior was filled soon after death. MORPHOLOGY Morphological features of Cyclonema are illustrated in Text- figure 1. Definitions of morphological terms used in this paper are in accordance with those in the Treatise on Invertebrate Paleon- toloy, Part I, Mollusca I (Knight, et al., 1960). Several aspects of the morphology of Cyclonema which require discussion are de- scribed below. 296 BULLETIN 261 columellar excavation columellar lip inner margin outer lip aperture basal surface aGpertural view Text-figure 1.— Morphological features of Cyclonema. The protoconch.—A generic characteristic of Cyclonema is loss of the apex; unless it is protected by encrusting bryozoans, the protoconch is absent. Of hundreds of Cyclonema examined for this study, only four complete specimens have been observed. ‘Two factors seem to account for loss of juvenile whorls: 1) formation of septae in the apical whorls, or, 2) the protoconch was of a dif- ferent shape than the teleoconch. CINCINNATIAN CYCLONEMA: THOMPSON 227 Many living and fossil snails have one or more septae be- tween the protoconch and teleoconch. If septae are formed, depo- sition stops adapically from the plug. Therefore, this part of the shell is subject to breakage during the life of the individual. The soft parts are protected from break-through at the apex by the presence of septae. Bryozoans protecting complete individuals must have encrusted the snail before the thin protoconch broke off. Due to a lack of complete specimens, presence of septae in Cyclo- nema is yet to be established (MacClintock, per. com., 1969). On the other hand, protoconchs of other individuals may have been destroyed after death, during preservation. In thin-sec- tion some complete protoconchs are conical, multispiral, and pro- ject as a slender spire above a trochiform adult shell. Increase in the coiling angle at the base of the protoconch provides a zone of weakness where the apex could easily be broken off in a turbu- lent environment. Ulrich (im Ulrich & Scofield, 1897, p. 847) suggested that Cyclora Hall was the young or the dwarfed form of associated gastropods with which it occurs, particularly Holopea or Cyclo- nema. Cyclora is a minute gastropod known only from steinkerns in Central North America. Until the shell and its structure are known, only speculations can be advanced concerning the relation- ship of Cyclora and Cyclonema. Cyclora minuta Hall is the type and most common species of Cyclora in the Cincinnatian Series. It is locally abundant and commonly associated with Cyclonema, especially C. bilix bilix (Conrad) and C. humerosum Ulrich in the Richmond Group. Cyclora minuta resembles the protoconchs of Cyclonema by being rounded in whorl profile and rapidly enlarging in cross-section. Text-figure 2 shows drawings made from acetate-peel-sections of Text-figure 2. — Acetate-peel-sections of Cyclora minuta. BULLETIN 261 no ho io) Cyclora minuta. In these peels the umbilical region is closed al- though it appears to be open in complete specimens. Peels of Cyclora compare well with axial thin sections of Cyclonema pre- serving an apex, as shown on Plate 35, figure 1. Of the various species of Cyclora, Cyclora minuta is the most probable species as the young of Cyclonema bilix or Cyclonema humerosum. Cyclora pulcella Miller could also be the young of Cyclonema bilix. It is larger than Cyclora minuta and expands rapidly to a highly ventricose body whorl. Surface ornament con- sists of numerous fine growth lirae, which resembles those of Cyclonema bilix. The two are found associated in the Richmond Group (Upper Ordovician) of Ohio. Remaining species of Cyclora, (C. alta Foerste, C. depressa UI- rich, C. hoffmanni Miller, and C. parvula (Hall)) are unlike Cyclonema in being high-spired or in having median angulations on the whorl profiles. Cyclora occurs in such local abundance associated with Cyclo- nema that it may represent a mass death of Cyclonema spat. How- ever, such dense populations of juveniles are rarely preserved, which suggests alternatively that Cyclora was a minute genus sympatric with Cyclonema and other large gastropods. The operculum.—No operculum has been found associated with Cyclonema. However, one of the characteristics of the genus is a groove in the columellar lip which may have functioned in conjunction with an operculum. An operculum would not be neces- sary for individuals that were permanently coprophagous on crin- oids, as no apertural protection would be required (Bowsher, 1955. p. 7). However, many individuals of Cyclonema were probably radulate feeders and would have a protective operculum as do all non-sedentary, shelled gastropods. If Cyclonema bore an operculum is was probably corneous and thus not preserved. Ornament. —'Three orders of spiral ornament cancelled by collabral growth lines are common on Cyclonema. These typically form a delicately reticulate pattern on the shell surface. Spiral lines are added by intercalation at the whorl base above the suture. ‘Terms used herein to describe the size of spiral ornament are cords, costae, and threads. Cords are the most prominent spiral lines and may approach CINCINNATIAN CYCLONEMA: THOMPSON 229 coarse ridges but never are as pronounced as keels or carinae. With the exceptions of C. limatum and C. transversum which lack spiral ornament, cords are always present even if other spiral ornament is absent. Costae are of moderate prominence, being finer than cords. Threads are the finest spiral elevations and are absent from many species of Cyclonema. When three orders of spiral ornament are present on a shell, two cords enclose two costae which in turn, are separated by a thread. If two orders are present, there may be two cords separated by one costa or two cords separated by one or more threads. If only one order of spiral ornament is present, it consists of cords. Growth lines are collabral in that they parallel the outer lip and are reflexed abaperturally. Herein they are termed growth lirae. Growth lirae are generally more pronounced than threads. They cancel spiral lines to form a polygonal pattern varying from squares to rhomboids; on some specimens the surface appears to be delicately pitted. Periodically on the shell, growth lirae may become thickened and form collabral growth wrinkles. These are especially apparent on large individuals and are characteristic of many species of Cyclonema. Unusually large growth wrinkles create elevated bumps or knobs where they meet the upper suture on the body whorl. Shell structure. — Cyclonema is the only gastropod in the Cin- cinnatian Series in which the shell is commonly preserved. ‘This suggests that the original shell was composed of calcite rather than aragonite. A shell of primary aragonite is unstable, and in the process of conversion to calcite, is vulnerable to solution and de- struction as is the case with most other Cincinnatian gastropods. The shell and shell microstructure of Cylonema are preserved and, therefore, must have been composed of primary calcite. Thin sections and etched shells of Cyclonema show two dif- ferent types of shell structure. Thin sections made parallel to the axis of coiling show three shell layers. A thin outer layer of pris- matic calcite is seen where the surface of one whorl is covered by an adjacent whorl but is absent from the exposed shell areas. The dark brown color is probably caused by conchiolin inclusions. ‘The second shell layer is “prismatic” nacreous calcite. The polygon elements extend the width of the layer, normal to the shell sur- 230 BULLETIN 261 face. The third layer appears to be an irregular nacreous structure (MacClintock, per. com., 1969). Etched and stained broken shell fragments, however, show two shell layers of prismatic structure. The prisms distinctly extend the width of each layer, normal to the surface. Two prismatic layers are typical of primitive molluscs; their occurrence in Cyclo- nema is as yet an unresolved problem (Rollins, oral com., 1969). PHYLOGENY OF CYCLONEMA Ulrich (in Ulrich & Scofield, 1897, p. 1046) suggested the first phylogeny of Cyclonema, based upon morphological similarities. According to Ulrich, Cyclonema could have developed from two stocks: Gyronema or Holopea. Cyclonema praeciptum Ulrich of the Murfreesboro Limestone (Blackriverian, Middle Ordovician) is intermediate between Cyclonema and Gyronema. C. praeciptum is a small trochiform shell with a faint umbilical depression, a straight columellar lip, and ornament of four strong cords. The columellar lip, in particu- lar, is transitional; it is unexcavated as in Gyronema but thickened and reflexed as in Cyclonema. The umbilical depression is not so pronounced as that typical of Gyronema. The ornament of C. praeciptum strongly resembles that of C. varicosum Hall, the second oldest species of Cyclonema (Upper Middle Ordovician) . In short, morphologic evidence suggests a relationship between Cyclonema and Gyronema. Weakly ornamented species of Cyclonema appear to be re- lated to Holopea as evidenced by C. limatum. Holopea has a smooth, polished surface ornamented only by collabral growth lirae. C. limatum Ulrich is similar but well-preserved specimens show faint spiral threads on the base of mature whorls. The ornament of C. limatum is identical to that of C. sublaeve Ulrich and closely resembles that of C. gracile. The shape of C. limatum is less convex and inflated than Holopea and, again, resembles C. sublaeve. The columellar lip is intermediate between Cyclonema and Holopea. It is not grooved as in Cyclonema nor does the reflexed fold form a true umbilicus as in Holopea. Knight (1934, 1946) proposed Holo- pea as the ancestral helicoidally coiled form of the Platyceratidae. Bowsher (1955) proposed an evolutionary sequence of platy- ceratid genera based upon ecologic affinities, rather than upon CINCINNATIAN CYCLONEMA: THOMPSON 231 morphology. According to Bowsher, Cyclonema and Naticonema developed from a common Early or Middle Ordovician stock. Dyeria developed from Cyclonema in Late Ordovician time and Platyceras evolved from Naticonema during Late Ordovician or Early Silurian time. The link between Cyclonema and Naticonema is evidenced morphologically by similarities of ornament and shape of the col- umellar lip. Both Cyclonema and Naticonema display cancellate ornament of spiral lines and transverse growth lines. Ornament of the two genera differs only in degree: revolving lines on Cyclonema are stronger than growth lirae, whereas on Naticonema growth lirae are stronger than the revolving lines. The shape of the columellar lips is similar. Both genera pos- sess a thickened, reflexed columellar lip, but that of Cyclonema is excavated and without an umbilicus, whereas Naticonema has a smooth columellar lip with an umbilical depression. Naticonema also has a parietal inductura and thus differs from Cyclonema. As far as known, C. limatum is the only species bearing a parietal inductura and it is poorly developed compared to that of Natt- conema. Morphological similarities and a common autecology — copro- phagy — indicate that Cyclonema and Naticonema shared a common ancestor. Bowsher did not attempt to identify this ancestor; per- haps it was Holopea, as suggested by Knight, or Gyronema, as sug- gested by Ulrich. From Cyclonema and Naticonema, the platy- ceratids developed by becoming uncoiled and by losing cancellate ornament, columellar lip, and parietal inductura. In the Cincinnatian Series, species of Cyclonema appear to fall into two groups, as shown on Text-figure 3. In the Maysville Group are an intergradational series of species with ornament of one or two orders, outer lip generally auriform, and spire height varying from high and slender to low and flattened. In the Rich- mond Group are species with third order ornament, aperture polygonal, and a tightly coiled trochiform shell. The two groups are united by the Maysville and Richmond forms of C. humerosum. CLASSIFICATION Prior to a revision of Paleozoic gastropod classification by Knight, Batten, and Yochelson in 1954, Cyclonema was variously BULLETIN 261 ie) ©9 no MAYSVILLE RICHMOND ene McMILLAN Arn eUe CYNTHIANA Corryville Ft Ancient Clarksville WHITEWATER ELKHORN P< | x Blanchester Mt. Hope lavatinae Bellevue EDEN C. bilix bilix | |x| LIBERTY EE BE BAe BRASSFIELD a C. bilix lata C. daytonense C. gracile C. humerosum C. inflatum C. limatum C. mediale eae ae Pol. |e alae ee a ee eee ea a a Text-figure 3.— Ranges of species of Cyclonema. x < ERE classified. Ulrich (in Ulrich & Scofield, 1897) placed it in the Trochonematidae (order Pectinibranchiata); Pelseneer 1906) assigned it to the family Turbinidae( suborder Rhipidoglossa) ; Zittel-Eastman (1937) include Cyclonema in the Trochonematidae (suborder Rhipidoglossa); and Wenz (1938) placed it in the family Cyclonematidae (superfamily Trochonematacea) . Except in Pelsener’s classification, Cyclonema was subsumed in the Trocho- nematacea which included trochoid and turbiniform shells with a simple aperture, no slit, strong spiral ornament, and well-preserved shells (Ulrich in Ulrich & Scofield, 1897, p. 1043). The super- family ‘Trochonematacea was “a catchall for several heterogeneous groups of fossil gastropods of the Paleozoic and Mesozoic” (Knight, et al., 1960, p. 1224) and recently has been greatly limited. Prior to the 1954 revision Platyceras was generally included in the family Capulidae, along with all sedentary attached gastro- pods. Knight (1934, p. 146) referred to the resemblance between Capulus and Platyceras as “superficial homeomorphy.” He adopted CINCINNATIAN CYCLONEMA: THOMPSON 233 the family name Platyceratidae Hall to include Platyceras Conrad, Orthonychia Hall, Platyostoma Conrad, and Strophostylus Hall. Cyclonema was not yet included in the Platyceratidae. It remained for Bowsher (1955) to rediscover the occurrence of Cyclonema on the tegmen of Upper Ordovician crinoids as reported by Clarke (1908). Based upon Bowsher’s work, Knight, Batten, and Yochelson (1954) included Cyclonema in the platyceratids. The latest classification (Knight, e¢ al., 1960, pp. 1240-1242) placed coprophagous Paleozoic gastropods having a calcitic shell in the family Platyceratidae Hall, 1859, superfamily Platyceratacea Hall, 1859, suborder Trochina Cox & Knight, 1960. ‘The following genera are included in the Platyceratidae: Naticonema Perner, 1903 Cyclonema Hall, 1852 C. (Cyclonema) Hall, 1852 C. (Dyeria) Ulrich in Ulrich & Scofield, 1897 C. (Ploconema) Perner, 1903 Platyceras Conrad, 1840 . (Tubomphalus) Perner, 1903 . (Platyostoma) Conrad, 1842 . (Platyceras) Conrad, 1840 . (Visitator) Perner, 1911 . (Orthonychia) Hall, 1843 (Praenatica) Perner, 1903 Pigehasbirtna Perner, 1907 Strophostylus Hall, 1859 ?Himantonia Perner, 1911 las} as) ac} as} as) as) Dyeria and Ploconema are subgenera of Cyclonema, based largely upon Bowsher’s study (1955). Dyeria is a flattened natici- form shell, with inner whorls contiguous and last whorl] vagrant and straight. It possesses an oval aperture and a seemingly wide umbilicus. Like Platyceras, Dyeria has a broad sinus and collabral growth wrinkles in gerontic whorls. These wrinkles decrease in size to faint collabral lirae on smaller whorls, cancellated through- out by sharp spiral cords and fine costae. Only the cancellation of the young whorls of Dyeria unites it with Cyclonema, but even this differs in being coarser and more irregular than that of Cyclonema. Although attached specimens of Dyeria have never been found, its low spire and undulating margin suggest a sedentary mode of life, perhaps coprophagy. In form and inferred mode of life, Dyeria resembles Platyceras more than Cyclonema. In this paper Dyeria is not considered a subgenus of Cyclonema. 234 BULLETIN 261 Ploconema Perner, 1903, is a Lower Devonian gastropod of Europe and no specimens were available to the author for study. Based upon Knight’s description (1941, p. 261), similarities shared by Ploconema and Cyclonema are their cancellate ornament, turbiniform shape, and flatly arched whorl profile. Gerontic whorls of Ploconema are free, it is phaneromphalous, and lacks an exca- vated columellar lip so characteristic of Cyclonema. Accordingly, Cyclonema is treated as a platyceratid genus without subgenera. SYSTEMATIC DESCRIPTIONS Phylum MOLLUSCA, Cuvier, 1797 Class GASTROPODA Cuvier, 1797 Subclass PROSOBRANCHIA Milne-Edwards, 1848 Order ARCHAEOGASTROPODA Thiele, 1925 Suborder TROCHINA Cox & Knight, 1960 Superfamily PLATYCERATACEA Hall, 1859 Diagnosis. — Primitively turbiniform with prosocline outer lip. Family PLATYCERATIDAE Hall, 1859 Diagnosis. — Coprohagous on crinoids and cystoids, progressive- ly becoming more adapted to a stationary life. Early members turbiniform or naticiform, with flat columellar lip but with irregu- lar collabral growth lirae. Ornament present in early members and gradually lost. Genus CYCLONEMA Hall, 1852 1852. Cyclonema Hall, Nat. Hist. New York, Geol. Sur. New York, Paleont., vol. 2, p. 89. 1859. Cyclonema Hall, Salter, Canadian Organic Remains, Geol. Sur., Canada, Dec Leppcsncye 1874. Cyclonema Hall, Miller, Cincinnati Quart. Jour. Sci., vol. 1, p. 319. 1889. Cyclonema Halli, Nettleroth, Kentucky Foss. Shells, Geol. Sur. Kentucky, p. 187. 1897. Cyclonema Hall, Ulrich in Ulrich & Scofield, Geol. Minnesota, Geol. Nat. Hist. Sur. Minnesota, vol. 3, pt. 2, p. 1056. 1908. Cyclonema Hall, Cumings, Dept. Geol. Nat. Res. Indiana, 32d Ann. Rep., p. 949. 1909. Cyclonema Hall, Grabau & Shimer, North American Index Foss., p. 668. 1931. Cyclonema Hall, McFarlan, Geol. Sur. Kentucky, ser. 6, vol. 36, p. 119. 1938. Cyclonema Hall, Wenz, Gastropoda, Band 6, Teil 1, p. 248. 1941. Cyclonema Hall, Knight, Paleozoic Gastropod Genotypes, Geol. Soc. America, Spec. Papers, No. 32, p. 88. 1944. Cyclonema Hall, Shimer & Shrock, Index Fossils of North America, p. 471. 1951. Cyclonema Hall, Wilson, Geol. Sur., Canada, Bull. 17, p. 77. | CINCINNATIAN CYCLONEMA: THOMPSON 235 1955. Cyclonema Hall, Bowsher, Univ. Kansas Paleo. Contrib., Mollusca 5, pp. 6; 7- 1960. Cyclonema Hall, Knight, et al., Treatise on Invert. Paleont., Geol. Soc. America and Univ. Kansas, vol. I, Mollusca, pt. 1, p. 1240. Type species. — Pleurotomaria bilix Conrad, 1842 (p. 271), by original designation. Diagnosis. —Turbiniform to trochiform, anomphalous, aper- ture polygonal to auriform, columeller lip lunate and excavated, ornament of three orders of spiral lines cancellated by collabral lirae which thicken into growth wrinkles. Description, —"Trochiform or turbiniform shell; early whorls simple, decollation common; sutures impressed to channeled, ramp indistinct to broad, body whorl expanded, not vagrant, periphery at whorl base, rounded basal periphery, flattened basal surface; aperture polygonal to auriform; anomphalous; columellar lip generally lunate and excavated, inner margin concave, outer lip thin, rounded, or arched onto body whorl, trending obliquely abaperturally; ornament of one to three orders of spiral lines can- cellated by collabral lirae into a delicate rectangular pattern, growth lirae thickening toward aperture to form characteristic growth wrinkles parallel to outer lip. Synonymic discussion. — The name Cyclonema was proposed by Hall (1852) for cancellated anomphalous gastropods from the “Clinton Group” of New York, which lack a marginal slit and selenizone. Distribution. —'The species herein described range from the Murfreesboro Formation (Middle Ordovician) of Tennessee to the Brassfield Formation (Lower Silurian) of Ohio. They have been reported from Tennessee, Kentucky, Ohio, Indiana, Illinois, Missouri, Iowa, and Minnesota. The Middle and Upper Ordovician formations in these states are summarized in Twenhofel, et al., HO 54. Discussion. — Early species of Cyclonema seem to be closely related to the genera Gyronema and Holopea, both of which differ from Cyclonema in being narrowly umbilicate. The ornament of Gyronema consists of spiral carinae with at least one principal carinate angulation on the whorl profile. The ornament of Holopea consists only of collabral lirae on the strongly rounded 236 BULLETIN 261 whorls. Gyronema and Holopea occur in the Middle Ordovician below the species of Cyclonema described here. Naticonema Perner also resembles Cyclonema from which it is distinguished by its low spire, globose body whorl, and wanting of faint irregular ornament. Cyclonema bilix (Conrad), 1842 Pl. 31, figs. 1-11; Pl. 35, figs. 1-6 1842. Pleurotomaria bilix Conrad, Acad. Nat. Sci. Philadelphia, Jour., 1st ser., Vole Saspee271s plandliGnet1oaelO: 1847. P. (2?) bilix Conrad, Hall [partim], Nat. Hist. New York, Geol. Sur. New York, Palaeont., vol. 1, p. 305. pl. 83, figs. 4b-e. 1849. Turbo bilix (Conrad), d’Orbigny, Prodrome de Paleont., vol. 1, p. 5 (gen ref.). 1852. Cyclonema bilix (Conrad), Hall, Nat. Hist. New York, Geol. Sur. New York, Palaeont., vol. 2, p. 89 (gen. ref.). 1859. C. bilix (Conrad), Hall, New York State Cab. Nat. Hist., 12th Ann. Reps, p. 74. 1863. C. bilix (Conrad), Billings, Geol. Canada, Geol. Sur., Canada, p. 217, fig. 225. 1873. C. bilix (Conrad), Meek [fartim], Geol. and Palaeont., Geol. Sur. Ohio, vol. 1, pp. 151-2, pl. 13, figs. 5a-b,g. 1874. C. bilix (Conrad), Miller, Cincinnati Quart. Jour. Sci., vol. 1, p. 319. 1874. C. bilix var. conica Miller, Cincinnati Quart. Jour. Sci., vol. 1, p. 320. 1880. C. bilix (Conrad), White, Indiana Dep. State Geol., 2d Ann. Rep., p. 492, pl. 2, figs. 3-5. 1882. C. (Pleurotomaria) bilix (Conrad), Zittel. Handbk. Pal., vol. 2, p. 188, fig. 234. 1889. C. bilix (Conrad), Miller, North American Geol. Palaeont., p. 400, fig. 663. 1894. C. bilix (Conrad), Keyes, Missouri Geol. Sur., vol. 5, pt. 2, p. 154. 1897. C. bilix (Conrad), Ulrich im Ulrich & Scofield, Geol. Minnesota, vol. 3. pt. 2, p. 1058, pl. 58, figs. 35-39. 1908. C. bilix (Conrad), Cumings, Dep. Geol. Nat. Res. Indiana, 32d Ann. Rep. p. 958, pl. 40, figs. 2-2d. 1909. C. bilix (Conrad), Grabau & Shimer, North American Index Foss., vol. 1, p. 668, figs. 925a,b. 19263 -G: uve (Conrad), Butts, Geol. Sur. Alabama, Spec. Rep. 14, p. 129, pl. SA eos 1931. C. bilix (Conrad), McFarlan, Paleont. Kentucky, Geol. Sur. Kentucky, ser. 6, vol. 36, p. 119. 1938. C. bilix (Conrad), Wenz, Gastropoda, Band 6, Teil 1, Abb. 493. 1941. C. bilix (Conrad), Knight, Geol. Soc. America, Spec. Papers, No. 32, p. 88, pl. 53, figs. 3a-e. 1944. C. bilix (Conrad), Shimer & Shrock, Index Foss. North America, p. 7G ply 192s. 3,0:3ile 1951. C. bilix (Conrad), Wilson, Geol. Sur. Canada, Bull. 17, p. 77. 1960. C. bilix (Conrad), Knight, et al., Treatise on Invertebrate Paleont., Boa America and Univ. Kansas, vol. 1, Mollusca, pt. 1, p. 1240, ig. 153, 11. Diagnosis.—Trochiform shell with straight to concave whorl profile and rounded periphery; three orders of spiral ornamenta- tion. CINCINNATIAN CYCLONEMA: THOMPSON 237 Description. —Trochiform; nucleus unknown; whorl profile straight to concave, rarely convex, periphery rounded at base of whorls, body whorl expanded; sutures varying from impressed to channeled, shoulders sharp and narrow, basal surface flattened; aperture polygonal to rounded, inner lip straight to concave, outer lip thin and rounded becoming straighter and reflected obliquely with age; columellar lip straight, thin, and unexcavated in juveniles, lunate and excavated in adult form; three orders of spiral lines apparent on mature whorls: cords, costae, and threads, 10 to 13 cords on body whorl separated by costae, one or more threads often present between cords and costae; collabral lirae best de- veloped on last whorl, vertical on small individuals becoming strongly oblique with age; ornament forming delicate rectangular pattern, entirely lacking on basal surface, strong transverse growth wrinkles common on body whorl. Discussion. — An identification table for all species of Cyclo- nema is presented on Text-figure 4. The type species of Cyclonema is variable, but spiral ornament distinguishes C. bilix from other species, being consistently of three orders. The lines are delicate and closely spaced, giving the surface a lacey or pitted appearance. Costae are not always present, in which case the cords are separated by fine threads. The cords may be closely spaced with only one thread in between or further separ- ated by two or three threads. In juvenile specimens the ornament consists of one order of closely spaced spiral lines. Two additional orders appear with growth. All growth stages in an individual display collabral lirae. The sutures of C. bilix are interesting in their variation from whorl to whorl on the same shell. Juvenile whorls are usually joined by impressed sutures, becoming incised in the middle whorl, and incised or channeled in the body whorl of large and old indi- viduals. Shape of the shell may range from conical to flattened, but generally is distinctly trochiform. C. bilix conicum (Miller) would appear to be a conical variety of C. bilix, but falls well within the range of coiling in the type specimens of C. bilix. As it agrees in BULLETIN 261 ze[nberzit ‘easeq pieMoz TOSOTSO Butwooeq Sp10D eSieROd 9-F apts Teanjrzsedeqe uo 9e4SOD 3UTRZ Tzoym Fo J~Tey rteddn uo juesqe seTyutIm yymMorb Aq aanqzizede je peanosqo spz05D ST-OT aseq pue sTz0ymM Ile uo spz00 eszeO0D g-1 quesqe eerITT yzMOoIb {spz00 pozeredes Huor3s fF eseq preMo} TASOTO spz0d OI-8 ‘seTyuUTIM yAMoOTBH buo73s SeATT 9RROTTEp BSOTO ‘gsoegzans peysttod ¥ yROoUsS TA0UMpTW qe ABsOTO ‘spxz0d 6-8 eainjzns uo sqoux ‘SeTXUTIM yqmMor6H Buoz#s ‘Spx0D OT-6 ST1I0OUM OMA FSET FO FTEY TamOT uo ZUeserd spiz05D spzo05 dzeys ZT-OT aA0OIb Tetpew ‘spx0D ZI-IT OzeTNOTAeT ‘aQzeOTTep ‘Spx0D ZT-TT ZNGEWYNYO dO YaLOWaWHO ‘puLauojI£/) JO saivads Tioum Apoq ojuo ‘wiosytine Taoym Apoq ojuo ‘wixzostine wzojztane TaepjTnoys ojuo ‘wizostane qTeuobAtod zeypno1ito Taoum Apoqg ojuo ‘TeuobAtTod -—Tzoym Apoq oju0o ‘wroztane punoz 03 TeuobAtod qTeuobAtod punod 03 qeuobAtod Tzoyum Apoq ojzuO ‘wxz0Ftane TeuobAtod punoz o3 qTeuobATod yaduo LNAWYNYO qun Luddy IOF 3[qe} UOTBOTZUaP] — “p “AINBIZ-3x9 J, pesseizdut pesseizdut pessoizdut peTouueyo 03 pesserzdut pestout of pessordwut moizeU ‘pesseidut morzeu ‘pesssidwt pestout peTeuueyo 0} pessoerzdut peTeuueyo TeqzuozTz0y4 Atdsep pestout of pessezdut possezdut poeTeuueyo 0} pestout peTeuueyo 03 poesseadut aunins duwez optm xeAU0D xdAU05 ATpeoirq X9AU0D zetTnbue 03 punoz XSAU0D qyubter4s xX8AU0D Tzoum Apog pezetgut ‘eatds pune ZTepueTs xeAuo0d pezeTyur ‘x9Auood retTnbue 0} punoxz quexz pozeTsurt ‘xeAUuo0d BSARBDUOD OF ‘zeTnbue qubterz3s esoqoTtb x9AU0D sereTy oseq “aaeouo0d BAPDUOD OF qy6terza4s MOIZEU ‘dzeys aTIA0dd UaadINOHS ‘THOHM TepueTs ‘ypty peuazzeTs ‘MOT Teotuos ‘yBry sTzoym Auew ‘ybty aTepueTts *ybty wnt pou LHOIGH auids wnSOOTIeA unsreAsueiry sASeTqQNS sueTnuts un jeptuerAd unjdtooead STetTpoul unjetsur unsozeuny Bsusu0jAep EVEL XT RTT XT salogds CINCINNATIAN CYCLONEMA: THOMPSON 239 every respect with C. bilix, C. bilix conicum Miller is not recog- nized as a distinct subspecies. Synonymic discusston.— When Hall discussed Plewrotomaria (?) bilix in 1847 he figured three specimens (AMNH No. 1379/1). The author examined these and found that two of Hall’s specimens are Cyclonema bilix and the third (pl. 83, fig. 4a) is C. mediale Ulrich. Meek’s 1873 description of C. bilix encompassed a multitude of species and subspecies, The shell figured on his plate 13, figures 5a, b is C. bilix bilix. That figured in figures 5c, d appears to be C. mediale Ulrich, described by Meek in the explanation of the plate as “a ventricose variety, with marks of growth very obscure” (plate 13). Meek’s plate 15, figures 5e, f is C. bilix lata Meek. And finally the unnamed “much elongated variety” figured by Meek on plate 13, figure 5g is, according to Ulrich (in Ulrich & Scofield, 1897, p. 1059) “the type of Miller’s var. conicum.” As restricted by Ulrich in 1897, C. bilix conicum Miller is included in C. bilix bilix. Miller’s subspecies was based upon its high-spired conical form, an unreliable character in the highly variable C. bilix bilix. White’s description in 1880 is quoted from Meek’s 1873 de- scription (p. 151). His figured specimen (pl. 2, figs. 3, 4) is a reproduction of Meek’s plate 13, figures 5c, d which is C. mediale. Confusion surrounding C. bilix bilix ended with Ulrich’s re- striction of the species in 1897 and separation of additional species. Subsequent descriptions of C. bilix bilix are accurate and valid. Types and materials.— The type species of Cyclonema was originally described and figured by Conrad as Pleurotomaria bilix. When Hall established the genus Cyclonema in 1852 he cited Pleurotomaria bilix of Conrad as the type of the genus. Conrad’s specimens have been lost, but his figured specimen (1842, pl. 16, fig. 10) was subsequently identified as the holotype by Knight @i92T, (p. 88). The above description is based primarily upon Ulrich’s 1897 hypotypic suite (USNM Nos. 4563, 4564, 4565). The author also had available Hall’s 1847 figured specimens (AMNH No. 1379/1), two hypotypes of Butts (1926, USNM No. 71556), and two plesio- types from the Field Museum of Natural History (No. 29418). 240 BULLETIN 261 Distribution. — Cyclonema bilix bilix is limited to rocks of Richmond age (Upper Ordovician) . It is especially abundant in the Arnheim Formation of the Richmond Group in Indiana, Ohio, and Kentucky. Hall (1847) recorded C. bilix bilix from Prairie du Chien, Wisconsin (Ordovician); Ulrich (im Ulrich & Scofield, 1897) reported it from Sterling and Savannah, Illinois; Foerste (1916) reported it from the Richmond Group of Ontario and Quebec; Butts (1926) noted the occurrence of the subspecies in rocks of Fernvale (Richmond) age in Alabama, and Bassler (1932) found it in the Fernvale of Central Tennessee. In addition, the author studied two plesiotypes of C. bilix bilix (FMNH No. 29418) from Aux Sables Creek, Minooka, Illinois, where the Maquoketa Formation (Upper Ordovician) is exposed. Cyclonema bilix lata (Meek) 1873 Plt 31, figsad2-18 1871. Cyclonema fluctuata James, Cat. L. Sil. Foss. Cincinnati Group, p. 8 (nom. nud.). 1873. C. bilix var. lata Meek, Geol. and Palaeont., Geol. Sur. Ohio, vol. 1, p. 52 -eple ts. tess et 1874. C fluctuata James, Cincinnati Quart. Jour. Sci., vol. 1, p. 152. 1874. C. bilix var. lata Meek, Miller, Cincinnati Quart. Jour. Sci., vol. 1, p. 320. 1897. C. bilix var. fluctuatum (James), Ulrich zz Ulrich & Scofield, Geol. Minnesota, vol. 3, pt. 2, p. 1058, pl. 78, figs. 40-42. 1908. C. bilix var. fluctuatum (James), Cumings, Dep. Geol. Nat. Res. In- diana, 32d Ann. Rep., p. 959, pl. 40, figs. 3-3b. 1931. C. bilix var. C. fluctuatum (James), McFarlan, Geol. Sur. Kentucky, Ser: 6, vols, 36, ps 120) splil4tics 16: 1932. C. fluctuatum James, Bassler, Tennessee Div. Geol., Bull. 38, p. 230, Die Zsa tions: 1949. C. fluctuatum James, Wilson, C. W., Tennessee Geol. Sur., Bull. 56, pl. 19, fig. 28-30. Diagnosis. — Cyclonema bilix with concave whorl profile, un- dulating surface of growth ridges, medial depression, and flaring base on body whorl. Description. — Distinctly trochiform shell, whorl profile con- cave, medial groove in lower two whorls, lower half of body whorl flaring outward below depression, rounded periphery at base of whorls. Sutures generally incised, may be channeled; upper shoulder narrow, rounded to angular; basal surface flattened. Aperture gen- erally polygonal to square, rarely round; inner lip channeled, thin and straight in small specimens, thickened and lunate in large ones; outer lip thin and commonly reflexed. Ornament delicate CINCINNATIAN CYCLONEMA: THOMPSON 241 and variable, three orders of ornament: cords, costae, and one thread on body whorl, or of two orders: cords and one to three threads on body whorl, or one order of undifferentiated spiral lines, 11 to 12 cords on body whorl, penultimate whorl has cords and costae, anti- penultimate whorl has cords only; collabral lirae delicate to coarse and may cause pitted pattern, strong growth wrinkles abundant on body whorl produce undulated surface. Synonymic discussion. — As originally published by James in 1871, the name Cyclonema fluctuata was included in a faunal list and undescribed. It is, therefore, a nomen nudem. Meek (1873, p. 152) subsequently described C. bilix var. lata which had “strong oblique rounded ridges, interrupted by a broad shallow depression around the middle of the upper slope of the body volution.” The following year James redescribed C. fluctuata. Miller (1874, p. 320) noted that Meek’s C. bilix var. lata “is the same described by Mr. James, as C, flwctwata, on page 152 of the April number of this Journal.” Despite its invalid use, the name C. bilix fluctuatwm (James) has persisted in the literature. It is here corrected to C. bilix lata (Meek) . Types and materials. — James’ collection of 29 type specimens was used by the author for the above description (FMNH No. 2453). Ulrich’s hypotype collections were also studied (USNM Nos. 45767, 53233). Whereabouts of Meek’s specimens are un- known. A lectotype (which he never figured) is herein designated from James’ collection. The lectotype is figured herein Plate 31, figure 12. Although embedded in matrix on the apertural side, the specimen illustrates well the ornament and medial groove typical of C. bilix lata. The remaining 28 specimens in James’ collection are designated as paralectotypes. Distribution. —Cyclonema bilix lata has the same general range and distribution as C. bilix bilix: the Richmond rocks of Ohio, Indiana, Kentucky, and Tennessee. It, too, is especially com- mon in the Arnheim Formation. Discussion. — A population of 52 specimens of Cyclonema from the Arnheim Formation at Waynesville, Ohio, was studied. The population is definitely composed of C. bilix lata as defined in the above description based upon James’ type specimens; only two or 242 BULLETIN 261 three specimens resemble C. bilix bilix with no medial groove or flaring base. C. bilix lata is retained as a valid subspecies of C. bilix based upon its distinctive appearance and its occurrence in a nongradational population. Characteristic of C. bilix lata is a medial depression on the body whorl, caused in part by thickened transverse growth wrinkles. The outer lip of the aperture reflects the groove by flaring at the periphery, flattened above and abruptly rounded below. A medial groove is acquired in the earliest whorls and becomes more promi- nent with age; it is not a function of growth. A protoconch is retained on one specimen in the Ulrich hypo- type collection (USNM No. 4567, Pl. 31, fig. 18). It is paucispiral and devoid of ornamentation due to recrystallization. The first two whorls are thin, almost planispiral, not vagrant; the third whorl is enlarged, and the fourth whorl expands rapidly into a neantic Cyclonema. Cyclonema daytonense Foerste Pl. 31, figs. 19-21 1885. Cyclonema bilix Foerste, (not Conrad), Bull. Sci. Lab. Denison Univ., vol. 1, p. 94. 1889. C. bilix Foerste, Proc. Boston Soc. Nat. Hist., vol. 24, p. 290, pl. 5, fig 15. 1893. C. bilix Foerste, Geol. Sur. Ohio, Pal., vol. 7, p. 551, pl. 26, fig. 15, var.; pl. 30, fig. 15 1899. C. daytonensis Foerste, 24th Ann. Rep. Indiana Geol. Nat. Hist. Sur., p. ide 1913. C. daytonensis Foerste, Savage, Geol Sur. Illinois, Bull. 23, p. 142, pl. 8, fig. 4; pl. 9, fig. 21. Diagnosis. —"Turbiniform shell with expanded body whorl, auriform aperture, and coarse cords separated by costae and threads becoming closely spaced toward shell base. Description, —'Turbiniform shell, nucleus unknown; sutures impressed, shoulder rounded and shallow; whorl profile gently convex, body whorl inflated, widest point at whorl base, basal sur- face abruptly rounded. Anomphalous. Aperture round to polygonal if base is flattened, outer lip auriform, expanded onto body whorl and oblique backward, inner margin concave; columellar lip lunate and excavated. Third-order ornament evident on body whorl, 10-12 strong sharp cords separated by costae becoming close together at base, threads apparent on upper part of body whorl, 10-11 cords on penultimate whorl, five cords on antipenultimate whorl, spiral CINCINNATIAN CYCLONEMA: THOMPSON 243 lines present on basal surface, strong oblique growth lines present in lower two whorls, growth wrinkles absent. Types and materials.—The author was unable to locate Foerste’s type specimens. The foregoing description is based upon 15 specimens from the Brassfield Formation (Lower Silurian) at Centerville, Ohio. These are in the Shideler Collection at Miami University (MU No. 6680). Distribution.— The range of C. daytonense, according to Bassler (1915, p. 331) is Upper Medinan: Dayton and Todds Fork, Ohio (Brassfield); Thebes, Illinois; and Edgewood, Missouri (Edgewood). Foerste (1903) also recorded it from the Clinton Formation (Lower Silurian) of western Tennessee. Cyclonema gracile Ulrich Pl 32, figs. 1-9 1897. Cyclonema gracile Ulrich, Ulrich im Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1062, pl. 82, figs. 55-61. 1897. C. gracile striatulum Ulrich, Ulrich in Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1062, pl. 82, figs. 59-61. (C. gracile striatellum on pl. 82, fig. 59. Diagnosis. — Small trochiform shell with slender globose whorls and one order of spiral lines cancellated by prominent growth lirae. Description. — Shell small, slender, trochiform. Nucleus un- known, but traces of nucleus indicate two planispiral volutions fol- lowed by conical shell increasing regularly. Sutures impressed to incised, whorls strongly convex, body whorl globose, round periphery at midwhorl rather than at whorl base. Aperture varying from circular to polygonal; outer lip thin, straight to convex lack- ing oblique recurvature, inner margin always straight; columellar lip thin, excavated, and slightly reflexed, larger specimens show thickened columellar lip with a groove; single order of ornament consisting of equal-sized delicate cords only on lower two whorls and extending across half of basal surface; reflexed collabral lirae prominent on lower three whorls when preserved. Growth wrinkles uncommon and faint. Discussion. — Location of spiral cords on C. gracile varies. Commonly cords are absent on the upper portion of the body whorl, appearing on the lower half as thin, closely spaced, and equal in size. Collabral lirae extend the height of each whorl indi- cating that cords were not destroyed during preservation. In a few 244 BULLETIN 261 specimens collabral lirae may be the sole ornament. In others cords may cover the entire whorl surface. In this instance the penultimate whorl bears delicate threads between cords, with these threads be- coming cords on the lower half of the body whorl. C. gracile striatulum was named by Ulrich (in Ulrich & Sco- field, 1897, p. 1062) as a variety having coarser spiral ornament than the typical C. gracile. Microscopic examination reveals spiral cords present on type specimens of C. gracile, so that the supposed varietal character is spurious. Accordingly, Ulrich’s “varietal name” is placed in synonomy of C. gracile. Cyclonema humerosum Ulrich Pl. 32, figs. 10-13 1897. Cyclonema humerosum Ulrich in Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1061, pl. 78, figs. 43-46. 1908. C. humerosum Ulrich, Cumings, Dep. Geol. Nat. Res. Indiana, 32d Ann. Rep., p. 960, pl. 40, figs. 5-5c. 1938. C. humerosum Ulrich, Wenz, Gastropoda, Band 6, Teil 1, Abb. 494. Diagnosis. — Deeply channeled suture, angular shoulder, broad ramp; otherwise similar to C. bilix. Description. —'Trochiform gastropod with deeply channeled sutures, horizontal ramps, and angular to rounded shoulders; nucleus unknown; whorl profile straight to concave between sutures; aperture polygonal, flattened at base and oblique abaperturally, outer lip rounded to straight and sometimes expanded onto body whorl at upper suture, inner margin straight, columellar lip thickened, lunate, and excavated. Variable ornament generally consists of three orders of 9-10 spiral lines crossed by growth lirae; cords may be separated by costae and threads, or coarse, prominent, and widely separated by two or three threads, or numerous, thin, closely packed and separated by threads, cords extend over half of basal surface; growth lirae are coarse and widely separated or fine and closely spaced to form pits on the shell surface; strong growth wrinkles at aperture often obscure spiral ornament, produce depressions in suture, and cause concave whorl] profiles. Discussion. —'This species is distinguished by its channeled suture and broad horizontal ramp, but is divisible into two groups based upon the shoulder and whorl profile. Specimens from the Richmond Group have a strongly angulated shoulder with straight to concave whorl profile so that the whorls resemble polygonal CINCINNATIAN CYCLONEMA: THOMPSON 245 blocks. This form appears related to C. bilix and is distinguished by its channeled suture and horizontal ramp. Those from the Mays- ville Group of Cincinnati have a rounded shoulder, ventricose whorl profile, and oblique flaring apertural lip, resembling the shape of C. semulans with the high spire of C. mediale. These forms were noted by Ulrich (zm Ulrich & Scofield, 1897, p. 1061). They are both retained in C. humerosum on the basis of the channeled suture and broad ramp. Types and materials.—The above description is based upon Ulrich’s syntypes (USNM Nos. 45771-49664, 45772-40641). The specimens herein figured on Plate 32, figures 10-13 are Ulrich’s figured specimens (1897, pl. 78, figs. 43-46). His specimen figured on plate 78, figure 43 is chosen as the lectotype (Plate 32, figure 10) ; the remainder are paralectotypes. Distribution. — The angular form of C. hwmerosum is found in Arnheim and Waynesville strata of Richmond age in Ohio and Indiana, especially in the Arnheim Formation. The rounded form occurs in and around Cincinnati, Ohio, in the McMillan Formation. Cyclonema inflatum Ulrich Pl. 32, figs. 14-18 1897. Cyclonema inflatum Ulrich, Ulrich 7m Ulrich & Scofield, Geol. Minnesota, vol. 3, pt. 2, p. 1060, pl. 78, figs. 31,32. Diagnosis. — Trochiform, slender spire, ventricose body whorl, coarse ornament of two orders, cords separated on upper half of whorl. Description. — Trochiform shell, nucleus of four slender conical whorls, fifth whorl expands to typical juvenile whorl; slender spire, body whorl inflated, whorl profiles usually convex, sometimes straight, never concave; sutures impressed to incised, rarely chan- neled with angular shoulders, knobs on final shoulder caused by growth wrinkles may be present; aperture rounded to polygonal, outer lip thin and usually rounded, but rarely straight and oblique abaperturally, inner margin straight to concave, columellar lip exceedingly thick and deeply grooved; coarse second order orna- ment of eight to nine cords separated by threads of mature body whorl, cords are widely spaced on upper half of whorl but closer at midwhorl, cords on juvenile whorls fewer in number and finer but always separated on upper portion of whorl; collabral lirae long and recurved, ornament extending over half of basal surface. 246 BULLETIN 261 Discussion. — In the original description, Ulrich (in Ulrich & Scofield, 1897, p. 1060) noted that C. inflatum resembles C. mediale in its ornament and may be “an extreme variety of that species.” However, the body whorl of C. inflatum expands rapidly, produc- ing a globose appearance as compared to the trochiform shell of C. mediale. No intermediate forms have been seen; therefore, C. inflatum is herein regarded as a distinct species. Types and materials. — Ulrich’s syntypes (USNM No. 45773) are the basis for the previous description. His two figured speci- mens (1897, pl. 78, figs. 31, 32) are herein figured on Plate 32, figures 14-18. The specimen figured on plate 78, figure 32 is desig- nated as the lectotype; the other specimen is the paralectotype. Distribution. — Cyclonema inflatum is found in the Fairview Formation (Mt. Hope and Fairmount members) of Cincinnati, Ohio, and nearby Kentucky. Ulrich’s syntypes are from the Fair- mount Member of Covington, Kentucky. Cyclonema limatum Ulrich Pl. 32, figs. 19-21 1897. Cyclonema (?Holopea) limatum Ulrich, Ulrich im Ulrich & Scofield, Geol. Minnesota, vol. 3, pt. 2, p. 1063, pl. 82, figs. 62-64. Diagnosis. — Turbiniform shell gradational to Holopea, convex whorls with round narrow shoulders, smooth polished surface, ornament of lirae, anomphalous. Description. — Large inflated shell, spire shorter than aperture, sutures incised and shoulders rounded, whorls convex, body whorl large and inflated; nucleus unknown, anomphalous; aperture ovate and auriform, outer lip rounded above and below, straight at widest expanse, extending onto body whorl at upper suture; columellar lip thin, irregular, slightly reflexed, not excavated, usually oblique inward toward aperture; surface of shell is smooth to polished, ornamented by closely spaced delicate collabral lirae which extend obliquely across body whorl, often forming small growth wrinkles at aperture, well-preserved specimens show faint spiral threads which become stronger on base of mature body whorl, ornament may ex- tend onto penultimate whorl. Discussion. — C. limatum looks like a transitional form between Cyclonema and Holopea and could be grouped with either genus. Because the pseudoumbilicus appears to be a minor depression CINCINNATIAN CYCLONEMA: THOMPSON 247 rather than a definite cavity, the form is retained as a species of Cyclonema. ‘The smooth surface distinguishes it from other Cyclo- nema. One specimen in the type lot displays an incomplete parietal inductura above the columellar lip. Another specimen is especially similar to Cyclonema with an excavated lunate columellar lip and wrinkled collabral lirae crossed at the base by strong spiral cords. This individual best illustrates the transitional nature of C. lima- tum. Types and materials. — Ulrich’s syntypic suite of nine specimens was available (USNM Nos. 40646-45774) . His figured specimens (in Ulrich & Scofield, 1897, pl. 82, figs. 62-64) are figured here on Plate 52, figures 19-21. Ulrich’s specimen figured on plate 82, figure 64 is designated as the lectotype. Distribution. — Ulrich’s specimens came from the Fairview Formation of Cincinnati, Ohio. As no additional specimens were identified by the author, this is the known range and distribution of this rare form. Cyclonema mediale Ulrich Pl. 33, figs. 1-4 1847. Pleurotomaria bilix Conrad, Hall [partim], Palaeont. New York, vol. 1, p2305,) pl. 83. figs 4a. 1873. Cyclonema bilix (Conrad), Meek [partim], Geol. Sur. Ohio, Pal., vol. 1, Pawlo2s spleclsyeticss cede 1897. C. mediale Ulrich, Ulrich im Ulrich & Scofield, Geol. Minnesota, vol. 3, Dips LOSI pla 78s tizss 295 30: 1908. C. mediale Ulrich, Cumings, Dep. Geol. Nat. Res. Indiana, 32d Ann. Rep., p. 960, pl. 40, figs. 4, 4a. 1909. C. mediale Ulrich, Grabau & Shimer, North American Index Foss., vol. thips 669) figs. 925 ied: 1931. C. mediale Ulrich, McFarlan, Paleont. Kentucky, Geol. Sur. Kentucky, ser. 6, vol. 36, p. 119. 1932. C. mediale Ulrich, Bassler, Tennessee Div. Geol., Bull. 38, p. 228, pl. 23, figs. 16, 17. 1944. C. mediale Ulrich, Shimer & Shrock, Index Foss. of North America, p. 471, pl. 192, figs. 27, 28. Diagnosis. —"Trochiform shell with slender ventricose whorls, flared apertural margin, ornament of cords cancellated by strong lirae. Description. — Trochiform shell with four to six whorls com- monly present, slender spire and ventricose body whorl; nucleus unknown; whorl profile convex, sutures impressed and shallow, without shoulders; aperture generally polygonal with flattened basal 248 BULLETIN 261 surface and flaring outer lip, oblique abaperturally; outer lip ex- panding upon body whorl; inner margin irregular; columellar lip variable; typically lunate and excavated but may be thin and re- flexed or flat and irregular; generally one order of spiral ornament consisting of eight to ten cords on body whorl becoming closer to- gether toward basal periphery, rarely separated by indistinct threads, on penultimate whorl the cords decrease to six or eight in number, growth lirae are strong and sweep obliquely across the shell parallel with apertural margin, at aperture growth wrinkles are present on old specimens and often exclude cords, wrinkles may cause body whorl to be slightly concave in profile; on basal surface ornament consisting of spiral cords on outer half of surface and strong lirae sweeping up to columellar lip. Discussion. — Cyclonema mediale closely resembles C. simulans but is distinguished by its coarser ornament over the entire shell surface, high spire, and shallow sutures. Synonymic discussion.— Prior to Ulrich’s recognition of C. mediale as a distinct species in 1897, specimens of it were twice described as C. bilix by Hall (1847) and by Meek (1873). The latter described it as “‘a ventricose variety, with marks of growth very obscure” (plate 13) and as similar to C. hageri Billings. His figured specimen on plate 13, figures 5 c,d appears to be C. mediale. Types and materials.— Ulrich’s syntypic suite (USNM No. 45775) is the basis for the above description. Plate 33, figures 1-3 herein are Ulrich’s figured specimens (im Ulrich & Scofield, 1897, pl. 78, figs. 29, 30). The specimen figured by Ulrich on plate 78, figure 29, is chosen as the lectotype. Distribution. — Cyclonema mediale is limited to the Fairview Formation, Fairmount Member, of Ohio, Indiana, and Kentucky. Ulrich’s syntypes are from the Fairmount Member of Covington, Kentucky, and vicinity. Bassler (1932) recorded its occurrence from Nashville, Tennessee, in the Leipers Formation which is cor- relative with the Fairmount Member of the Fairview Formation of Ohio. Cyclonema praeciptum Ulrich Pl. 33, figs. 5-8 1897. Cyclonema (?Gyronema) pracciptum Ulrich, Ulrich in Ulrich & Sco- field, Geol. Minnesota, vol. 3, pt. 2, pl. 78, fig. 26. 1932. C. (?Gyronema) praeciptum Ulrich, Bassler, Tennessee Div. Geol., Bull. 38, p. 190, pl. 4, fig. 6. CINCINNATIAN CYCLONEMA: THOMPSON 249 Diagnosis. — Small trochiform shell, slightly phaneromphalous, columellar lip unexcavated, second order ornament of four strong cords and costae. Description. — Shell small, conical and high-spired; nucleus unknown; sutures shallow and impressed with sloping shoulders; periphery rounded; aperture circular and not expanded onto body whorl; columellar lip straight, thin, slightly convex and reflexed with a depression behind it, seemingly phaneromphalous; orna- ment consisting of two orders: four strong and widely spaced cords on the body whorl separated by costae, no trace of threads or growth lines, cords continue across entire base, penultimate whorl displaying three cords with no costae, commonly two or three cords on antipenultimate whorl. Discussion. — This species is based upon siliceous internal molds from the Murfreesboro Formation of ‘Tennessee; therefore, the finest ornament is lacking, though it may have been present originally. Of the four best specimens in the type lot only one has a complete columellar lip. Ulrich’s figured specimen retains a par- tial columellar lip; other specimens have none preserved. Distinctive of C. praeciptum is its ornament of four strong cords resembling that of C. varicosum and linking it with Cyclo- nema. The slight umbilicus and convex columellar lip of C. prae- ciptum are not characteristic of Cyclonema. It is retained in Cyclo- nema for its resemblance to C. varicosum. C. praeciptum was named by Ulrich (1897) in explanation of plate 78, figure 26. On page 1046 he referred to it without name as the forerunner of Cyclonema from which Cyclonema was devel- oped from Gyronema. Types and matervials.— "The above description is based upon Ulrich’s figured specimen (1897, pl. 78, fig. 26) and syntypes (USNM No. 46052). Ulrich’s figured specimen is chosen as the lectotype and herein is figured on Plate 33, figures 5, 6. Distribution. — C. praeciptum is known only from the Mur- freesboro Limestone of the Stones River Group (middle Middle Ordovician) , Murfreesboro, Tennessee, where the type collection was made. Cyclonema pyramidatum James Pl. 33, figs. 9-12 1871. Cyclonema pyramidatum James, Cat. L. Sil. Foss. Cincinnati Group, p. 8. 1874. C. pyramidatum James, Cincinnati Quart. Jour. Sci., vol. 1, p. 152. 250 BULLETIN 261 1897. C. pyramidatum James, Ulrich in Ulrich & Scofield, Geol. Minnesota, vol. 3, pts 2, ps L061) pls 78, figs: 33) 34. Diagnosis. —"Trochiform highly conical form, flat whorl pro- file abruptly rounded at base, third order ornament which extends over basal surface. Description. — Large trochiform shell; nucleus unknown; su- tures impressed to incised, shoulders weak, whorl profile straight to weakly convex, periphery at base of whorls, basal surface abruptly flattened; aperture rounded to suboval; outer lip extending back- ward from upper suture; columellar lip thickened; ornament con- sisting of three orders: coarse cords widely spaced across whorls, numbering seven or eight on body whorl, costae alternating with cords, faint threads separating costae and cords on well-preserved specimens, ornament present on all whorls, collabral lirae faintly present on all whorls, growth wrinkles absent, ornament extending over entire base to columellar lip. Types and materials. — The above description is based upon James’ three syntypes (FMNH No. 1539) and Ulrich’s hypotypes (USNM No. 45776). James’ specimen figured here on Plate 33, figures 9-11 is chosen as the lectotype. ‘The remaining two syn- types are designated paralectotypes. Distribution. — Cyclonema pyramidatum occurs in the Fair- view Formation of Cincinnati, Ohio. Cyclonema simulans Ulrich Pl. 33, figs. 13-16 1897. Cyclonema simulans Ulrich, Ulrich im Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1061, pl. 78, fig. 47. Diagnosis. —Turbiniform and broadly convex in whorl pro- file, apertural margin strongly oblique and arched onto body whorl forming a horizontal shoulder, spiral cords obscured at aperture by growth wrinkles. Description. —Turbiniform, shell flattened, up to three whorls preserved, partial apex indicates a rapidly planispiral termination at fourth whorl; whorl profile usually convex but may be straight, periphery varies from center of convex whorls to base of flattened whorls; sutures variable: impressed to incised to channeled, shoul- der rounded to angular; outer lip round and strongly oblique abaperturally, arching onto body whorl and forming a horizontal shoulder at apertural margin; inner margin may be straight, irregu- CINCINNATIAN CYCLONEMA: THOMPSON 251 lar, or concave; columellar lip thickened and excavated; ornament of one order of spiral cords, equal-sized and distant, 10-15 on body whorl, crossed by distinct growth lirae parallel to oblique aperture, forming growth wrinkles at aperture which obscure spiral orna- ment, ornament extending through antipenultimate whorl, basal surface ornamented only by lirae. Discussion. — In the original description of C. simulans Ulrich (in Ulrich & Scofield, 1897, p. 1061) stated that the spiral cords are weak on the last two whorls, but his type specimens display strong cords on all three whorls. The cords are equal-sized on all but one specimen of the type lot which has a costae between two cords (Plate 33, figure 16). This is an exception to the usual one order of spiral ornament. The shape and sutures of this species resemble that of C. inflatum, but the apertural margin of C. simulans differs in its prominent arched and flattened configuration. The ornament of the two species also differs in that C. inflatum displays two orders of spiral lines, while C. stmulans has only one order. Types and materials.—'The author based the above descrip- tion upon Ulrich’s syntypic suite (USNM No. 45777). The figured specimen of Ulrich (in Ulrich & Scofield, 1897, pl. 78, fig. 47) is chosen as the lectotype and figured here on Plate 33, figures 13, 14. Distribution. — Ulrich gave the location of his type collection of C. simulans as the Corryville Member of the McMillan Forma- tion of Cincinnati, Ohio, and vicinity. In the University of Cin- cinnati collection are specimens from the Fairview Formation of Cincinnati and vicinity, thus extending the range to the entire Maysville Group. Cyclonema sublaeve Ulrich Psa hess 7-19 1897. Cyclonema sublaeve Ulrich, Ulrich in Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1062, pl. 78, figs. 48, 49. 1909. C. sublaeve Ulrich, Grabau & Shimer, North American Index Foss., vol. 1, p. 669, fig. 925}. Diagnosis. — Slender trochiform shell with convex whorls, without shoulders, smooth surface with weak cords on lower half of body whorl, collabral lirae on entire whorl. Description. —‘Trochiform shell with narrowly convex whorl profile, ventricose body whorl expanding at aperture; nucleus un- 252 BULLETIN 261 known; spire slender with as many as six whorls preserved, su- tures impressed, without shoulder; outer lip round and expanded onto body whorl, inner margin irregular, columellar lip lunate and excavated; shell surface appearing smooth, with cords indis- tinct to absent on upper half of body whorl, and weak on lower half to basal periphery, collabral lirae present on entire body whorl and thickened at aperture, ornament of penultimate whorl same as that of mature body whorl, ornament lacking above pen- ultimate whorl. Discussion. — Based upon the similar ornament, C. swblaeve would appear to be a large form of C. gracile. However, the latter has globose whorls with deep sutures and a high slender spire, as well as a different aperture, and is generally more delicate than C. sublaeve. The shapes of C. swbhlaeve and C. mediale are almost identical, but the ornament readily distinguishes them. Types and materials. —The above description is based upon the two syntypes of Ulrich (USNM No. 45778). He figured them in 1897 on plate 78, figures 48 and 49; herein they appear on Plate 33, figures 17-19. The specimen figured by Ulrich on figure 49 is designated as the lectotype. Distribution. — Cyclonema sublaeve is limited to the Mt. Hope and Fairmount members of the Fairview Formation of the Cin- cinnati vicinity in Ohio and Kentucky. Ulrich’s syntypes are from the Fairmount Member of Covington, Kentucky. Cyclonema transversum Ulrich Pl. 34, figs. 1-5 1897. Cyclonema transversum Ulrich, Ulrich im Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1062, pl. 82, figs. 65-67. Diagnosis. — Broadly convex turbiniform shell, abruptly round- ed at base, auriform aperture expanded onto body whorl, spiral ornament absent, collabral lirae present. Description. — Flattened turbiniform shell; nucleus unknown; broadly sloping convex whorls, body whorl expanding broadly, basal periphery angular, two or three whorls preserved, sutures impressed; aperture large and auriform; outer lip strongly oblique abaperturally and flaring; outer lip flaring high onto body whorl; inner margin rounded to irregular; columellar lip thickened, lun- ate, and broadly excavated; spiral ornament generally absent, faint CINCINNATIAN CYCLONEMA: THOMPSON 253 costae may be present on abapertural side of body whorl, surface covered by collabral lirae parallel to oblique outer margin, rarely thickened into growth wrinkles at aperture. Discussion. — C. transversum is distinct from any other species of Cyclonema by its exceedingly flattened shell, auriform aperture, and lack of spiral lines. Its ornament is an extreme of C. sublaeve but differs radically in its flattened shape which most nearly ap- proaches that of C. simulans. Types and materials. — The description is based upon Ulrich’s syntypic suite (USNM No. 45779-80). The specimen figured by Ulrich (in Ulrich & Scofield, 1897) on plate 82, figure 65 is chosen as the lectotype and figured here on Plate 34, figures 1 and 2. Distribution. — C. transversum is generally limited to the Fair- mount Member, Fairview Formation, in the vicinity of Cincinnati, Ohio, and Covington and Newport, Kentucky, where Ulrich col- lected his syntypic suite. One tray of specimens in the University of Cincinnati collection is from the Mt. Hope Member of the Fair- view Formation in Cincinnati. Cyclonema varicosum Hall Pl. 33, figs. 20-22; Pl. 34, figs. 8-10 1861. Cyclonema varicosa Hall, New York State Cab. Nat. Hist., 14th Rep., yo VAI TGNGe 1870. C. ventricosa (in error for varicosa) Hall, New York State Mus. Nat. Hist., 24th Rep. pl. 8. 1873. C. varicosa Hall, Meek, Geol. Sur. Ohio, vol. 1, p. 152. 1874. C. varicosa Hall, Miller, Cincinnati Quart. Jour. Sci. vol. 1, p. 321. 1882. C. cincinnatiense Miller, Jour. Cincinnati Soc. Nat. Hist., vol. 5, p. 230, pl. 9, figs. 8, 8a-c. 1893. C. bilix var. varicosum Foerste, Geol. Sur. Ohio, Pal., vol. 7, p. 552, PlosvAw tics 9s 1897. C. varicosum Hall, Ulrich in Ulrich & Scofield, Geol. Minnesota, vol. 3, pt 2, p: 1060; pl, 78; figs: 27, 28. 1909. C. varicosum Hall, Grabau & Shimer, North American Index Foss., vol. 1, p. 669, fig. 925 h,i. 1909. C. varicosum Hall, Bassler, Geol. Sur. Virginia, Bull. 2a, p. 184, fig. 21. 1914. C. varicosum-cincinnatiense Foerste, Jour. Cincinnati Soc. Nat. Hist., WOleZin pls 9Nepledea ties. 012) ab: 1931. C. varicosum Hall, McFarlan, Kentucky Geol. Sur., ser. 6, vol. 36, p. LOS plarSeetieGs 1932. C. varicosum Hall, Bassler, Tennessee Div. Geol., Bull. 38, p. 224, pl. 21, fig. 13. 1944. C. varicosum Hall, Shimer & Schrock, Index Foss. North America Det, pls) 192) figs. 25) 26: 1949. C. varicosum Hall, Wilson, C. W., Tennessee Geol. Sur., Bull. 56, pl. 13, figs. 15-17. Diagnosis. —‘Turbiniform shell with impressed sutures and 254 BULLETIN 261 wide ramp limited abaxially by a sharp cord, four to six prominent cords on body whorl separated by costae and threads, cancellated by strong lirae. | Description. — Coarse and heavy turbiniform shell, generally three poorly preserved whorls, nucleus unknown; sutures im- pressed, wide and sloping ramp limited abaxially by a sharp cord; whole profile convex, body whorl ventricose and expanded at aperture; aperture large and flattened on base; outer lip round and flaring; inner margin straight; columellar lip straight to lunate and excavated; coarse ornament of prominent sharp cords which approach carinae, four to six cords on body whorl decreasing to three on next two whorls, separated by a costa and many threads, cords becoming closer together toward periphery, all spiral orna- ment being irregular and wrinkled; collabral lirae strong on all whorls, especially strong and oblique at aperture of large speci- mens; ornament present on each whorl preserved; seven to eight closely spaced cords on half of basal surface and upper surface of aperture. Discussion. — C. varicosum is the oldest indisputable species of Cyclonema. Its morphologic resemblance to C. praeciptum and to Gyronema has been discussed. C. cincinnatiense Miller is a small shell from the Rogers Gap Formation of Kentucky. It was identified by Ulrich (in Ulrich & Scofield, 1897, p. 1060) as a small form of C. varicosum and is herein retained in synonymy. Types and materials.—'The description is based upon Hall’s holotype (AMNH No. 1380/1), herein figured on Plate 34, figures 8 and 9. Also available were Ulrich’s hypotype collection (USNM No. 45781) and a collection identified by Bassler (USNM Nos. 34215, 34248-45782, 34269). Ulrich’s figured specimen (in Ulrich & Scofield, 1897, pl. 78, fig. 28) is herein figured on Plate 34, fig- ure 10. Also studied were specimens of C. cincinnatiense Miller from the Faber collection (FMNH No. 8872) and Ulrich’s collection (USNM No. 87063). The latter were figured by Foerste (1914, pl. 1, figs. 12 a,b) and are herein figured on Plate 33, figures 20 and 21. Distribution. —C. varicosum is limited to the Cynthiana For- mation (Middle Ordovician) of Kentucky, and the correlative CINCINNATIAN CYCLONEMA: THOMPSON 255 Catheys Formation of Tennessee. Hall’s holotype is from the Upper Trenton Group of Nashville, Tennessee, which includes the Catheys Formation. Shimer and Shrock (1944, p. 471) also gave the range of C. varicosum as Trenton, Mississippi Valley. Ulrich reported an imperfect, undated specimen from Wycoff, Minnesota (in Ulrich & Scofield, 1897, p. 1060) . CYCLONEMA FROM OUTSIDE OF THE CINCINNATIAN PROVINCE Forty-three species of Cyclonema have been named which oc- cur outside of the Cincinnati Arch region. These are found in Quebec, Ontario, Nova Scotia, New York, Pennsylvania, New Jersey, Maryland, West Virginia, Kentucky, Tennessee, Ohio, In- diana, Illinois, Wisconsin, and Minnesota and range from Middle Ordovician to Middle Mississippian. Descriptions of Ordovician and Silurian Cyclonema beyond the Cincinnatian Province generally indicate the presence of an umbilicus. By definition these forms are not Cyclonema and should be referred to a new genus. Devonian Cyclonema probably belong to one or more new gen- era (Yochelson, per. com., 1968; Rollins, per com. 1969) . It has long been known that many of the Silurian and Devonian species placed in Gyronema and Cyclonema have nothing in common with the respective genera except the presence of spiral lirae. Probably several undescribed genera are included within this complex. Until a thorough revision of these genera can be made, it is prefer- able to use the classic generic names in an expanded and loose sense. (Yochelson zz Boucot, Martinsson, Thorsteinsson, Walliser, Whitting- ton, & Yochelson, 1960, p. 44). Ulrich (in Ulrich & Scofield, 1897, p. 1058) expressed this opin- ion: We have not had the opportunity to examine any of the Devonian species that are referred to Cyclonema by various authors, but judging from the literature alone we feel satisfied that not one has a sufficient right to maintain its position in the genus. Prosser and Kindle (1913, p. 292) reported that they had sub- mitted a specimen of a Devonian Cyclonema ... to Dr. Grabau who wrote as follows: I suppose the best thing to do would be to refer this to Cyclonema. I am, however, inclined with Ulrich to hold that there are no true Cyclonemas in the Devonic. It is beyond the scope of this paper to describe species outside BuLLeETIN 261 ho Or nr of the Cincinnatian Province. However, many type and figured specimens of these forms were examined by the author, and the information compiled is given below. Objective descriptions are given where possible; otherwise, the descriptions are subjective. The Catalogue of Type Invertebrate Fossils of the Geological Sur- vey of Canada (Bolton, 1965) was relied upon heavily. Below is a list of questionable forms of Cyclonema. Astericks indicate objec- tive descriptions. . bellulum Billings . concinnum Hall crenulatum Meek cushingi Ruedemann decorum Billings doris (Hall) hageri Billings . haliburtont McLearn . hallianum Salter . hamiltoniae Hall . marylandense Prosser montrealense Billings . multilirum Hall obsolescens Hall parvimedium McLearn percingulatum Billings . phaedra Billings . thalia (Billings) . varians Billings . varispirum Twenhofel * * * * AAAAAAAAAAARAAAAAAAAND oo The following is a list of forms referred to other genera. No descriptions of these species are included here. . cancellatum = Strophostylus cancellatus (Hall) commune —= Eotomaria commune (Billings) elevatus = Strophostylus elevatus (Hall) ? normaliana = Gyronema historicum (Hudson) . humilis = Platyceras (Platyostoma) humile (Billings) . leavenworthanum = Yunnania leavenworthana (Hall) liratum = Trochonema (Gyronema) liratum (Hall) mediocris = Holopea? mediocris (Billings) obsoleta = Holopea obsoleta (Hall) percarinatum = Gyronema percarinatum (Hall) pervetusta = Euconia? pervetusta (Conrad) rugaclineata = Poleumita rugaelineata (Hall & Whitfield) semicarinatum = Gyronema semicarinatum (Salter) . subangulatum = Yunnania subangulata (Hall) . Sulcatum = Poleumita sulcata (Hall) . tennesseensis = Strophostylus tennesseensis (Roemer) aaanaaaagagaagaagagana . textile = Strophostylus textilis Ulrich & Scofield . ventricosum —= Strophostylus ventricosus (Hall) CINCINNATIAN CYCLONEMA: THOMPSON 257 Cyclonema bellulum Billings 1866. Cyclonema bellulum Billings, Geol. Sur., Canada, Cat. Sil. Fossils Anticosti, p. 55. 1928. C. bellulum Billings, Twenhofel, Geol. Sur., Canada, Mem. 154, p. 249, pl. 43, figs. 9, 10. Repository. — Syntypes GSC No. 2532, a, NMC; plesiotypes in Peabody Museum. Age. — Jupiter Formation, Middle Silurian. Locality.— ‘The Jumpers, Anticosti Island, Quebec. Description. — Conical shell, anomphalous; aperture round, upper outer lip angular, inner lip thickened and reflexed; orna- ment of two orders of spiral lines cancelled by collabral growth lirae and wrinkles (Iwenhofel, 1928, p. 249). Strophostylus cancellatus (Hall) 1843. Littorina cancellata Hall, Geol. Rep. 45th Dist. New York, pp. 72, 73, HS sO tabs allege tl Os 5. 1852. Cyclonema cancellata (Hall), Hall, Pal. New York, vol. 2, p. 90, pl. 28, figs. la-g. 1915. Strophostylus cancellatus (Hall), Bassler, U. S. National Mus., Bull. 92, vol. 2, p. 1241. ‘Age. — Middle Silurian, Niagaran Series, Clinton Group, Cat- aract Formation. Locality. —Sodus and Rochester, New York; Ontario; George- town, Indiana; Louisville, Kentucky. Eotomaria commune (Billings) 1866. Cyclonema communis Billings, Geol. Sur., Canada, Cat. Sil. Fossils Anti- costi, p. 55. 1928. Spirorapha? communis (Billings), Twenhofel, Geol. Sur., Canada, Mem. 154, p. 240. 1960. Eotomaria Ulrich (= Sphirorapha Perner, 1907), Knight, et al., Treatise on Invert. Paleont., pt. I, Mollusca, 1, p. 1024. Repository. — Syntypes GSC No. 2530a-c, NMC. Age. — Middle Silurian, Jupiter Formation. Locality.—The Jumpers, Anticosti Island, Quebec. Cyclonema concinnum Hall 1876. Cyclonema concinna Hall, New York Geol. Sur., Illustrations of De- vonian Foss., Gasteropoda, pl. 12. 1879. C. concinna Hail, Pal. New York, vol. 5, pt. 2, p. 38, pl. 12, figs. 38-40. 1913. C. concinnum Hall, Clarke & Swartz, Maryland Geol. Sur., Middle & Upper Devonian, p. 671, pl. 67, figs. 27-29. Repository. — Figured specimens (2) 166935, 167007 USNM. BULLETIN 261 ho Or (oe) Age. — Upper Devonian, Chemung Group. Locality. — Nichols, Tioga County, New York. Description. —Trochiform shell, spire slender and body whorl ventricose; whorl profile flattened; umbilicus small, covered by thickened and reflected lip; ornament on upper whorls consisting of double carina on periphery, last whorl showing faint carination near upper part and four or five carinate bands on lower surface (Hall, 1879, pp. 38,39; Clarke & Swartz, 1913; ps Ovi). Cyclonema crenulatum Meek 1871. Cyclonema crenulata Meek, Acad. Nat. Sci. Philadelphia, Proc., p. 79. 1873. C. crenulata Meek, Ohio Pal., vol..1, p. 213, pl. 19, figs. 2a-d. Age.— Lower Devonian, Upper Helderberg Group. Locality. — Columbus, Ohio. Description. — Shell turbinate-subtrochiform, thin; spire depressed conical; volutions four, increasing rather rapidly in size, those of the spire convex, but not rounded; last one large, convex on the upper slope of the periphery, which is rather narrowly rounded; suture well defined between the upper volutions, and somewhat canaliculate farther down; aperture ovate. Surface ornamented by sharply elevated, revolving lines or small ridges, which are beautifully and minutely crenated by the crossing of the fine, very oblique lines of growth. Of these revolving lines, from sixteen to eighteen may be counted on the body volution, and six on the next above, while those farther up appear to be quite smooth. (Meek, 1873, p. 213). Cyclonema cushingi Ruedemann Pl. 34, fig. 11 1912. Cyclonema cushingi Ruedemann, New York State Mus., Bull. 162, p. 110, pl. 7, figs. 8-10. 1951. C. cushingi Ruedemann, Wilson, Geol. Sur., Canada, Bull. 17, p. 78, pl. 13, figs. 9-11. Repository. — Holotype (mold and cast), NYSM No. 9175, 10039k/1. Hypotypes, GSC No. 9772, a, NMC. Age.— Middle Ordovician, Ottawa Formation, Hull beds; Trenton Group, Snake Hill Formation. Locality. — Hull, Quebec; Snake Hill, Saratoga County, New York. Remarks. — Holotype (NYSM No. 9175) consists of externai and internal molds, and holoplastotype; three whorls present, de- formed, ornament of faint spiral lines and growth wrinkles. Wil- son’s (1951, pl. 13, figs. 10, 11) figures of plesiotypes (GSC No. 9772) resemble Cyclonema with two orders of spiral lines crossed by collabral lirae but differ from Cyclonema in having a small umbilicus. Probably not Cyclonema. CINCINNATIAN CYCLONEMA: THOMPSON 259 Cyclonema decorum Billings 1866. Cyclonema decora Billings, Geol. Sur., Canada, Cat. Sil. Fossils Anti- costi, p. 56. 1928. C. decorum Billings, Twenhofel, Geol. Sur., Canada, Mem. 154, p. 249, ple 42e ties, 10h 10: Repository. — Holotype, GSC No. 2529, NMC. Age. — Middle Silurian, Chicotte Formation. Locality. — Southwest Point, Anticosti Island, Quebec. Description, — About 4 whorls, aperture nearly circular, apical angle about 90 degrees, 16 mm. high, 15 mm. wide, aperture 8 mm. in diameter, surface covered with strong, revolving striae of which there are about 2 to a mm. (Twenhofel, 1928, p. 249). Cyclonema doris (Hall) 1862. Pleurotomaria doris Hall, 15th Ann. Rep. New York Cab. Nat. Hist., p. 43, (advance sheets, 1861, p. 15). 1876. Cyclonema crenistria Hall, Illust. Dev. Foss. New York Geol. Sur., Gasteropoda, pl. 12, fig. 23. 1879. C. doris (Hali), Hall, Pal. New York, vol. 5, pt. 2, p. 34, pl. 12, fig. 23. Repository. — Figured specimen (Hall, 1879, pl. 19, fig. 1) , AMNH No. 2868/2. Hypotype, NYSM No. 3262, 10040/1. Age. — Lower Devonian, Upper Ulster Group. Schoharie For- mation. Locality. — Schoharie, New York. Remarks. — Internal molds with two to three whorls, turbini- form, faint trace of spiral lines on body whorl and basal surface, trace of umbilicus; should be referred to another genus. Strophostylus elevatus (Hall) 1868. Cyclonema? elevata Hall, 20th Rep. New York State Cab. Nat. Hist., p. 342, pl. 15, fig. 4. 1915. Strophostylus elevatus (Hall), Bassler, U. S. National Mus., Bull. 92, vol. 2, p. 1241. Age. — Middle Silurian, Niagaran Series. Locality. — Racine, Wisconsin; Huntington, Indiana. Cyclonema hageri Billings 1862. Cyclonema hagcri Billings. “New Species of Lower Silurian Fossils,” p. PAs), sates, AVL 1863. C. hageri Billings, Logan, Geol. Sur., Canada, Rept. Prog., p. 178, fig. 169. 1865. C. hageri Billings, Geol. Sur., Canada, Palaeoz. Foss., vol. 1, p. 29, alee, Wile Repository. — Holotype, GSC No. 1697, NMC. Age. — Middle Ordovician, Trenton beds. Locality. — Smith quarries, Montreal, Canada. 260 BULLETIN 261 Cyclonema haliburtoni McLearn 1924. Cyclonema haliburtoni McLearn, Geol. Sur., Canada, Mem. 137, p. 147, plo2ietio.s: Repository. — Holotype, Peabody Museum, No. 462b. Age. — Silurian, Ross Brook Formation. Locality. — Arisaig, Nova Scotia. Description. —‘Three to four rapidly enlarging whorls, apical angle of more than 60 degrees; ornament of eight or nine re- volving threads, separated by relatively broad concave interspaces (McLearn, 1924, p. 147). Cyclonema hallianum Salter 1859. Cyclonema hallianum Salter, Geol. Sur., Canada, Can. Org. Rem., dec. 1, pe 26) piiG, etic: 1863. C. hallianum Salter, Billings, Geol. Sur., Canada, Geol. Canada, p. 178, fig. 168. 1951. C. hallianum Salter, Wilson, Geol. Sur., Canada, Bull. 17, p. 78, pl. 13, figs. 14, 15. Repository. — Lectotype, GSC No, 1195, NMC. Hypotype, GSC No. 9773, NMC. Age. — Middle Ordovician, Ottawa Formation, Leray-Rockland beds. Locality. — Paquette Rapids, Allumette Island, Ottawa River, Quebec. Description. — Large for genus, one specimen measuring 32 mm., lacking the upper whorl; apical angle approximately 70 degrees; five or six rapidly enlarging whorls, more rounded than some species of the genus but nevertheless some- what flattened on sides and base; section of whorl circular to subquadrate; periphery near the base of the whorl; umbilicus very small; sutures well defined but not deep; aperture not seen; growth lines strong, directed obliquely backward from the top, and crossed by very fine revolving lines which are frequently obliterated (Wilson, 1951, p. 78). Cyclonema hamiltoniae Hall 1861. Cyclonema hamiltoniae Hall, Descriptions of New Species of Fossils, p. 19; 1862. C. hamiltoniae Hall, 15th Rep. New York State Cab. Nat. Hist., p. 47, pl. 5, fig. 16 (non fig. 15). 1879. C. hamiltoniae Hall, Pal. New York, vol. 5, pt. 2, p. 37, pl. 12, figs. 34-36. 1909. Sphaerodoma hamiltoniae (Hall), Grabau & Shimer, North American Index Foss., vol. 1, p. 701. 1913. C. hamiltoniae Hall, Prosser & Kindle, Maryland Geol. Sur., Middle & Upper Devonian, p. 289. Repository. — Figured specimen (Hall, 1879, figs. 34, 36) AMNH No. 5406/1 and 5406/2. CINCINNATIAN CYCLONEMA: THOMPSON 261 Age. — Middle Devonian, Hamilton Group. Locality. — Schoharie County, New York; Pratt’s Falls, New York. Remarks. — AMNH No. 5406/1 retains shell material; on mu- seum identification card, Knight suggested that this be selected as holotype. Four whorls preserved, low-spired, wide flat ramp which is probably a selenizone, sutures incised, approximately eleven spiral lines on body whorl crossed by growth lirae, five spiral cords on second whorl, spiral lines continue onto basal surface; no evi- dence of umbilicus. Presence of ramp (selenizone?) removes C. hamiltoniae from Cyclonema; it may be Baylea de Koninck, 1883. Gyronema historicum (Hudson) 1905. Eunema historicum Hudson, Bull. New York State Mus., vol. 80, p. 288, pl. 4, fig. 5. 1905. Cyclonema? normaliana Raymond, American Jour. Sci., 4th ser., vol. AU So TE 1908. Gyronema historicum (Hudson), Raymond, Ann. Carnegie Mus., vol. 4, p. 208, pl. 54, figs. 5, 6. Age. — Middle Ordovician, Chazyan Stage, Valcour Formation. Locality.—Valcour Island and Plattsburg, New York. Platyceras (Platyostoma) humile (Billings) 1866. Cyclonema humilis Billings, Geol. Sur., Canada, Cat. Sil. Fossils Anti- costi, p. 56. 1928. Diaphorostoma humile (Billings), Twenhofel, Geol. Sur., Canada, Mem. 154, p. 254, pl. 42, figs. 13, 14. 1960. Platyceras (Platyostoma) Conrad, 1842 (= Diaphorostoma, Fischer, 1885), Knight, et al., Treatise on Invert. Paleont., pt. I, Mollusca 1, p. 1240. Repository. — Syntypes, GSC Nos. 2531, a-e, NMC. Age. — Middle Silurian, Jupiter Formation. Locality. — The Jumpers, Anticosti Island, Quebec. Yunnania leavenworthana (Hall) 1858. Pleurotomaria leavenworthana Hall, Trans. Albany Inst., vol. 4, p. 24. 1906. Cyclonema leavenworthana (Hall), Cumings & Beede, Indiana Dept. Geol. & Nat. Res., 30th Ann. Rep., p. 1344, pl. 25, figs. 29-31. 1933. Yunnania leavenworthana (Hall), Knight, Jour. Paleont., vol. 7, No. 1p. 39: Repository. — Holotype and paratypes, AMNH Nos. 7665/ 12,3. Age. — Middle Mississippian, Salem limestone. °62 BULLETIN 261 Locality. —Spergen Hill and Bloomington, Indiana; Alton, Illinois. Remarks. — Type collection of tiny trochiform shells, three to four whorls; nucleus appears to be almost planispiral, expanding rapidly to juvenile whorls; body whorl not greatly expanded, su- tures impressed to incised, shoulders rounded, periphery at mid- whorl; columellar lip thin, reflexed, not channeled, umbilical de- pression behind it; ornament of spiral cords, five to nine on body whorl, four to seven on penultimate whorl, four to seven on anti- penultimate whorl, third cord below suture on body whorl is a carina, collabral lirae absent. Trochonema (Gyronema) liratum (Hall) 1861. Cyclonema lirata Hall, Descriptions of New Species of Fossils, p. 19. 1862. C. lirata Hall, 15th Rept. New York State Cab. Nat. Hist. p. 47, ple 5. figs 5) (72072 fic(6)))- 1879. C. lirata Hall, Pal. of New York, vol. 5, pt. 2, p. 35; pl. 12, figs. 27-29. 1897. [Non] Gyronema liratum Ulrich, Ulrich im Ulrich & Scofield, Geol. Minnesota, vol. 3, pt. 2, p. 1056. 1913. Trochonema (Gyronema) liratum (Hall), Clarke & Swartz, Maryland Geol. Sur., Middle & Upper Devonian, p. 674, pl. 68, fig. 13. Age. — Middle Devonian, Hamilton Group. Locality. — Chenango and Madison Counties, New York. Cyclonema ? marylandense Prosser 1913. Cyclonema ? marylandense Prosser, Prosser im Prosser & Kindle, Maryland Geol. Sur., Middle & Upper Devonian, p. 292, pl. 36, fig. 10. Repository. — Holotype 166960 USNM. Age.— Middle Devonian, Hamilton Group, Romney Forma- tion. Locality. — West Virginia bank of Potomac River four miles below Cumberland, Maryland. Description. — Subconical shell, body whorl ventricose, upper whorls short and rounded; ornament of eighteen revolving lines on body whorl, eight to nine on penultimate whorl (Prosser iz Prosser & Kindle, 1913, p. 292). Holopea ? mediocris (Billings) 1866. Cyclonema mediocris Billings, Geol. Sur., Canada, Cat. Sil. Foss. Anti- costi, p. 56. 1928. Holopea ? mediocris (Billings), Twenhofel, Geol. Sur. Canada, Mem. 154, p. 251, pl. 43, fig. 11. Repository. — Holotype, GSC No. 2461, NMC. Age.— Middle Silurian, Jupiter Formation. CINCINNATIAN CYCLONEMA: THOMPSON 263 Locality.— Four miles west of Southwest Point, Anticosti Island, Quebec. Cyclonema montrealense Billings Pl. 34, figs. 6, 7 1862. Cyclonema montrealensis Billings, “New Species of Lower Silurian Fossils,” p. 30, fig. 28. 1863. C. montrealensis Billings, Logan, “Geology of Canada,’ Geol. Sur., Canada, Rept. Prog., p. 178, fig. 170. 1865. C. montrealensis Billings, Geol. Sur., Canada Palaeoz. Foss., vol. 1, pe Ok wee, 23s 1903. C. montrealense Billings, Weller, Geol. Sur., New Jersey, Pal., vol. 3, p. 16 ply LA ties3 3) 1912. C. montrealense Billings, Ruedemann, New York State Mus., Bull. 162, oh INO, WG 75 wnkes Ze 1951. C. montrealense Billings, Wilson, Geol. Sur., Canada, Bull. 17, p. 79, pol, a3 ames, iA, ashe Repository. — Holotype, GSC No. 1694, NMC. Syntype GSC No. 1694a, NMC. Hypotype, hypoplastotype, NYSM No. 9176, 10040m/1. Figured specimen (Weller, 1903, pl. 12, fig. 33) FMNH No. 37890. Age. — Middle Ordovician, Upper Mohawkian, Trenton Group, Snake Hill beds. Locality. —Smith quarries, Montreal, Quebec; Snake Hill, Saratoga County, New York; Branchville, New Jersey. Remarks. — NYSM hypotype is external mold with hypoplasto- type, four whorls shown, high-spired, appears to have medial an- gulation on body whorl, other ornament lacking; may be Gyro- nema. Field Museum type (No. 37890) has three whorls, low-spired, body whorl expanded, sutures incised, shoulder rounded, colum- ellar lip unknown, faint umbilicus present, second-order ornament crossed by collabral growth lirae. Wilson’s (1951, pl. 13, figs. 12, 13) figures of the holotype (GSC No. 1694) resemble Cyclonema in being low-spired turbini- form, with two orders of spiral lines crossed by collabral growth lirae. However, it has a small to absent umbilicus and thus is probably not Cyclonema. Cyclonema multilirum Hall 1861. Cyclonema multilira Hall, Descriptions of New Species of Fossils, p. 20. 1862. C. multilira Hall, 15th Rept. New York State Cab. Nat. Hist. p. 48, pl. Gy asites, 7/5 1879. C. multilira Hall, Pal. New York, vol. 5, pt. 2, p. 36, pl. 12, figs. 30-33. 264 BULLETIN 261 Age. — Middle Devonian, Hamilton Group. Locality. — Smyrna, Chenango County, New York. Description. — Turbiniform, ventricose shell, five or more whorls, body whorl large and extremely ventricose; ornament of one order of strong revolving lines, ten or twelve on body whorl, five or six on upper whorls, “the space from the suture to the upper of these lines is greater than between the lines, those of the periphery being more closely arranged than those above or below” (Hall, 1879, p. 36). Cyclonema obsolescens Hall 1876. Cyclonema obsoleta Hall, Illustrations of Devonian Fossils, New York Geol. Sur., Pal., Gasteropoda, pl. 12, fig. 37 (not described). 1879. C. (obsoleta) obsolescens Hall, Pal. New York, vol. 5, pt. 2, p. 38, pl. 12, fig. 37. Repository. — ‘Type, NYSM No. 3263, 10041/1. Age. — Upper Devonian, Chemung Stage. Locality. —Southern New York. Remarks.— Known only from internal mold; three whorls preserved; eight coarse spiral lines and growth lirae on body whorl. Hall (1879, p. 38) described it as: “There is a faint indica- tion of the flattened band upon the upper side of the last volution, which, in this specimen, is limited below by a depression or line of fracture.’ Should be referred to another genus. Holopea obsoleta (Hall) 1852. Cyclonema ? obsoleta Hall, Pal. New York, vol. 2, p. 90, pl. 28, figs. 3a,b. 1889. Holopea obsoleta (Hall), Foerste, Boston Soc. Nat. Hist., Proc., vol. 24, p. 348. Age. — Middle Silurian, Lower Clinton Stage. Locality. — Medina and Lockport, New York. Cyclonema parvimedium McLearn 1924. Cyclonema parvimedium McLearn, Geol. Sur., Canada, Mem. 137, p. 146, pl. 21, figs. 13, 14. Repository. — Holotype, GSC No. 5655, NMC. Age.— Lower Silurian, Beechhill Formation. Locality. — Arisaig, Nova Scotia. Description. — Subconical form, height almost equal to width, three or four rapidly expanding whorls; aperture unknown from McLearn’s specimen; second-order ornament of cords and costae CINCINNATIAN CYCLONEMA: THOMPSON 265 cancelled by collabral growth lirae and wrinkles (McLearn, 1924, p- 146). Gyronema percarinatum (Hall) Pl, 34, figsn 12013 1847. Pleurotomaria percarinata Hall, Pal. New York, vol. 1, p. 177, pl. 38, fig. 4. 1855. P. percarinata Hall, 12th Rept. New York State Cab. Nat. Hist., p. 74. 1874. Cyclonema percarinata (Hall), Miller, Cincinnati Quart. Jour. Sci., vol. 1, pe 321. 1882. C. percarinata (Hall), Whitfield, Geol. Wisconsin, vol. 4, p. 211, pl. 5, rae, NS), 1889. C. percarinata (Hall), Lesley, Geol. Sur., Pennsylvania, Rept. P4, p. 172, fig. 1915. Gyronema percarinatum (Hall), Bassler, U. S$. National Mus., Bull. 92, vole Ly ips1575: Repository. — Syntype, AMNH No. 752/1, James Hall Collec- tion. Age. — Middle Ordovician, Mohawkian Series, Trenton Group. Locality. — Middleville, New York. Remarks. — Syntype is interior mold, three whorls, trochiform shell, aperture unknown; ornament of three coarse spiral cords, four to five closely spaced cords on basal surface. Cyclonema percingulatum Billings 1857. Cyclonema percingulata Billings, Geol. Sur., Canada, Rept. Prog., 1853- ri rillcnss Cat’ Sil. Fouile, Anticon Gale one Canada, p. 55. Repository. — Syntypes, GSC nos. 2534a, b, d. Plesiotypes in Peabody Museum. Age. — Middle Silurian, Jupiter Formation. Locality. — Southwest Point, Anticosti Island, Quebec. Description. — Conical shell, spiral angle about 83 degrees, three ventricose whorls, whorl profile rounded; ornament of two orders; cords on body whorl closely spaced on lower portion, more distant on upper surface, separated by shallow concave spaces with one costae, collabral growth lirae and wrinkles present (Billings, 1857, p. 304). Euconia ? pervetusta (Conrad) 1838. Cyclostoma ? pervetusta Conrad, Ann. Rept. New York State Geol. Sur., p. 133; zbid., 1839, p. 65. 1843. Euomphalus pervetustus (Conrad), Hall, Geol. New York, vol. 4, p. 48, figs. 1, 2. 266 BULLETIN 261 1843. Pleurotomaria pervetusta (Conrad), Hall, Rept. Geol. 4th Dist., New York p. 48) figs. 12: 1852. P. pervetusta (Conrad), Hall, Pal. New York, vol. 2, p. 12, pl. 4 (bis), figs. 3a-d. 1899. Cyclonema pervetusta (Conrad), Whitfield & Hovey, Bull. American Mus. Nat. Hist., vol. 11, pt. 2, p. 162. 1909. Euconia (?) pervetusta (Conrad), Grabau & Shimer, North American Index Fossils, vol. 1, p. 642, fig. 874. Age. — Lower Silurian, Upper Medinan Series. Locality. — Medina and Lockport, New York. Cyclonema phaedra Billings 1862. Cyclonema phaedra Billings, “New Series of Lower Silurian Fossils, p. 188. 1865. C. phaedra Billings, Palaeoz. Fossils, Geol. Sur., Canada, vol. 1, p. 188. Repository. — Holotype, GSC No. 783, NMC. Age. — Lower Ordovician, Beekmantown Formation. Locality. —St. Antoine de Tilly, Quebec. Poleumita rugaelineata (Hall and Whitfield) 1872. Euomphalus (Cyclonema) rugaelineata Hall & Whitfield. 24th Rept., New York State Cab. Nat. Hist., p. 186. 1889. Cyclonema rugaelineata (Hall & Whitefield), Nettleroth, Kentucky Fossil Shells, Geol. Sur., Kentucky, p. 187, pl. 33, fig. 21. 1915. Poleumita rugaclineata (Hall & Whitfield), Bassler, U. S. National Mus., Bull. 92, vol. 2, p. 1019. Age. — Middle Silurian, Niagaran Series, Louisville Formation. Locality. — Louisville, Kentucky. Gyronema semicarinatum (Salter) 1859. Cyclonema semicarinata Salter, Geol. Sur., Canada, Can. Org. Rem., deca Laps 275) pla 6, tigsy Zab 1897. Gyronema semicarinatum (Salter), Ulrich im Ulrich & Scofield, Geol. Minnesota, vol. 3, pt. 2, p. 1055, pl. 78, figs. 17, 18. 1951. Gyronema semicarinatum (Salter), Wilson, Geol. Sur., Canada, Bull. 17, ps 75, ply 12) tigse 118-205 Repository. — Syntype, GSC No. 1208, NMC. Plesiotypes, USNM No. 45826. Age. — Middle Ordovician, Leray-Rockland beds; Middle Ordo- vician, Decorah Formation. Locality. — Paquette Rapids, Allumette Island, Ottawa River, Quebec; near Cannon Falls, Minnesota. Yunnania subangulata (Hall) 1858. Pleurotomaria subangulata Hall, Trans. Albany Inst., vol. 4, p. 25. 1906. Cyclonema subangulatum (Hall), Cumings & Beede, Indiana Dept. Geol. & Nat. Res., 30th Ann. Rept., p. 1345, pl. 25, fig. 32. CINCINNATIAN CYCLONEMA: THOMPSON 267 1929. C. ? subangulatum (Hall), Bell, Geol. Sur.. Canada, Mem. 155, p. 176, pla sie tigs, 35 3a, 4, 4a, 5) 6. 1933. oe subangulata (Hall), Knight, Jour. Paleont., vol. 7, No. 1, Repository. — Hypotypes, GSC Nos. 7620a, NMC. Plesiotypes, Peabody Museum No. 3194; AMNH No. 7664--/1. Age.— Middle Mississippian, Salem limestone. Locality. — Spergen Hill, Indiana. Remarks. — ‘Two specimens (AMNH No. 7664-+-/1) examined, small trochiform shells, four to five whorls, impressed sutures, shoulders broad and flat, body whorl little expanded, ornament of two cords on shoulder, third cord terminates shoulder, fourth cord is one-quarter whorl below third cord, several small cords below periphery onto basal surface. “Cyclonema Hall, 1852... . hardly needs comparison as its peculiarly flattened columellar lip and fine revolving lirae are sufficient to distinguish it at a glance” (Knight, 1933, p. 39). Poleumita ? sulcata (Hall) 1843. Euomphalus sulcatus Hall, Geol. New York, vol. 4, p. 137, fig. 4, p. 138; fabsaills 255 treats 1852. Cyclonema sulcata (Hall), Hall, Pal. New York, vol. 2, p. 347, pl. 84, figs. la-d. 1884. C. sulcatum (Hall), Whiteaves, Geol. Sur., Canada, Palaeoz. Fossils, vol. Seep te ea paeligempla seatoae5 1903. Poleumita ? sulcata (Hall), Clarke & Ruedemann, Mem. New York State Mus., vol. 5, p. 62, pl. 10, figs. 1-4. 1906. Poleumita sulcata (Hall), Whiteaves, Geol. Sur., Canada, Palaeoz. Fossils, vol. 3, pt. 4, p. 337. Repository. — Holotype, GSC No. 2851, NMC. Age. — Middle Silurian, Guelph Formation. Locality. — Durham, Ontario. Strophostylus tennesseensis (Roemer) 1860. Turbo tennesseensis Roemer, Silurian Fauna West Tennessee, p. 77, plaess aves li7: 1889. Cyclonema tennnessecnsis (Roemer), Miller, North American Geol. Pal., p. 401. 1915. Strophostylus tennesseeensis (Roemer), Bassler, U. S. National Mus., BUlles92. volae2uapeel242: Age. — Middle Silurian, Niagaran Series, Brownsport Forma- tion. Locality. — Decatur County, Tennessee. Strophostylus textilis Ulrich 1897. Strophostylus textilis Ulrich, Ulrich im Ulrich & Scofield, Geol. Minne- sota, vol. 3, pt. 2, p. 1064, pl. 82, figs. 49-54. 268 BULLETIN 261 1897. Cyclonema textile (Ulrich), Miller, North American Geol. Pal., 2d app., p. 766. 1909. Holopea textilis (Ulrich), Grabau & Shimer, North American Index Fossils, vol. 1, p. 677, fig. 943. 1915. Strophostylus textilis (Ulrich), Bassler, U. S. National Mus., Bull. 92, vol. 2, p. 1242. Repository. — Syntypes, USNM Nos. 45999-46002. Age.— Middle Ordovician, Trenton Stage, Prosser and Flan- agan Formations. Locality. — St. Paul, Minnesota; Burgin, Kentucky. Cyclonema thalia (Billings) 1857. Pleurotomaria thalia Billings, Geol. Sur., Canada, Rept. Prog., 1853-56, 1866. Pe aicas thalia (Billings), Billings, Geol. Sur., Canada, Cat. Sil. Fossils Anticosti, pp. 17, 55, fig. 5. 1928. C. thalia (Billings), Twenhofel, Geol. Sur., Canada, Mem. 154, p. 250, pl. 42, fig. 12. Repository. — Hypotype, GSC No. 2129, NMC. Plesiotypes, Peabody Museum. Age. — Upper Ordovician, English Head or Vaureal Formation. Locality.— Carleton Point, Anticosti Island, Quebec. Description. — Conical shell, apical angle 74 degrees, three whorls; umbilicus small, aperture round, inner lip thickened and reflected; body whorl with seven keels: sharp keel close to suture, another halfway to outer upper margin, third and strongest keel at periphery, below it is marginal concave band bordered on under- side by fourth sharp keel, three additional keels between fourth and umbilicus, fine growth lirae present (Billings, 1857, p. 303; Twenhofel, 1928, p. 250). Cyclonema varians Billings 1857. Cyclonema varians Billings, Geol. Sur., Canada, Rept. Prog., 1853-56, 1928. C. Senne Billings, T'wenhofel, Geol. Sur., Canada, Mem. 154, p. 251, pleAs a tigs 75.8: Repository. — Syntypes, GSC Nos. 2533a-g, NMC. Age. — Middle Silurian, Chicotte Formation. Locality. — Southwest Point, Anticosti Island, Quebec. Description. — Turbiniform subspherical shell; whorls three, rapidly enlarging and ventricose, body whorl very large and ventri- cose, whorl profile round to broadly angular, suture channeled; umbilicus absent to small; single order ornament of spiral threads, CINCINNATIAN CYCLONEMA: THOMPSON 269 eight to ten in one mm., crossed by collabral growth lirae (Bill- mes, 697, 0p: 2007. Lwenhofel, 1928, \p.. 251)’. Cyclonema varispirum Twenhofel 1928. Cyclonema varispirum Twenhofel, Geol. Sur., Canada, Mem. 154, p. 250, ple 26, figs) 5: Repository. — Peabody Museum. Age. — Ordovician, English Head and Vaureal Formations. Locality. — Anticosti Island, Quebec. Description. — Small, conical shell, apical angle of about 75 degrees, not more than three whorls; whorl profile rounded; phaneromphalous; aperture round, inner lip thickened and a slight depression behind it; upper half of body whorl ornamented by six prominent spiral lines about 1.5 mm apart, lowest on _peri- phery, separated by one to five costae, lower half of whorl orna- mented by spiral lines of different sizes, about two in one mm, cancelled by collabral growth lirae, basal surface cancellated (Twen- hofel, 1928, p. 250). Strophostylus ventricosus (Hall) 1852. Cyclonema ventricosa Hall, Pal. New York, vol. 2, p. 90, pl. 28, figs. 2a-c (non Hall, 1870). Age. — Middle Silurian, Lower Clinton Stage. Locality. — Sodus, New York. LOCALITY DATA Localities and occurrences of Cyclonema are given in Text- figure 5, compiled from specimens from University of Cincinnati and Miami University collections. The author collected at many of these classic Cincinnatian localities, as well as fresh cuts created by highway construction. Each new locality is described, including the species of Cyclonema collected at each one. Cynthiana Formation Roadcuts at Falmouth, Kentucky, on Route 27 Cyclonema varicosum Fairview Formation, Fairmount Member Gage Street, Cincinnati, Ohio C. humerosum, C. gracile Mulberry Street, Cincinnati, Ohio C. humerosum Roadcut for new Route 27, on Herman Road, south of Layhigh, Ohio C. simulans Clover Lick Creek, south of Williamsburg, Ohio, on Route 133 C. transversum 270 BULLETIN 261 2) P) B) Po) D) 8) 2) ) e) D D) aTetpoul O[toeib * WNSOOTAeA ° UnsaeAsueay * @AoeTGNS * Sue[TnuTS ° unqjeptuedr unjetgur °* wnsoaeuny * @SuoUOjAEp * BzeT XTTtq * Cincinnati, Ohio: Emming Street —- Fairmount es [a EERE es Hl >| | Oxford - Waynesville Lane's Mills - Arnheim Indian Creek, Reily - Arnheim csO cut, Bridgetown - Arnheim West Middletown - Arnheim ' ESET || SAS xfx[xfxfx TT txt fx mia Be ia il West Chester RR cut - Arnheim Guilford - Fairview Lick Run, Oregonia - Arnheim Madison — Arnheim Russelville - Arnheim Richmond —- Arnheim Weisburg - Waynesville-Liberty Versailles - Mt. Hope Schlosser's Quarry, Covington - Fairview Old Crow Distillery, Frankfort - Cynthiana Lexington - Cynthiana Fayette County - Cynthiana Nashville - Catheys a! sel SI x | NNGL AMONLINAA WNWICANI Text-figure 5.— Localities and occurrences of Cyclonema, compiled from UCM and MU collections. CINCINNATIAN CYCLONEMA: THOMPSON 211 Fairview Formation, Mt. Hope and Fairmount members Roadcut where New Biddinger Road crosses I-74 northwest of Harrison, Ohio C. gracile, C. inflatum Arnheim Formation Roadcut on Route 4 at Excello, Ohio C. bilix bilix Stream cut between Blue Ball and Red Lion, Ohio C. bilix bilix Roadcut on Route 42 northeast of Waynesville, Ohio C. bilix lata Roadcut where I-75 crosses old Route 25, between Maud and West Chester, Ohio C. bilix bilix, C. bilix lata, C. humerosum Waynesville Formation, Ft. Ancient Member Roadcut northeast of Brookville, Indiana C. bilix lata Waynesville Formation, Blanchester Member Acton Lake Dam, Hueston Woods State Park, Ohio C. bilix lata Liberty Formation Devil’s Backbone, Route 725 west of Camden, Ohio C. bilix bilix Roadcut on Route 127 between Collinsville and Somerville, Ohio C. bilix bilix REFERENCES Austin, T., and Austin, T. (the younger) 1843-1849. Monograph on Recent and fossil Crinoidea. London, Bristol, 128 pp., 16 pl. Bassler, R. S. 1915. Bibliographic Index of American Ordovician and Silurian fossils. United States National Museum, Bull. 92, 2 vols., 1521 pp., 4 pl. 1932. The stratigraphy of the Central Basin of Tennessee. Tennessee Div. Geol., Bull. 38, 268 pp. Billings, E. 1857. Descriptions of new fossils from the Silurian rocks of Canada. Geol. Sur. Canada, Rept. Prog. 1853-56, pp. 256-346. 1870. Notes on the structure of the Crinoidea, Cystoidea, and Blastoidea. American Jour. Sci., 2d ser., vol. 50 (whole no. 100), pp. 225- 240, figs. 1-14. Bolton, T. E. 1965. Catalogue of type invertebrate fossils of the Geological Survey of Canada. Vol. II, Geol. Sur., Canada, Ottawa, 344 pp. Bowsher, A. L. 1955. Origin and adaptation of platyceratid gastropods. Univ. Kansas Paleont. Contr., Mollusca, Art. 5, pp. 1-11, pls. 1, 2. Boucot, A. J., Martinsson, A., Thorsteinsson, R., Walliser, O.H., Whittington, H. B., and Yochelson, E. L. 1960. A Late Silurian fauna from the Sutherland River Formation, Devon Island, Canadian Arctic Archipelago. Geol. Sur. Canada, Bull. 65, 51 pp; 10 pl. Butts, C. 1926. The Paleozoic rocks, in Geology of Alabama. Geol. Sur. Ala- bama, Spec. Rept. 14, pp. 14-230, pl. 3-76. ho I no BULLETIN 261 Caster, K. E., Dalvé, E. A., and Pope, J. K. 1955. Elementary guide to the fossils and strata of the Ordovician in the vicinity of Cincinnati, Ohio. 47 pp., 8 pl., Cincinnati Mus. Nat. Hist., Publication. Clarke, J. M. 1908. The beginnings of dependent life. New York State Mus., Bull. 121 (61st Ann. Rept., vol. 1), pp. 1-28. 1921. Early parasitism of the snails upon the crinoids, in Organic dependence and disease; their origin and significance. Yale Univ. Press, New Haven, pp. 64-77. Clarke, J. M., and Swartz, C. K. 1913. Gastropoda of the Upper Devonian of Maryland. Maryland Geol. Sur., Middle and Upper Devonian of Maryland, pp. 661- 689. Conrad, T. A. 1842. Observations on the Silurian and Devonian systems of the United States, with descriptions of new organic remains. Acad. Nat. Sci. Philadelphia, Jour. 1st ser., vol. 8, pt. 2, pp. 228-280, pls. 12-17. Cox, ESR: 1960. General characteristics of Gastropoda, in R. C. Moore, ed., Treatise on invertebrate paleontology, pt. I, Mollusca 1, pp. 84-169, Geol. Soc. America and Univ. Kansas Press. Cumings, E. R. 1908. The stratigraphy and paleontology of the Ordovician rocks of Indiana. Dept. Geol. & Nat. Res. Indiana, 32d Ann. Rep., pp. 607-1189, pls. 1-55. Foerste, A. F. 1893 (1895). Fossils of the Clinton Group in Ohio and Indiana. Geol. Sur. Ohio, Rep., vol. 7, pt. 2, pp. 516-601, pls. 25-37a. 1903. Silurian and Devonian limestones of western Tennessee. Jour. Geol., vol. 11, pp. 554-583, 679-715. 1914. The Rogers Gap fauna of central Kentucky. Cincinnati Soc. Nat. Hist., Jour., vol. 21, No. 4, pp. 109-156, 4 pls. 1916. Upper Ordovician formations in Ontario and Quebec. Geol. Sur. Canada, Mem. 83, 279 pp. Frankenberg, D., and Smith, K. L. 1967. Coprophagy in marine animals. Limnol. Oceanog., vol. 12, pp. 443-450. Graham, A. 1955. Molluscan diets. Malac. Soc. London, Proc., vol. 31, pp. 144-159. Hall, J. 1847. Descriptions of the organic remains of the lower division of the New York System. Palaeont. New York, vol. 1, 338 pp. 1852. Nat. Hist. New York, Palaeont. New York, vol. 2, 362 pp. 1879. Nat. Hist. New York, Palaeont. New York, vol. 5, pt. 2, No. 1, 492 pp. Hinde, G. J. 1885. Descriptions of a new species of crinoids with articulating spines [Hystricrinus carpenteri, Arkona, Ontario]. Annals and Mag. Nat. Hist. for March 1885, ser. 5, vol. 15, pp. 157-173, pl. 6. Imbrie, J., and Newell, N. D., eds. 1964. Approaches to paleoecology. New York, John Wiley, 432 pp. James, U. P. 1871. Catalogue of the Lower Silurian fossils, Cincinnati group, found at Cincinnati and vicinity—within a range of forty or fifty miles. Cincinnati, published by the author, 14 pp. CINCINNATIAN CYCLONEMA: THOMPSON 273 Keyes, C. R. 1888a. The sedentary habits of Platyceras. American Jour. Sci., 3d ser., vol. 36, pp. 269-272. 1888b. On the attachment of Platyceras to palacocrinoids, and its effects in modifying the form of the shell. American Philos. Soc., Proc., vol. 25, No. 128, pp. 231-243, pl. 1. Knight, J. B. 1932. Holopea symmetrica Hall, genotype of Holopea Hall. Jour. Wash- ington Acad. Sci., vol. 22, pp. 473-476. 1933. The gastropods of the St. Louis, Missouri, Pennsylvania out- lier, V, The Trochoturbinidae. Jour. Paleont., vol. 7, pp. 30-58, pls. 8-12. 1934. The gastropods of the St. Louis, Missouri, Pennsy!vanian outlier, VII, The Euomphalidae and Platyceratidae. Jour. Paleont., vol. 8, pp. 139-166, pls. 20-26. 1941. Paleozoic gastropod genotypes. Geol. Soc. America, Spec. Paper 32, S10. pp: 96. pls: 1946. [Review of] Les différences ches les gastéropodes capuliformes; Organization des Platyceratidae, by Genevieve Delpey, 1940. Geol. Mag., vol. 83, pp. 280-284. Knight, J. B., Batten, R. L., and Yochelson, E. L. 1954. Gastropoda, in Mollusca, [Pt.] 5 of Kummel, B., ed., Status of invertebrate paleontology, 1953. Harvard Coll. Mus. Comp. Zoology Bull., vol. 112, No. 3, pp. 173-179. Knight, J. B., and others 1960. Systematic descriptions [ Archaeogastropoda], in R. C. Moore, ed., Treatise on invertebrate paleontology, pt. I, Mollusca 1, Geol. Soc. America & Univ. Kansas Press, pp. 169-310. MacClintock, C. 1967. Shell structure of patelloid and_ bellerophontoid gastropods (Mollusca). Peabody Mus. Nat. Hist., Yale Univ., Bull. 22, 140 pp: 32) pls: McFarlan, A. C. 1931. In Jillson, W. R., The Ordovician fauna of Kentucky. Kentucky Geol. Sur., Paleont. of Kentucky, pp. 47-165, pls. 1-16. McLearn, F. H. 1924. Palaeontology of the Silurian rocks of Arisaig, Nova Scotia. Geol. Sur. Canada, Mem. 137, 239 pp. Meek, F. B. 1873. Descriptions of invertebrate fossils of the Silurian and Devonian systems. Geol. Sur. Ohio, Rep., vol. 1, pt. 2, Palaeont., pp. 1-243, pls. 1-23. Meek, F. B., and Worthen, A. H. 1866. Geology and palaeontology, pt. 2, Palaeontology of Illinois. Ulinois Geol. Sur., vol. 2, pp. 289-565, pls. 1-20. 1868. Palaeontology of Illinois. Illinois Geol. Sur., vol. 3, pp. 291-359, pls. 1-6. 1868. Notes on some points in the structure and habits of the Palaeozoic Crinoidea. Acad. Nat. Sci. Philadelphia, Proc., pp. 323-334. 1873. Palaeontology. Illinois Geol. Sur., vol. 5, pp. 323-629, 32 pls. Miller, S. A. 1874. Monograph of the Gasteropoda. Cincinnati Quart. Jour. Sci., vol. 1, pp. 319-321. 1877. The American Palaeozoic fossils. Cincinnati, published by the au- thor, 245 pp. BULLETIN 261 bo) ~I TN 1882. Descriptions of three new orders and four new families in the Class Echinodermata and eight new species from the Silurian and Devonian formations. Jour. Cincinnati Soc. Nat. Hist., vol. 5, pp. 221-231. 1889. North American Geol. and Palaeontology. Cincinnati, published by the author, 664 pp. Nettelroth, H. 1889. Kentucky fossil shells. Kentucky Geol. Sur., 245 pp., 36 pls. Pelseneer, P. 1906. In Lankester, R. E., A treatise on zoology, part 5, Mollusca. ion- don. Prosser, C. S., and Kindle, E. M. 1913. Gastropoda of the Middle Devonian of Maryland. Maryland Geol. Sur., Middle and Upper Devonian of Maryland, pp. 280-306. Shimer, H. W., and Shrock, R. R. 1944. Index fossils of North America. New York, John Wiley, 837 pp., 303 pl. Simpson, G. G., and Beck, W. S. 1965. Life, an introduction to biology. New York, Harcourt, Brace, & World, 869 pp. Trautschold, H. 1867. Einige Crinoideen und andere Thierreste des jungeren Bergkalks in Gouvernement Moskau. Soc. Imp. Nat. Hist. Moscou, Bull., vol. 4, No. 3, pp. 1-47, pls. 1-5. Twenhofel, W. H. 1928 (1927). Geology of Anticosti Island. Canada Dept. Mines, Geol. Sur., Mem. 154, 481 pp., 60 pls. Twenhofel, W. H., et al. 1954. Correlation of Ordovician formations of North America. Geol. Soc. America, Bull., vol. 65, pp. 247-298. Ulrich, E. O., and Scofield, W. H. 1897. The Lower Silurian Gastropoda of Minnesota. Geol. Minnesota, Final Rept., vol. 3, pt. 2, Paleont., pp. 813-1081, pls. 61-82. Wenz, W. 1938. Gastropoda in Schindewolf, O. H., ed., Handbuch der Palao- zoologie, Bd. 6, Teil 1, pp. 1-240, figs. 1-471. White, C. A. 1880. Fossils of the Indiana rocks. Indiana Dept. Statistics Geol., 2d Ann. Rep., pp. 471-522, 11 pls. Wilson, A. E. 1951. Gastropoda and Conularida of the Ottawa Formation of the Ot- tawa-St. Lawrence Lowland. Geol. Sur. Canada, Bull. 17, 149 pp., 19 pls. Yonge, C. M. 1960. General characters of Mollusca, in R. C. Moore, ed., Treatise on invertebrate paleontology, pt. I, Mollusca 1, pp. 13-136, Geol. Soc. America & Univ. Kansas Press. Zittel, K. A. von. 1937. Textbook of paleontology. C. R. Eastman, ed., New York, Macmil- lan, 2d ed., 839 pp., 1594 pls. PLATES 276 Figure 1,2. 3,4. 10. une 12-15. 16-18. 19-21. 22,23. BULLETIN 261 EXPLANATION OF PLATE 31 Cyclonema. bilix. bilix.(Conrad) <..0<.:.c.c2.--.une eee 236 Respectively apertura] and abapertural views of lectotype. Rich- mond Gr., Waynesville Fm., Versailles, Ind. USNM No. 45763; 1.5. Specimen figured by Ulrich, 1897, pl. 78, fig. 35; Knight, 1941, pl. 53, fig. 3c. Cyclonema bilix bilix (Conrad): |... 4.5..c0 eee 236 Respectively apertural and abapertural views. Richmond Gr., Waynesville Fm., Waynesville, Ohio. USNM No. 45764; 2.25. Specimen figured by Ulrich, 1897, pl. 78, fig. 36. Cyclonema’ bilix*bilix™ (Conrad)? ee 236 Cincinnatian Ser., near Cincinnati, Ohio. AMNH No. 1379/1; 1.5. James Hall Coll.; specimen figured by Hall, 1847, pl. 83, fig. 4c. Cyclonema) bilix bilix’ (Conrad) ee 236 Richmond Gr., Waynesville Fm., Versailles, Ind. USNM No. 45763; ><1.5. Specimen figured by Knight, 1941, pl. 53, fig. 3b. Cyclonema /bilix bilix (Conrad) 03.0.2 ee 236 Richmond Gr., Waynesville Fm., Versailles, Ind. USNM No. 45766; 1.5. Specimen figured by Ulrich, 1897, pl. 78, fig. 39. Cyclonema) bilix bilixe(Conrad) 22 236 Richmond Gr., Waynesville Fm., Clarksville, Ohio. USNM No. 45765; 2.25. Specimen figured by Ulrich, 11897; 0pl.a7S,enie: 37. Cyclonema -bilix bilix (Conrad) 3..4..5...0..06050.00 ee 236 Richmond Gr., Waynesville Fm., Versailles, Ind. USNM No. 45766; 1.5. Specimen figured by Ulrich, 1897, pl. 78, fig. 38. Cyclonema:bilix:bilix (Conrad))2.0... 0: thie ee 236 Apertural view of specimen embedded in matrix. Cincinnatian Ser., near Cincinnati, Ohio. AMNH No. 1379/1; 1.5. James Hall Coll.; specimen figured by Hall, 1847, pl. 83, figs. 4d&e. Cyclonema bilix bilix (Conrad), .......6...20.....-00.- ee 236 Abapertural view of specimen embedded in matrix. Richmond Gr., Fernvale, Fm., 10 mi. NW. of Athens, Limestone Co., Ala. USNM No. 71556; X2.25. Figured by Butts, 1926, pl. 34 tigs 12. Cyclonema: bilix lata (Meek) ..62.] ee 240 Cincinnatian Ser.. Warren and Clinton Cos., Ohio. FMNH No. 2453. James Coll. 12. Abapertural view of lectotype; De RG 6g UES. Seis). Cyclonema) bilix lata (Meek) oe ee 240 16,17. Respectively apertural and abapertural views, 1.5. 18. Enlarged view of protoconch; 2.25. Richmond Gr., Waynes- ville Fm., Versailles, Ind. USNM No. 45767. Specimen fig- ured by Ulrich, 1897, pl. 78, figs. 40-42. Cyclonema daytonense Foersté: .....:....ccccf0..0s08-0.d ee 242 Brassfield Fm., (Silurian), Centerville, Ohio. MU No. 6680; Salas Shells of Cyclonema spp. attached to thecae of Glyptocrinus dyeri Meek. Richmond Gr., Dent, Ohio; 1.5. 1. UCM unnum- bered specimen; 2. UCM No. 23038. PLATE 31 BULL. AMER. PALEONT., VOL. 58 BULL. AMER. PALEONT., VOL. 58 PLATE 32 “— —_ mre . Figure 1274, 3,4. 8,9. 10. 11-13. 14-18. 19-21. CINCINNATIAN CYCLONEMA: "THOMPSON rai | EXPLANATION OF PLATE 32 Page Gycionema gracile Wilrich)...5.0.0030t. bake Pin. een eee 243 Respectively apertural and abapertural views of lectotype. Fairview Fm., Mt. Hope Mem. at Newport, Ky. USNM No. 45768; X2.25. Specimen figured by Ulrich, 1897, pl. 82, fig. 55. Gyclonemangnachle WIGICH 5.5. 5. sctssceocecesssssceen tanec oe on acapcmaesenes . 243 Fairview Fm., Mt. Hope Mem., Harrison, Ohio. MU No. 6679; IES Collected by author. Gyclonema’ gracile U1richy oo oecctcchs.t sc osccass so gocsseseepaccuie tase ancauboasccnsseees 243 Fairview Fm., Mt. Hope Mem., Newport, Ky. USNM No. 45770; <3. Originally figured by Ulrich, 1897, pl. 82, figs. 59-60 as C. gracile striatellum. 5. Apertural view. 6. View showing apical whorls and ornament. 7. Abapertural view. Cyclonemial Qracile- WUC coe. sscs hs ideedecaseassccced oven enninanchtncvodwonseee Fairview Fm., Mt. Hope Mem., Newport, Ky. USNM No. 45768; 2.25. Specimens figured by Ulrich, 1897, pl. 82, figs. 56 and 58. Cyclonema: humerosum Ulrich) 2.0.05. cccveseccccccsss.-coriecsvosseescsvssssnseose Abapertural view of lectotype showing polygonal whorl pro- file; 1.5. Richmond Gr., Arnheim Fm., Waynesville, Ohio. Figured by Ulrich, 1897, pl. 78, fig. 43. Gyclonema humerosumi Wich oi... oo... ..5..scck 0 pcenoccadeseccateresssesveeeecenss McMillan Fm., Corryville Mem., Cincinnati, Ohio. USNM No. 45771; 1.5. Figured by Ulrich, 1897, pl. 78, figs. 44-46. 11. Side view showing reflected outer lip. 12,13. Respectively abapertural and apertural views of one specimen. Gyclonema intlatUime Onicha ee ee eee nee eer Fairview Fm., Fairmount Mem., Covington, Ky. USNM No. 45773. 14,15,16. Lectotype. Figured by Ulrich, 1897, pl. 78, fig. 32. 14,15. «1.5. 16. Enlargement to show partial apex; 2.25. 17,18. Views showing ornament and globose body whorl; X1.5. Figured by Ulrich, 1897, pl. 78, fig. 31. Cyclonema) limatum: Ulrich ..o..o5...055.5..csccccceecnececcseestiosoceessesoeeneseee Fairview Fm., Fairmount Mem., Covington, Ky. USNM No. 45774. 19,20. Lectotype. Note typical columellar lip; X1.5. Figured by Ulrich, 1897, pl. 82, fig. 64. 21. Abapertural view showing typical ornament. Figured by Ulrich, 1897, pl. 82 figs. 62,63. 243 244 244 245 246 Figure 1-4. 5-8. 9-12. 13-16. 17-19. 20-22. BULLETIN 261 EXPLANATION OF PLATE 33 Cyclonema. mediale. Ulrich ....2..:)01)6.. 228. 4 1,2. Respectively apertural and abapertural views of lectotype. Fairview Fm., Fairmount Mem. at Covington, Ky., and vicin- ity. USNM No. 45775; 1.5. Figured by Ulrich, 1897, pl. 78, fig. 30. 3. Abapertural view of specimen figured by UIl- rich, 1897, pl. 78, fig. 29. USNM No. 45775; X1.5. 4. Aper- tural view of Hall’s specimen figured in 1847, pl. 83, figs. 4a, b as C. bilix. Cincinnatian Ser. near Cincinnati, Ohio. AMNH No. 1379/1; X2.25. Cyclonema praeciptum Ulrich i200 .U2 nee ee Murfreesboro Fm., Murfreesboro, Tenn. USNM No. 46052; <3. 5,6. Lectotype, figured by Ulrich, 1897, pl. 78, fig. 26. 7,8. Apertural and abapertural views of one specimen. Cyclonema pyramidatum JaMeS ................ccccccccccecseeteeneesteeneeees Cincinnatian Ser., Maysville Gr. at Cincinnati, Ohio. James Coll., FMNH No. 1539; 1.5. 9-11. Respectively apertural, basal, and abapertural views of lectotype. 10. View of spiral cords on basal surface. 12. Abapertural view of a specimen from James Collection. Cyclonema‘simulans Ulrich! ee ee McMillan Fm., Corryville Mem. at Cincinnati, Ohio, and vi- cinity. USNM No. 45777; 1.5. 13,14. Lectotype, figured by Ulrich, 1897, pl. 78, fig. 47. 15. Side view showing reflected outer lip flaring at shoulder. 16. Abapertural view of speci- men displaying unusual ornament. Note costae between two cords. Cyclonema ‘sublaeve Ulrich’ 225..20°.0..08,.22 22 Fairview Fm., Fairmount Mem. at Covington, Ky. USNM No. 45778; 1.5. 17,18. Lectotype, figured by Ulrich, 1897, pl. 78, fig. 49. 19. Specimen figured by Ulrich, 1897, pl. 78, fig. 48. Cyclonema varicosum Halll .......0)...20.05...aeok eee Specimens originally described as C. cincinnatiense Miller. 20, 21. Cynthiana Fm., RR cut 59.1 miles S. of Ludlow, N. of Rogers Gap, Ky. USNM No. 87063, 2.25. 22. Cincinnatian Ser. at Newport, Ky. FMNH No. 8872. Faber Coll.; 2.25. 248 249 250 251 253 BuLL. AMER. PALEONT., VOL. 58 PLATE 33 Figure if BULLETIN 261 EXPLANATION OF PLATE 35 Page Cyclonema bilix bilix (Conrad) . .............. 236 Photomicrograph of Cyclonema bilix preserving apex. " Waynes- ville Fm., Millville-Oxford Rd., Oxford, Ohio. MU No. 1.16H9; 20. Photomicrograph of Cyclonema bilix preserving partial apex. Richmond Gr., cut just north of railroad arch one mile N. of Harmon’s Station, Ind. MU No. 2.13F; 20. Enlarged photomicrographs of portions of figure 2, showing shell structure of Cyclonema bilix; X40. Enlarged portion of shell in preceding figure 5; X60. PLATE 35 BuLL. AMER. PALEONT., VOL. 58 INDEX Note: Light face figures refer to the page numbers. Bold face figures refer to the plate numbers. A Alabamaeeeese. 240 Allumette Island, Quebec... 260, 266 Alta Cy.ClOnam cc. 228 Alton, Illinois . 262 Anticosti Island, Quebec ......... .. 257, 259, 261, 263, 265, 268, 269 antiquatus, Hipponix 224 Arisaig, Nova Scotia 260, 264 Arnheim Formation 240, 241, 245, 271 australis, Hipponix ... 224 B IBayleanies eee ects. 261 Beechhill Formation 264 Beekmantown Formation) 222... 266 bellulum, Cyclonema. 256, 257 bilix, Cyclonema ........ 223, 228, 236, 237, 239, 240, 242, 244 245, 248 bilix bilix, Cyclonema .. 31,35 227, 236, 239. 240, 241, 242 bilix conicum, Cyclonema 237, 239 bilix lata, Cyclonema 31 239, 240, 241, 242 Blackriverian _............ 230 Bloomington, Indiana 262 Branchville, New Jersey .. 263 Brassfield Formation 235,243 Brownsport Formation 267 Burgin, Kentucky 268 Cc cancellatus, Strophostylus 256, 257 Cannon Falls, Minnesota 266 OMS een 232 Cataract Formation . 257 Catheys Formation .... 255 Centerville, Ohio 243 Chemung Group ........ 258, 264 Chenango County, New York . 262 Chicotte Formation . 259, 268 Cincinnati, Ohio 245, 246, 247, 250, 251, 252, 253 Cincinnatian Series .... 229,231 cincinnatiense, Cyclonema .........33 254 Clinton Formation . 243 Clinton Group 235, 257, 264, 269 Columbus, Ohio .......... 258 commune, Eotomaria 256, 257 concinnum, Cyclonema 256, 257 Corryville Member 251 Covington, Kentucky 246, 248, 252, 253 crenulatum, Cyclonema 256, 258 Cumberland, Maryland ....... 262 cushingi, Cyclonema ....... 34 256, 258 Cyclora®:..... fe 227, 228 Cynthiana Formation 254, 269 D daytonense, Cyclonema ...... 31 242, 243 Dayton, Ohio ......... 243 decadactylus, Glyptocrinus 223 Decatur County, Tennessee .... 267 Decorah Formation 266 decorum, Cyclonema 256, 259 depressa, Cyclora 228 doris, Cyclonema . 256, 259 Durham, Ontario 267 Dyeria | 7220: 231, 233 E Edgewood Formation. 243 Edgewood, Missouri .. 243 elevatus, Strophostylus .... 256, 259 English Head Formation 268, 269 Motomaniag 256, 257 Euconia 256, 265 281 E Fairmount Member Fairview Formation Fernvale Formation Flanagan Formation fluctuatum, Cyclonema G Georgetown, Indiana Glyptocrinus INDEX .. 246, 248, 252, 293, 269, 271 .. 246, 247, 248, 250, 251, 252, 293, 269, 271 240 268 241 257 222, 223, 224 gracile, Cyclonema 32 230, 243, 244, gracile striatulum, Cyclonema 3) ew? Guelph Formation Gyronema H hageri, Cyclonema haliburtoni, Cyclonema hallianum, Cyclonema Hamilton Group .. hamiltoniae, Cyclonema cies Helderberg Group ...... Hipponix historicum, Gyronema hoffmanni, Cyclora . Holopea Hull, Quebec ..... humerosum, Cyclonema humile, Platyceras (Platyostoma) ......... Huntington, Indiana .. I Illinois Indiana 252 244 267 220, 230, 231, 235, 236, 249, 254, 255, 256, 261, 263, 265, 266 248, 256, 259 256, 260 256, 260 261, 262, 264 . 256, 260, 261 258 224 256, 261 228 .. 220, 227, 230, 231, 235, 236, 246, 256, 262, 264 258 32 227, 228, 231, 244 256, 261 259 .. 235, 240, 243, 255, 262 235, 240, 241, 245, 248, 255, 257, 259, 262. 267 inflatum, Cycloneman 32 245, 246, 251 TOWAY See eee 235 J Jupiter Formation .... 257, 261, 262, 265 K Kentucky .. 235, 240, 241, 246, 248, 252, 253, 254, 255, 257, 266, 268 L leavenworthana, Wann an ae 256, 261 Leipers Formation ..... 248 Leray - Rockland beds 260, 266 limatum, Cyclonema ......... 32 229, 230, 231. 246, 247 liratum, Trochonema (Gyronema) ..... ae 256, 262 Lockport, New York .. 264, 266 Louisville Formation 266 Louisville, Kentucky .. 257, 266 M Madison County, ING WRN OGKar ste 262 Maquoketa Hormatione.. ee 240 Maryland 255, 262 marylandense, Cyclonema 2.2060 256, 262 Maysville Group ........ 231, 245, 251 MeMillan Formation. 245, 251 mediale, Cyclonema ........... 33 239, 245, 246, 247, 248, 252 Medina, New York ...... 264, 266 Medinan Series ........... 243, 266 mediocris, Holopea?: <2... 256, 262 Middleville, ING WieVOnk #2 ee 265 Minnesota eee oh COD CARD. 268 Minooka, Illinois ......... 240 minuta, Cyclora ........ 227, 228 Mississippi Valley ....... 255 Missourie.. 235, 243 Montreal, Quebec .... 259, 263 282 INDEX montrealense, Cyclonema 34 256,263 Mt. Hope Member ..... 246, 252, oa 1 multilirum, Cyclonema 256, 263 Murfreesboro Formation . 230, 235, 249 Murfreesboro, Tennessee 249 N Nashville, Tennessee 248, 255 Naticonema , ~sil, BB) 2ES New Jersey ..... ........ 255, 263 Newport, ae f 253 New. Gviorks °.2)..0%...... 2195255257, 258, 259, 261, 262, 263, 264, 265, 266, 269 Niagaran Series 257, 259, 266, 267 Nichols, New York .. 258 Nova Scotia 255, 260, 264 oO obsolescens, Cyclonema 256, 264 obsoleta, Polopes 256, 264 Ohio 225, 228, 235, 240, 241, 243, 245, 246, 247, 248, 250, 251, 252, PATS}, DARD. 258 Ontario 219, 240, 255. 257, 267 Orthonychia 233 Ottawa Formation 258, 260 Ottawa River, Quebec 260, 266 Pp parvimedium, Cyclonema ....... 256, 264 parvula, Cyclora 228 Pennsylvania 255 percarinatum, Gyronema . 34 256, 265 percingulatum, Cyclonema .... 256, 265 pervetusta, Euconia? 256, 265 phaedra, Cyclonema 256, 266 Plattsburg, New York 261 Platyceras (Platyceras) PPA OPPA. PRY PBI PBPL ABB Platyceras (Platyostoma) 233. 256, 261 Pleurotomaria 235, 239 Ploconema 233. 234 Poleumita . 256, 266, 267 praeciptum, Cyclonema 33 230, 248, 249, 254 Prairie du Chien, Wisconsin . 240 Pratt’s Falls, New York . 261 Prosser Formation ... 268 pulcella, Cyclora ...... 228 pyramidatum, Cyclonema 33 249, 250 Q Quebec oo... 219, 240, 255. 257, 258, 259, 260, 261, 263, 265, 266, 268, 269 R Racine, Wisconsin .... 259 Richmond Group ......... 225, 227, 228, 231, 240, 241, 244, 245 Rochester, New York ..... 257 Rogers Gap Formation 254 Romney Formation 262 Ross Brook Formation 260 rugaelineata, Poleumita ... 256, 266 S Salem Limestone ....... 261, 267 Saratoga County, New York .... 258, 263 Savannah, Illinois 240 Schoharie County, New York .............. 261 Schoharie Formation 259 Schoharie, New York ................ 259 semicarinatum, Gyronema: 6... .idess. 256, 266 283 INDEX simulans, Cyclonema 36 245, 248, 250, 251 Smyrna, New York 264 Snake Hill Formation 258, 263 Sodus, New York 257, 269 Spergen Hill, Indiana ....... 262, 267 ' St. Antoine de Tilly, Quebec ys 2... 266 Sterling, Illinois 240 Stones River Group 249 St. Paul, Minnesota 268 Strophostylus PAP ele 259, 267, 269 subangulata, Yunnania 256, 266 sublaeve, Cyclonema 3a 2o00N 2518 252: 253 sulcata, Poleumita 256,267 T Tennessee ................ 235, 240, 241, 243, 248, 249, 255, 267 tennesseensis, Strophostylus . 256, 267 textilis, Strophostylus 256, 267 thalia, Cyclonema 256, 268 Thebes, Illinois 243 Todds Fork, Ohio 243 transversum, Cyclonema 34 229, 252 Trenton Group 255. 258, 259, 263, 265, 268 Trochonema (Gyronema) 256, 262 Turbo 224 U Ulster Group 259 Vv Valeour Formation 261 Valcour Island, ING@wWie YORK (oo. | 261 varians, Cyclonema 256, 268 varicosum, Cyclonema 33, 34 230, 249, 253, 254, 255 varispirum, Cyclonema 256, 269 Vaureal Formation 268, 269 ventricosus, Strophostylus 256, 269 WwW Waynesville Hormationye..-- ee 245, 271 Waynesville, Ohio . 241 West Virginia ...... 255, 262 Wisconsin ............ ..... 240, 255, 259 Wycoff, Minnesota 255 Y Yunnania 256, 261, 266 284 MUS. COMP. ZOOL. LIBRARY BWELETINS. fee (et OF HARVARD AMERIC AN UNIVERSITY (Founded 1895) Vol. 58 No. 262 NEW VASUM SPECIES OF THE SUBGENUS HYSTRIVASUM By S. C. HoLuisTer 1971 Paleontological Research Institution Ithaca, New York 14850 U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION 1970 - 71 PRESIDENT x5 ee La ae re a a WILLIAM B. HErRoy VICE PRESIDEN a5 asco ese cereeeeee a er ereee ee e DANIEL B. Sass SECRETARY) <5 ier ae REBECCA S. HArris DIRECTOR, (LP REASURERS 22s carers etcetera ens See ee ee KATHERINE V. W. PALMER COUNSEL: 45. ee ee se ae ee eae ARMAND L. ADAMS REPRESENTATIVE #A AAS COUNGCIE pecs cee en Davw NICOL Trustees ResBecca S. Harris (Life) DonaLp W. FIsHER (1967-1973) AXEL A. Otsson (Life) MERRILL W. Haas (1970-1973) KATHERINE V.W. PALMER (Life) PHILip C, WAKELEY (1970-1973) DANIEL B. Sass (1965-1971) _ WILLIAM B. HEroy (1968-1974) KENNETH E. CASTER (1966-1972) VirciL D. WINKLER (1969-1975) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PALMer, Editor Mrs. Fay Briccs, Secretary Advisory Board KENNETH E. CASTER HANS KUGLER A. Myra KEEN Jay GLENN Marks AXEL A. OLSSON Complete titles and price list of separate available numbers may be had on application. For reprint, Vols. 1-23, Bulletins of American Paleontology see Kraus Reprint Corp., 16 East 46th St., New York, N.Y. 10017 U.S.A. For reprint, vol. I, Palaeontographica Americana see Johnson Reprint Cor- poration, 111 Fifth Ave., New York, N. Y. 10003 U.S.A. Subscription may be entered at any time by volume or year, with average price of $18.00 per volume for Bulletins. Numbers of Palaeontographica Ameri- cana invoiced per issue. Purchases in U.S.A. for professional purposes are de- ductible from income tax. For sale by Paleontological Research Institution 1259 Trumansburg Road Ithaca, New York 14850 U.S.A. PULLER TING OF AMERICAN PaekON TOLOGY (Founded 1895) Vol. 58 No. 262 NEW VASUM SPECIES OF THE SUBGENUS HYSTRIVASUM By S. C. HoLiisTER January,.29; 11971 Paleontological Research Institution Ithaca, New York 14850 U.S.A. Library of Congress Card Number: 72-147232 Printed in the United States of America Arnold Printing Corporation CONTENTS ANIDELHREN OE et psec sae tere Sees ees eek eee Stoo ere ee ees ete PE ee 289 in ERO GI CETO Mayers oer ee ee a es te, ee eee els ee Sees ee 289 REV eae NETS CLC SC ELD EEO Sire et tae sean ner irene see cuenta sore eee 290 (Gemre: (ACGTD: IRON Le ee eee ee eee ee ee ee 290 Subgenus Hystrivasum Olsson and Petit 2.0.0.0... 0000000 290 Review of species of Hystrivasum in southern Florida 0. 298 NEW VASUM SPECIES OF THE SUBGENUS HYSTRIVASUM S. C. Hollister ABSTRACT This paper describes four new species, V. squamosum, V. schrinerae, V. palmerae, and V. vokesae, and one new subspecies, V’. olssoni kissimmense, in the subgenus Hystrivasum of the genus Vasum. All of them were found in the Pinecrest Formation of the upper Miocene, along the Kissimmee River, Florida. The paper is supplemental to the excellent paper, The Genus Vasum in the New World, by Emily H. Vokes of Tulane University, published in 1966, which deals with both Recent and fossil forms. INTRODUCTION The excavations along the Kissimmee River in Florida have brought to light some interesting additions to the extinct subgenus Hystrivasum that are earlier than the Caloosahatchee fauna. Appar- ently Vaswm was active in that period, judging by the number of specimens found. The species so far known are limited to the Choctawatchee, the Pinecrest, and Caloosahatchee Formations, in the upper Miocene and lower Pliocene. When Olsson and Harbison (1953) described V. locklint, they specified three or four plicae on the columella. A series of the type species reveals that senility begins at about the eleventh whorl; and that at the ninth whorl the shell is still small. At full maturity there are three plicae, the posterior one being the largest and the anterior one the smallest; and the surface of the canal anterior to the plicae is even with the top of the anterior plica (Pl. 36, fig. 6). The grooves between plicae are graduated also, and in the same order. Shells of about nine whorls or smaller may exhibit a small plica at the pos- terior edge of the canal surface, adjacent to the sulcus between it and the third plica. This small plica evanesces as the shell grows larger (Pl. 36, fig. 1). A series of over 100 specimens embracing the forms herein designated shows that in the fully adult stage there are but three plicae; and that at earlier stages there are four plicae. In Vasum s.s. the plicae are four in number in the adult stage; they alternate in size, the larger starting at the posterior end. The surface of the canal anterior to the plicae is even with the top of the small fourth plica. In both subgenera, the surface of the arcuate columella posterior to the plicae is even with the bottom of the sulcae separating the plicae. In the study of members of a genus it is necessary first to determine the ontogenetic development of the individuals and to 290 BULLETIN 262 note changes that may occur in each significant feature from one stage to the next. Comparison of the members of two different species should be made at like stages of development. SYSTEMATIC DESCRIPTIONS Genus VASUM Roeding, 1798 Subgenus HYSTRIVASUM Olsson and Petit, 1964 Type species by original designation, Vaswm horridwm Heil- prin, 1887. Caloosahatchee Pliocene. This subgenus embraces small to medium large shells that are biconic, the body cone being the longer; the shell wall heavy, with a stout columella; the exterior with strong spiral cords either smooth, imbricated, squamous or spinose; a strong shoulder spiral variously ornamented; a less strong one variously ornamented forming an upstanding and outward flaring sutural collar; between the shoulder and sutural cords, a wide concave to flat band with spiral threads; umbilicate; within the mature stage three slightly oblique plications of graded size and spacing on the columella, the largest posterior; the gerontic stage being reached at about 11 whorls; in immature stages four plicae graduated as in the adult stage, the fourth (an- terior) plica occurring on the edge of the canal wall, evanescing in the adult stage. The most conspicuous character of the subgenus is the sutural collar. Vasum (Hystrivasum) horridum Heilprin Pl. 36, figs: 1, 4,536 Vasum horridum Heilprin, 1887, Wagner Free Inst. Sci.. Trans., vol. 1, pp. TP ISZeuple a ett 6, Oaemplenl Ganetican72- Original Description. — Shell turbinate, thick, with the greatest width at about one-third the distance from the apex to the base; spire moderately ele- vated, of about 6 to 7 whorls, most of which are doubly coronated or calcitra- pated by prominent lamellar or flattened spurs; the spurs regularly increasing in size, with the apices turned slightly backward. Body-whorl strongly angulated on the shoulder, beautifully coronated, and crossed by about eight prominent revolving ridges, the four immediately fol- lowing the shoulder coronation nearly equal, scaly, the sixth and seventh, more particularly, carrying long lamellar spines or tubercles, those of the sixth row inflexed upward. Columellar plaits three, the uppermost by far the most prominent; aperture about two-thirds the length of shell, flexuous inferiorly; umbilicus long and broad. (Heilprin, 1887, p. 132.) The description by Heilprin is of a shell that is barely adult. It attains 11 or more whorls. The shell here figured, PRI 28205, is 115 mm high and has about 10 whorls, the earlier five lost. New spPEcIES VAsum: Ho. LIisTER 291 Type. — The holotype is in the Wagner Free Institute of Sci- ence, Philadelphia, Pa. Type locality. — Caloosahatchee River, west of Ft. Thompson, Caloosahatchee Formation, lower Pliocene. This species can readily be separated from all others by its fewer and stronger open spines on the shoulder and sutural collar, by its rapid waistlike constriction at the base of the body, and by the spirals on the body between shoulder and waist being limited to four primaries with sometimes a secondary one at the waist. Vasum (Hystrivasum) locklini Olsson and Harbison Pil 36; f1gs-2. 3 Vasum locklini Olsson and Harbison, 1953, Acad. Nat. Sci. Phila., Mon. No. 8, p. 194, pl. 40, fig. 1. Original description. — Shell biconic, solid, white, sculptured with strong, spiniferous or scabrous spiral cords in the adult stage. Whorls 10 or more, forming a medium-height spire, the earliest whorls of which have a more elevated form and a simpler sculpture of spirals and Fusus-like ribs. Sutures indistinct, wholly or partly covered by the sutural cord. On the last whorl, the shoulder is strongly angled and bears a crown-like ring of crowded, re- flexed, fluted spines or tubercles, generally 18 in number. Another similar but lower ring of tubercles adjoins the sutures. In the middle zone of the body- whorl between the shoulder and above the plicated columella, there are 5 smaller cords, the upper one the strongest and somewhat spiniferous, the others merely scabrous; these cords are separated by quite wide, flattened and nearly smooth intervals. Anterior canal has three or four strongly spini- ferous cords. Base not constricted, the inner lip with a shelf of callus. Columella has 4 horizontal to slightly oblique folds. Tip of anterior canal narrowly umbilicate or perforate. (Olsson and Harbison, 1953.) Height 80 mm, diameter 57 mm. (Holotype, ANSP 19313.) This species differs from V. horridum by its broader form, its unconstricted base and finer, more spiniferous sculpture. Mrs. Vokes (1966, p. 23) noted an error in the records of the Locklin collection. The holotype was found at Acline, Florida, the beds of which correspond to the Brighton facies of the Pinecrest, Caloosahatchee Group, late Miocene. The shell here figured is PRI 28207, about 10 whorls (the first five missing), 93 mm high. It was collected on the spoil banks of the Kissimmee River, near Brighton, Florida. It is older in time than V. horridum. Olsson and Harbison’s plate 40, figure 1 shows a shell with four primary and one secondary spirals on the body below the shoulder, while their description gives five, the uppermost largest. The same can be said of Plate 36, figures 2, 3 herein. There is also a broad 292 BULLETIN 262 furrow at the bottom of the body, and another just below the shoul- der, features which distinguish it from V. schrinerae, n.sp., Plate 37, figures 2, 3. Vasum (Hystrivasum) squamosum, new species Pl. 37, figs. eee This shell is large, ponderous, shaggy, biconic—95° for the spire, 60° for the body — about 10 whorls, the first five lost; the body contracting to a “waist” at its base; at the shoulder there is a prominent row of outwardly flaring open spines or scales about one centimeter long; below the shoulder a band of five equal and uni- formly spaced strong spiral squamous cords, the grooves between being flat-bottomed with a single small thread; between this band and the shoulder a prominent groove with two spiral threads along its generally flat bottom; above the shoulder a flattish sloping surface with three spiral threads, other threads flaring out on each spine; a prominent upward-flaring squamous collar about one centi- meter high on the last whorl girdling the suture beyond; the suture formed just below the first body cord; the successive sutural expos- ures growing progressively less coarse to the decorticated apex; at the “waist” a prominent spiral groove with a secondary cord smooth to squamous and with two or three finer, wavy threads; below this “waist” four or five prominent squamous spirals over the beak, forming a shaggy skirt over the lower outline of the shell, between each pair of spirals a secondary cord; the ovate aperture lined with a smooth callus which flares over the parietal wall with a free edge, folds at the sutural collar, to form an anal notch, another strong notch at the shoulder cord, other notches along the lip at each of the body cords; along the inner lip of the beak a flaring edge, which with the terminus of the canal forms a wide, flaring umbilicus, deeply perforated; on the columella, three transverse folds, the strongest at the top and growing successively weaker toward the canal. Height, 122 mm, width, 90 mm. This shell appears to be at the beginning of the gerontic stage, which is usually marked by coarser growth lines and a detached callus over the parietal wall. Type. — Holotype PRI 28201. Type locality. — Spoil bank, E. side Kissimmee River canal, Sec. 36, T36S, R33E, Highlands County, Florida; Pinecrest, Caloosa- hatchee Group, late Miocene. New species VAsumM: HOLLISTER 293 Variations from the holotype exist both in size and detail of sculpture. The holotype is the largest so far seen by me. Some shells have six cords on the body. Some shells are less prominently squamous than the holotype. The separation of the shoulder cord, the prominent groove at the waist, the contraction at the waist, the more prominent shagginess of the spirals on the beak, and the stockiness of the shell are all fairly constant characters. The chief differences between V. horridum and V. squamosum are that there are fewer and larger spines on the shoulder of the former, it has but four cords on the body, and there is a more pro- nounced contraction at the waist than in the latter. Vasum (Hystrivasum) schrinerae, new species Pie oi. ess 23 This shell is large, shaggy, ponderous, biconic—the apical cone 85°, the body cone 50° — about eleven whorls, about the first five lost; the body, except for spines, tapering uniformly from the shoulder to the end of the canal with little or no waistlike contrac- tion at the base of the body; seven equal squamous spiral cords from the shoulder cord to the bottom of the body; five more prominent squamous spirals pass across the back of the beak; above the shoulder there is a relatively flat area with two spiral threads; above this area is an upward-thrusting row of squamous spines up to about a centimeter high bordering the suture beyond; the suture is formed in a way to expose the first cord below the shoulder cord; the whorls of the spire progressively less spinose upward from the shoulder; on the beak five graduated squamous spiral cords, the largest at the top, with a secondary thread in the interstices; the aperture suboval, smooth within, the outer lip notched at the external cords; the inner lip a callus extending as a shield over the external cords, which shield folds at the top to form an anal notch; three transverse plicae on the arcuate columella, graduated in size, the largest above; the inner lip of the canal forming the flaring margin of a prominent, deeply perforated umbilicus. Height, 113 mm, width, 78 mm. This species is similar to V. locklini in that the body is not constricted but differs from it since that shell has but four or five primary cords around the base of the body, exclusive of the shoulder cord, while this has five or six more squamous spirals with no prom- inent groove at the base of the body. 294 BULLETIN 262 Type.— Holotype PRI 28202. Type locality. — This specimen was found on the Kissimmee River spoil bank about half a mile north of where V. locklint PRI 28206 was found; NE Section 24, T37S, R33 E, east side of canal, Highlands County, Florida. Pinecrest, Caloosahatchee Group, late Mhocene. Discussion. — This shell is named for Mrs. Howard Schriner, whose extensive collection of Vaswm deposited in the Paleontologi- cal Research Institution has made this study possible. Vasum (Hystrivasum) olssoni E. H. Vokes Pl. 39, figs. 1, 4 Vasum (Hystrivasum) olssoni E. H. Vokes, 1966, Tulane Studies in Geol., voli 5) No. 1 pps 22) 235 pla Setic 2 epleno erties Original description.— Shell massive with approximately eight post-nu- clear whorls in the adult. Nucleus of 114 smooth, polished whorls, ornamentation beginning gradually with about nine axial] nodes on each of the first six whorls. On the median whorls axial ornamentation reduced to small growth lines which, crossing the spiral cords, give rise to a scabrous appearance. Spiral ornamen- tation consisting of a series of strong cords, about 12 in number; three slightly stronger and bearing open spinelets in young individuals. The most posterior of these three semispinose cord immediately adjacent to the suture, the second at the shoulder, and the third at the base of the siphoned canal. In addition, two weaker ribs between the two posterior cords. Occasionally smaller inter- calary riblets between the spiral cords but not invariably. Aperture elongate; outer lip crenulated by the spiral cords, with flaring notches corresponding to the three primary cords. The posterior notch forming a large channel. Inner lip with a heavy callus formed over the parietal wall and a strong siphonal fasciole. Columella bearing four plications diminishing in size from posterior to anterior, and the first very wide and the last almost obsolete. Dimensions of the holotype: height 107 mm., diameter 68 mm. Holotype —USNM 645141. Type locality.—TU (Tulane University) 729, west side of Kissimmee River, 14 mile south of U.S. Corps of Engineers Structure 65-D, (S % Sec. 33, 1T36S, R33E), Highlands County, Florida. Horizon. — Pinecrest Beds, Florida; upper Miocene. (E. H. Vokes, 1966.) Discussion. — This shell has only a slight constriction to a “waist” at the base of the body. It has three scabrous prominent spiral cords, one at the shoulder, a second forming the sutural collar, and a third immediately below the “waist.” Below the last, one or more of the spirals on the back of the canal may also be scabrous. The number of smooth primary spiral cords on the body below the shoulder is usually six; and they are uniformly spaced. In the broad furrow between the shoulder and the sutural collar there are two secondary threads. Vasum (Hystrivasum) olssoni kissimmense, new subspecies Pl; 39; figs./29a Description. — Shell heavy, spirally ribbed, somewhat inflated, New species VAsum: HOLLISTER 295 biconic — spire about 70°, body about 50° —angled shoulder at about four-tenths the height from the apex, about nine whorls, about five apical whorls missing, ribbed by smooth spiral cords on spire and body, heavy scabrous ribs on the back of the siphonal canal; a strong cord forming the sharply angulate shoulder keels; an upstanding sutural collar with an irregularly wavy edge, between collar and shoulder a broad concave furrow with a prominent sec- ondary central cord and a lesser thread on either side; the suture clasping the preceding whorl loosely, revealing a primary cord below the preceding shoulder; below the shoulder, the first primary separated above and below by a groove broader than the rib, with a small secondary cord at the center; on the remainder of the convex body surface mildly constricted to a “waist” and with four smooth cords with smooth grooves between, whose width is that of the cords; the groove at the waist broader with a prominent secondary thread at its center; four heavy, scabrous, oblique spirals across the back of the siphonal canal; the aperture suboval, smooth within, the parietal wall glazed; three graduated somewhat oblique plicae on the columella near the siphon, the posterior plica strongest; the outer lip folded at the sutural collar to form an anal groove; a second strong fold at the shoulder; crenulations at the remaining external cord terminals; the anterior border of the lip flaring to form a narrow umbilicus deeply perforated. Height of incomplete shell, 91 mm, breadth 59 mm. Type. — Holotype PRI 28243. Type locality.— This shell was found by Emily H. Vokes, where V. olssoni E. H. Vokes was found. Pinecrest, Caloosahatchee Group, late Miocene. Discussion. — This shell has a less round-shouldered, more sharply angulate outline than JV. olssont, with five rather than six primary cords below the shoulder, the first of which is set off on each side with a secondary thread. The shoulder and sutural cord are scabrous on JV. olssont, while on V. olssoni kissummense they are not. The spaces between shoulder and sutural collar have two cords on JV. olssoni, while on this shell there are three, the middle one strongest. Vasum (Hystrivasum) palmerae, new species Pl. 38, figs. 1,4 Description. — Shell heavy, medium large, biconic — 80° above, 60° below, round-shouldered, heavily spirally smoothly ribbed; the 296 BULLETIN 262 periphery a little above mid-height; about 11 whorls (gerontic) with about five whorls missing; a group of three equal, heavy, smooth, spiral ribs at the rounded shoulder outline, the central cord at the periphery, the spaces between equal in width to the ribs, the posterior rib at the shoulder; a strong, smooth rib forming the upthrust sutural collar, with a concave space between shoulder and collar ribs about twice as wide as the shoulder rib, and with a faint single thread at its center; the suture loosely clasping the pre- ceding whorl revealing the three peripheral cords on the last three whorls, showing the last four whorls to be round-shouldered; the early whorls remaining on the spire without spiral cords; below the periphery the body contracts with a slight constriction to a “waist,” there being four closely spaced smooth cords on the body, smaller than the three peripheral cords, and with narrower smooth spaces between; at the “waist,” a wider space with a secondary thread at its center; below the “waist,” on the back of the siphonal canal, five graduated, closely spaced smooth cords, the posterior the largest, and equal in size to the peripheral cords; the aperture subovate, smooth within; the outer lip thick (gerontic), the edge missing; a heavy (gerontic) callus loosely laid on the parietal wall, leaving a face edge; three plicae, obliquely crossing the callus on the columella, graduated in size, the posterior plica the largest; the anterior fold of the siphon forming a flaring umbilicus, deeply perforated. Evidence of the gerontic stage is seen in the more closely spaced rest periods on the last quarter turn. Height of the incomplete shell 104 mm, breadth 71 mm. Type. — Holotype PRI 28203. Type locality. — Spoil bank, E. side Kissimmee River canal, 2 mi. SE of U.S. Corps of Engineers Structure 65-D, Highlands County, Fla. Pinecrest, Caloosahatchee Group, late Miocene. Discussion. — This is a distinctive species, being both round- shouldered and devoid of scabrous cords. The nearest is V. olssoni, but that shell, while superficially rounded in outline, has a scabrous shoulder cord at the periphery and a scabrous sutural collar, with two strong secondary cords between. Even the earlier whorls of that shell show these features. The only other species of the subgenus Hystrivasum which has no spines is V. vokesae Hollister, infra, which has an angulate shoulder and axial ridges. I take pleasure in naming this species after Katherine V. W. New species Vasum: HOoLLIsTeER 297 Palmer, the distinguished director of the Paleontological Research Institution, Vasum (Hystrivasum) vokesae, new species Plas: tesa. 3 Description. — Shell heavy, biconic—spire 90°, base 60° — with the angulate shoulder at four-tenths the height from the apex; about nine whorls, about the first four missing; axial sculpture of constricted growth lines form about 12 flat axial ribs extending from the shoulder to the anterior end, obliquely sloping downward to the nght, causing undulations in the spiral cords, most prominent at the shoulder; the periphery at the shoulder; the spiral sculpture consisting of smooth cords, the first forming a sutural collar, the second the shoulder keel, with a broad concave furrow between with three secondary wavy threads; the body contracted slightly at a “waist” at the base of the body; between the shoulder and the “waist” six smooth spiral cords, the second from the shoulder some- what stronger than the others; at the “waist” a groove with a weak thread at the bottom; below the “waist” four coarse cords graduated in size, the broadest posterior; the sutures on the spire revealing one spiral rib below the shoulder; one side of the spire corroded; the aperture subovate, smooth within, the callus extending with a face edge over the columella; three graduated plicae on the columella, the stronger posterior; a fold at the top of the outer lip, forming a recurved anal notch; the outer lip notched at the exterior cords; at the base the margin flaring outward to form an umbilicus, deeply perforated. Height (incomplete) 90 mm, breadth 69 mm. Type. — Holotype PRI 28204. Type locality. —Spoil bank, E. side Kissimmee River canal, W368; R33-E, Sec; 36, Highlands County, Fla. Pinecrest, Upper Miocene. Discussion. — This is an uncommon form, distinctive in its lack of spines. In its adult form, it somewhat resembles V. jacksonense E. H. Vokes of Jackson Bluff, Choctawhatchee River, western Florida; but that species has spines at the shoulder and suture in the intermediate whorls while this does not. It is a pleasure to name this shell after Mrs. Emily H. Vokes in recognition of her contributions to American molluscan paleontology. REVIEW OF SPECIES OF HYSTRIVASUM IN SOUTHERN FLORIDA On the basis of constriction of the shell at the base of the body, one may group V. vokesae, V. palmerae, V. olssomt, V. schrin- 298 BULLETIN 262 erae, and V. locklini in one lot, all having but little constriction; and V. squamosum and V. horridwm in a sequence having pro- nounced constriction. The order in which these forms developed is not known. Taking the whole group together, it would appear that the shells developed phylogenetically from smooth to grossly squamous. On this basis, V. vokesae and V. palmerae would be the oldest, and V. horridum the youngest. V. 0. kissimmense would appear to precede V. olssoni. It would seem that V. schrinerae and V. squamoswm were contempor- ary, but this is not a certainty. It seems possible that V. jacksonense of western Florida was contemporary with V. olssoni, but this is conjectural. Even more speculative is the parentage of this shell, and the point in time when this trend branched from a primary stock. More specimens of this subgenus will certainly be found. At some future time a better definition of the stages of its evolution will be more discernable than at present. At such a time a more ac- curate appraisal of species definition can be made than is at present possible. The new names here given may or may not survive; but the author believes that until that distant day arrives these distinctive forms should not be lost to view by letting them remain unnoticed. In the meantime, naming them makes communication possible con- cerning their position. REFERENCES Roding, Peter Friedrich 1798. Museum Boltonianum. Pars 2, pp. I-VIII, 1-199. Herrmannsen, August Nicolaus 1846-1852. Indicis generum malacozoorum primordia . . . 1846, vol. I, pp. I-XXVII, 1-637; 1849, vol. II, pp. XXVIII-XLII, 1-717. Sup- plementa et Corrigenda. 1852, pp. I-V, 1-140. Heilprin, Angelo 1887. Explorations on the West Coast of Florida. Wagner Free Inst. Sas Trans., vol. 1, 134 pp., 19 pls. Reprint Paleont. Amer., vol. IV, No. 33, pp. 359-510, pls. 54-74. Dall, William Healey 1890-1903. Contributions to the Tertiary fauna of Florida. Wagner Free Inst. Sci.. Trans., vol. 3, pts. 1-6, 1654 pp., 60 pls. Wenz, Wilhelm 1944. Handbuch Paldozool., Gastropoda., Leif 9, Bd. 6, Teil 7, pp. 1201- 1505, text-figs. Olsson, Axel A., and Harbison, Anne 1953. Piacene Mollusca “of southern Florida, Acad. Nat. Sci. Phila., Mon. No. 8, pp. (5) 457 (65), 65 pls. Olsson, Axel A., and Petit, Richard E. 1964. Some Neogene Mollusca from Florida and the Carolinas. Bull. Am. Paleont., vol. 47, No. 217, pp. 505-574, 7 pls. Vokes, Emily H. 1966. The genus Vasum in the New World. Tulane Studies in Geol., vol. 5, No. 1, pp. 1-36, 6 pls. PLATES 300 BuLLETIN 262 EXPLANATION OF PLATE 36 Figure Page 1,4. Vasum (Hystrivasum) horridum Heilprin, 1887 |... 290 PRI 28205. Length 115 mm, about 10 whorls. Caloosahatchee River, N bank, 3 mi. W of La Belle, Fla. 1. Ventral view. 4. Dorsal view. Caloosahatchee Formation. 2.3. Vasum (Hystrivasum) locklini Olsson and Harbison 1953 ........ 291 PRI 28207. Length 95 mm, about 10 whorls. Kissimmee River spoil bank, Tp 7 S, R 33 E, Sec. 2. 2. Ventral view. 3. Dor- sal view. Pinecrest. 5,6. Vasum (Hystrivasum) horridum Heilprin, 1887 ...................... 290 Juvenile, PRI 28206. Found with PRI 28205. Length 43 mm, about 9 whorls. Found with specimen in figure 1. 5. Apical detail showing location of sutures. 6. Plicae on columella, showing the feeble fourth plica which evanesces in adulthood. Caloosahatchee Formation. PLATE 36 BULL. AMER. PALEONT., VOL. 58 i New species VASUM: HOLLISTER 301 EXPLANATION OF PLATE 37 Figure Page 1,4. Vasum (Hystrivasum) squamosum, new species 292 Holotype PRI 28201. Length, 122 mm, about 10 whorls. Kissim- mee River, Fla. Pinecrest. 1. Ventral view. 4. Dorsal view. 2,3. Wasum (Hystrivasum) schrinerae, new species 293 Holotype PRI 28202. Length 113 mm, about 11 whorls. Kissim- mee River, Fla. Pinecrest. 2. Ventral view. 3. Dorsal view. 302 BULLETIN 262 EXPLANATION OF PLATE 38 Figure Page 1,4. Vasum (Hystrivasum) palmerae, new species .. 296 Holotype PRI 28203. Length, 104 mm, about 11 whorls. Kissim- mee River, Fla. Pinecrest. 1. Ventral view. 4. Dorsal view. 2,3. Vasum (Hystrivasum) vokesae, new species ...... pe ee xa ASE Holotype PRI 28204. Length, 90 mm, about 11 whorls. Kissim- mee River, Fla. Pinecrest. 2. Ventral view. 3. Dorsal view. ‘BULL. AMER. PALEONT., VOL. 58 PLATE 38 BULL. AMER. PALEONT., VOL. 58 PLATE 89 ri Pe Limca ee a . NEw spPEciIEs VAsuM: Ho. LIsTER 303 EXPLANATION OF PLATE 39 Figure Page 1,4. Vasum (Hystrivasum) olssoni E. H. Vokes 294 Hypotype PRI 28208. Length, 81 mm, about 11 whorls. Kissim- mee River, Fla. Pinecrest. 1. Ventral view. 4. Dorsal view. 2,3. Vasum (Hystrivasum) olssoni kissimmense, new subspecies. 294 Holotype PRI 28209. Length, 91 mm, about 10 whorls. Kissim- mee River, Fla. Pinecrest. 2. Ventral view. 3. Dorsal view. the plate numbers. INDEX Note: Light face figures refer to page numbers. Bold face figures refer to A Acline, Florida 291 Cc Caloosahatchee Formation 291 Caloosahatchee River, Florida ms 291 Choctawatchee River, Florida 297 H Highlands County, Florida 293, 296, 297 horridum, Hystrivasum 36 290 Vasum 36 290, 291, 298 Hystrivasum 289-298 J Jackson Bluff 297 jacksonense, Vasum 297, 298 K Kissimmee River, Florida 189, 291, 292, 294 kissimmense, Hystrivasum 39 295 Vasum 39 295 E locklini, Hystrivasum 36 291 Vasum 36 289, 291, 293. 294, 298 (@) olssoni, Hystrivasum 39 294, 295 Vasum 39 294-296, 298 olssoni, kissimmense, Hystrivasum 295 Vasum 295, 298 Pp palmerae, Hystrivasum 38 296 Vasum ; 38 289, 296, 298 Pinecrest Formation .. 189, 291, 292, 294-297 S schrinerae, Hystrivasum 37 293 Vasum 37 289, 292, 293, 298 squamosum, Hystrivasum ....... 37 292 Vasum 37 289, 292, 298 Vv Viasum 289-298 vokesea, Hystrivasum 38 297 Vasum 38 289, 297, 298 304 i oe Aa! j iii aan) ie ; . WOU ETE 3 2044 072 271 729