- . Pe ey fly ats IE | Ca Pes ih Na ty a tay Pe > wile Oe a St) : Se : hea : uae : de ‘ ida rarnse: ates 8 MA Ban Gd ERY ‘ 4; nts, ists (\ i May ayh, oe + hs, ‘ ‘ carte G Py » ™ ae Eyes ats € sa = treys Ye ue teen HARVARD UNIVERSITY sh LIBRARY OF THE Museum of Comparative Zoology rx ; i iy Toe A A) Par ii a ht (ie -Cceem, BOE iin : oe ae i AMERICAN: PALEONTOLOGY re Le. @ ae) gee MUS. COMP. ZOOL. LIBRARY. BULLETINS 2° 873 HARVARD OF UNIVERSIIM AMERICAN PALEONTOLOGY VOL, LAI 1972-1973 IN MEMORIAM Don L. Frizzell 1906-1972 Thomas G. Perry 1919-1972 CONTENTS OF VOLUME LXII Bulletin No. Pages 271. The Trace Fossil Zoophycos as an Indicator of Water Depth. By Richard G. Osgood, Jr. and Eugene J. Szmuc 1-22 272. Mature Modification and Dimorphism in Select- ed Late Paleozoic Ammonoids. By Richard Arnold Davis 23-130 273. Upper Cretaceous and Cenozoic Silicofiagel- lates and Ebridians. By Hsin Yi Ling 131-229 274. Siluro-Devonian Microfaunal Biostratigraphy in Nevada. By W. A. McClellan ........ 230-375 Plates 1-2 3-22 23-32 33-44 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. ine bien iN OF AMERICAN PALEONTOLOGY (Founded 1895) Vol. 62 No. Mis. comp. 290, LIBRARY Ake a JUN 2 1979 ; 1 FAA HARVARD LINN Crpy 1972 Paleontological Research Institution Ithaca, New York 14850, U.S.A. SVL Tea tO yy VADIBAMA “9g YOOIOTVOAIAT freee bebaget} S42 t0Y¥ oe Lt alt ; ere oe MTT) YRERE . Yousogs.c Tdag ally igen Padua mo BUREE TINS OF AMERICAN PALEONTOLOGY (Founded 1895) Vol. 62 No. 271 THE TRACE FOSSIL ZOOPHYCOS AS AN INDICATOR OF WATER DEPTH By RICHARD G. OsGoopn, JR. AND EUGENE J: SZMUC May 31, 1972 Paleontological Research Institution Ithaca, New York 14850 U. S. A. Library of Congress Card Number: 72-79600 Printed in the United States of America Arnold Printing Corporation CONTENTS Page BEANS 1 AC fa ee ee en I et se ee aS OY SER ee See eae Se 5 imtroduction) == PERE were... oe a ee ee” See ae ee 5 Morphology of Zoophycos ............---.---00-------- ee eal iets eee Ss ie 6 racesrosstlsmaspindicesnot: vwatentc ep theese ee een nee nee 8 The Lower Mississippian section in northeastern Ohio ~............0.............. eR Dd 9 Occurrence of Zoophycos in the Mississippian of northeastern Ohio ~................. 11 @onelusionpean deap toby ern sig pete ses oe eae te eee i ee eae eee 15 TBS Oy Cay 2a OF) 0) 0h 6 1 een Ie Pewee re D2 ta nae ee aR eR ce eek a ee tea 16 Appendix—detarled) localityaidataeses. eee. eee eee ee eee 18 a ‘ 7 i af q 4 e j ee “nn = hE in, ¥ . ie .. ee ; a 2 ® db: damede ti ot dots Pee | ag ; ; ait) weeded yee to palqalag eae vi at en etea® 16 i bs 4 . ariidery big ag i : 4 a ¢i ; eas vileal didte 4 a _— e@ er i 1 THE TRACE FOSSIL ZOOPHYCOS AS AN INDICATOR OF WATER DEPTH RicHARD G. OsGoop, JR.! AND EUGENE J. Szmuc? ABSTRACT A geographically widespread occurrence of the trace fossil Zoophycos is described from the Lower Mississippian Cuyahoga Formation of northeastern Ohio. Although Seilacher (1955, 1964, 1967a, 1967b) stated that Zoophycos is most common in “intermediate water depths,’ numerous environmental indi- cators (oscillation ripple marks, large scale cross lamination, and Lingula) demonstrate that in northeastern Ohio Zoophycos flourished in shallow water which was above wave base. At present the genus encompasses too wide a range of morphologic variables. Detailed studies are needed in order to deter- mine the limiting factor of the environment. Water depth does not appear to provide the answer. INTRODUCTION As Seilacher demonstrated, one of the major values of trace fossils is that they can be used to indicate water depth in cases where other evidence is absent. In a series of papers, Seilacher (1955, 1963, 1964, 1967b) established several “ichnofacies’ each with its suite of trace fossils and each indicative of a certain en- vironment. The Zoophycos Facies, characterized by the roostertail- like trace fossil of the same name was proposed for an environment which was “sublittoral to bathyl, below wave base, and without turbidite sedimentation” (Seilacher 1964, p. 311). It should be noted that Seilacher (1964, fig. 7) listed four deep-water deposits containing Zoophycos, and that in 1967 he reported the first oc- currence of Zoophycos in “deep-sea”? cores of Recent sediments take by Lamont-Dougherty Geological Observatory. At the same time he conceded that Zoophycos may occasionally occur in shal- lower water “. . . due to local channeling or restriction” (Seilacher, 1967b, p. 418). In spite of these exceptions the authors conclude, upon analysis of Seilacher’s works, that Seilacher believed that the majority of occurrences of Zoophycos represent intermediate water depth. Further justification for this belief will be given below. The purpose of this paper is to discuss a major widespread occurrence of Zoophycos from the Lower Mississippian rocks of northeastern Ohio. As will be demonstrated, the body fossils, pri- mary sedimentary structures, and the regional geologic setting, all indicate that large numbers of Zoophycos occur here in rocks that were deposited in shallow water that was above wave base. The validity of Zoophycos as a reliable depth indicator is thereby somewhat in doubt. 1 Department of Geology, College of Wooster, Wooster, Ohio 44691 2 Department of Geology, Kent State University, Kent, Ohio 44242 6 BULLETIN 271 MORPHOLOGY OF ZOOPHYCOS Diagnosis — slightly helicoid trace fossils possessing a marginal tube; the Sprezte radiating from the center frequently give the genus a “rooster-tail” like appearance. Discussion — Zoophycos Massalongo, 1855 is a common form which has been reported from nearly every continent in rocks rang- ing from Ordovician through Tertiary in age. As Hantzschel (1962, 1965) and Simpson (1970) pointed out the genus is extremely variable in form. It is badly in need of a monographic study, and no attempt will be made here to discuss the genus in depth. For a more detailed analysis of Zoophycos and its taxonomic problems the reader is referred to Pliéka (1968, 1970), Lessertisseur (1955), Hantzschel (1965), and Simpson (1970). Perhaps the wide range of morphology exhibited by Zoophycos can best be demonstrated by considering three forms figured in the literature. Sarle (1906, fig. 1) illustrated a specimen from the Silurian of New York State which resembles a “‘rooster-tail.” The marginal tube is clearly visible as are the arcuate Spreite. A more typical occurrence of Zoophycos is shown by Hantzschel (1962, figs. 137-la, 2a). It is a flat helix with the Spreite radiating from the apex of the cone. No marginal tube is present but this may be due to imperfect preservation. According to Seilacher (1967a) this form, which he had found in the Alpine Tertiary section, is a variant of a more complex Cretaceous form, which takes on a flat antler-like appearance (Seilacher, 1967a, p. 79 top). Compounding the problem is the fact that many times Zoophycos has a distinct three dimensional aspect. Moreover, as Sarle (1906, fig. 2) pointed out several helices can be interlaced, making study even more difficult. In its most extreme three dimensional form the Zoophycos structure can resemble a corkscrew with Spreite, where the vertical dimensions exceed the diameter of the helix. These forms are assigned by most authors to Daedalus Rouault, 1850.3 3Simpson (1970) was well aware of the morphological variation included in Zoophycos and made some attempt to limit it by restricting the circular forms to Spirophyton Hall, 1963. However, as one can see, and as Simpson himself admitted, the Zoophycos still contains a wide variety of morphologic expres- sions (see Simpson, 1970, fig. 1). ‘TRACE Fossi1Ls: OsGoop & SZMUC 7 The Mississippian forms from Ohio contribute little to the general knowledge of the morphology or ethology exhibited by Zoophycos. They closely resemble those specimens illustrated by Hantzschel (1962, fig. 137-la) and Simpson (1970, fig. Ib). They occur in gray, micaceous siltstones and their overall pat- tern is somewhat masked by their three-dimensional aspect. One specimen (PI. 1, fig. 2) retains a small fragment of the marginal tube. The tube is ovoid in cross-section and measures 5 mm by 3 mm. Because the species of Zoophycos are so poorly defined, no attempt at specific identification will be made here. Interpretation — The interpretations given to Zoophycos are as varied as the morphology of the genus itself. Several earlier authors (e.g. Rouault, 7m Lebesconte, 1884) believed that it was the impression of marine algae. It has also been assigned to the Porifera by Lebesconte (1887) and to the Alcyonaria by Lucas (1938). Other workers regarded it as inorganic, caused by either current activity (Nathorst, 1886), or gas bubbles (Korn, 1929). Today it is generally agreed that Zoophycos represents the feeding structure of an unknown soft-bodied wormlike organism (Hantzschel 1962, 1965; Seilacher 1967a). A notable excepton is Pli¢ka (1968, 1970) who, working with Tertiary material from the Carpathians, described the arcuate Spreite as the impression of the prostomia of sabellid annelids. The present authors accept the trace fossil assignment although they are unable to comment on Pli¢ka’s material. The three di- mensional preservation of Zoophycos, as well as the lack of any microstructure, rules out a vegetable origin. Moreover, the arcuate Spreite are a variant of a feeding method frequently observed in trace fossils. Phycodes and Rhizocorallium could be cited as ex- amples. Basically each arc represents the course of the organism as it moved along, ingesting the sediment. When the elastic limits of the body were reached the animal contracted and proceeded to excavate a new burrow directly adjacent to the old one. Seilacher (1967a) postulated that the antler-shaped Zoophycos from the Cretaceous are actually a less efficient variant of the more compact Tertiary forms. In the former the area between the horns is left unexploited whereas this does not occur in the compact forms. Because the burrows of Zoophycos are normally three dimensional 8 BULLETIN 271 it is probable that they were excavated below the depositional inter- face. The above description of the origin of the burrow is greatly simplified. The only detailed attempts to describe the habits of the organism are those of Bischoff (1968) and Simpson (1970). In summary, Zoophycos is variable in overall appearance but all forms assigned to the genus possess the arcuate Spreite. Because of its variability it must be regarded as a form genus. It represents a feeding burrow although the actual mechanics of formations of the burrow are still not clear for all members of the genus. TRACE FOSSILS AS INDICES OF WATER DEPTH Seilacher (1955) compared the trace fossils from five sections of diverse geologic ages. He found some sections (e.g. Lower Cam- brian of the Salt Range of Pakistan) were characterized by shallow resting traces (Cubichnia of Seilacher, 1953a) which probably served as places of temporary concealment. He interpreted these as indicative of a shallow-water environment well within the euphotic zone, an area where predators would be most active. Conversely other sections such as the Tertiary Alpine Flysch contained no Cubichnia but numerous grazing traces (Pascichnia of Seilacher 1953a) . Seilacher interpreted Pascichnia as two-dimensional feeding trace analogous to strip mining, where the organism attempts to cover a large area with a minimum amount of effort. This can lead to unusual geometric patterns such as the tight spiral of Helmin- thoida. Observations of Recent sediments have served largely to con- firm Seilacher’s hypotheses. It is difficult to observe Cubichnia in the process of formation since the organism quickly covers itself with sediment. However, Recent stelleroids and ophiuroids are known to burrow for protection (Seilacher, 1953b), and it is not unreasonable to assume that Rusophycus, which is abundant in lower Paleozoic sediments represents a burrow of trilobites. While Pascichnia remain unreported in photographs taken within the 4For a more detailed discussion of Seilacher’s ichnofacies see Osgood (1970, pp. 399-404). TRACE FossiLs: OsGoop & SZMUC 9 euphotic zone their presence has been confirmed by photographs taken at great depth (see Seilacher 1967b, pl. II). In 1964 Seilacher expanded his analysis to include 42 sections of varying geologic age and locality. He formally named the suite of trace fossils dominated by Pascichnia as the “Nereites Facies” while the Cubichnia suite was entitled the “Cruziana Facies.” In addition he proposed the “Zoophycos Facies’ at this time. Unlike the Nereztes Facies and Cruziana Facies which normally contained several different trace fossils, Zoophycos was commonly the sole trace fossil. Seilacher (1964, 1967b) cited several examples from the geologic record to support his views. Moreover, in the Ordo- vician of Iraq there is a vertical gradation through the Nereites- Zoophycos-Cruziana Facies. In subsequent papers Seilacher (1963, 1967b) enlarged the number of facies to six. These additional facies, which need not concern us here, are indicative of shallow water or special environ- mental conditions. The authors of this paper take no issue with Seilacher’s inter- pretation of the environmental significance of the Cruziana and Nereites Facies. They are supported by both well-reasoned argu- ments and Recent observations. The Zoophycos Facies rests on weaker evidence. Why should this particular three-dimensional feeding burrow be confined to “intermediate” depth water and why are there virtually no other trace fossils occurring with it? THE LOWER MISSISSIPPIAN SECTION IN NORTHEASTERN OHIO The Mississippian stratigraphic units in northern Ohio com- prise a composite thickness of more than 300 meters of fine-to- coarse-grained clastics that were deposited in the northwestern part of the Appalachian marginal basin. They include shallow-water marine, transitional, and to a lesser degree nonmarine sediments. The stratigraphic sequence shown in Text-figure | is conform- able except for an erosional break of considerable relief at the base of the Berea Formation and a minor unconformity or reworked surface at the Cuyahoga-Logan contact. Four major types of lithologic groups are shown in Text-figure 1: 1. Conglomerate, 2. Sandstone and pebbly sandstone, 3. Gray shale and siltstone, 4. Black and gray shale and siltstone. 10 BULLETIN 271 FORMATION MEMBER DEPOSITIONAL ENVIRONMENT REDISTRIBUTED DELTAIC SAND-SHEET BLACK HAND DELTAIC BAR-FINGER = WOOSTER PRODELTAIC ARMSTRONG PRODELTAIC AND SHALLOW OFFSHORE MARINE RITTMAN DELTAIC BAR-FINGER MEADVILLE PRODELTAIC AND SHALLOW OFFSHORE MARINE —< co =>) Se —< S= => <5) "STRONGSVILLE STAGNANT SHALLOW SEA BEDS" SHARPSVILLE SHALLOW OFFSHORE MARINE ORANGEVILLE SHALLOW OFFSHORE MARINE SUNBURY STAGNANT SHALLOW SEA Eeearr| DELTAIC AND NON-MARINE CHANNEL SILTSTONE AND GRAY SHALE @ ZooPHYCoS IN SILTSTONE SANDSTONE BLACK SHALE V VERTICAL LINGULA Text-figure 1. Composite section of Lower Mississippian stratigraphic units in northern Ohio and their deduced depositional environments. Vertical dimensions of the units are not drawn to scale. CONGLOMERATE = GRAY SHALE TRACE FossiLts: OsGoop & SZMUC a The Berne Member of the Logan Formation is a thin, wide- spread fine-pebble conglomerate which contains a moderately abun- dant marine invertebrate fauna. Hyde (1915) interpreted the con- glomerate as a wave-reworked “lag concentrate” of pebbles derived from the underlying pebbily sandstones of the Black Hand Member. The sandstones are predominately deltaic in origin. The Berea Sandstone is a channel-deltaic unit composed of nonmarine, transi- tional, and marine strata (Pepper, et al., 1954). The Rittman Member and Black Hand Member are regarded as delta-complex deposits composed primarily of bar-finger sands which grade later- ally into finer clastics of the Wooster Member and Meadville Mem- ber (Barclay, 1968; Szmuc, 1970) . The gray shale beds and the flaggy siltstone-shale beds of the Orangeville Member, Sharpsville Member, and Wooster Member, and the upper portion of the Meadville Member are composed of prodeltaic and shallow-water offshore marine sediments (Barclay, 1968; Szmuc, 1970). A sparse to abundant marine fauna composed of brachiopods, bryozoans, corals, and many other invertebrates is dispersed irregularly throughout these units. The black shales of the Sunbury Member and the siltstones and black and gray shales of the basal portion of the Meadville Member (here designated informally as the “Strongsville Beds’’) contain a depauperate biota composed of conodonts, plant debris, and inarticulate brachiopods. These strata were deposited in re- stricted, stagnant, and deoxygenated shallow seas. The Strongsville Beds are noteworthy because they typically display one to six meters of gray and black shales intercalated be- tween two areally extensive siltstone beds which at many expos- ures contain profuse numbers of Zoophycos on their upper bedding surfaces. One or both of the Zoophycos-bearing siltstones are prom- inently displayed at Brandywine Creek, Cuyahoga Falls, Strongs- ville, and Valley City (Sections 1, 2, 3, and 4 of this report). OCCURRENCE OF ZOOPHYCOS IN THE MISSISSIPPIAN OF NORTHEASTERN OHIO The main objective of this study was to locate Zoophycos in the field and to search for sedimentary structures, body fossils and 12 BULLETIN 271 trace fossils which would provide some evidence of water depth. Numerous exposures were sampled and described in detail in a five-county area, including the seven representative localities shown in Text-figure 2. The results of the study are presented below. N Lake Erie Yi 93 CUYAHOGA | 0 10 20 ? [fs biaouea ee cient [ee a A sl] miles A o} e SUMMIT MEDINA hee plese Q7 ASHLAND Text-figure 2. Map of five counties in northeastern Ohio showing out- crops of Lower Mississippian strata at selected localites. 1. Brandywine Creek. 2. Gorge Park, Cuyahoga Falls. 3. Strongsville. 4. Valley City. 5. Killbuck Creek. 6. Wooster Quarry. 7. Buck Creek. See Appendix at end of report for detailed locality data. TRACE Fossi_s: OsGoop & SzMuUC 13 A) Stratigraphic distribution of Zoophycos Zoophycos is confined to certain siltstones of the Meadville Member and Armstrong Member. The sandstones, conglomerates, and the gray and black shales are devoid apparently of Zoophycos. B) Abundance of Zoophycos The density of distribution of Zoophycos in the Strongsville Beds is comparable to certain beds in the Mississippian Borden Group of Kentucky, where their intertwined patterns locally cover entire bedding planes. Although Zoophycos is more sparsely repre- sented on bedding planes in the Armstrong and upper part of the Meadville, its common presence clearly demonstrates that it is not a chance occurrence. It was usually possible to locate three to four specimens on a surface of four square meters. The authors were able to confirm Seilacher’s (1964) observa- tion that only rarely does Zoophycos occur with other trace fossils. The only associated form is Palaeophycus sp. (as defined by Osgood, 1970). This is a common trace fossil and not diagnostic of any particular environment. C) Associated invertebrate and plant fossils Few body fossils were found in association with Zoophycos. This is not too surprising because the section is predominantly clastic, and fossil occurrences within this part of the Mississippian tend to be localized. Fragmented pelecypod, sponge, crinoid, and articulate brachiopod remains were found from a few centimeters to 20 meters (vertical distance) of Zoophycos, but not within the same or adjacent beds. There are, however, two significant excep- tions: 1) At the Strongsville locality (Section 3) specimens of Lingula cf. melie Hall were found in situ within the Zoophycos beds (PI. 2, fig. 1). As most of them assume the life position it is unlikely that they were washed into the area. It is well known that Recent Lingula prefers a shallow-water environment and is the only living brachiopod which can sustain itself for short periods of time in brackish waters (Rudwick, 1965). According to Hatai (1940) Recent Lingula extends from the low-water line to about 20 or 23 fathoms, although one specimen of Lingula unguis was recorded from a depth of about 50 fathoms near Seto, Japan. 14 BULLETIN 271 2) At the Valley City locality (Section 4) a black shale two to three meters thick is in contact with the upper Zoophycos siltstone of the Strongsville beds. Within the shale are a few thin (2 to 3 mm thick) beds of cross-laminated siltstone. This shale is also present at the Strongsville locality and apparently represents a local basin. Its significance for this study is that it contains abundant carbon- ized cordaite fragments, some several centimeters long. While this is not indicative of any particular water depth, the abundance of the plant fragments would seem to demonstrate a near-shore occur- rence. D) Sedimentary features associated with Zoophycos Several lines of evidence point to abundant current or wave activity. 1) Many of the siltstone beds in the Meadville Member and Armstrong Member pinch and swell and some are abruptly lenticu- lar. Cross-laminations are common and many are large-scale sets which range from 3 to 5 meters in lateral extent and display dips of 5 to 15 degrees. While we are unable to assign the large-scale struc- tures to a particular depositional environment (e.g. point bar) it seems unlikely that they originated below wave-base. 2) Oscillation ripple marks are abundant at the Killbuck Creek locality (Section 5) and occur within 5 cm (vertically) of Zoophycos. ‘They have an amplitude of 1 cm and a wave length of 7 to 10 cm., and many grade laterally into interference ripple marks. It is not uncommon to find three or four ripple-marked beds within a thickness of 20 cm. While the authors realize that such ripple marks may be produced by various mechanisms (see McKee, 1965) it is difficult to visualize the origin of such large numbers below wave-base. It is worthy of note that Seilacher (1967b, fig. 2) placed Zoophycos below the occurrence of oscillation ripple marks. E) Regional geological setting It is instructive to look at the environmental setting of the formations both underlying and overlying the Cuyahoga. In north- eastern Ohio the Berea Sandstone occurs some 45 meters below the Zoophycos beds (Szmuc, 1970, p. 43). Pepper, et al. (1954) demon- strated convincingly that the Berea and the subjacent Bedford TRACE FossiLs: OsGoop & SZMUC 15 Formation represent a deltaic, prodeltaic, and channel-fill environ- ment. The reader is referred to their paper for a more complete discussion. Although the Logan Formation, which lies some 35 meters above Zoophycos, has not been thoroughly studied by the writers, environmental indicators are abundant. The Quarry of the Wooster Medal Brick and Tile Company at Wooster (Section 6) contains one of the best exposures of the upper Cuyahoga Formation and lower Logan Formation in northeastern Ohio. In this exposure interference ripplemarks, ripple drift, and small scale channel cross-lamination are common. Rare casts of mud cracks have also been found. The Berne Conglomerate in the basal portion of the Logan consists of quartz pebbles in a sandy matrix containing chonetid brachiopods. The stratigraphic position of the Cuyahoga beds between del- taic and delta-derived sediments is a compelling argument for a shallow-water habitat of the Ohio Zoophycos. The argument is strongly enhanced by the environmental setting of the Meadville, Armstrong, Rittman, and Black Hand Members. The deduced depo- sitional histories (see Text-fig. 1) of these units are based not only on the criteria presented in this paper, but also on their body-fossil content, geometry, and stratigraphic relations with contiguous units such as the largely nonmarine Pocono Sandstone of Pennsylvania (Hyde, 1915; Barclay, 1968; Szmuc, 1970). Environmental interpre- tations on these bases indicate that the Zoophycos in the Armstrong Member is sandwiched between the Rittman and Black Hand bar- finger sands, the stratigraphic separation of which is about 35 meters. Moreover, the Zoophycos-bearing beds in the Armstrong and in the upper part of the Meadville are intimately associated with off-shore marine and prodeltaic deposits. There is nothing in the Ohio Mississippian section which sug- gests any significant deepening of the epeiric sea during Cuyahoga sedimentation. On the contrary, all available evidence indicates that Zoophycos lived in shallow-water, offshore environments. CONCLUSIONS AND PROBLEMS 1) In Ohio Zoophycos is closely associated with shallow-water environments, as is amply attested by our interpretation of the Strongsville Beds. 16 BULLETIN 27] 2) Seilacher’s Zoophycos Facies apparently must be broadened or expanded from an equivocal assignment of “intermediate depth” to include deposits which form well above wave base and proximate to the outer margins of bar-finger sands. This opinion is strongly indicated by our interpretation of the Armstrong beds and upper Meadville beds and related units of the Cuyahoga Formation. 3) It seems likely that water depth, which in turn reflects many physical factors (temperature, light), is not the sole factor in deter- mining the distribution of Zoophycos. This conclusion is buttressed by the presence of this genus in two different shallow-water eco- logical niches, the Strongsville and the Armstrong-Meadville, as well as by Seilacher’s accounts of Zoophycos in relatively deep-water deposits. 4) ‘Trace-fossil workers are now faced with the task of con- ducting a closer examination of this genus. Several questions re- main unanswered, e.g., why is Zoophycos usually not associated with other trace fossils, how much morphologic variation is to be per- mitted to exist within the genus, and finally what are the specific physical, chemical, and biotic factors which control its distribution? BIBLIOGRAPHY Barclay, C. C. 1968. Sedimentary structures and depositional history of the coarse- clastic rocks of the Cuyahoga Formation in northern Ohio. Kent State Univ. unpubl. master’s thesis, 108 pp. Bischoff, B. 1968. Zoophycos, a polychaete annelid, Eocene of Greece. Jour. Paleont., vol. 42, pp. 1439-1443, 2 pls. Fale J. 1863. Observations upon some spiralgrowing fucoidal remains of the Paleozoic rocks of New York. 16th Ann. Rept. New York State Cabinet, pp. 76-83. Hantzschel, W. 1962. Trace-fossils and Problematica. In Treatise on Invertebrate Pale- ont., Moore, R. C. (ed)., pt. W., Miscellanea, Lawrence, Kansas, University of Kansas Press, pp. 177-245, figs. 109-149. 1965. Vestigia invertebratorum et Problematica. Fossilium Catalogus, 1. Animalia, s’Gravenhage, Junk, 142 pp. Hatai, K. 1940. The Cenozoic Brachiopoda of Japan. Sci. Rep. Tohuku Imp. Univ., ser. 2, vol. 20, 413 pp. Hyde, J. E. 1915. Stratigraphy of the Waverly formations of central and southern Ohio. Jour. Geol., vol. 23, pp. 655-682; 757-779. TRACE Fossits: OsGoop & SZMUC 17 Korn, H. 1929. Fossile Gasblasenbahnen aus dem Thiiringer Palaeozokum. Eine neue Deutung von Dictyodora, Z. Naturwiss., Bd. 89, pp. 25-46, 3 figs. Lebesconte, P. 1883. Presentation a la société des oeuvres posthumes de Marie Rouault par P. Lebesconte, suivies d’une note sur les Cruziana et Rhyso- phycus. Soc. Geol. France, Bull., ser. 3, vol. 11, pp. 466-472. 1887. Constitution générale du Massif breton comparée a celle du Finisterre. Soc. Geol. France, Bull., ser. 3, vol. 14, pp. 776-820, 2 pls. Lessertisseur, J. 1955. Traces fossiles d’activité animale et leur significance paléobio- logique. Soc. Geol. France, Mem. 74, 150 pp., 68 figs., 11 pls. Lucas, G. 1938. Les Cancellophycus du Jurassique sont des Alcyonaires. Compte Rendues Acad. Sci., vol. 206, p. 1914. Massalongo, A. 1855. Zoophycos, novum genus plantorum fossilium. Pp, 52, 3 pls. Verona. McKee, E. D. 1965. Experiments on ripple lamination. In Middleton, G. V., Primary sedimentary structures and their Hydrodynamic Interpretation. Soc. Econ. Paleont. and Minerol., Spec. Pub., No. 12, pp. 66-84, 6 figs. Nathorst, A. G. 1886. Nouvelles observations sur les traces d’animaux et autres phéno- menes d’origine purement mécanique décrits comme “Algues fos- siles.’ Kgl. Svenska Vetensk. Akad. Handl., vol. 21, No. 14, 58 pp., 14 figs. 5 pls. Osgood, R. G. Jr. 1970. Trace fossils of the Cincinnati area. Palaeont. Americana, vol. 6, No. 41, pp. 281-444, 29 figs., 27 pls. Pepper, J. F., Dewitt, W., and Demarest, D. F. 1954. Geology of the Bedford Shale and Berea Sandstone in the Ap- palachian Basin. United States Geol. Sur., Prof. Paper 259, 109 pp., 61 figs., 13 pls. Plicka, M. 1968. Zoophycos and a proposed classification of sabellid worms. Jour. Paleont., vol 42, pp. 836-849, 2 pls. 1970. Zoophycos and similar fossils. In Crimes, T. P. and Harper, J. C., Trace Fossils. Geological Journal (Liverpool), Special Issue, No. 3, pp. 361-71, 4 figs., 2 pls. Rouvault, M. 1883. See Lebesconte, P. Rudwick, M. J. S. 1965. Ecology and paleoecology. In Treatise on Invertebrate Paleon- tology. Moore, R. C. (ed.), pt. H, vol. 1, Brachiopoda, Lawrence, Kansas, University of Kansas Press, pp. 199-214. Sarle, C. J. 1906. Arthrophycus and Daedalus of burrow origin. Rochester Acad. Sci., Proc., vol. 4, pp. 203-210, 4 figs. Seilacher, A. 1953a. Uber die Methoden der Palichnologie, Studien zur Palichnologie, No. 1. Neus Jahrb. Geologie u. Palaont., Abh., Bd. 96, pp. 421- 452, 10 figs., 1 pl. 18 BULLETIN 271 1953b. Uber die Methoden der Palichnologie, Die fossilien Ruhespuren (Cubichnia). Neues Jahrb. Geologie u. Palaont., Abh., Bd. 98, pp. 87-124, 5 figs., 5 pls. 1955. Spuren und Lebensweise der Trilobiten; Spuren und Fazies im Unterkambrium. In Schindewolf, O. H., and Seilacher, A., Beitrdge zur Kenntnis des Kambriums in der Salt Range (Pakistan). Akad. Wiss. Lit. Mainz. math.-nat. KI., Abh., No. 10, pp. 86-143, figs. 1-11, pls. 16-27. 1963. Lebenssuren und Salinitatsfazies. Fortschr. Geol. Rheinland und Westfalia, Bd. 10, pp. 81-94, 7 figs. 1964. Biogenic sedimentary structures. In Imbrie, J., and Newell, N. Approaches to Paleoecology, New York, John Wiley and Sons, pp. 296-316, 7 figs. 1967a. Fossil behavior. Scientific American, vol. 217, pp. 72-80. 1967b. Bathymetry of trace fossils. Marine Geology, vol. 5, pp. 413-429, 4 figs., 2 pls. Simpson, S. 1970. Notes on Zoophycos and Spirophyton. In Crimes, T. P. and Harper, J. C., Trace Fossils. Geological Journal (Liverpool), Special Issue, No. 3, pp. 505-515, 4 figs. Szmuc, E. 1970. The Mississippian System. In Banks, P., and Feldman, R., Guide to the Geology of Northeastern Ohio. Northern Ohio Geol. Soc., pp. 23-67, 31 figs., 3 pls. APPENDIX — DETAILED LOCALITY DATA 1. Brandywine Creck locality. Top of section is at former State Route 8 bridge at Little York, 4.2 miles south of Northfield Center; Northfield Township, Summit County, Northfield 7.5 minute Quadrangle. 2. Gorge Park locality. City Park in Cuyahoga Falls, outcrop is in a tributary valley on north bank of the Cuyahoga River 0.8 miles east of State Route 8 bridge; Summit County, Akron East and Akron West 7.5 minute Quad- rangles. 3. Strongsville locality. Baker Creek, 0.1 mile west of junction of State Routes 82 and 237 and 1.25 miles west of Strongsville. Outcrop is some 300 meters south of the bridge over route 82; Strongsville Township, Cuyahoga County, Berea 7.5 minute Quadrangle. 4. Valley City locality. West branch of Rocky River where crossed by State Route 252 less than one mile south of intersection of State Routes 252 and 303; Medina County, West View 7.5 minute Quadrangle. 5. Killbuck Creek locality. Outcrop begins some 200 meters downstream from where an unnamed tributary of Killbuck Creek is crossed by Wayne County Route 36, 2.5 miles north of village of Congress; Wayne County, West Salem 7.5 minute Quadrangle. 6. Wooster Quarry locality. Shale pit (abandoned 1970) of Wooster Medal Brick Company on north side of Wayne County Route 22, 1.7 miles south of intersection of County Routes 22 and 106, Wooster: Wayne County, Wooster 7.5 minute Quadrangle. Buck Creek locality. Buck Creek where crossed by State Route 60 at Here- ford; Ruggles Township, Ashland County, New London 7.5 minute Quad- rangle. “I PLATES 20 BULLETIN 271 EXPLANATION OF PLATE 1 Figure Page 1. Zoophycos spr*.2...24 5 2 eee ee ee eee 6 A large incomplete specimen from the Brandywine Creek locality (#1), UCGM 40644, x 0.4. Respository of figured specimens, University of Cincinnati Geology Museum, Cincinnati, Ohio, 45221. 2° (LOOBNY COS SDi oy ee cece ost ee Re ea 6 A more typical “rooster-tail’” form with a small portion of the marginal tube preserved. Buck Creek locality (#7), UCGM 40645, X 0.5. BULL. AMER. PALEONT., VOL. 62 PrAte; 1 BULL. AMER. PALEONT., VOL. 62 PLATE 2 TRACE FossiLs: OsGoop & SZMUC Dal EXPLANATION OF PLATE 2 Figure Page ie Eingularct meliear Hallgren et cette tacts tinct nw cette ae 13 Preserved in situ. Although the bedding planes are not visible the specimen was taken directly from the outcrop thus assur- ing correct orientation. Strongsville locality (#3), UCGM 40646, X 1.2. 2. Large scale cross stratification with a dip of 5°-15° 14 The lateral distance shown in the photograph is approximately 10 meters. Killbuck Creek locality (#5). INDEX Note: Light face figures refer to pages. Bold face figures refer to plates. Armstrong Member .... Berea Formation Berne Member Bischoti baie. Black Hand Member .. Borden Group Brandywine Creek, section #1 Buck Creek, Section 357) Cruziana Facies Cubichnia Cuyahoga Falls, section #2 Cuyahoga Formation .. Daedalus Hantzschel, W. ............ ivi Cay irae ear 2 ee ‘Ichnofacies” Killbuck Creek, SeChlOn7s5iee ee PAN GULA ees ; Logan Formation 11, 18, 20 18, 20 11s 5, 9, 14-16 14, 18, 21 13, 21 OAS Meadville Member ...... 11, 13-16 cf. melie, Lingula ....2 13 Nereites Facies ............ 9 Orangeville Member .. alg Pascichnia® 22.0. 8 PlickageMisy wees ee. 6,7 Rittman Member ......... Hale 15) Sarle..\C. fet.) tne taken 6 Sellacher= Ay oe). 5-9, 13, 16 Sharpsville Member .... 11 SIMPSONS eee ee 6-8 Spirophyton- 2. 6 “Strongsville Beds” .... 11, 14, 15 Strongsville, Secuiony Grant IG, 216}, alts}, 2A SZMUCH tein Wy a5 Valley City, section #4 .............. 11, 14,18 Wooster Member ...... Wal Wooster Quarry, Sections 09 ee 15, 18 Zoophycos Facies ....... 5, 9, 16 Zoophycos Sp ............. 1 6 ig MUS. COMP. ZOOL. BULIERING «| OF SEP 23 1972 RVARD AMERIG AN Haven Ge PALEONTOLOGY (Founded 1895) Vol. 62 No. 272 MATURE MODIFICATION AND DIMORPHISM IN SELECTED LATE PALEOZOIC AMMONOIDS By RicHarp ARNOLD Davis 1972 Paleontological Research Institution Ithaca, New York 14850 U. S. A. PALEONTOLOGICAL RESEARCH INSTITUTION 1971 - 72 PRESIDENT (ince ee eos ees aa es a OA a SCF Sos Be ee Ee a RR DANIEL B. SAss WICKES PRESIDEN DS o0e teneeaeteeras stn ek TUES ould ee Se Blenboehs 2OGr cee eee MerrRILL W. HAAS SRERE TARY. recs ts eas 5 ye OE IE Sieh 2S bel CEN REBECCA §S. HARRIS DIRECTOR: WEREASURER( (cnt ost se a ctoeeee e eee ene eeees KATHERINE V. W. PALMER COUINSE TE a Cie he Rha Sk ee ea eee ee Ae ARMAND L. ADAMS IREPRESEN TA TIVES ACA ANS 5 CO UsNGIMi ys oases ee sa ee eee JOHN POJETA, JR. Trustees Repecca S. Harris (Life) DoNnALD W. FIsHER (1967-1973) AxeL A. Oxsson (Life) MerRILL W. Haas (1970-1973) KATHERINE V.W. PALMER (Life) Puitip C. WAKELEY (1970-1973) DANIEL B. Sass (1971-1974) Ceci, H. KINDLE (1971-1974) KENNETH E. CAsTER (1966-1972) Vircit D. WINKLER (1969-1975) Harry S. Lapp (1971-1974) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PALMER, Editor Mrs. Fay Bricos, 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. BULLETINS OF AMERICAN PAL EOnrOlLoG y (Founded 1895) Vol. 62 No. 272 MATURE MODIFICATION AND DIMORPHISM IN SELECTED LATE PALEOZOIC AMMONOIDS By RicHarp ARNOLD Davis September 13, 1972 Paleontological Research Institution Ithaca, New York 14850 U. S. A. Library of Congress Card Number: 72-83384 Printed in the United States of America Arnold Printing Corporation CONTENTS Page PANS trial Cty coscceet eae Sess EE Ee rele prec oe he, MER ene core Ee see tia hohe eiten ta scasseeedepees 27 Tru OC UGE Omnis ose cee 2 cee cc oP cc SE LE TA aN ci otek ae 27 ates Ontorencticy shel liVloditicatio myyse eset see see aa ee 30 MD TTAO Tp AAS ITN eee ere. et eer, ee 2 SA Eee eee ee eee Ee 36 IDKsevereyfoxahi ai = 1 Dee ey = pment Oe i ee ene ee ee es ee ere 43 Superfamily ADRIANITACEAE ................. aiter Sey vane iste) ene ri lass 43 Biarrially ge A RD AINE DAU ea 2 ee ee en eee 43 SuperfamilyseA\G Av nl ChRAGDACEA Tat 61 amily eG Adri BRAC TID IA Bian eee tet Ree ree eee eee 61 Supertamily@Y CLOLOBACE Ale 65 Beer ena ivan © VAC Ve OL © BD AE eo acs es ne te eee rere ees 66 Rarmilyss Valo RIO CE RAG AI ee ee 76 Subfamily, VND RTO CE RAGIINAR ooo. oct eke ee re ee aay 76 Supertaniilya ViEAReACISET @ NileneAl© By ANB eee eee eee 81 1p ered KoPee ING (Ped Se BG 8 ICG) Hef BD D5 pe ae ek a este ee eae Te 81 Subfamily. MAR AEIONITINAB Ss ses 6 og ee Sirs est se estes 81 Subfamily KeA GAM 1 DIN By oe oe: oot eee ee ee 88 INGRETENCES ee 2eeeese FIORE Be Geel Ae oom I eg he eh see es 2h asec He eee ee 90 LPAI ing SPN Ow AONE ee ie NUN a2 Oe Seen ae ts De ee 101 Index i ' i aly ) ery Ce PN wag cult i i bie AE UA chi i if . CoMabikol 1 Tacs m Agusta | iJ LA Time Ant a at , an ‘ it ae +f rehe # ; oon +, e MATURE MODIFICATION AND DIMORPHISM IN SELECTED LATE PALEOZOIC AMMONOIDS! Ricuarp ArNoLp Davis, University of Cincinnati ABSTRACT Many ammonoid cephalopod taxa display late ontogenetic modifications of the shell. These modifications include any number of the following: change in coiling, modification of whorl section, change in ornament, development of an apertural constriction, development of an apertural shell thickening, forma- tion of a characteristic ultimate peristome (with lappets or a rostrum, for ex- ample), changes in shell deposition, progressive approximation of the ultimate septa, progressive simplification of the ultimate few sutures, thickening of the last septum, and development of muscle scars. Such modifications are related to the attainment of sexual maturity. The ecologic and physiologic implications of these mature modifications are uncertain. Long ago, sexual dimorphism was suggested to account for the widespread existence of pairs of morphologically distinct mature ammonoids which are virtually identical as juveniles. This explanation is most probably valid. The following genera of the family Adrianitidae display mature modifi- cations: Adrianites, Crimites, Epadrianites, Hoffmannia, Neocrimites, Paler- mites, Pseudagathiceras, Sizilites, and Texoceras. In specimens of all of these, changes in coiling and an apertural constriction are present. Changes in orna- ment are present in Neocrimites, Pseudagathiceras, Sizilites, and possibly Hoff- mannia. Lappets are known in Adrianites, Neocrimites, and Palermites. Changes in whorl cross-section occurred in Adrianites, Crimites, Hoffmannia, Palermites, and Sizilites. Possible changes in shel] secretion are known in Adrianites and Texoceras. Agathiceras, of the family Agathiceratidae, displays changes in coiling, whorl cross-section, and ornament and has an apertural construction and lappets. Dimorphism is present in the genus; the two forms appear to differ only in mature diameter. Three genera of the Cyclolobidae are known to bear mature modifications: Mexicoceras, Waagenoceras, and Cyclolobus. All three have an apertural con- striction and changes in coiling and whorl cross-section. Mexicoceras has a mid-ventral salient in the peristome, and Cyclolobus has lappets. Four genera of the Marathonitidae display mature modifications: Hyatto- ceras, Pseudovidrioceras, Marathonites, and Peritrochia. All four have an apertural constriction. Hyattoceras and some Marathonites display changes in coiling. Hyattoceras, Pseudovidrioceras, and some Marathonites show changes in whorl cross-section. Marathonites and Hyattoceras each appear to include dimorphs; in both genera, the two members of a pair differ in the nature of the mature modifications rather than just in size. The genera Waagenina and Stacheoceras of the Vidrioceratidae show mature modifications. Both have an apertural constriction, lappets, and changes in whorl shape. Stacheoceras shows changes in coiling. Waagenina appears to include dimorphs; the two members of a pair differ in the nature of the mature modifications. INTRODUCTION An externally shelled cephalopod, at death, has left an auto- 1Contribution No. 106, Department of Geology, University of Cincinnati. 28 BULLETIN 272 biography of at least part of its life cycle in the form of the shell. Its growth lines, the increments between the growth lines, and, in- deed, the shape of the conch, as a whole, record a life history of the anterior margin of the body; the septa and, hence, the sutures give witness to the ontogeny of the septal mantle. Were the conch complete it would give much of the story of the architectural career of its author, but Nature has seen fit to obliterate the last chapters of most of these autobiographies, and many men have followed her lead by inadvertently destroying por- tions of the body chamber during preparation of the shell. The rela- tively few well-preserved shells that remain tell an interesting tale. Many shells indicate that toward the end of the recorded span of life, changes in the animal occurred — the last-formed part of the shell has been modified with respect to the earlier-formed por- tion. These changes in some taxa apparently were minor, but in others, profound. The modifications may be present in both the septa and in the conch wall or only in the septa. Moreover, in some taxa, two conchs which were identical in early growth stages may be strikingly different after modification, revealing dimorphism. The purpose of this work is to examine these shell modifications and any dimorphism thereby indicated. Five ammonoid families have been studied in detail: the Adrianitidae, Agathiceratidae, Cyclolobidae, Marathonitidae, and Vidrioceratidae. At least some taxa of all of these families are known to exhibit modification in the last-formed part of the shell. That suitable material of these taxa is available for the present study is due predominately to the long-term contessorative efforts of the late A. K. Miller, of W. M. Furnish, and of Brian F. Glenister, all of the University of Iowa. All known genera of the five families enumerated have been studied, and those with modifications are described. This work should not be construed as an authority on tax- onomy. I have not made the thorough sutural studies upon which to found a taxonomic revision. The taxonomy used in this work is based mostly on the synthesis of Bogoslovsky, Librovitch, and Ruzhencev (1962), because theirs is the most recent study of most of the taxa concerned. Newer works, when available, were used. Where the Soviet Treatise is internally inconsistent or apparently incorrect, PaLeozoic AMMONOIDs: DAvIs 29 its taxonomy has been modified. The diagnoses given are intended solely to convey my understanding (or lack thereof) of the taxa being discussed. Some of the taxa discussed in this work originally were not designated with names conforming to the present International Code of Zoological Nomenclature (for example, Stacheoceras (Mara- thonites) J. P. Smithi Bose, 1919, and P. tridens form B Haniel, 1915). In order to simplify the tracing of taxonomic history, how- ever, I have given, at least once, each taxonomic name as it was originally proposed. This paper is, in the main, the dissertation I presented to the University of Iowa. Professor Brian F. Glenister and Professor W. M. Furnish advised me in the preparation of that thesis. I am greatly indebted for their gifts of time, experience, and enthusiasm. In addi- tion notes and photographs they made relating to their comprehen- sive study of Permian ammonoid type specimens were invaluable. Revisions were done during my current employment at the Uni- versity of Cincinnati. During most of the time I worked on the thesis I held a National Science Foundation Graduate Fellowship. For that I am most grateful. The various scientific institutions listed below graciously lent, traded, or gave specimens to the University of Iowa (SUI) or al- lowed them to be studied, as did Francis G. Stehli of Case-Western Reserve University and, likewise, M. Collignon of Académie Moirans (the abbreviations are those used in this work): The American Museum of Natural History (AMNH); British Museum (Natural History) (BMNH); Geologisch Instituut der Universiteit van Amsterdam (GIUA); The University of Copenhagen; Institut und Museum fiir Geologie und Paliontologie der Universitat Tiibingen (GPIT); Istituto di Geologia dell’Universita Palermo (IGUP); The Geological Survey of Pakistan; Institut Teknologi Bandung (ITB); Istituto di Geologia e Paleontologia dell’Universita di Pisa (MGPU); Muséum national d’Histoire naturelle, Paris (MNHN); Institut fiir Palaontologie der Rhein. Friedrich-Wilhelm Universitat, Bonn (PIUB); University of Paris, Sorbonne (UPSM); The Uni- versity of Texas (Texas); Texas Tech University; Mineralogisch Geologisch Museum Technische Hogeschool Delft (THD); The United States National Museum (USNM); Yale Peabody Museum (YPM). 30 BULLETIN 272 Dr. Claude Spinosa (Boise State College, Boise, Idaho, USA) and Dr. Eric J. Denton (The Laboratory, Citadel Hill, Plymouth, England) both have generously provided me with unpublished in- formation on particular aspects of their work with cephalopods. I am grateful to them. LATE ONTOGENETIC SHELL MODIFICATION In the externally shelled cephalopods as a whole, the changes in morphology which occurred toward the end of that span of life recorded in the shell included any number of the following: . changes in coiling, . changes in whorl section, . changes in ornament (including coloring), . development of an apertural constriction, . development of an apertural shell thickening, . formation of a characteristic ultimate peristome (with lap- pets or a rostrum, for example), 7. changes in shell deposition (such as, production of a black border at the terminal peristome in Nautilus), 8. progressive reduction of interseptal interval (approximation), 9. progressive simplification of the ultimate few sutures, 10. thickening of the last septum, 11. development of muscle scars. Some taxa are not known to have developed modifications. This may reflect an actual lack of such modifications (Ruzhencev, 1962, p. 255) or be due to either unavailability of suitably pre- served material or to inadequate study. A modified individual generally has at least several aspects of its conch affected. Various modifications occurred at diverse times in the ontogeny of the individual; for example, a change in coiling was wrought before the formation of an apertural constriction, Within any genus there seems to have been but one or two schemes of overall modification. Within any one such scheme, of course, the development of a particular aspect of modification varied from individual to individual. In years past, most authors (for example, Hyatt, 1874) at- tributed late ontogenetic shell modifications to senility — the gerontic individual just couldn’t maintain discipline in its shell- ON Mm RW Ne PaLeozoic AMMonoIDs: DAvis 31 forming faculties, so chaos resulted. Hyatt (1874) also noted that what he interpreted as pathologic dwarfs commonly are modified very similarly to those he regarded to be large gerontic forms. Coémme (1917) considered at least some modifications as indica- tive that their bearer was a “small, degenerate hybrid”. Apparently struck by the similarity of some modifications to varices in snails, to the parabolic nodes of certain Mesozoic ammonoids, and to phrag- mocone constrictions, certain authors (for example, Nikitin, 1884; Siemiradzki, 1925; Davitashvili and Khimshiashvili, 1954; Sazonov, 1957; fide Makowski, 1962) have suggested that the modifications are not late ontogenetic features at all, but were produced early or periodically and eroded or resorbed to allow further growth. Kerr (1931) was so impressed by the apparent external uselessness of most shell modifications that he concluded ammonoid shells were internal. Only one genus of externally shelled cephalopods is ex- tant — Nautilus. In this form, shell modifications occur at and are directly related to the onset of sexual maturity (Willey, 1902; Stenzel, 1964). Interpretation of late ontogenetic shell modifications in terms of senility, pathology, and genetic problems appears to be unlikely because of the great overall uniformity of modifications within each taxon or subdivision of that taxon. Resorption and erosion should have left partially resorbed and partially eroded individuals — none are known (Makowski, 1962); and to remove all modifications would, in some cases, necessitate erosion or resorption of more than one and one-half whorls of the shell. These facts, coupled with the knowledge that the conch changes in Nautilus are associated with maturity, strongly indicate that the late ontogenetic shell modifica- tions in the externally shelled cephalopods are terminal and truly are mature modifications. (“Mature” here is used as meaning sexually mature. This word has been used previously, for example, by Miller and Furnish, 1940a, apparently to indicate that an individual had attained what were considered to be its taxonomically diagnostic characteristics; in this work the word is placed in quotes when it is used in the sense of Miller and Furnish. The state of sexual maturity has been denoted previously as “fully mature”. ) The various mature modifications must have served some 32 BULLETIN 272 useful purpose (or, at the very least, have been neutral in effect), otherwise these modications would not have persisted. One could reasonably assume that mature modification pre- pared the animal for a mode of life different from that of its youth; this may well not have been entirely the case. It is known that at least some of the modern dibranchiate cephalopods (for example, Loligo and Sepia), reach maturity only to quickly breed and die (Lane, 1960, and personal communication, E. J. Denton). Lane (1960) and Wells (1962) pointed out that captive Octopus always die after brooding their eggs, and Wells noted that it is possible that cephalopods, in general, spawn only once and then die. It is known that periodically great numbers of mature Nautilus shells are piled onto the beaches of the southwestern Pacific Ocean, sug- gesting mass death, perhaps after mating. At least the possibility exists that the ammonoid had to face its environment as a mature individual for only a brief period of time; hence mature modifica- tions may have been related mainly to sex and have had little other ecologic significance. If the two sexes of a taxon were morphologically different and spent much of their lifespan as adults, it is difficult to envision how they could have occupied the same ecologic niche and still be of such different morphologies. But, then, perhaps the two sexes lived in different environments (Westermann, 1964, p. 39 et seq.; 1969). The two sexes, after all, would have needed to have been in the same place for only a short time. Each mature modification must be examined both to suggest what sexual significance the given modification might have had and to indicate its possible nonsexual ecological implications. In order to keep such speculations from becoming completely idle, the biology of extant organisms must be borne in mind — particularly the biology of the surviving cephalopods and, of these, especially Nautilus. Modifications relating to sex might include mechanisms: 1. for sex recognition, 2. for mating battles, either actual or ritual, between conspecific individuals of the same sex, . for the enclosure of sex organs, 4. for the accommodation of sex organs, OW PatEozoic AMMONOIDs: Davis 33 5. for the support of sex organs, 6. to aid copulation, 7. to aid oviposition, 8. for brooding eggs, young, or both. (Because almost any feature could be claimed to have been used for sex recognition, this aspect will not be mentioned in the following discussion. ) Modifications (both those related to sex and those not pertain- ing to sex) might affect the animal’s: . hydrodynamic and hydrostatic characteristics, . mobility and maneuverability, . sensory ability, . security from external organic and inorganic dangers, . feeding, . disposal of waste. Ganev in coiling most probably would have had hydrodynamic effects. Likewise the orientation of the animal would have changed; this would have altered the position and orientation of the peristome and, hence, the potential orientation of the hyponome. Changes in whorl section also would have altered the hydro- dynamic characteristics of the conch. Development of an angular venter (for example, in Hyattoceras and in Cyclolobus) or of a ventral keel would seem to be a modification for a more mobile existence. A broadening of the venter in transverse section, particu- larly if coupled with a change in coiling to render the venter flat as viewed laterally, would seem admirably suited for bottom dwelling (Ruzhencev, 1962). In Nautilus the conch of the male is broader than that of the female in order to accommodate the spadix. Changes in ornament, like the loss of color banding ventrally and addition of coloring dorsolaterally in Nautilus, could have been used for camouflage (see Cowen, et al., 1971). Miller (1944) specu- lated that the spines on the penultimate one-half whorl of Pseud- agathiceras might have served to protect the bottom-dwelling animal from attack from above. The loss of longitudinal ornament and the appearance of transverse plications in the ultimate one- quarter volution of Sizilites, as well as the spines in Pseudagathiceras would certainly have affected the hydrodynamics. The purpose of — the deep depression in each flank of the ultimate living chamber of Agathiceras swessi is unclear. Nn PWN 34 BULLETIN 272 Development of an apertural constriction, an apertural shell thickening, or both would have strengthened the ultimate shell mar- gin; this would have been of particular importance inasmuch as shell repair apparently ceased after mature modifications were completed. Perna (1915) pointed out that constriction of the aperture would have afforded the animal protection from outside influences, not the least of which would have been the attempt by a potential preda- tor to wrench the cephalopod from its conch (Berry, 1928). The addition of shell materia] at the aperture would have affected the hydrostatic characteristics of the conch, thereby altering the orienta- tion of the hyponome, but an even greater effect on the hyponome would have been the barricading of the aperture (Perna, 1915) — the hyponome would have needed to shoot over the constriction (or shell thickening or both) or to extend beyond it, as in Nautilus. The thickening of the shell material might have been simply a device to rid the body of excess calcium carbonate. A highly con- stricted aperture would have imposed limitations on the size of food that could have been consumed, unless the cephalopod could extrude its body as do the modern cowries. Perhaps young ammon- oids were protected by living behind the apertural constriction of a parent (Schmidt, fide Berry, 1928). The purpose of the two pro- nounced depressions within the apertural constriction of Cyclolobus is unclear. Likewise, the purpose of the slight apertural shell thick- ening in Nautilus has not been established. Lappets might have served in mating (or other) battles; they don’t appear strong enough to have functioned as real weapons, but they might have done service in bluffing such as occurs in the extant cephalopods Loligo and Sepia. They could have been utilized as supports for sex organs or perhaps for protection of eggs or young. Lappets might also have been used as supports of nonsexual organs; Gillet (1937) suggested that these structures might have supported arms. Mikesh and Glenister (1968) contemplated that hollow lateral shell extensions in Solenochilus, a Carboniferous nautilid, might have enclosed extensions of the mantle which served a sensory function. The development of lappets may have been to eliminate part of the weight of the shell, while still retaining some of its supporting and protective attributes. On the other hand the lappets may have added weight anteriorly to alter the orientation of the conch. Lappets might, in addition, have served a hydrodynamic function. PaLteozoic AMMoNoOIDs: Davis 35 Ruzhencev (1962) suggested that they supported the animal when it advanced from the shell and perhaps allowed the creature to move into and out of the conch more rapidly; to him this indicated a more predational way of life. The rostrum has been taken by many authors to indicate loss of swimming ability, but some creatures with rostra seem from other features to have been nektonic (Dunbar, 1924). As pointed out by Perna (1915) a rostrum might have served as a funnel support; in fact, the hyponome may have been bifid, one half lying on either side of the rostrum (Trueman, 1941). The rostrum could have sup- ported the animal when it advanced from its shell. This structure may have been used as a weapon, either real or apparent, or as a support for sensory or other organs. It is likely that the rostrum would have had a hydrostatic effect, bringing the aperture down, and might also have resulted in streamlining. Dunbar (1924) suggested that a hyponomic sinus would be needless for an animal with a long muscular body which could be protruded from the shell; in fact, he said, this protrusion would displace more water so that the animal would have become more buoyant the instant it started to swim. Perhaps the rostrum served for brooding. Jeannet (1948) regarded all ammonoids bearing rostra as dibranchiates but stated no reasons. In Nautilus there apparently is a change in shell deposition about the time the final aperture is formed — the “black layer” which is restricted to the dorsum in juveniles is extended to ring the aperture. Zittel (1895) equated this “black layer” with the runzelschicht of ammonoids. The raised points on the venter of the interior of the modified portion of the shell of, for example, some of the adrianitids may be a ventral extension of runzelschicht and, if so, could be homologous to the black ring of the mature Nautilus. Pruvot-Fol (1937) suggested that the black matter in Nautilus con- sists of metabolic wastes. Willey (1902) noted that usually, but not always, the last few septa of Nautilus are progressively more crowded. Such approxima- tion also occurred in at least some ammonoids (and fossil nautiloids, too, for that matter). Makowski (1962) reasoned (for Quenstedto- ceras, a Mesozoic ammonoid ) that lengthening of the shell stopped before septal secretion ceased; this resulted in a shortening of the body chamber and a progressive approximation of the ultimate few septa. Whether this actually occurs in Nautilus is unknown. Shorten- 36 BuLLETIN 272 ing of the living chamber might be linked with an enlargement in whorl cross-section. In any case there probably would have been an effect on the center of gravity and, hence, on orientation of the live animal. In ammonoids other than those with simple sutures septal crowding was accompanied by a sutural simplification. Makowski (1962) indicated that further growth of such specimens and eventual return of the sutures to the normal shape have never been ob- served. He stated further that the septal crowding present at places in the phragmocones of some ammonoids is never accompanied by sutural simplification and that the phragmocone constrictions in goniatites and other forms are never accompanied by densely spaced septa and simplified sutures. (Suture simplification followed by further complication are, however, known in the early ontogenetic stages of Agathiceras [fide Miller and Furnish, 1939] and Paracel- tites [personal communication, Claude Spinosa] ). Sutural simplifica- tion accompanying septal approximation would seem to be merely a mechanical adjustment to septal crowding. The ultimate septum of externally shelled cephalopods common- ly is greatly thickened. This thickening, surely of hydrostatic im- port, also may have served to provide a stronger base for muscle support. Perhaps the animal disposed of excess calcium carbonate in this manner. The purpose and cause of the thickening of the ulti- mate septum in Nautilus is unknown. Makowski (1962) reported that in certain (but not all) taxa supplementary prismatic shell material was added at the base of the ultimate body chamber for muscle attachment. At present the physiology and ecology of Nautilus are virtually unknown. Until the basic research on these subjects is done, evalua- tion of the hypotheses concerning the physiologic and ecologic im- plications of ammonoid mature modifications is premature. More- over the possibility that the ammonoid was not closely similar to any extant animal cannot be precluded completely. The various mature modifications might have been suited for anatomies not now within our sphere of knowledge. DIMORPHISM Since before the middle of the Nineteenth Century paleon- tologists working with the ammonoid cephalopods have recognized PaLeEozoic AMMONOIDs: Davis 37) that mature individuals commonly occur in paired groups. One of each pair is larger and generally has a simple peristome; the smaller form commonly has a more ornate aperture. Particularly impressive are the facts that the pairing is widespread in time and space and that the two groups of a pair are closely similar except near and at maturity. This pairing has been attributed to sexual dimorphism. Phenetic differences between two groups of individual am- monoids collected from the same horizon and locality could be due to any of a number of factors. The two groups might represent two separate taxa (of any level); in other words, phyletic splitting had occurred. If the taxa are conspecific, the presence of both in one place simultaneously could be due, for example, to a recent breakdown of the barrier which led to the phyletic split, to ocean water depth stratification of the taxa, to activity at different times of the day, or to post- mortem transportation. The two groups might indicate dimorphism (that is, the existence in one taxon of two distinct phenetic groups). Dimorphism could seem present in the local collection because of: a high proportion of pathologic individuals, a high proportion of mutant individuals, post-mortem deformation, post-mortem sorting, preferential destruction, or faulty sampling. In one area pathologic conditions could result in two groups, but such conditions would be unlikely to be widespread and long- lived. Likewise, in a small area, taxonomically unimportant but phenetically striking mutation (for example, a high proportion of six- legged frogs in a single pond) could produce apparent dimorphism, but, again, over a broad area and extended period of time such mutations would be lost or become of sufficient frequency to be taxonomically important. Post-mortem deformation could produce apparent dimorphism (for example, Davis and Campbell, 1968, dis- cussed specimens of the longiconic nautiloid Pseudorthoceras knoxense from Carboniferous rock near Knoxville, Iowa, — those specimens lying horizontally are flattened, whereas those standing Dk ON 38 BULLETIN 272 vertically are round in cross-section), but deformation is almost always recognizable by actual breaks in the specimen, loss of bi- lateral symmetry, or both, and, moreover, identical conditions of deformation would be confined to a small geographic area. Sorting or preferential destruction might, for example, remove middle-sized specimens, leaving apparent dimorphism — again studies of collec- tions from other strata and localities would reveal the local nature of such conditions of sorting or preservation. A non-representative sample of the local fauna could give a distorted picture of even that fauna. Actual dimorphism should be recognizable throughout the whole taxon. Dimorphism could be the result of: 1. alternation of morphologically distinct generations, 2. polymorphism, such as exhibited by certain hymenopteran insects, for example, 3. morphological differences between different ontogenetic stages (including neoteny, such as exhibited by the axolotyl, and instars), or 4. sexual dimorphism. Of these four, only the last has been documented in the Cephalopoda. Whether two groups are representatives of separate taxa or are sexual antidimorphs (opposite members of a dimorphic pair) is a basic question. The criteria for the identification of sexual dimorph- ism in ammonoids are well known (Makowski, 1962; Callomon, 1963; Westermann, 1964): 1. There should be distinct dimorphism between sexual anti- dimorphs. 2. Sexual antidimorphs should have identical phylogenies. Sexual antidimorphs should have identical early ontogenies. 4. Sexual antidimorphs should have the same stratigraphic range. 5. The sex ratio should be consistent both with that in modern related organisms and within the total geographic and strati- graphic range of the taxon. If sexual dimorphism is to be recognized there must be some ob- servable difference between the two sexes. Between two sexually antidimorphic groups intermediate forms might exist either because the ranges of variability of the two groups overlap, because of the Ww PaLeozoic AMMONOIDs: DAvIs 39 existence of intermediate mutant or pathologic individuals, or be- cause of the presence of intersexes in the taxon. Theoretically, at least, the two sexes of a species need not evolve in the same way or at the same rate, particularly with respect to phenetic characters directly involved with sex. Hence, sexual anti- dimorphs might well not have identical phylogenies and ranges. McCaleb’s (1968, p. 29) conclusion that “dimorphism is a_pre- dominant feature at the inception of an evolution lineage and de- creases throughout phylogeny”, if generally applicable to am- monoids, may be important. The respective ontogenies of the two sexes of a species need not be identical. Sexual characters can appear early in ontogeny. Mc- Caleb’s (1968) conclusions regarding dimorphism in Syngastrioceras oblatum (from the Upper Carboniferous of Arkansas), perhaps cast doubt on the almost universal application of the assumption that sexually dimorphic characters are most pronounced at maturity. What he considered to be antidimorphs differ most as juveniles, and “the conch differences decrease in the more mature forms” (p. 51). Even if the actual sex ratios in now extinct forms were con- sistent with such ratios in related extant groups, there are many possible sources of deviation. Differential mortality could produce local concentrations of one or the other sex, and, likewise, different geographic distributions in life, differential preservation, and sorting could result in local deviations. In all these cases study of the taxon throughout its whole range would disclose an approximation of the actual ratio. The general collector tends to gather the more spec- tacular fossils, so might gather the larger or more striking of the antidimorphs or might consider poorly preserved specimens of the smaller antidimorph to be juveniles of the larger and count them as such. Moreover, the sex ratios reported for the extant cephalopods (Pelseneer, 1926; Fretter and Graham, 1966; Mangold-Wirz, 1963 ) vary so markedly that virtually no antidimorph ratio could be re- jected as inconsistent. In short, each criterion for the identification of sexual dimorph- ism can be open to serious doubt. It does, however, seem highly unlikely that paired groups of ammonoids with both members having closely similar ranges, phylogenies, and ontogenies and in a con- 40 BULLETIN 272 sistent ratio throughout their geographic and stratigraphic ranges could be anything but sexual antidimorphs. The conclusion that two forms are sexual antidimorphs presup- poses that the two forms are conspecific. Hence, the person making the conclusion has no alternative but to refer to both forms by the same binomen. Makowski (1962) recognized two sorts of dimorphism in am- monoids, based primarily on number of whorls: In Type A — one antidimorph generally has five to six whorls but may have as few as four, and the other antidimorph generally has seven to nine whorls but may have as few as six. The larger form has a relatively greater whorl height adapertural of whorl five to five and one-half. In Type B — one antidimorph generally has seven to nine whorls but may have as few as six, and the other antidimorph has at least one whorl more than its opposite. (Guex, 1968, added a third type, ‘O’, in which the smaller antidimorph has but three to four whorls. ) Westermann (1964) also recognized two kinds of dimorphism, based on conch morphology. In the simpler and rarer type the anti- dimorphs differ only in size but not in other morphologic characters. In the more abundant type one antidimorph is smaller and has a more highly modified peristome than the other; the two antidimorphs may also differ in other mature modifications. Westermann recog- nized dimorphism, intermediate between the two main types, in which the antidimorphs differ both in size and in minor morphology, for example, in the transverse ribs on the mature conch. Zeiss (1969) recognized three categories of dimorphism. In Group I, one antidimorph is large and variocostate whereas the other is small and equicostate. Both antidimorphs of Group II are ornamented similarly, but there are differences in size and in the shape of the apertural region. Dimorphism in Group III is suspected but not clearly recognizable. The various systems do not correspond. For example, each of Makowski’s dimorphism types includes representatives of both of Westermann’s categories. Beginning with De Blainville (1840), who was the first person to suggest dimorphism in ammonoids (fide Makowski, 1962), most PaLeozoic AMMONOIDs: DAvIs 4] workers have considered the smaller of each dimorphic pair to be the male. Makowski (1962, p. 58) stated that in all known inverte- brate groups in which sexual dimorphism is expressed by notable differences in size, it is the male which is smaller: “Not a single case of opposite morphological conditions has so far been reported in this respect.” Wells (1962, p. 33) in discussing extant forms noted that: “In cephalopods the males are usually larger than their mates.” Being more specific, Wells (1966, p. 581) stated: “In Octopus, Sepia, Sepiola, and Loligo, at least, the occurrence of mating appears to be determined by the male, which is generally larger than the female. . .”. Mangold-Wirz (1963) gave length and age measurements for sixteen extant cephalopod species. Although in some cases the maxi- mum size of males exceeds that of females, in every example given save one the length of the female upon reaching maturity is greater than that of the male at maturity. In that one case, Sepia officinalis, the female is just at the upper end of the size range of the males. (Of interest is the fact that, except in Sepia officinalis, the female takes longer to reach maturity. Moreover, in those cases in which the maximum length of one sex exceeds that of the other, it appears that the maximum age of the one also exceeds that of the other.) Westermann (1969) pointed out that size relationships of the sexes of extant cephalopods are extremely variable even at the genus level. Although he gave no measurements with his examples, he concluded that “wherever marked sexual dimorphism in_ size (> 1.5 in diameter) is present in the cephalopoda, the female is larger than the male.” Mangold, Lu, and Aldrich (1969) discussed dimorphism in the extant squids J/lex illecebrosus illecebrosus, I. illecebrosus argentinus, and J. illecebrosus coindetu, in all of which it is generally accepted that females are larger than males. In all three subspecies the mean mantle length of females exceeds that of males. However, in J. dlecebrosus coindetu, and apparently also in J. illecebrosus argen- tinus, the males and females differ in proportions; for example, in I, illecebrosus coindetui the arms of the male are longer, the head of the male is broader, and the diameter of the largest suckers is larger in males than in females. In Nautilus the male is slightly broader than the female (Willey, 1902). Stenzel (1964) illustrated (after Willey, 1902) the maximum 42 BuLLeETIN 272 and minimum whorl width differences between the sexes of Nautilus. The male is shown to be as much as 25% wider than the female. (Westermann’s 1969 statement about this illustration that the fe- male is 50% wider is apparently a typographic error.) Coémme (1917, fide Makowski, 1962) stated that in ammonoids the smaller antidimorph of a pair is the less abundant, as are the males of modern cephalopods. Pelseneer (1926, and extracted in Fretter and Graham, 1966) collated reports of sex ratios for modern cephalopods varying from 3:1 in favor of males to nearly 7:1 against; most of his examples give females the majority. Man- gold-Wirz (1963) gave sex ratios for 16 extant cephalopod species which range from 143 males for every 100 females to 39 males for every 100 females; she discussed that season of sampling, place of sampling, and relative susceptibility of the sexes to capture may be significant in her statistics, Westermann (1969) also discussed sex ratios in extant cephalopods, paying particular attention to migra- tion of populations and the commonly concomitant segregation of sexes. Mangold, Lu, and Aldrich (1969) studied 382 males and 351 females of Illex illecebrosus coindetii as well as 452 males and 457 females of J. dlecebrosus illecebrosus. Willey (1902) listed 150 male: 66 female Nautilus pompilius, but 10 male: 16 female Nautilus macromphalus. One is forced to wonder whether size differences and (especially) sex ratios in modern forms are sufficiently well understood to extra- polate to fossil cephalopods. Within the mature living chamber of an Eleganticeras elegantu- lum macroconch (the larger antidimorph of a pair) Lehmann (1966) found a cluster of spherical structures of the same size as the pro- toconch of the species. He cautiously interpreted these structures as egg coatings. This, if the brooding of eggs by the female in Argo- nauta and Octopus proves to be the general case in the extant cephalopods, might be taken to indicate that the macroconch is the female. As related in the excellent historical surveys of Makowski (1962) and Callomon (1963), most students of ammonoid dimorph- ism have concentrated their attentions on Mesozoic fossils. However Foord and Crick (1897), Haug (1897), Perna (1914), Demanet (1943), McCaleb and Furnish (1964), Furnish and Knapp (1966), PaLreozoic AMMONOIDs: DAVIs 43 McCaleb (1968), and Davis, Furnish, and Glenister (1969) have all at least suggested the existence of dimorphism in ammonoids from the Paleozoic. The greatest obstacle to study of dimorphism in Paleozoic am- monoids is the marked lack of suitably preserved faunas. In order to establish that dimorphism exists, it is necessary to study large num- bers of fossils which retain mature modifications. In addition, the internal whorls must be well preserved, if ontogeny is to be deci- phered and whorls counted. In none of the five families studied 1s any fauna known to me which fully satisfies the requirements of abundance and suitable preservation. The Agathiceras fauna from the Road Canyon Formation of Texas discussed by Davis, Furnish, and Glenister (1969, pp. 103, 105-107) lacks preservation of internal whorls. Of the taxa discussed in the descriptive portion of this work only four, Agathiceras, Hyattoceras, Marathomtes, and Waagenina, exhibit two distinct mature forms. Unfortunately, paucity of avail- able mature individuals of the last three forces me to regard the dimorphism apparent in these three genera as only theoretical. On the other hand, dimorphism in A gathiceras seems to be statistically justifiable (Davis, Furnish, and Glenister, 1969). But even this case is established only on the basis of a single collection from one horizon and locality and, because the ontogeny and phylogeny of the studied specimens is unknown, any too positive attribution of the dimorphism apparent in Agathiceras to sex seems to me to be premature. DESCRIPTIVE PART Superfamily ADRIANITACEAE Schindewolf, 1931 Family ADRIANITIDAE Schindewolf, 1931 Diagnosis. — The Adrianitidae includes ammonoids in which the suture underwent goniatitic ontogenetic development; sub- sequent new elements were then added in the saddle positioned on the early adolescent umbilical seam, and these elements migrated toward the dorsum and venter respectively. Genus ADRIANITES Gemmellaro, 1887 Diagnosis. — Adrianites includes adrianitids in which the 44 BULLETIN 272 “mature” suture on each side has six or seven lobes between the bifid ventral lobe and the umbilical shoulder. Synonymy. — Glenister and Furnish (1961, p. 726) suggested that Neocrimites (Sosiocrimites) Ruzhencev, 1950, and Aricoceras (Neoaricoceras) Ruzhencev, 1950, are synonyms of Adrianites. Specific composition. — Adrianites elegans Gemmellaro, 1887, is the type species of Adrianites by original designation. Adrianites kingi Gemmellaro, 1887, is the only species which was referred to Aricoceras (Neoaricoceras) by Ruzhencev (1950). Adrianites instg- nis Gemmellaro, 1887, and A. insignis var. biassalensis Toumanskaya, 1931, are the only two taxa which were referred to Neocrimites (Sosiocrimites) by Ruzhencev (1950); Furnish and Glenister (in Davis, Furnish, and Glenister, 1969, explanation to plate 3) consid- ered A. insignis to belong in Neocrimites. In addition to the pre- viously listed taxa, A. isomorphus Gemmellaro, 1888, is referred to Adrianites, and the following inadequately described taxa may be- long in the genus: A. bobkovae Toumanskaya, 1949, A. permicus Toumanskaya, 1935, A. planus Toumanskaya, 1935, and A. vino- gradovi Toumanskaya, 1949. A. schmidti Toumanskaya, 1937a, and A. bobkowi Toumanskaya, 1937a, are apparently nomina nuda, Immature shell. — The conch of Adrianites has been described as discoidal to subspherical, involute, and with a small umbilicus (Ruzhencev, 1950, p. 204). Constrictions are present in most, if not all, individuals of Adrianities. In the type species A. elegans they are prominent on the shell exterior, producing a slight but conspicuous decrease in whorl height immediately adoral of each constriction. Similar de- creases in whorl height occur in representatives of A. insignis and A. isomorphus, even though the constrictions in these two taxa are less prominent than in the type species. In A. kimgi, on the other hand, the only evidence of constrictions on the shell exterior is the periodic closer spacing of the transverse lirae. The maximum num- ber of constrictions per whorl apparently varies from two (in A. tsomorphus) through three (in A. elegans and A. kingi) to four (in A. insignis). In the type species Adrianites elegans the longitudinal and transverse lirae are equally conspicuous. In the genus as a whole the relative prominence of these two features varies from that dis- played by A. tsomorphus, in which the transverse components are PaLeozoic AMMONOIDs: Davis 45 much the less striking, to that shown by A. king, in which the longi- tudinal ornament is restricted to the flanks in the form of scallops in the transverse lirae. The longitudinal lirae are weak or absent in the constrictions. In some individuals the longitudinal ornament affects both the shell exterior and interior. The overall trend of each half of the external suture is arcuate. Mature shell. — After about two-thirds of the ultimate whorl of Adrianites had been formed, there occurred a slight decrease in the radius of curvature of coiling, followed by a slightly greater in- crease; this resulted in the venter being somewhat flattened in longitudinal section. This change in coiling is particularly evident in the umbilici of specimens of A. tsomorphus and A. kingit where it resulted in an actual decrease in the size of the umbilicus. In A. elegans and in at least some representatives of A. imsigmis the umbilicus seems little affected (but in these taxa, the flattening of the venter is, itself, slight). In at least some individuals, for example of A. tsomorphus and A. elegans, the change in coiling was accompanied by a slight but distinct increase in relative whorl width; this bulging appears greatest in the dorsolateral portions of the flanks. Near the adapertural end of the mature body chamber of Adrianites is a constriction whose trend is somewhat different from those adapical of it. Shortly before the apertural constriction was formed, a decrease in the radius of curvature of coiling occurred, leading directly into the constriction. As in the immature constrictions of Adrianites, longitudinal lirae are not present in the ultimate constriction or are less prom- inent there than adapical of it. The growth lines are more closely spaced and are commonly less prominent in the terminal constriction than adapical of it. Beginning in the adoral portion of the apertural constriction each successive growth line shows a more accentuated ventrolateral salient on each side, forming the lappets of the ulti- mate peristome. The lappet figured by Gemmellaro (1888, pl. D, fig. 10) is straight. Each lappet bears an adaperturally directed branch of the ultimate constriction. The leading edge of the dorsal shell of Adrianites has a distinct lip (for example, USNM-a and SUI 32442). The surface of the dorsal shell is ornamented with irregularly spaced ridges and raised points 46 BuLLeETIN 272 arranged in a generally radial pattern; this is interpreted as runzel- schicht. The ventral surface of the internal mold of the mature body chamber in some individuals (for example, USNM-b) bears minute, irregularly spaced pits which correspond to raised points on the in- ward-facing surface of the shell. In one place on USNM unnum- bered specimen b the outermost portion of the shell has broken away, revealing that the raised points on the inward-facing surface of the shell correspond to globular- or rod-shaped bodies within the shell itself. The presence of these bodies in some and their absence in other individuals even in the same species remains unexplained. Gemmellaro reported the following living chamber lengths for members of Adrianites: one and one-third whorls in A. elegans (1887, p. 44), more than one volution in A. imsignis (1887, p. 45), and a whorl and a half in A. king (1887, p. 47) and in A. tsomorphus (1888, p. 14). The ultimate constriction and final septum were ob- served by the present author in only one individual (A. tsomorphus — SUI 32442); they lie about one and one-third whorls apart. The maximum diameter of specimens of Adrianites known to the author are: A. elegans — 20% mm and 21 mn, A. kingi — 22 mm, A. itsomorphus — 25 mm, 26 mm, 27 mm, 27 mm, and A. insignis — 27 mm and 29 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887, 1888), Toumanskaya (1931, 1935, 1937a, 1949), Miller and Furnish (1940a), Ruzhencev (1950), Glenister and Furnish (1961), Bogoslovsky, Librovitch, and Ruzhencev (1962), Davis, Furnish, and Glenister (1969), three mature and one nearly mature specimens of A. tsomorphus (USNM unnumbered, SUI 32442), two mature examples of A, cf. A. insignis (GPIT unnum- bered, BMNH C 37654), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — The following mature specimens of Adrianites are figured: two A. elegans — IGUP 85 (PI. 3, figs. 1-3), (Pl. 3, figs. 5-7), two A. insignis — MGPU unnumbered (PI. 5, figs. 4, 5), IGUP 84 (PI. 6, figs. 7, 8), one A. cf. A. insignis — BMNH C37654 (Pl. 5, figs. 1-3), four A. tsomorphus — SUI 32442 (PI. 3, fig. 4), IGUP 86 (PI. 4, figs. 1-3), USNM unnumbered a (PI. 4, figs. 7, 8), USNM unnumbered b (PI. 4, fig. 9), and one A. kingi — IGUP 81 (Pl. 5, figs. 6-8). PaLEozoic AMMONOIDs: DAvIs 47 Genus CRIMITES Toumanskaya, 1937b Diagnosis. — Crimites includes narrowly umbilicate adrianitids in which the “mature” suture on each side has three complete lobes between the bifid ventral lobe and the umbilical shoulder. Specific composition. — The type species of Crimites is Agathi- ceras krotowi Karpinsky, 1889, by subsequent designation of Glenis- ter and Furnish (1961, p. 726). In addition to the type species the following are referred to Crimites: C. elkoensis Miller, Furnish, and Clark, 1957, C. glomulus Ruzhencev, 1952, C. pamuricus var. darensis Toumanskaya, 1949, C. singularis Bogoslovskaya, 1962, and C. subkrotowit Ruzhencev, 1938. Adrianites globosus Chernov, 1939, is a synonym of Crimites krotowi (fide Ruzhencev, 1956a, p. 249). Crimites busterensis Toumanskaya, 1937b, C. pamiricus Toumans- kaya, 1937b, C. smithi Toumanskaya, 1937b, C. spathi Toumans- kaya, 1937b, and C. undosus Ruzhencev, 1952, are apparently all nomina nuda. Adrianites gemmellarot Toumanskaya, 1931, A. hamiel Toumanskaya, 1931, Agathiceras oyensi Haniel, 1915, A. rothpletz Haniel, 1915, and Crimites subkrotovi var. murgabensis Toumans- kaya, 1949, may belong in Crimites. Immature shell. — The conch form of Crimites has been described as spherical to strongly globose (Ruzhencev, 1950, p. 202). The shell is involute. Only one individual of Crimites known to the author (Ruzhen- cev, 1956a, pl. 39, fig. 3) has immature constrictions; three shallow ones are visible in its outermost preserved whorl. The relative prominence of the longitudinal and transverse lirae of Crimites is variable; the spiral ornament may be much the more striking, may be just as conspicuous as the transverse lirae, or may be represented only in the form of scallops in the growth lines. In those individuals with prominent transverse lirae, each lira is at the crest of a transverse shell plication. On the internal mold the peak of each plication is, itself, scalloped. Along the umbilical shoulder of some representatives of the genus there runs a thicken- ing of the shell layer (Ruzhencev, 1941, p. 884). In addition to the three lobes between the bifid ventral lobe and the umbilical shoulder of Crimites, on each side there are three lobes between the umbilical seam and the dorsal lobe, and there are a variable number of lobes on the umbilical wall. Each “internal 48 BuLLETIN 272 lateral lobe” is tied to its respective “external lateral lobe”. The lobe just ventrad of the shoulder may be bifid. Mature shell. — Only comparatively slight changes in coiling occurred in the final stages of the ontogeny of Crimites. In some individuals, after al] but about the last quarter of the ultimate volu- tion was formed there was a slight decrease in the radius of curvature of coiling, followed by a like increase; this resulted in a slight flat- tening of the venter as viewed in longitudinal section. This change in coiling is accompanied by a gentle increase in the ratio W/D. The umbilicus appears to have been little affected. Near the adapertural end of the mature living chamber of Crimites is a broad constriction. The plications in the shell of Crimites do not seem to occur in the ultimate constriction, although growth lirae are present. Longi- tudinal ornament extends into the adapertural constriction; at least the transverse lirae there are scalloped. No specimen of Crimites known to the author retains the ulti- mate peristome. The ultimate constriction of Crimites varies from three-quarters to just less than one whorl adapertural of the ultimate septum. All three mature specimens of Crimites known to the author have a diameter between 22 and 23 mm. Material. — The preceding observations are based on study of: Haniel (1915), Toumanskaya (1931, 1937a, 1937b, 1949), Ruzhen- cev (1941, 1950, 1951, 1952, 1956a), Miller, Furnish, and Clark (1957), Glenister and Furnish (1961), Bogoslovskaya (1962), and two mature and one nearly mature specimen of Crimites krotowti (SUT 5981). Illustrations. — Two mature specimens of Crimites krotowt are figured: SUI 5981a (PI. 6, fig. 6) and SUI 5981b (PI. 6, figs. 3-5). Genus EPADRIANITES Schindewolf, 1931 Diagnosis. — Epadriamtes includes globose, fairly broadly umbilicate adrianitids in which the “mature” suture on each side has four or five lobes between the bifid ventral lobe and the umbilical shoulder, four or five lobes between the umbilical seam and the dorsal lobe, and two or three lobes on the umbilical wall. Synonymy.— Those specimens which have been referred to PaLEozoic AMMONOIDs: DAvis 49 Basleoceras Ruzhencev, 1950, are regarded as congeneric with in- dividuals of Epadriamtes. Specific composition. — The type species of Epadrianites is Agathiceras timorense Boehm, 1907, by original designation. Agathiceras beyrichi Haniel, 1915, is the type species, and Adriamites haueri Gemmellaro, 1888, is the only other species referred to Basleoceras by Ruzhencev (1950, p. 203). In addition, Agathaceras timorense var. involuta Haniel, 1915, is referred to Epadrianites. Immature shell. — The conch of Epadrianites has been described as moderately involute and spherical or with width greater than the diameter (Ruzhencev, 1950, p. 203). The majority of specimens of Epadrianites bear no evidence of constrictions. One specimen of E. timorense (SUI 32439) has six gentle transverse ridges in its outermost preserved whorl on which the longitudinal lirae are less distinct than elsewhere; another individual of the same species (PIUB unnumbered) is similarly ornamented. The ridges of both of the examples are apparently constrictions. The most striking ornamental feature of Epadrianites is the presence of prominent longitudinal lirae with faint transverse growth lines. Basleoceras and Epadrianites were distinguished on the basis of the difference in the spacing of the longitudinal lirae (Ruzhencev, 1950), but Haniel (1915, pl. 50, fig. 14) illustrated what is an ap- parently transitional form. Ruzhencev (1950, p. 203) stated that Basleoceras has growth lines with a weak ventral sinus, whereas in Epadrianites the growth lines each form a ventral salient. As far as the present author is able to determine, there is little if any dif- ference in the trend of the growth lines of the two “genera”. Mature shelil.— Only one mature specimen of Epadrianites is known to the author (IGUP 75). After about three-quarters of the ultimate whorl was formed, there was a slight decrease in the radius of curvature of coiling followed immediately by a slightly greater increase. Just before the apertural constriction was formed, there was a marked decrease in the radius of curvature leading directly into the constriction. These changes in coiling result in a flattening of the longitudinal section of the venter with a terminal upturning of the venter. The longitudinal ornament continues on into the ultimate constriction. The final peristome of Epadrianites is 50 BuLueTIN 272 unknown; the growth lines seem to retain their immature trend as far as preserved. The exact length of the mature living chamber of Epadriamtes is not known, although Gemmellaro (1888, p. 17) stated that it is much greater than one whorl. The diameter of the one known mature individual is 66 mm. Material. — The preceding observations are based on study of: Gemmellaro (1888), Haniel (1915), Miller and Furnish (1939), Ruzhencev (1950), Glenister and Furnish (1961), one immature individual of Epadrianites beyricht (SUI 32440), three immature specimens of FE. timorense (SUI 32439, 12321), and photographs and notes taken by W. M. Furnish and Brian F, Glenister in the summer of 1965. Illustrations. —One mature specimen of Epadrianites haueri is figured — IGUP 75 (PI. 8, figs. 1-4). One immature example of E. tumorense is also illustrated — PIUB 21b (PI. 9, figs. 8, 9). Genus HOFFMANNIA Gemmellaro, 1887 Diagnosis. — Hoffmannia includes strongly evolute, transversely plicate adrianitids in which the “mature” suture on each side has five lobes between the bifid ventral lobe and the umbilical seam. Specific composition.—The type species of Hoffmannia is Adrianites (Hoffmannia) hoffmanni Gemmellaro, 1887, by mono- typy. In addition to the type species, Adrianites (Hoffmannia) burgensis Gemmellaro, 1888, is referred to Hoffmannia. H. fisher Plummer and Scott, 1937, is probably not closely related to the genus (fide Miller and Furnish, 1940a, p. 110). Immature shell. — The conch of Hoffmannia is serpentine, evo- lute, with narrow whorls and a broad umbilicus (Bogoslovsky, Librovitch, and Ruzhencev, 1962, p. 394). All specimens of Hoffmannia known to the author have con- strictions which extend from seam to seam. There are two or three of these constrictions per whorl. The flanks of specimens of Hoffmannia are marked by con- spicuous simple or dichotomizing transverse plications. These plica- tions are restricted to the flanks, but on the venter there are deli- cate transverse ribs which appear to be growth lirae. Mature shell.—Only one individual known to the author (IGUP 78) may be mature. Its venter has been eroded, and ap- PaLeozoic AMMONOIDs: Davis 51 parently the creature had been seriously injured in life, for the plica- tions about one-eighth whorl adapical of the terminal constriction are markedly disturbed. The apparent flattening of the venter of the last quarter volu- tion as viewed in longitudinal section may be a mature modification or might be the result of erosion. The apparent rapid increase in whorl height in the region just adapical of the terminal constriction may be a modification, may have resulted from the animal’s injury, or may be the product of erosion of the shell apical of the region. Nonetheless, there does seem to be a gradual increase in the coarse- ness of the ventral ribbing in an adapertural direction throughout the ultimate whorl. ~The living chamber of Hoffmanma is one and one-half whorls long (Gemmellaro, 1887, p. 50). The diameter of the one possibly mature individual is 24 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887, 1888), Plummer and Scott (1937), Miller and Furnish (1940a), Glenister and Furnish (1961), Bogoslovsky, Librovitch, and Ruzhencey (1962), two immature specimens of Hoffmannia hoffmanni (USNM unnumbered, SUI 32434), and notes and photographs taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — One specimen of Hoffmannia is figured, a mature individual of H. hoffmanni — IGUP 78 (PI. 10, figs. 1-3). Genus NEOCRIMITES Ruzhencev, 1940a Diagnosis. — Neocrimites includes narrowly umbilicate adriani- tids in which the “mature” suture on each side has four or five lobes between the bifid ventral lobe and the umbilical shoulder, three to five lobes between the dorsal lobe and the umbilical seam, and one or two lobes on the umbilical wall. Synonymy. — Neocrimites (Metacrimites) Ruzhencev, 1950, and Neocrimites (Neocrimites) were considered consubgeneric by Glenister and Furnish (1961, p. 726, 727); Aricoceras (Aricoceras) Ruzhencev, 1950, and A. (Metaricoceras) Ruzhencev, 1950, were referred to Neocrimites by the same authors (ibid.). Specific composition.—The type species of Neocrimites is Adriamites fredericksi Emeliancev, 1929, by original designation. 52 BuLLeTIN 272 Adrianites newelli Miller and Furnish, 1940a, the type species, and Adrianites adamsi Miller and Furnish, 1940a, were the only taxa referred to Neocrimites (Metacrimites) by Ruzhencev (1950, p. 202). In addition to the type species, Ruzhencev (1950, p. 202; 1956a, p. 255) included the following in Neocrimites (Neocrimites): Adrianites defordi Miller and Furnish, 1940a, A. dunbari Miller and Furnish, 1940a, Waagenia koswae Krotow, 1885, Adrianites mara- thonensis Bose, 1919, A. nalivkini Toumanskaya, 1949, A. plummeri Miller, 1944, Agathiceras stuckenbergi Karpinsky, 1889, and Adria- mites warrem Miller and Crockford, 1936. Miller and Furnish (1940a, p. 116), however, believed that the type of A. marathonensis might be only an immature Waagenoceras dienert. Ruzhencev (1950, p. 203) included the following in Aricoceras (Aricoceras): Adriamtes ensifer Gemmellaro, 1887, the type species, Agathiceras cancellatum Haniel 1915 (sensu Haniel, p. 75), and Adrianites (Neocrimites) meridionalis Teichert and Fletcher, 1943. Agathiceras martini var. globosa Haniel, 1915, is apparently a synonym of Neocrimites can- cellatum (Furnish — personal communication, 1965 notes). The type species and only taxon which has been referred to Aricoceras (Metaricoceras) is Agathiceras cancellatum form. discoidalis Haniel, 1915, although the suture of Agathiceras cancellatum form. globosa Haniel, 1915 (pl. 50, fig. Ic) agrees with Ruzhencev’s (1950, p. 203) diagnosis of the subgenus. Furnish and Glenister (in Davis, Furnish, and Glenister, 1969, explanation to plate 3) included Adrianites insignis Gemmellaro, 1887, in Neocrimites. Immature shell. —The conch form of Neocrimites has been described as spherical to subdiscoidal (Glenister and Furnish, 1961, p. 728). The conch is involute (zbid.) to comparatively involute (Ruzhencev, 1950, p. 202). At least some individuals of Neocrimites bear transverse con- strictions. These constrictions are irregularly spaced, which may account for their apparent lack in some individuals. The amplitudes of these features are not uniform, nor do the variations seem to follow any regular pattern. The outermost preserved whorl of one specimen (one of IGUP 82) has nine transverse bands in which the growth lines are disturbed; these apparently reflect constric- tions and, if so, constitute the largest number observed by the present author in one whorl. Other than in this specimen, the PaLEozoic AMMONOIDs: DAvis 53 maximum number of constrictions observed per volution is four. The constrictions run from shoulder to shoulder. The shell of Neocrimites bears both longitudinal and transverse lirae, both of which in some individuals are so prominent as to be plications. The relative prominence of the transverse and longi- tudinal ornament varies. The spiral ornament of some specimens tends to fade at constrictions, and the growth lines are more closely spaced there. Along the umbilical shoulder of some representatives of the genus there runs a thickening of the shell layer (Ruzhencev, 1941, p. 884). Mature shell — After nearly three-quarters of the ultimate whorl of Neocrimites had been formed there was a slight decrease in the radius of curvature of coiling, followed by a slightly greater increase. Just prior to the formation of the ultimate constriction there was another decrease in the radius of curvature which led directly into the constriction. In the majority of known specimens all of these changes in coiling are slight. The trend of the ultimate constriction of Neocrimites differs from that of those adapical of it. This terminal constriction is devoid of longitudinal ornament. After almost all of the ultimate constriction of Neocrimites had been formed the ventrolateral portions of each successive growth line formed a larger salient, so that the ultimate peristome has one prominent ventrolateral lappet on each side, each bearing a branch of the terminal constriction. These lappets curve toward the dorsum. Neocrimites sp. of Glenister and Furnish (1961, pp. 729-731) was said to have a terminal flare adapertural of the ultimate con- striction. The internal mold of the living chamber of Neocrimites dunbari was said to bear a small, low, rounded ridge or raised line along the venter of the mature living chamber (Miller, 1944, p. 99). Gemmellaro (1887, p. 46) stated that the living chamber of Neocrimites ensifer is one and one-half whorls long. Neocrimites sp. of Glenister and Furnish (1961, pp. 729-731) was said to have a body chamber only one whorl long. In SUI 32443 the living chamber is no longer than one volution, and in SUI 32605 it is no more than one and one-quarter whorls long. The smallest mature individual of Neocrimites known to the author is 27 mm in diameter (viz. N. sp. of Glenister and Furnish, 54 BULLETIN 272 1961). The largest (SUI 32443) is not yet mature at a diameter of 40 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887), Haniel (1915), Bose (1919), Wanner (1932), Miller and Crockford (1936), Miller and Furnish (1940a), Ruzhen- cev (1940a, 1941, 1950, 1956a), Miller (1944), Toumanskaya (1949), Glenister and Furnish (1961), Bogoslovskaya (1962), Arm- strong, Dear, and Runnegar (1967), Davis, Furnish, and Glenister (1969), about one hundred immature Neocrimites (N. sp. — GPIT unnumbered, SUI 32444-32448, 32221, 32601-32603, defordi — SUI 1398, discoidalis — SUI 32450, dunbari — SUI 1360, 1763-1765, 13595, 32443, fredericksi — SUI 32449, 32452, 32543, globosus — SUI 32451, newelli — SUI 1361, 1478, 13596), eight mature indi- viduals (SUI 32443, 1360, 32600, 32604-32606), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — The following mature specimens of Neocrimites are figured: N. cancellatus (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969) — PIUB unnumbered (PI. 10, figs. 4,5), GIUA T328 (PI. 3, figs. 8, 9), N. ensifer — IGUP 82 (PI. 7, figs. 1-3), and (PI. 7, figs. 4, 5). In addition, one immature specimen is illustrated — N. ensifer — IGUP 82 (PI. 6, figs. 1, 2). Genus PALERMITES Toumanskaya, 1937a Diagnosis. — Palermites includes moderately evolute adrianitids in which the “mature” suture on each side has five lobes between the bifid ventral lobe and the umbilical shoulder, five lobes between the dorsal lobe and the umbilical seam, and one or two lobes on the umbilical wall. Specific composition. — The type species of Palermites is Adriamtes distefanot Gemmellaro, 1887, by original designation. In addition, Adrianites distefanoi var. minor Toumanskaya, 1931, is referred to Palermites. Immature shell.—The conch of Palermites is not broad, is moderately involute, and has a large umbilicus (Ruzhencev, 1950, p. 203): Every specimen of Palermites known to the author bears trans- verse constrictions, concave outward on both the shell exterior and the steinkern. Most individuals have three constrictions per whorl. PaLeozoic AMMONOIDS: DAVIs 55 Each constriction continues from umbilical seam to umbilical seam. Longitudinal lirae are restricted to the umbilical region but are absent from the umbilical wall. The lira which is most prominent is situated on the shoulder. On the more ventral portions of the conch, longitudinal ornament is present only as scallops in the trans- verse lirae. Transverse lirae are crowded slightly adoral of each con- striction. Mature shell. — After slightly more than half of the ultimate whorl of Palermites was formed there was a slight decrease in the radius of curvature of coiling followed by a slightly greater increase; this change in coiling is evident in the course of the umbilical seam but does not appear to have affected the venter. After about three- quarters of the last volution was formed, there was another pair of changes in coiling similar to the previous but affecting both the seam and the venter. Coupled with the latter changes in coiling was a gradual increase in the ratio W/H, so that the venter appears somewhat flattened both in longitudinal and transverse section. Close to the ultimate constriction the height increased relative to the width, so that the venter again took on a smaller radius of curvature in transverse section; there is also a tightening of coiling leading directly into the ultimate constriction. The terminal constriction of Palermites is marked by a gentle ridge which parallels the trend of the constriction. From its broadest point on the venter the constriction becomes narrower and shallower toward the umbilical shoulders. Ventrolateral lappets in Palermites were commenced after al- most all of the ultimate constriction was formed. These lappets are shorter and more delicate and appear to be more strongly oblique than in other genera of the family. The living chamber of Palermites distefanoi is considerably longer than the ultimate whorl (Gemmellaro, 1887, p. 48). Two mature individuals of Palermites are known to the author, both from Sicily. Their diameters are 30% mm and 45 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887), Toumanskaya (1931, 1937a), Ruzhencev (1950), Glenister and Furnish (1961), about a dozen immature individuals (USNM unnumbered), three other immature speci- mens (SUI 32455), one mature example (SUI 32456), and notes 56 BULLETIN 272 and photographs taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. —Two mature specimens of Palermites distefanot are figured: SUI 32456 (PI. 9, figs. 3-5) and IGUP 76 (PI. 9, figs. Sa fy Genus PSEUDAGATHICERAS Schindewolf, 1931 Diagnosis. — Pseudagathiceras includes large-umbilicate adriani- tids in which the “mature” suture is straight in overall trend and on each side has three or four lobes between the bifid ventral lobe and the umbilical shoulder, three lobes between the dorsal lobe and the umbilical seam, and one or two lobes on the umbilical wall. Specific composition. — The type species of Pseudagathiceras is Agathiceras (Doryceras?) wichmanni Haniel, 1915, by original des- ignation. In addition, P. difuntense Miller, 1944, and P. spinosum Miller, 1944, are referred to Pseudagathiceras. Immature shell. — The shell of Pseudagathiceras has been de- scribed as very broad and evolute or moderately involute, with a fairly large umbilicus (Ruzhencev, 1950, p. 203). The umbilical shoulders are rounded. Every specimen of Pseudagathiceras known to the author with the possible exception of the holotype of the type species bears transverse constrictions. These extend from umbilical seam to um- bilical seam. The maximum number of constrictions observed in any one whorl is five; the majority have but three per volution, but these are smaller specimens. Pseudagathiceras, with the possible exception of the holotype of the type species, bear irregularly spaced transverse plications. The plications are stronger near the umbilicus, so much so that some individuals appear nodose. All specimens of Pseudagathiceras in which shell is preserved bear longitudinal lirae. These lirae seem to fade out on the umbilical walls. In most specimens the transverse lirae are much less promin- ent than the longitudinal ornament, but in one specimen available to the author the lirae in the two directions are equally distinct. Mature shell. — After about two-thirds of the ultimate whorl was formed there was a slight decrease in the radius of curvature of coiling followed by a slightly greater increase in the radius of coiling. Just prior to the formation of what may be an apertural PaLeozoic AMMONOIDs: DAvis Ly constriction there was a decrease in the radius of curvature of coil- ing. The umbilicus displays only a gradual increase in the radius of curvature followed by decrease in the vicinity of the apertural (?) constriction, There seems to be a constriction or particularly prom- inent plication just where the first change in coiling occurs. The transverse plications are more prominent on the ultimate living chamber of Pseudagathiceras than on the phragmocone. In the adapical half of the living chamber certain of the plications bear a ventrolateral spine on each side. Not every plication is so favored, and the spines do not seem to be regularly positioned on the circumference. In the adapertural half of the living chamber no spines were formed, but the plications are prominent. Miller (1944, pp. 101, 103) reported that the living chamber of Pseudagathiceras is almost one whorl long. The maximum diameter (exclusive of spines) of the Pseudaga- thiceras figured by Miller (1944, pl. 29, figs. 1, 2) is 21 mm, Material. — The preceding observations are based on study of: Haniel (1915), Miller (1944), Ruzhencev (1950), Glenister and Furnish (1961), about one and one-half dozen immature specimens of Pseudagathiceras difuntense (SUI 32457, 1363, 1362, 1770, 13621), and photographs and notes taken by W. M, Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — One mature specimen of Pseudagathiceras spin- osum is figured — YPM 16310 (PI. 9, figs. 1, 2). One immature ex- ample of P. wichmanni is also illustrated —THD 12752 (PI. 10, figs. 6-8). Genus SIZILITES Toumanskaya, 1937a Diagnosis. — Sizilites includes large-umbilicate adrianitids in which the “mature” suture is arcuate in overall trend and on each side has four lobes between the bifid ventral lobe and the umbilical seam and has four lobes between the dorsal lobe and the seam. Specific composition. — The type species of Sizilites is Adrianites affinis Gemmellaro, 1888, by original designation. In addition, A. craticulatus Gemmellaro, 1888, is referred to the genus. Immature shell.—The conch of Sizilites is described as not wide, moderately involute, and with a large umbilicus (Ruzhencevy, 1950, p. 204). The umbilical shoulder has a large radius or is absent. Every specimen of Sizilites known to the author bears two to 58 BULLETIN 272 four constrictions in the outermost preserved whorl. These constric- tions tend to fade out on the venter and on the umbilical wall por- tions of the conch, but they are prominent elsewhere. In some individuals of Sizilites longitudinal lirae occur on all but the umbilical wall portions of the shell, but in other specimens these lirae fade on the venter to become merely scallops in the trans- verse lirae. The longitudinal ornament fades at constrictions. Mature shell. — After about one-half of the ultimate whorl of Sizilites was formed there was a slight decrease in the radius of curvature of coiling followed by a slightly greater increase. After about two-thirds of the whorl was formed there occurred another pair of changes in coiling similar to the first pair. These latter changes were apparently followed by a gradual relative increase in width, Just prior to the formation of the apertural constriction a decrease in the radius of curvature of the coiling occurred, leading directly into the constriction. The apertural constriction of Szzilites is much more prominent and of a somewhat different trend from those adapical of it. The longitudinal ornament ceases about one-quarter whorl adapical of the apertural constriction. The growth lines, on the other hand, become more prominent, to the extent of becoming plications in the last quarter volution. The mature living chamber of Stzilites craticulatus was stated by Gemmellaro (1888, p. 15) to be one and one-half whorls long. The two mature specimens of Sizilites known to the author are each 154 mm in diameter. Material. — The preceding observations are based on study of: Gemmellaro (1888), Toumanskaya (1937a), Ruzhencey (1950), Glenister and Furnish (1961), seventeen immature specimens (six USNM unnumbered, five SUI 32454, and six GPIT unnumbered), one mature individual (GPIT unnumbered) and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the sum- mer of 1965. Illustrations. —One mature specimen of Sizilites craticulatus is figured: IGUP 87 (Pl. 11, figs. 1, 2). Two immature examples of Sizilites are also illustrated: S. craticulatus — MGPU unnumbered (Pl. 11, figs. 8-10) and S. affims — IGUP 88 (PI. 11, figs. 3-5). PaLEozoic AMMONOIDs: DAvIs 59 Genus TEXOCERAS Miller and Furnish, 1940a Diagnosis. — Texoceras includes adrianitids in which the “ma- ture” suture on each side has three complete lobes between the bifid ventral lobe and the umbilical seam, two complete lobes between the dorsal lobe and the seam, and one lobe on the seam. Specific composition. — The only species which has been re- ferred to Texoceras is Agathoceras [sic] texanuwm Girty, 1908. This species was made the type species of the genus by original designa- tion. Marathonites delawareanus Plummer and Scott, 1937, is a synonym (fide Miller and Furnish, 1940a, p. 111). Immature shell.— The conch of T'exoceras is sublenticular to thickly subdiscoidal and is deeply involute, with an open, moderately small umbilicus (Miller and Furnish, 1940a, p. 111). Most individuals of Texoceras examined display no constric- tions. Two specimens (SUI 32462, 32461) have four constrictions per whorl at a diameter of about 6 mm; but another example (SUI 32437) displays no constrictions on a whorl of the same diameter. Available larger specimens lack constrictions except at the ultimate peristome. The growth lines of T’exoceras are prominently scalloped; the points of these scallops extend orad to form discontinuous longi- tudinal lirae. This spiral ornament is absent from the umbilical walls. Each growth lira lies at the crest of a gentle plication; these plica- tions, as displayed on the internal mold, are crenulate. Each side of the conch bears about ten coarse transverse plications per whorl; these are restricted to the dorsolateral portions of the conch and are quite distinct from the smaller plications which bear growth lines. The larger plications are not everywhere evenly spaced. The internal molds of all Texoceras living chambers known to the author display a gentle longitudinal ridge in mid-ventral posi- tion. In some individuals (for example, SUI 32461 R, Z, and AE) this ridge extends the full length of the living chamber; in others (such as SUI 32461 N and AF, and 13609) it is discontinuous. Only a few suitably preserved phragmocones were examined by the author; all of them seem to bear the ventral longitudinal ridge on the internal mold. Miller and Furnish (1940a, p. 111) stated that this ridge is present only on some specimens of Texoceras. Mature shell.— After about three-quarters of the ultimate 60 BULLETIN 272 whorl of Texoceras had been formed there occurred a slight decrease in the radius of curvature of coiling, followed by a slightly greater increase; this resulted in a flattening of the venter of the last quarter- volution as viewed laterally. Just before the ultimate peristome was reached another decrease in the radius of curvature of coiling oc- curred, leading directly into an apertural constriction. These changes in coiling are also visible in the umbilical region. The ornament of the immature portion of the shell continues to the adapertural end of the mature living chamber. In most indi- viduals the apertural constriction is relatively deep and distinct. In SUI 32461 M and AG, however, it is relatively shallow, but the peristome is flared and thus apparently mature. As pointed out by Miller and Furnish (1940a, p. 113), the inner surface of the test of Texoceras is pustulose; this has produced pits in the surface of the steinkern. The pits (and, hence, the pustules) appear to have no regular arrangement and, indeed, vary as to size and spacing from individual to individual, Every known specimen with a distinct apertural constriction bears these features; they seem to be most distinct and closely spaced in the ultimate constriction, fading apically so that they are apparently restricted to the ultimate one-quarter whorl. In the two specimens with in- distinct constrictions (SUI 32461 M and AG), the pits in the in- ternal mold appear to be present only in patches in the vicinity of the aperture (2.e. for about % whorl). The ultimate peristome of Texoceras is immediately adjacent and parallel to the ultimate constriction. In SUI 32461 P and Z the peristome is apparently scalloped and is situated approximately % mm from the constriction. The last few septa of Texoceras are approximated, and the characteristically rounded lobes become shallower and more pointed. The ultimate living chamber of Texoceras varies from seven- eighths of one whorl to just under one volution in length. In 15 mature specimens of Texoceras the diameter varies from a minimum of 22 mm to a maximum of 29 mm, with the majority clustering toward the low end of the range, Material. — The preceding observations are based on study of: Girty (1908), Plummer and Scott (1937), Miller and Furnish (1940a), Ruzhencev (1950), Glenister and Furnish (1961), Bogo- PaLteozoic AMMONOIDs: Davis 61 slovsky, Librovitch and Ruzhencev (1962), about 40 immature in- dividuals, and about 40 mature specimens (SUI 13609, 32435- 32438, 32461, and 32462). Illustrations. — Eight mature specimens of Texoceras texanwm are figured: SUI 13609 (PI. 11, fig. 15), 32461 I (PI. 11, fig. 12), 32461 M (PI. 11, fig. 7), 32461 P (PI. 11, figs. 13, 14), 32461 Z (PI. 11, fig. 6), 32461 AA (PI. 10, fig. 9), 32461 AG (PI. 11, fig. 11), and 32461 AJ (PI. 10, fig. 10). Superfamily AGATHICERATACEAE Arthaber, 1911 Family AGATHICERATIDAE Arthaber, 1911 Diagnosis. —The Agathiceratidae comprises ammonoids_ in which the suture underwent goniatitic ontogenetic development; following this, the adolescent lateral lobe became trifid, but the in- ternal lobe remained undivided. Genus AGATHICERAS Gemmellaro, 1887 Diagnosis. — Agathiceras comprises agathiceratids with “ma- ture” sutures in which the three subdivisions of the primary lateral lobe are discrete and subequal in size. Synonymy. — Agaticeras Gregorio, 1930, and Agathoceras Girty, 1908, are apparently merely typographic errors. Taxonomic composition. — Ruzhencev (1950) recognized three subgenera: Agathiceras (Agathiceras), A. (Gaetanoceras) Ruzhen- cev, 1938, and A. (Paragathiceras) Ruzhencev, 1950. Glenister and Furnish (1961) questioned the validity of the latter two but appar- ently revised their opinion in Davis, Furnish, and Glenister (1969). The type species of Agathiceras is A. swessi Gemmellaro, 1887, by original designation. In addition, the following are referred to Agathiceras: A. anceps Gemmellaro, 1887, A. anceps var, kitschiensts Toumanskaya, 1931, A. anceps var. sarabansis Toumanskaya, 1931, A. applanatum Teichert, 1944, A. applini Plummer and Scott, 1937, A. asiaticum Toumanskaya, 1935, A. asselicum Ruzhencev, 1938 (junior synonym of A. uralicum - fide Ruzhencev, 1950), A. beschui Toumanskaya, 1931, A. bodraki Toumanskaya, 1931, A. brouweri Smith, 1927, A. ciscoense Smith, 1903, A. contractwm Plummer and Scott, 1937, A. frechi Bise, 1919, A. frechi var. ircutensis Toumans- kaya, 1949. A. girtyi Bose, 1919, A. katschae Toumanskaya, 1931, A. martini Haniel, 1915, A. planum Toumanskaya, 1931, A. sundat- 62 BULLETIN 272 cum Haniel, 1915, A. tornatwm Gemmellaro, 1887, and Gontatites uralicus Karpinsky, 1874. A number of other taxa, inadequately de- scribed, may also belong in Agathiceras: Gomiatites fultonensis Mil- ler and Gurley, 1896, Ammonites hildrethi Morton, 1836, Agathiceras kinshanensis Grabau, 1924, Agathiceras mediterraneum ‘Youmans- kaya, 1949, and Agathiceras tegengrem Grabau, 1924. Furnish (personal communication, 1965) concluded that the holotype of Agathiceras martini var. globosa Haniel, 1915, is an adrianitid, as are the specimens described and figured by Wanner (1932 Immature shell. —Glenister and Furnish (1961, p. 695) described the conch form of Agathiceras as generally ellipsoidal in cross-section but noted that some individuals are parabolic or circular. W/D decreased in ontogeny, and Dixon (1960, p. 54) con- cluded that the seven species he studied (A. applint, A. frechi, A. girtyi, A. suesst, A. sundaicum, A. tornatum, and A. uralicum) can best be differentiated on the basis of differences in the rates of onto- genetic change of W/D. The constrictions of the phragmocone of Agathiceras are pre- dominantly internal thickenings of the shell but are expressed as depressions on the shell exterior of some individuals. As many as six constrictions have been observed in a single whorl, but some in- dividuals (for example, A. applanatum of Glenister and Furnish, 1961, p. 696, and “A. asselicum” of Ruzhencev, 1938, p. 263) ap- parently bear no constrictions. There does seem to have been an ontogenetic increase in the number of constrictions per whorl. Except for Agathiceras martini, the genus is characterized by longitudinal lirae which are present on the ventral and lateral por- tions of the conch and even on the umbilical wall; at least some individuals bear traces of these “lirae” on the internal mold. The number of such lirae per individual seems to have remained essen- tially constant throughout ontogeny, and the lirae are evenly spaced, This longitudinal ornament is present as far back as the second whorl. The siphuncle of Agathiceras was not ventral in the earliest growth stages, so that the earliest formed sutures lack the bifurca- tion of the ventral lobe. The umbilical lobe of the “mature” sutures resulted from an ontogenetic coalescence of the two lobes adjacent PaLtEozoic AMMONoOIDs: Davis 63 to the early adolescent umbilical seam. At “maturity” the prongs of the ventral lobe are about the same size as the lateral lobes and are straight. Mature shell. — After two-thirds to three-quarters of the length of the mature living chamber of Agathiceras had been formed, a slight decrease in the radius of curvature of coiling occurred, followed by a slightly greater increase. This resulted in a flattening of the venter as viewed in longitudinal section. In at least some forms (for example, A. swesst) the changes in coiling were accompanied by a distinct increase in the whorl width; this bulging is greatest on the dorsolateral portions of the flanks but is discernible across the venter where it resulted in a slight increase in the radius of curvature of the venter as viewed in transverse section. In at least some individuals (for example, many SUI 32460) the umbilical wall portion of the shell just adapical of the mature peristome flares dorsad, resulting in a decrease in the size of the umbilicus. In Agathiceras suessi each flank bears a deep depression about one-quarter whorl adapical of the adaperturalmost constriction. The position of the deep depression corresponds to the change in spiral and the initiation of the lateral bulge. These depressions affect both the shell exterior and the internal mold more profoundly than any ordinary constriction, are elongate in a radial direction, and oc- cupy about the middle third of the flanks. Other species of the genus apparently lack these depressions: one specimen of A. sp. (SUI 12297) has an ordinary constriction in a position corresponding to that of the depressions of A. swessi, but over one hundred individuals of A. uralicum (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969) have neither constrictions nor depressions between the apertural constriction and slightly less than one-half whorl adapical of it (SUI 32460), The adapertural constriction of Agathiceras has a trend some- what different from that of all the constrictions preceding it; more- over, the adapertural constriction has a greater amplitude, strongly affecting both the shell exterior and the internal mold, In Agathi- ceras suesst there is a distinct ventrolateral bulge on each side im- mediately adapical of the ultimate constriction and corresponding in position to each ventrolateral Jappet of the terminal peristome; in 64 BULLETIN 272 the constriction itself there is one pit on each side just ventral of the ventrolateral bulge. At least some specimens possess small raised points on the shell interior. These points seem to lie in definite radial rows near the umbilicus, whereas their arrangement is random on the flanks and venter, The significance of these features is not apparent at present. The mature living chamber of Agathiceras is seven-eighths of a whorl to one whorl in length. The mature diameters of seven Agathiceras sp. are 16, 21, 23, 25, 33, 55, and about 55 mm. The maximum diameters of seven Agathiceras suessi are 20, 35, 36, 37, 37, about 40, and 42 mm. One mature A. wralicum is 33 mm in diameter. A sample (SUI 32460) consisting of 110 mature specimens of Agathiceras uralicum (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969) from one horizon in the Road Canyon Forma- tion at one location in the Glass Mountains region of Texas has been studied statistically. Within this population of 110 specimens two distinct size groupings are recognizable (see Davis, Furnish, and Glenister, 1969): 1. one group of 28 individuals with an average diameter of 20.7 mm (as calculated from measurement of 19 specimens), and 2. another group of 82 individuals with a mean diameter of 30.0 mm (as calculated from measurement of 38 specimens). Conch proportions, ornament, and mature modifications in both groups appear the same, Poor internal preservation precludes onto- genetic study and even the determination of the number of whorls. Material. — The preceding observations are based on study of: Morton (1836), Karpinsky (1874, 1889), Krotow (1885), Gem- mellaro (1887, 1888), Miller and Gurley (1896), Haug (1898), Smith (1903, 1927), Girty (1908), Haniel (1915), Bose (1919), Fredericks (1921), Grabau (1924), Gregorio (1930), Toumanskaya (1931, 1935, 1939b, 1939c, 1949), Plummer and Scott (1937), Ruzhencev (1938, 1950, 1951, 1962), Miller and Furnish (1939, 1940a, 1957b), Miller (1944, 1945a), Teichert (1944), Miller and Youngquist (1947), Gerth (1950), Miller and Downs (1950), Glenister and Furnish (1961), Unklesbay (1962), Hayasaka (1963, 1965), Chao (1965), Davis, Furnish, and Glenister (1969), about PaLeozoic AMMONOIDs: Davis 65 1500 immature specimens (Agathiceras sp. — SUI unnumbered, applini — SUI 1386, 1766, 1768, 13612, browwers — SUI 32429, ciscoense — SUI 13764, 17025, frechi — SUI 13765-13767, 32420, 32421, girtyi — SUI 1400, 1966, 2126, 13623, 32418, 32419, swesst — GPIT unnumbered, SUI 8297, 12613, 32424, 32426-32428, 32432, 32433, USNM unnumbered, F. Stehli loan, swndaicwm — SUI 13615, tornatum — SUI 32423, USNM unnumbered, wralicum — SUI 1387, 1767, 10567-10570, 13611, 32413-32415, 32417), about 250 mature Agathiceras (A. sp. — BMNH C73338, GPIT 24543, GPIT PV24409, SUI 12297, 32432, 32458, F. Stehli loan, swesst — GPIT 24543, SUI 32433, USNM unnumbered, F. Stehli loan, wralicum — SUI 10569, 32460), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — Eight mature specimens of Agathiceras are figured: two A. sp. — SUI 12297 (PI. 14, fig. 9), SUI 32458 (PI. 13, figs. 8, 9), three A. swesst — IGUP 119 (PI. 12, figs. 1-4, Pl. 12, figs. 7, 8), and MGPU unnumbered (PI. 12, figs. 5, 6), three A. uralicum (fide Furnish and Glenister in Davis, Furnish, and Glenis- ter, 1969), SUI 32460 BA (PI. 13, figs. 1,2), SUI 32460 BE (PI. 13, figs. 5-7), SUI 32460 BN (PI. 13, figs. 3, 4). One immature speci- men of A. martint is also illustrated — THD 12735 (Pl. 14, fig. 8). Superfamily CYCLOLOBACEAE Zittel, 1903 Diagnosis. — The Cyclolobaceae includes those ammonoids with sutures that underwent goniatitic development, following which the umbilical, internal lateral, and dorsal lobes each split into three, and the lateral lobe split into three or two resulting in the formulas: CVU PAL hi Uy Unt, te Ti DiDyD,.) pl aL Pipe) eR eee ge eg ey et Fe Py al or Can We Illa (DD LD ) sae | ee Dae Die ee ee Ze le &2 In the first case, subsequent new elements were added by successive bifurcation of that subdivision of the lateral lobe nearest the um- bilicus, according to the scheme: a Ginn Gale oh Snes Ele EL (LE 18 ) ete. re: hey en marie? 1 -1 2-1-1 2-1- In the second case the subdivision of the lateral lobe nearest to the 66 BuLLeETIN 272 ventral lobe bifurcated once; other subsequent new elements were added by successive bifurcation of the subdivision of the lateral lobe nearest the umbilicus. Family CYCLOLOBIDAE Zittel, 1903 Diagnosis. — The Cyclolobidae includes cyclolobaceans with a “mature” suture in which the lateral and internal lobes are denticu- late both at their bases and also on the sides. Genus MEXICOCERAS Ruzhencev, 1955 Diagnosis. — Mexicoceras includes cyclolobids in which initial subdivision of the primary lateral lobe was through bifurcation; the “mature” suture includes five or six pairs of digitate external lateral lobes. Specific composition.— The type species of Mextcoceras is Waagenoceras cummingsi var. guadalupense Girty, 1908, by original designation (W. clavatum Plummer and Scott, 1937, is a synonym). This is the only species which has been referred to the genus aside from MV. globosum Chao, 1965, a nomen nudum. Miller and Furnish (1940a) recognized three sympatric sub- species of Mexicoceras guadalupense: W. guadalupense guadalupense Girty, 1908, W. guadalupense smithi Miller and Furnish, 1940a, and W. guadalupense thompson Miller and Furnish, 1940a. Immature shell.—The conch of Mexicoceras is subspherical (Bogoslovsky, Librovitch, and Ruzhencev, 1962). The three sub- species of the type species were defined mainly on differences in conch proportions (Miller and Furnish, 1940a): Mexicoceras guada- lupense smitht has W greater than D in “moderate sized specimens”; M. g. thompson has W about two-thirds of D in “moderate sized specimens”; in the typical subspecies W/D is between the ratios of the other two in “moderate sized specimens”. Miller and Furnish (1940a) stated that the three subspecies are completely inter- gradational and that “large individuals” have a greater uniformity in conch proportions than “moderate sized individuals”. The majority of individuals of Mewxicoceras examined by the author have at least one constriction visible in the outermost pre- served whorl. There does not seem to be a regular pattern for the spacing of constrictions. In SUI 1782, for example, the first con- striction occurs one whorl beyond the protoconch, at a diameter of PaLeozoic AMMoNoIDs: Davis 67 0.9 mm; the next constriction is about 255° further, at a diameter of 1.4 mm; the third is about 780° (2 whorls + 60°) further, at a diameter of 3.8 mm; and the fourth is about 175° further, at a diameter of 4.8 mm. Apparently the lack of constrictions in the outermost preserved whorl of some individuals may be merely a function of irregular spacing of constrictions, rather than an actual lack of constrictions, The shell is thicker at a constriction than between constrictions, but constrictions as observed in median longitudinal sections of in- dividuals of Mexicoceras vary considerably. In some instances (for example, the first constriction in SUI 1782) both the shell exterior and the internal mold are concave outward at the venter. At other constrictions (such as the second constriction of SUI 1782) the shell exterior is convex outward, and the internal mold seems affected little if any. At the third constriction of SUI 1782 the shell exterior is virtually unaffected, but the internal mold is concave outward. And at the fourth constriction of SUI 1782 the internal mold is con- cave outward at the venter, but the shell exterior appears to be slightly convex outward. In the majority of examined specimens which seem to fall with- in Mexicoceras guadalupense smithi (for example, most of the SUI 12612 series) immediately adapical of each definite constriction are first a ridge and then a groove, both of which parallel the constric- tion. The groove is more distinct near the umbilicus than on the venter, where it may disappear entirely; the groove is everywhere more shallow than the immediately adjacent constriction. In general a constriction is shallower and broader at the venter than at the umbilicus. Most well-preserved individuals of Mexicoceras display trans- verse undulations in the internal mold. Some of these undulations are due to shell plication, but some are also due to thickenings in the shell. The undulations (hence, the plications, the shell thicken- ings or both) are irregularly spaced and of different amplitudes, but there does not seem to be a regular pattern for these differences in amplitude. As with constrictions, these undulations are commonly less prominent at the venter than near the umbilicus. Those ammonoids which Miller and Furnish (1940a) referred to Mextcoceras guadalupense smithi are characterized by nodes on 68 BULLETIN 272 the umbilical shoulders, which are longitudinally elongate. In plicate individuals not every plication has a node. In some individuals (for example, SUI 12612AE) only the inner whorls bear nodes, and no individual of the species of diameter larger than 25 mm has been observed to bear nodes. In SUI 12612AB the nodes lie slightly ven- tral of the shoulder so that this individual seems to have two shoulders on each side. Growth lines in Mexicoceras parallel] the trend of the closest constriction. Mature shell.— The approach to maturity in Mewicoceras is heralded by a slight decrease in the radius of curvature of coiling fol- lowed by a slightly greater increase; this occurs about two-thirds of the way through the ultimate whorl. These changes in coiling appear to coincide with a change in conch proportions: the whorl height decreases in the last third of the living chamber, whereas the width continues to increase. Miller and Furnish (1940a, p. 163) reported that mature Mexicoceras guadalupense has a constriction just adapical of the ultimate peristome. Seven specimens available to the author display a body chamber which terminates in a constriction. Miller and Furnish further stated (ibid., p. 161) that specimens of the species rarely if ever have constrictions on the fully mature portion of the conch except at the aperture. Of the seven specimens only one (Texas-k) has a constriction in the living chamber other than that at the apertural end; in this individual the second constriction is about 230° adapical of the first. Texas-k’s adapertural constriction apparently lacks the ventral salient present in the apertural constric- tions of the other six individuals. No individual examined possesses a recognizable ultimate peristome. Growth lines and plications in the shell of the living chamber of SUI 12614 indicate that the ventral salient developed late in the ontogeny. There is a decrease in the septal interval towards the mature body chamber. The ultimate septum of a mature individual is distinctly thicker than those adapical of it. Six of the seven individuals with the apertural constriction preserved have living chambers slightly less than one whorl] in length; the body chamber of Texas-k is about one and one-quarter volutions in length. Plummer and Scott (1937, p. 161) reported PaLeozoic AMMONOIDs: DAvIs 69 specimens of Waagenoceras clavatum having living chambers longer than one volution and with the last three or four septa crowded. The significance of Plummer and Scott’s specimens and of Texas-k is unclear. The maximum diameter of mature individuals ranges from 48 mm (USNM 144423) to at least 200 mm (unidentified individual mentioned by Miller and Furnish, 1940a, p. 163). Material. — The preceding observations are based on study of: Girty (1908), Bése (1919), Diener (1921), Plummer and Scott (1937), Miller and Furnish (1940a), Miller and Unklesbay (1943), Miller (1944), Ruzhencev (1955, 1956b), Bogoslovsky, Librovitch, and Ruzhencev (1962), Chao (1965), Furnish (1966), Davis, Furnish, and Glenister (1969), Furnish and Glenister (1970), about 70 immature individuals (AMNH unnumbered, SUI 1781, 1782, 12609, 12610, 12612, 12616-12619, 13598, Univ. Texas unnumbered, USNM 144419, 144422, 144437) and about ten mature specimens (AMNH unnumbered, SUI 12614, 12615, Univ. Texas unnumbered, USNM 144423). Illustrations. —One mature specimen of Mextcoceras guadalu- pense guadalupense is figured —USNM 144423 (PI. 15, figs. 1-4). Two immature individuals of Mexicoceras are illustrated: M. guada- lupense guadalupense —USNM 144422 (PI. 15, fig. 7; Pl. 17, figs. 1,2), and M. guadalupense thompsoni—USNM 144419 (PI. 15, fics. 5,6). Genus WAAGENOCERAS Gemmellaro, 1887 Diagnosis. —Waagenoceras includes globose cyclolobids in which initial subdivision of the primary lateral lobe produced three lobes; the “mature” suture includes seven or eight external lateral lobes. Synonymy. — Wanneroceras Toumanskaya, 1937c, a nomen nu- dwm based on W. gemmellarot Toumanskaya, 1937c, another nomen nudum, is listed as a synonym of Waagenoceras by Bogoslovsky, Librovitch, and Ruzhencev (1962) and of Timorites by Miller, Fur- nish, and Schindewolf (1957). Specific composition.— The type species of Waagenoceras is W. mojsisovicsi Gemmellaro, 1887, by subsequent designation ( Die- ner, 1921, p. 25). In addition to the type species the following taxa 70 BULLETIN 272 are referred to Waagenoceras: W. dieneri Bose, 1919, W. dienert girtyi Miller and Furnish, 1940a, W. dieneri karpinskyi Miller, 1944, W. lidacense Roever, 1940, W. nikitini Gemmellaro, 1888, and W. stachei Gemmellaro, 1887. W. adrianense Gregorio 1930, W. minutum Gregorio, 1930, and W. nikitini var, pergloboswm Gregorio, 1930, may belong in Waagenoceras. W. coahwila Toumanskaya, 1937c, is apparently a nomen nudum. W. gemmellaroi Haniel, 1915, was retained in Waagenoceras by Ruzhencev (1955); other authors (for example, Miller and Furnish, 1940a) have referred this species to Timorites. W. richardson’ Plummer and Scott, 1937 (W. dieneri richardsom of Miller and Furnish, 1940a) was recognized as being transitional between Waagenoceras and Timorites by the latter two authors; Glenister and Furnish (in Davis, Furnish, and Glenister, 1969) based a new genus, Newellites, on W. richardsont. Immature shell. —The conch of Waagenoceras is globose (Gem- mellaro, 1887, p. 11) to subspherical (Bogoslovsky, Librovitch, and Ruzhencev, 1962, p. 396), is involute, and has a small and deep umbilicus (Gemmellaro, 1887, p. 11). Most individuals of Waagenoceras examined display two to four constrictions in the outermost preserved whorl. The constric- tions seem to be variably spaced; for example, in SUI 1784 the first constriction is 346° from the protoconch, the second is 514° fur- ther, and the third is 280° further. The shell in a constriction is thicker than between constrictions, but constrictions, as observed in median longitudinal sections of in- dividuals of Waagenoceras, are variable. In some instances (for ex- ample, the first constriction of SUI 1784) the shel] exterior is un- affected, and the internal mold is concave outward at a constric- tion; in other cases (such as the second and third constrictions of SUI 1784) both the shell exterior and the internal mold are concave outward at a constriction. Most individuals of Waagenoceras examined by the author bear transverse undulations in the surface of the internal mold. Although many of these are due to plications in the shell, at least some are the result of thickenings in the shell. Generally these undulations are of low amplitude, but their amplitude and spacing are variable. In SUI 1402 the outermost preserved whorl has a non-undulate sur- face, but the next whorl within bears strong transverse plications. PaLeozoic AMMonoIDs: Davis 7a Well-preserved individuals of Waagenoceras bear transverse growth lines. These lines are crowded at constrictions; in one un- numbered individual from AMHN, for example, just adapical of a constriction at a diameter of about 40 mm there are 34 growth increments per millimeter of circumference, but about 1 mm after the constriction there are 20/mm. As noted by Gemmellaro (1888, p. 4) in some individuals clusters of growth lines occur in various places not corresponding to constrictions. Waagenoceras dieneri karpinskyi was defined on the basis of the presence of reticulate ornament (in three individuals). Gemmellaro (1887, p. 11) described the runzelschicht of Waagenoceras as consisting of fine “dotting” connected to one an- other by subtle undulating striations. Mature shell. —In at least some individuals of Waagenoceras, after formation of two-thirds of the ultimate whorl there occurred a slight decrease in the radius of curvature of coiling followed by a slightly greater increase, so that the venter appears slightly flattened in longitudinal section in the final one-third volution; these changes in coiling are likewise apparent in the course of the umbilical wall. Gemmellaro (1887, p. 12, 13; 1888, p. 4) reported that the ven- tral portion of at least the first two-thirds of the ultimate whorl of Waagenoceras is narrow, whereas in the ultimate one-third whorl the conch is wide and depressed. In specimens SUI 32317 and 32318 the mature shell is genicu- late and has a narrow, almost angular venter. Although sutural de- tails are not preserved in either of the specimens at hand nor in similar specimens from the same locality (Texas Tech unnumbered), on the basis of associated fossils and sutural generalities, Furnish (1967, personal communication) referred these specimens to W. rich- ardsom. The conch form of these two individuals may be due, at least in part, to postmortem deformation; the conch form certainly is unlike that of any other known cyclolobid. The two examples and others from the same locality may well not be congeneric with Waagenoceras at all (indeed, Furnish and Glenister, in a footnote in Davis, Furnish, and Glenister, 1969, erected the genus Newellites for “Waagenoceras” richardsoni); on the other hand, SUI 32317 and 32318 may possibly represent the antidimorph of “ordinary” Waagenoceras, or, perhaps, they are referable to Timorites. (A 72 BULLETIN 272 thorough study of the Cyclolobidae is necessary before this can be resolved. ) No known individual of Waagenoceras bears any constrictions in the wall of the ultimate body chamber except for that at the adapertural end. Striations and undulations in the shell are present in the living chamber, however. The internal mold of most mature Waagenoceras living cham- bers bears numerous, irregularly arranged and spaced, minute pits, but these are absent in some individuals. In those individuals pos- sessing these pits, they mark an area extending a variable distance adapical from the ultimate constriction (1/4 whorl in SUI 32405; between 1/3 and 1/2 whorl in SUI 32410; nearly one full whorl in an unnumbered AMNH specimen). As in many other taxa, the interseptal distance of Waagenoceras decreases in the space occupied by the last several septa. Likewise, the ultimate septum is thickened. The ultimate peristome of Waagenoceras lacks either lappets or a ventral prolongation. The ultimate living chamber of Waagenoceras was reported by Gemmellaro (1887, p. 11) to be one and one-half volutions long, and that of W. dieneri was reported by Miller and Furnish (1940a, p. 171) to be about one whorl long. In the four specimens avail- able to the author in which both the apertural constriction and the ultimate septum are visible, the living chamber is about one and one-quarter whorls long. The maximum diameter of mature individuals of Waagenoceras ranges from about 90 mm (AMNH unnumbered) to 160 mm (IGUP 32). The diameters of SUI 32317 and 32318 are 190 mm and 170 mm respectively. Material. — The preceding observations are based on study of: Gemmellaro (1887, 1888), Mojsisovics (1888), White (1891), Smith (1903), Bose (1919), Diener (1921, 1927), Berry (1928), Gregorio (1930), Miller (1933, 1944, 1945a, 1945b, 1953), Greco (1935), Toumanskaya (1937c), Plummer and Scott (1937), Marez Oyens (1938), Roever (1940), Miller and Furnish (1940a, 1957a), Miller and Unklesbay (1943), Hayasaka (1947, 1965), Ruzhencev (1955, 1956b), Miller, Furnish, and Schindewolf (1957), Bogoslovsky, Librovitch, and Ruzhencev (1962), Furnish (1966), Davis, Furnish, PaLEozoic AMMONOIDs: Davis 73 and Glenister (1969), Furnish and Glenister (1970), about 25 im- mature undifferentiated Waagenoceras dienert (AMNH unnum- bered, SUI 1401, 12492, 13601, 13602, 16690, 32402, 32406-32410), about 10 mature undifferentiated W. dieneri (AMNH unnumbered, SUI 32405, 32410, 32411), 1 immature W. dieneri dieneri (SUI 16690), about 20 immature W. dieneri girtyi (SUI 1366-1370, 1779, 1780, 1783, 1784, 12611, 13599, 13600), 1 mature W. dieneri girtyi (SUI 12613), 1 immature W. lidacense (GIUA drawer E229 un- catalogued), 1 immature and 2 mature specimens of W. richardsoni (SUI 1402, 32317, 32318 respectively), and notes and photographs taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — Three mature specimens of Waagenoceras are figured: W. mojstsovicst —IGUP 32 (PI. 16, fig. 1), IGUP 34 (PI. 16, figs. 2,3), and W. richardsont — SUI 32318 (PI. 16, figs. 6, 7). One immature specimen of W. stachez is also illustrated — IGUP 37 GPT. 6, figs. 4;.5). Genus CYCLOLOBUS Waagen, 1879 Diagnosis. — Cyclolobus includes those narrow, ellipsoidal to lenticular cyclolobids in whose “mature” suture nine to fourteen pairs of external lateral lobes are present. L! divides the first lateral saddle medially, and U is relatively inconspicuous and is not sub- divided. Synonymy. — Bogoslovsky, Librovitch, and Ruzhencev (1962) listed Godthaabites Frebold, 1932, and Procyclolobus Toumanskaya, 1939a, as synonyms of Cyclolobus. Nassichuk, Furnish, and Glen- ster (1965) considered Cyclolobus (Cyclolobus) and Cyclolobus (Krafftoceras) Diener, 1903, to be consubgeneric. Specific composttion.— The type species of Cyclolobus is Phylloceras oldhami Waagen, 1872, by original designation and by monotypy; Furnish and Glenister (1970) considered C. insignis Diener, 1903, to be a junior synonym. In addition, the following taxa are referred to Cyclolobus: Godthaabites kullingi Frebold, 1932, Arcestes (Cyclolobus Waag.) persulcatus Rothpletz, 1892, C. teich- ertt Furnish and Glenister, 1970, and C. walkeri Diener, 1903. Fur- nish and Glenister (1970) suppress all the following as junior syn- onyms of C. walkeri: C. astrei Besairie, 1936, C. (Krafftoceras) haydeni Diener, 1903, C. (Krafftoceras) kraffti Diener, 1903, and 74 BULLETIN 272 C. walkeri madagascariensis Besairie, 1936. The relationships of Cyclolobus hoshanensis Sun, 1939, are unclear. Cyclolobus subcum- minst Haniel, 1915, is a perrinitid. Immature shell. — The conch of Cyclolobus is thinly ellipsoidal to lenticular (Bogoslovsky, Librovitch, and Ruzhencev, 1962). Most individuals of Cyclolobus formed constrictions at least sometime in their ontogeny, but the spacing and, even, shape of these structures seem to be quite variable. In C. walkeri (sensu Vail- lant-Couturier-Treat, 1933, and Besairie, 1936) there are up to four constrictions per whorl, generally restricted to diameters of less than 25 mm, but constrictions may occur up to a diameter of 80 mm, albeit very slightly prominent; near the ultimate septum of nearly all these specimens is a depression which Vaillant-Couturier- Treat (1933, p. 25) thought could be considered a constriction. In “C. krafftc” constrictions are restricted to the early whorls. In “C. haydenw” there are four to five constrictions per whorl persisting in the adult. The holotype of the type species bears six constric- tions in a whorl of about 105 mm diameter. In C. walkert (sensu Vaillant-Couturier-Treat, 1933) and C. cf, C. kullingi the constric- tions in the earliest whorls are falciform, but in later whorls these structures became biconvex. The constrictions of the holotype of the type species are falciform at a diameter of about 105 mm. At least some specimens of Cyclolobus have prominent trans- verse plications in their early volutions; these fade out by a diameter of 10 mm in C. oldhamt, by 30 mm in C. kullingi, and by 5 mm in “C. krafftv’ according to Nassichuk, Furnish, and Glenister (1965). In C. walkeri (sensu Vaillant-Couturier-Treat, 1933) barely percep- tible ribs may be present even at maturity. The transverse growth lines of specimens of Cyclolobus parallel the constrictions, and at least in “C. insignis” they are bunched in places (Diener, 1903, p. 165). The suture of Cyclolobus is strongly arched at “maturity”. Mature shell. — After about two-thirds of the ultimate whorl of C'yclolobus was formed, there occurred a slight decrease in the radius of curvature of coiling followed by a slightly greater in- crease. The changes in coiling are much more prominently displayed in the outline of the umbilicus than in the whorl periphery. In at least C. walkert (sensu Vaillant-Couturier-Treat, 1933) these changes PaLeozoic AMMOoNOIDs: Davis 75 in coiling were accompanied by an accentuation of the angularity of the shoulder and by development of a dorsal bulge which covers the preceding whorl and masks part of the umbilicus; in addition the venter became keeled in the last three-fourths to two-thirds of the ultimate volution (Vaillant-Couturier-Treat, 1933, p. 25). Some individuals of Cyclolobus display constrictions in the ulti- mate living chamber in addition to the terminal constriction. In “C. insignis” these features extend across the venter (5/whorl); in C. oldhami they are restricted to the umbilical region; constric- tions are obsolete in C. walkeri (sensu Vaillant-Couturier-Treat, 1933). In “‘C. haydeni” there are four to five constrictions per whorl persisting in the adult (Besairie 1936, p. 105). The mature’ living chamber of Cyclolobus terminates in a bi- convex constriction. The two convexities closer to the venter form a pair of lappets. Within the constriction, just ventrad of each lappet, is a deep pit, apparently affecting both the shell exterior and the internal mold. At least some Cyclolobus walkeri (sensu Vaillant-Couturier- Treat, 1933) bear gentle biconvex ribs in the living chamber. The length of the ultimate living chamber of Cyclolobus varies from eight-ninths of a whorl to one full whorl, The mature diameter of Cyclolobus is variable: “C. haydent” — 57 mm (Diener, 1903, p. 168), “C. insignis” —66 mm (1bid., p. 165), C. walkeri (sensu Vaillant-Couturier-Treat, 1933) —90 mm (UPSM #28) to nearly mature at 160 mm (MNHN Vaillant-Cou- turier-Treat, 1933, pl. 2, fig. 1). Material. — The preceding observations are based on study of: Waagen (1872, 1879), Mojsisovics (1873, 1882), Rothpletz (1892), Diener (1903, 1904, 1921, 1927); Haniel (1915), Grabaw (1924), Vaillant-Couturier-Treat (1926, 1933), Smith (1927), Besairie (1930, 1936), Frebold (1932), Wanner (1932), Miller (1933), Tou- manskaya (1939a), Sun (1939), Miller and Furnish (1940b), Ruz- hencev (1955), Jeannet (1959), Bogoslovsky, Librovitch, and Ruz- hencey (1962), Nassichuk, Furnish, and Glenister (1965), Furnish (1966), Davis, Furnish, and Glenister (1969), Furnish and Glen- ister (1970), about three dozen immature examples of Cyclolobus sp. (BMNH C34155, Collignon unnumbered, Copenhagen unnum- bered, SUI 12313, 12343, 12344, 32397-32401, 32403, 32404), two 76 BULLETIN 272 mature Cyclolobus sp. (Collignon unnumbered, SUI 32396), about ten immature specimens of C. oldhami (BMNH C10459, GPIT un- numbered, Geological Survey of Pakistan unnumbered, USNM unnumbered), three immature individuals of C. walkeri (BMNH C36641-C36643 ), and photographs and notes taken by W. M. Fur- nish and Brian F. Glenister in the summer of 1965. Illustrations. —Two mature specimens of Cyclolobus walken are figured: MNHN B7520 (PI. 17, fig. 7), and BMNH C36642 (PI. 17, fig. 8). Two immature examples of Cyclolobus are also illus- trated: C. walkeri — MNHN B7517 (PI. 17, figs. 3-5), and “C. astrev’? — UPSM unnumbered (PI. 17, fig. 6). Family VIDRIOCERATIDAE Plummer and Scott, 1937 Diagnosis. — The Vidrioceratidae comprises cyclolobaceans with “mature” sutures in which there are three to ten pairs of ex- ternal lateral lobes which are denticulate only at the base. Subfamily VIDRIOCERATINAE Plummer and Scott, 1937 Diagnosis. — Vidrioceratinae comprises ellipsoidal vidrioceratids. Genus WAAGENINA Krotow, 1888 Diagnosis. — Waagenina comprises vidrioceratins in which four or five lobes arose from each primary lateral lobe; of these four or five lobes of the “mature” suture, the dorsal component is bifid. Synonymy.— The following were considered synonyms of Waagenina by Bogoslovsky, Librovitch, and Ruzhencev (1962): Grioceras Toumanskaya, 1939a, Martoceras Toumanskaya, 1938, Pamirites Toumanskaya, 1938, and Waagenia Krotow, 1885 (non Kriechbaumer, 1874, fide Bogoslovsky, Librovitch, and Ruzhencev, 1962) (non Neumayr, fide Diener, 1897b). Specific composition.— The type species of Waagenina is Waagenma subinterrupta Krotow, 1885. (Popanoceras krasnopoly- skyt Karpinsky, 1889, Marathonites krasnopolskyi var. asymmetrica Ruzhencev, 1933, M. k. var. bidentata Ruzhencev, 1933, M. k. var. quadridentata Ruzhencev, 1933, M. k. var. tridentata Ruzhencev, 1933, M. k. forms, a, B, y, and A of Voinova, 1934, and M. k. formae a, b, c, d, e, and f of Maximova, 1935, are synonyms.) In addition to the type species, the following are referred to Waagenina: Stacheo- ceras benedictinum Gemmellaro, 1887, Pamirites clinei Toumans- PaLeozoic AMMmonorpDs: Davis rad kaya, 1938, Stacheoceras darae Gemmellaro, 1887, Marathomtes dieneri Smith, 1927 (= Popanoceras timorense form 8 Haniel, 1915), Stacheoceras perspectivum Gemmellaro, 1887, and P. timo- rense form y Haniel, 1915. P. tridens form 8 and P. t. form y Haniel, 1915, and Waagenia jazwae Krotow, 1885, may belong in Waagenima., Immature shell. —The conch of Waagenina is inflated, ellipsoi- dal, involute, and has a narrow umbilicus (Ruzhencev, 1940d, p. 118). In specimens of Waagenina perspectivum the constrictions are narrow, affect both the shell exterior and the internal mold, and extend neither across the venter nor to the umbilical shoulders. In other species the constrictions are shallow and broad, extend from shoulder to shoulder, but affect the shell exterior only slightly. The occurrence and spacing of these constrictions are variable, In some specimens of Waagenina the internal mold is marked by gentle transverse undulations which correspond in position to the growth lines. In some individuals (for example, SUI 32597, 32598) there are stronger undulations in the internal mold; they are restricted to the flanks of the conch and correspond in spacing to the interseptal intervals, Growth lines are more closely spaced at constrictions than between. In some individuals of Waagenina (such as, SUI 10588, 32595) there is a definite shell thickening in the umbilicus. This thickening is bordered by a distinct edge which approximately corresponds to the umbilical shoulder. In a number of examples of Waagenina (for example, SUI 10588, 32595) there are numerous minute holes on the flanks of the phragmocone steinkern. Other individuals (such as, SUI 32596) lack these features. In size, shape, and arrangement, these small pits are similar to those near the ultimate constriction of many adrianitids. The pits do not correspond in form to the runzelschicht observed in some specimens (for example, GPIT PV24409). Mature shell. — The only mature representatives of Waagenina known to the author were studied by Gemmellaro and referred by him to Stacheoceras darae. In these specimens there was little, if any, change in coiling in the ultimate whorl. However, the venter of the ultimate portion of the conch appears more broadly rounded than in inner whorls. 78 BULLETIN 272 The mature living chamber of Waagenina darae terminates in a constriction. There appear to be two distinct trends of the ultimate constrictions in this genus: in the specimen of Gemmellaro’s 1887 plate 4, figures 2 and 3 (IGUP 68) there is a distinct ventral] re- éntrant, whereas in that of his 1887 plate 4, figure 11 (IGUP 41) the reéntrant is slight. The ultimate peristome is marked by a ven- trolateral lappet on each side, flanking a ventral sinus. The ultimate living chambers of Waagenina perspectivum and W. darae were stated by Gemmellaro (1887, pp. 36, 39) to be longer than the ultimate whorl and only as long as the terminal volution, respectively. Maximum diameters of only two individuals (of Waagenina darae) are known to the author: 54% mm (IGUP 64) and 78 mm (IGUP 68). Material. — The preceding observations are based on study of: Krotow (1885), Gemmellaro (1887), Karpinsky (1889), Diener (1897b), Smith (1927), Schindewolf (1931), Ruzhencev (1933, 1938, 1940d, 1951, 1956a, 1962), Voinova (1934), Greco (1935), Maximova (1935), Toumanskaya (1938, 1939a, 1949), Bogoslov- skaya (1962), Bogoslovsky, Librovitch, and Ruzhencev (1962), about 20 immature specimens of Waagenina (subinterrupta — SUI 10588, 32595-32598, darae — GPIT PV24397, PV24409, perspec- tivwm —GPIT PV24409), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. —Three mature specimens of Waagenina darae are figured:,IGUP 64 (Pl;18) figs. 5,6), (PINS iiss 95910) and IGUP 68 (Pl. 18, figs. 11-13). In addition, three immature in- dividuals of Waagenina are illustrated: W. subinterrupta — SUI 32597 (PIN lS htigss 3.4), SUL 32597 (CPI2 19; fiets9)eandeWaene= Spectiuum — IGUP 66 (PI. 18, figs. 1, 2). Genus STACHEOCERAS Gemmellaro, 1887 Diagnosis. — Stacheoceras comprises vidrioceratins with “ma- ture” sutures in which there are six to twelve subdivisions of the primary lateral lobe on each side. Synonymy. — Neostacheoceras Schindewolf, 1931, is a synonym of Stacheoceras. Specific composition. — The type species of Stacheoceras is S. PaLreozoic AMMONOIDS: Davis 79 mediterraneum Gemmellaro, 1887, by subsequent designation (Diener, 1921, p. 22), but Smith (1927) and Schindewolf (1931) considered Arcestes antiquus Waagen, 1879, to be the type species of Stacheoceras by original designation. In addition, the following species are referred to the genus: Stacheoceras andrussow: Touman- skaya, 1931, S. arthaberi Smith, 1927 (= Popanoceras tridens form 8 and « of Haniel, 1915), S. boeset Toumanskaya, 1931, S. borisstaki Toumanskaya, 1931, Popanoceras collignoni Besairie, 1936, S. medt- terraneum Gemmellaro var, crimensis Toumanskaya, 1931, S. diblasu Gemmellaro, 1887, S. gaudryi Gemmellaro, 1888, S. gemmellarot Miller, 1944, S. gordoni Miller, Furnish, and Clark, 1957, S. gruene- waldti Gemmellaro, 1887 (= S. gruenwaldti of Hayasaka, 1965), Neostacheoceras hanieli Schindewolf, 1931 (= Popanoceras timo- rense form 9 of Haniel, 1915), Stacheoceras iwaizakiense Mabuti, 1935, S. karpinskyi Gemmellaro, 1887, S. rothi Miller and Furnish, 1940a, S. sexlobatum Miller and Cline, 1934, Popanoceras timorense form 8, £, and » of Haniel, 1915, Stacheoceras towmanskyae Miller and Furnish, 1940a, Arcestes tridens Rothpletz, 1892, Popanoceras tridens form ¢ Haniel, 1915, Stacheoceras trimurti Diener, 1897a, Popanoceras tschernyschewi Stoyanow, 1910, and Stacheoceras vogtt Toumanskaya, 1931. The following may also belong in Stacheoceras: S. discoidale Toumanskaya, 1935, S. globosum Gemmellaro, 1887, S. globulinwm Gregorio, 1930, S. pelagicum Gemmellaro, 1887, S. quadridens Hayasaka, 1947, S. sosiense Gregorio, 1930, S. tepense Toumanskaya, 1931, and S. tietzei Gemmellaro, 1887. Stacheoceros [sic] marcoui Gemmellaro, 1887, and Stacheoceras trimarti Diener, 1899, of Furnish (1966) are both apparently nomina nuda. Immature shell. — The immature conch of Stacheoceras is sub- globular to subdiscoidal, with a small umbilicus (Miller and Furnish, 1940; p.. 129). Constrictions in the shell of Stacheoceras are predominantly in- ternal thickenings in the shell and, therefore, affect the shell ex- terior slightly, if at all. The number of constrictions per whorl varies from zero to four, with no apparent orderly relation between diameter and the number of constrictions per volution. Growth lines in Stacheoceras parallel the constrictions. In some individuals there is a shell thickening in the umbilicus. This thickening is bordered by a distinct edge. 80 BuLLeTIN 272 Mature shell.—In at least some specimens of Stacheoceras, after about three-quarters of the ultimate whorl was formed, there was a decrease in the radius of curvature of coiling followed by a slightly greater increase. In SUI 32610A an earlier change in coiling occurred after slightly less than two-thirds of the ultimate volution had been produced. There is a terminal dorsal flaring of the shell into the umbilicus displayed by SUI 1364W and 32608D. The ultimate living chamber of Stacheoceras terminates in a constriction. In addition to this terminal constriction, the body chambers of IGUP 71 and SUI 16652 each bear a constriction about one-half whorl adapical of the peristome and another about three-quarters adapical of the ultimate constriction. There are gentle transverse undulations in the steinkern of the final living chamber of Stacheoceras. There is one short, broad, ventrolateral lappet on each side in the ultimate peristome of Stacheoceras. Each lappet bears a branch of the terminal constriction. The length of the ultimate living chamber in Stacheoceras is variable. Gemmellaro (1887, p. 29 et seq.) reported the body cham- ber lengths in S. mediterranewm and S. diblasii as one and one-half and one and one-third whorls, respectively. Wanner (1932, p. 272) noted that the body chamber of S. tridens is one and two-fifths volutions long. One specimen of S. gemmellaroi (SUI 32612) has an ultimate living chamber of just less than one whorl in length. Two specimens of S. towmanskyae (SUI 32607E, 16652F) have body chambers of one and one-eighth and seven-eighths whorls, re- spectively. Wanner (1932, p. 272) reported the mature diameter of one specimen of Stacheoceras tridens as 125% mm. One S. tietzet (IGUP 71) is mature at a diameter of 47% mm, One S. gemmellaroi (SUI 32612) is mature at 65 mm. One S. towmanskyae has a mature diameter of about 85 mm. Three specimens of S. sp. (SUI 32610D, 32608D, 32610A) have maximum diameters of about 90 mm, about 90 mm, and 107 mn, respectively. Material. — The preceding observations are based on study of: Waagen (1879), Krotow (1885), Gemmellaro (1887, 1888), Roth- pletz (1892), Haug (1894, 1898), Diener (1897a, 1921), Stoyanow (1910) Haniel (1915), Smith (1927), Gregorio (1930), Schinde- wolf (1931), Toumanskaya (1931, 1935), Wanner (1932), Miller PaLeozoic AMMONOIDs: DAvis 81 and Cline (1934), Mabuti (1935), Greco (1935), Besairie (1936), Plummer and Scott (1937), Hayasaka (1940, 1947, 1965), Miller and Furnish (1940a, 1957a, 1957b), Miller and Unklesbay (1943), Miller (1944, 19452), Miller, Furnish, and Clark (1957), Triimpy (1960), Gordon and Merriam (1961), Bogoslovsky, Librovitch, and Ruzhencev (1962), Shevyrev (1965), Furnish (1966), Davis, Furnish, and Glenister (1969), about 130 immature specimens of Stacheoceras (S. sp. — Copenhagen unnumbered, SUI 12314, 13597, 32608-32611, 32613, antiquum — GPIT unnumbered, gemmellaroi — SUI 1365, 13610, 13656, sexlobatum — SUI 706, tridens — SUI 32615, towmanskyae — SUI 1364, 16652, 32607), about ten mature individuals (S. sp. — SUI 32608, 32610, gemmellaroi — SUI 32612, toumanskyae — SUI 1364, 16652, 32607), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — Four mature pugcueene of Stacheoceras are figured: two S. sp. — SUI 32608D (PI. 19, fig. 5), SUI 32610A (PI. 19, figs. 6-8), one S. tvetzei — IGUP 71 (PI. 4, figs. 4, 5), and one S. towmanskyae — SUI 13640 (PI. 19, figs. 3, 4). In addition, three immature individuals of Stacheoceras are illustrated: S. gaudryi — IGUP 59 (PI. 4, fig. 6), S. mediterranewum — IGUP 62 (PI. 19, figs. 1,2), and S. pelagicum — MGPU unnumbered (PI. 18, figs. 7, 8). Superfamily MARATHONITACEAE Ruzhencevy, 1938 Family MARATHONITIDAE Ruzhencev, 1938 Diagnosis. — The Marathonitidae comprises ammonoids whose suture underwent goniatitic development, following which the pri- mary lateral, umbilical, and internal lateral lobes each split into three, producing the basic formula: ee ee Te Usich Dep. Dig lee e ee eee ee Oink LS Subsequent complication arose through denticulation of the lobes with a bifurcation of the dorsad Ls and the ventrad /» or a trifurca- tion of D, or with all three. Subfamily MARATHONITINAE Ruzhencev, 1938 Diagnosis. — The Marathonitinae comprises marathonitids with sutures in which the dorsal lobe is trifid and the three (or four) 82 BuLLeETIN 272 subdivisions of the initial lateral lobe are primarily trifid; during phylogeny this latter trifidity developed into complex subdivision, particularly in the ventrad two or three subdivisions of the primary lateral lobe. Genus HYATTOCERAS Gemmellaro, 1887 Diagnosis. — Hyattoceras comprises marathonitins with “ma- ture” sutures in which each branch of the ventral lobe has denticles on its dorsad side; there are four subdivisions of the primary lateral lobe of which the ventrad three are strongly subdivided. Synonymy. — Abichia Gemmellaro, 1887, (not Abichia as used by Andrussow, 1907) is considered to be congeneric with Hyatto- ceras. Familial assignment. — Furnish and Glenister (in Davis, Fur- nish, and Glenister, 1969) considered Hyattoceras to belong in a family Hyattoceratidae. Specific composition. — The type species of Hyattoceras is H. geinitzi Gemmellaro, 1887, by subsequent designation (Diener, 1921, p. 25). In addition to the type species, the following are re- ferred to Hyattoceras: H. (Abichta) abichi Gemmellaro, 1887, 7. guembeli Gemmellaro, 1888, H. subgeimitzi Haniel, 1915, and H. turgidum Gemmellaro, 1887. Immature shell.— The immature conch of Hyattoceras is el- lipsoidal to discoidal, involute, and has a narrow umbilicus (Bogo- slovsky, Librovitch, and Ruzhencev, 1962). The only ornament characteristic of immature Hyattoceras is the transverse striae. Mature shell. — As the middle one-third of the ultimate volu- tion of Hyattoceras geinitzi was formed there was a progressive nar- rowing of the venter. The narrowest place is at the end of this middle one-third and corresponds to two changes in coiling, first a slight decrease in the radius of curvature of coiling, followed im- mediately by a slightly greater increase. These changes in coiling caused the venter of the ultimate one-third whorl to appear flat- tened in lateral view. The venter of this ultimate one-third whorl also became progressively more flattened in transverse section, for, after the marked narrowing of the venter in the middle one-third of the ultimate whorl, the venter became progressively broader. Also in the last one-third of the terminal volution there developed a dorsad flaring of the peristome, completely closing the umbilicus. PaLeozorc AMMONOIDs: DAvIs 83 In Hyattoceras guembeli and H. turgidwm the changes in coiling are less striking, and the narrowing of the venter followed by a flattening appears to be less pronounced or even absent. The mature conch of Hyattoceras abicht is markedly geniculate, with a narrowing of the venter followed by a broadening similar to that of Hyattoceras gemmitzt. Haug (1897) suggested that Abichia is the antidimorph of Hyattoceras, the former being male and the latter, female. The ultimate living chamber of Hyattoceras terminates in a pronounced constriction. In the ventral region of H. geinitz this constriction is immediately adoral of a tranverse ridge, and the ventral part of the constriction is depressed, producing a slight mid- ventral salient in the peristome. The mature living chamber of Hyattoceras geinitzt was reported by Gemmellaro (1887, p. 16) to be one and one-third whorls long, of H. abichi to be one and one-third volutions long (1887, p. 18), and of H. guembeli to be almost one and one-half whorls long (1888, D7). The maximum diameter of three mature Hyattoceras geinitzi is about 40 mm, of one mature H. guembeli is 67 mm, of one mature H, turgidum is 23% mm, and of five mature H. abichi is between 18 mm and 23 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887, 1888), Haug (1897), Haniel (1915), Smith (1927), Plummer and Scott (1937), Miller and Furnish (1940a), Toumanskaya (1949), Bogoslovsky, Librovitch, and Ruzhencev (1962), Davis, Furnish, and Glenister (1969), two immature speci- mens of Hyattoceras sp. (GIUA Dr. 511 no. T581, SUI 32581), three immature (BMNH (33681, C73335, C73336) and three mature (GPIT unnumbered, USNM unnumbered) examples of Hi. geinitzt, three mature individuals of H. abichi (USNM unnum- bered), about ten immature specimens of H. subgeinitzi (GIUA Dr. 551 no, T582, PIUB unnumbered, SUI 12322, 32463) and photo- graphs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — Six mature specimens of Hyattoceras are fig- ured: two H. abichi—IGUP 55 (PI. 21, figs. 1-3), USNM unnum- bered (PI. 21, figs. 4, 5), two H. geinitzi —IGUP 52 (PI. 20, figs. 5-8), GPIT unnumbered (PI. 21, figs. 10), one H. guembeli — IGUP 84 BuLLETIN 272 unnumbered (PI. 20, figs. 3, 4), and one H. turgidum — IGUP 51 GEIN20; figs: 15 2): Genus PSEUDOVIDRIOCERAS Ruzhencev, 1936 Diagnosis. — Pseudovidrioceras comprises those marathonitins with “mature” sutures in which the prongs of the ventral lobe are undenticulate, in which each of the subdivisions of the primary lateral lobe terminates in three denticles, and in which there are three complete lobes plus part of a fourth on each side between the bifid ventral lobe and the umbilical shoulder. (Furnish and Glenister [in Davis, Furnish, and Glenister, 1969] considered Pseudovidrio- ceras to be a subgenus of Marathonites.) Specific composition. — The type species of Pseudovidrioceras is Vidrioceras girtyi Miller and Cline, 1934, by original designation. The only other species which has been referred to Pseudovidrioceras is Stacheoceras pygmeum Gemmellaro, 1887, Peritrochia novomexi- cana Miller and Parizek, 1948, and P. dunbari Miller and Furnish, 1940a, may belong in Pseudovidrioceras. Immature shell.—The conch of Pseudovidrioceras is sub- discoidal (Miller and Cline, 1934, p. 290) to discoidal (Gemmellaro, 1887, p. 41). The venter is rounded, and the conch is compressed laterally. The umbilical shoulders are rounded, and the umbilicus is closed. In the one known specimen of P. girtyi W is greater than H in all whorls save the last; in P. pygmeum the height is greater than the width. In Pseudovidrioceras pygmeum the only ornament on the im- mature shell consists of the fine, radial striae which are sinuous in the ventral region. Mature shell.— There were apparently no changes in coiling in the growth of the mature living chambers of Pseudovidrioceras before the formation of the apertural constriction. In P. girtyi, how- ever, there was a change of conch proportions such that H exceeds W in the ultimate whorl. In P. pygmeum the dorsal part of the ultimate one-third volution extends over the umbilicus, completely covering it. The living chamber of the type species of Pseudovidrioceras lacks constrictions except for that at the aperture. On the other hand, in P. pygmeum (according to Gemmellaro, 1887) the internal mold of the ultimate whorl bears a few broad and superficial PaLreozoic AMMONOIDs: Davis 85 “strangolamenti” (apparently minor constrictions) which extend from the umbilicus straight across the venter without sinuations. A transverse bulge is present in at least Pseudovidrioceras pyg- meum just orad of the ultimate constriction. Miller and Cline (1934, p. 290) concluded that the aperture of P. girtyi is large and flaring; the aperture of P. pygmeum is neither. The interseptal spacing of the last several septa of Pseudo- vidrioceras girtyi decreases progressively. The length of the mature living chamber of Pseudovidrioceras is one whorl. The maximum diameter of many specimens of P. pygmeum doesn’t exceed 9 mm (Gemmellaro 1887, p. 41), but one specimen is at least 11, and another, 12 mm in diameter (ibid.). The soli- tary known specimen of P. girtyi has a mature diameter of 15% mm. Material. — The preceding observations are based on study of: Gemmellaro (1887), Toumanskaya (1931), Miller and Cline (1934), Ruzhencev (1936, 1950), Miller and Furnish (1940a), Miller and Parizek (1948), Bogoslovsky, Librovitch, and Ruzhencev (1962), Davis, Furnish, and Glenister (1969), and photographs and notes taken by W. M. Furnish and Brian F. Glenister in the summer of 1965. Illustrations. — One mature specimen of Pseudovidrioceras pyg- meum is figured — IGUP 65 (PI. 21, figs. 11-13). Genus MARATHONITES Bose, 1919 Diagnosis. — Marathonites comprises marathonitins with “ma- ture” sutures in which each branch of the ventral lobe is bifid and each of the three subdivisions of the primary lateral lobe is trifid. Familial assignment. — Furnish and Glenister (in Davis, Furnish, and Glenister, 1969) considered Marathonites to belong in the family Vidrioceratidae. Taxonomic composition.—The type species of Marathonites was Stacheoceras (Marathonites) J. P. Smithi Bése, 1919, by original designation, Plummer and Scott (1937) and Miller and Furnish (1940a) considered S. (M.) J. P. Smithi Bose, 1919, to be a junior synonym of Popanoceras ganti Smith, 1903; if the two names denote the same taxon, then the type species of the genus should be called Marathonites ganti (Smith, 1903). In addition to the type species, 86 BULLETIN 272 the following taxa are referred to Marathonites: M. (Almites) busterensis Toumanskaya, 1949, M. electraensis Plummer and Scott, 1937, M. gracilis Smith, 1927, M. arathomites invariabilis Ruzhencev, 1933, Stacheoceras kussicum Toumanskaya, 1931, S. k. var. djidairensis Toumanskaya, 1931, M. (Almites) pamiricus Toumanskaya, 1949, M. (A.) pressulus Ruzhencev, 1956a, Popano- ceras romanowskyt Karpinsky, 1889, M. sellardsi’ Plummer and Scott, 1937, Stacheoceras swevt Toumanskaya, 1931, M. sulcatus Bose, 1919, M. (M.) wuralensis Ruzhencev, 1940d, Stacheoceras uralicum Fredericks, 1921, and M. vidriensis Bose, 1919. Two subgenera of Marathomites have been recognized: Mara- thonites (Almites) Toumanskaya, 1941, and Marathonites (Mara- thomtes) Bose, 1919. In addition, Furnish and Glenister (in Davis, Furnish, and Glenister, 1969) considered the previously discussed Pseudovidrioceras to be a subgenus of Marathonites. Immature shells. — The conch of Marathonites is subglobose, strongly involute, and narrowly umbilicate (Ruzhencev, 1940d, p. 125). The ratio W/D decreases during ontogeny. Most immature specimens of Marathonites exhibit at least one constriction in the outermost preserved whorl. The distance be- tween constrictions varies (for example, in SUI 1065, a specimen of M. ganti, there are three constrictions in one whorl, but two of the interconstrictional distances are one-quarter whorl). Nonetheless there seems to be a general increase in the number of constrictions per whorl with ontogeny up to a maximum of six. The constrictions affect the internal mold only. Commonly individuals of Marathonites bear transverse undula- tions in the surface of the internal mold, These undulations ap- parently correspond in position and trend to the growth lines on the shell exterior. These shell plications are much more prominent immediately adapical of a constriction than adapertural of it; this latter position corresponds to a crowding of growth lines. In the region adapical of a constriction the plications are not absolutely parallel to that constriction, but each successive plication in an adapertural direction has a trend which is more closely similar to that of the constriction. In at least some individuals of Marathonites the shell exhibits longitudinal lirae. These structures are present only on the flanks PaLEozoic AMMONOIDs: Davis 87 in specimens of M. ganti and are less prominent than the growth lines. In M. sellardsi there is one striking rib on each shoulder and one single, less prominent lira just dorsal and another just ventral of each main rib. Development of this rib is even more pronounced in M. uralensis in which there are two very prominent ribs, one on each shoulder. Mature shell. —There are two distinct mature conch morpho- logies displayed by representatives of Marathomites. In at least M. ganti, M. invariabilis, and M. pressulus the mature living chamber is distinguished only by a prominent aper- tural constriction. In four specimens of Marathonites sp. from Timor (SUI 12301, 12304-12306) the mature living chamber also has an apertural con- striction, but the conch is geniculate with the venter broad and rounded except at the more adapertural of the two changes in coiling. Here the venter is narrow. (Furnish and Glenister [im Davis, Furnish, and Glenister, 1969] referred these four specimens to Pseudovidrioceras, which they considered a subgenus of MMara- thonites.) In both groups of mature forms the length of the living chamber is slightly less than one whorl to approximately one whorl. A group of three mature specimens of M. ganti varies from 28 to 33 mm in diameter. One individual of M. invariabilis (Ruzhencev, 1956a, pl. 37, fig. 3) has a mature diameter of 50 mm; three others (SUI 10594B, 32616B, 10594A) have diameters of 39 mm, 49 mm, and 51 mm, respectively. One mature example of M. pressulus (ibid., pl. 38, fig. 2) is 34 mm in diameter. Three of the four specimens of the other mature form of Marathonites are 28 or 29 mm in diameter. The significance of these two mature forms of Marathonites is unclear in the light of the material available, However, if the dif- ferences are of subgeneric taxonomic value, they are at variance with the subgenera of Marathonites as currently defined [viz. M. (M.) gantt, M. (Almites) tnvariabilis and M. (A.) pressulus all have the same type of modification]. Perhaps the two forms are antidimorphs. Material. — The preceding observations are based on study of: Karpinsky (1889), Smith (1903, 1927), Bose (1919), Fredericks (1921), Schindewolf (1931), Toumanskaya (1931, 1939b, 1941, 1949), Miller and Cline (1934), Plummer and Scott (1937), Ruzhencev (1938, 1940c, 1940d, 1950, 1956a, 1962), Miller and 88 BULLETIN 272 Furnish (1940a), Miller and Youngquist (1947), Miller and Downs (1950), Bogoslovsky, Librovitch, and Ruzhencev (1962), Davis, Furnish, and Glenister (1969), about 60 immature specimens of Marathonites (M. sp. — SUI 32589, ganti— SUI 1061-1067, 1898, 10525, 11046, 13817-13819, 17033, 17034, 32588, 32590, 32594, invariabilis — SUI 10594, 32616, 32617, J. P. Smithi — SUI 13821, sellardsi — SUI 1396, 1406, 32591, John Britts Owen Collec- tion 695), and about ten mature examples of Marathonites (M. sp. — SUI 12301, 12304-12306, gantz — SUI 1063, 13817, invartabilis — SUI 10594, 32616). Illustrations. — Four mature specimens of Marathomtes are figured: two M. sp. — SUI 12301 (PI. 14, fig. 7, Pl. 21, figs. 7-9), SUI 12305 (PI. 21, fig. 6), one M. ganti — SUI 1063 (PI. 22, figs. 5-7), and one M. invariabilis — SUI 10594 A (PI. 22, figs, 8-10). In addition, one immature specimen of M. gantz is illustrated — SUI 17033 (PI. 22, figs. 1, 2). Subfamily KARGALITINAE Ruzhencev, 1960 Diagnosis. — The Kargalitinae comprises marathonitids with sutures in which the dorsal lobe is either bifid or trifid and the ven- trad lobe of the three (or four) subdivisions of the primary lateral lobe is primarily bifid. Genus PERITROCHIA Girty, 1908 Diagnosis. — Peritrochia includes kargalitins with “mature” sutures in which the branches of the ventral lobe are not subdivided; the dorsad of the three subdivisions of the primary lateral lobe and the ventrad of the three subdivisions of the primary internal lateral lobe each bifurcated during ontogeny; the dorsal lobe is entire. Familial assignment. — Furnish and Glenister (in Davis, Furnish, and Glenister, 1969) considered Peritrochia to belong in the family Vidrioceratidae. Synonymy. — Paratrochia Diener (1921, p. 10) is apparently a typographic error, Specific composition.— The type species and only named species referred to Perttrochia is P. erebus Girty, 1908, by monotypy. Immature shell. — The conch of Peritrochia is parabolic (Bogo- slovsky, Librovitch, and Ruzhencev, 1962, p. 392), subdiscoidal to subglobular with a small umbilicus. PaLeozoic AMMONOIDs: DAvis 89 There are up to five constrictions per whorl in Perttrochia. These features affect only the internal mold. In addition to constric- tions, most individuals display gentle transverse plications as well as growth lines. From the Bone Spring Limestone in Texas one specimen of Peritrochia (SUI 32584) was recovered which appar- ently is a new species; this individual bears transverse plications which are relatively conspicuous. The trends of the growth lines, plications, and contrictions are parallel; early in ontogeny all three are essentially straight, becoming more sinuous with ontogenetic development. In addition to the transverse ornament, well-preserved shells and internal molds of Peritrochia exhibit faint longitudinal undula- tions. In the immediate vicinity of the umbilicus is an area in which the shell appears thicker than ventrad of this area. This thickened shell forms a distinct edge on the umbilical shoulder. Mature shell.— There is little if any change in coiling, in conch proportions, or in both in the ultimate living chamber of Peri- trochta. Constrictions are lacking on the ultimate whorl save for the apertural modification. Transverse plications, striations, and longi- tudinal ornament are present in the ultimate living chamber, as is the spire of thickened shell at the umbilicus. The ultimate body chamber of Peritrochia appears to be just less than one whorl long. The maximum diameter of Peritrochia varies from 18 to 24 mm. Material. — The preceding observations are based on study of: Gemmellaro (1887), Girty (1908), Toumanskaya (1931), Greco (1935), Plummer and Scott (1937), Miller and Furnish (1940a, 1957b), Ruzhencev (1940c, 1940d), Mullerried, Miller, and Furnish (1941), Miller (1945a), Miller and Youngquist (1947), Miller and Parizek (1948), Miller and Downs (1950), Unklesbay (1962), Bogo- slovsky, Librovitch, and Ruzhencev (1962), Davis, Furnish, and Glenister (1969), about 20 immature (SUI 32583) and eight ma- ture (SUI 32583, 32585, 32586) representatives of Peritrochia erebus, and one immature specimen of a new species of Peritrochia (fide W. M. Furnish, 1967, personal communication). 90 BULLETIN 272 Illustrations. —Two mature specimens of Peritrochia erebus are figured: SUI 32585 (PI. 14, figs. 4-6) and SUI 32586 (PI. 14, figs. 1, 2). In addition, two immature specimens of Peritrochia are illustrated: P. n. sp. — SUI 32584 (PI. 14, fig. 3) and P. erebus — SUMG2583t hr ( PlO22 ehiesh Sy 4): REFERENCES Andrussow, N. 1907. About the genus Arcicardium Fischer. Annual of Geology & Mineralogy of Russia, vol. 9, pp. 105-114, pls. 3, 4 [in Russian and German]. Armstrong, J. D., Dear, J. F., and Runnegar, B. 1967. Permian ammonoids from eastern Australia. Geol. Soc. Australia, Jour., vol. 14, pt. 1, pp. 87-97, pls. 5, 6. Arthaber, G. 1911. Die Trias von Albanien. Beitr. zur Palaont. u. Geol. Osterr.-Un- garns, Bd. 24, pp. 169-277, pls 17-24. Berry, Edward W. 1928. Cephalopod adaption—the record and its interpretation. Quar. Rev. Biology, vol. 3, No. 1, pp. 92-108. Besairie, Henri 1930. Recherches géologiques & Madagascar. Soc. Hist. Nat. Toulouse, Bull., vol. 60, 2d fascicule, pp. 1-272, pls. 1-27. 1936. Recherches géologiques &@ Madagascar, Ire Suite—La géologie du Nord-Ouest, Chapitre 3—Les fossiles. Acad. Malgache Mém., Fasc. 21, pp. 105-207, pls. 4-24. Blainville, M. H. D. de 1840. Prodrome d’une monographie des ammonites, pp. 1-31 of Supple- ment Du Dictionaire Des Sciences Naturelles, Bertrand, Paris. Boehm, G. 1907. Geologische Mitteilungen aus dem Indo-Australischen Archipel. VIb Jiingeres Paldozoicum von Timor. N. Jb. Min., Geol., Palaont., Beilage-Band 25, pp. 303-323, pls. 10, 11. Bohmers, J. C. A. 1936. Bau und Struktur von Schale und Sipho bei permischen Am- monoidea. Univ. Amsterdam, pp. 1-125, pls. 1, 2. Bose, Emil. 1919. The Permo-Carboniferous ammonoids of the Glass Mountains, West Texas, and their stratigraphical significance. Univ. Texas Bull., No. 1762 (1917), pp. 1-241, pls. 1-11. Bogoslovskaya, M. F. 1962. Artinskian ammonoids from the Central Urals. Acad. Sci. USSR, Works of Paleont. Institute [Trudy], vol. 87, pp. 1-117, pls. 1-11 [in Russian]. Bogoslovsky, V. I., Librovitch, L. S., and Ruzhencev, V. E. 1962. Pp. 334-409 of Molluscs-Cephalopods. I. vol. (V. E. Ruzhencey, ed.) of Principles of Paleontology [Osnovy] (Yu. A. Orlov, overall editor), Publishing House, Acad. Sci. USSR, Moscow [in Russian]. Callomon, J. H. 1963. Sexual dimorphism in Jurassic ammonites. Leicester Lit. & Phil. Soc., Trans., vol. 57, pp. 21-56, pl. 1. Chao, King-Koo 1965. The Permian ammonoid-bearing formations of South China. Scientia Sinica, vol. 14, No. 12, pp. 1813-1825, pls. 1, 2. PaLeozoic AMMONOIDs: DAvIs 91 Chernov, A. A. 1939. Order Ammonoidea. The Ammonoids. Atlas of the principle forms of fossils of the fauna of the USSR, vol. 6. Permian System, pp. 160-190 [in Russian]. Coémme, S. 1917. Note critique sur le genre Cadmoceras. Soc. Géol. France, Bull., ser. 4, vol. 17, pp. 44-54, pl. 6. Cowen, Richard, Gertman, Richard, and Wiggett, Gail 1971. Color patterns in Nautilus, and their implications for cephalopod paleobiology [Abstract]. Geol. Soc. America, Abstracts with pro- grams, vol. 3, No. 2, pp. 104-105. Davis, Richard Arnold, and Campbell, Carlyle B. 1968. An orthocerid cephalopod from the Cherokee Group of Marion County, Iowa. Iowa Acad. Sci., Proc., vol. 73, pp. 279-284. Davis, Richard Arnold, Furnish, W. M., and Glenister, Brian F. 1969. Mature modification and dimorphism in Late Paleozoic am- monoids. pp. 101-110, pls. 2-5 Sexual Dimorphism in Fossil Metazoa and Taxonomic Implications (G. E. G. Westermann, editor), In- ternational Union of Geological Sciences, ser. A, No. 1. Davitashvili, L. Sh., and Khimshiashvili, N. G 1954. On the question of the biological significance of the apertural formation of ammonites. Works [Trudy] of the Paleobiology Sec- tion of the Academy of Science of the Georgian Soviet Socialist Republic, vol. 2, pp. 44-76 [in Russian]. Demanet, F. 1943. Les horizons marins du Westphalien de la Belgique et leurs faunes. Mus. Roy. Hist. Nat. Belgique, Mém., No. 101, pp. 1-166, pls. 1-9. Diener, Carl 1897a. The Permocarboniferous fauna of Chitichun, No. I, Geol. Surv. India, Mem., Palaeontologia Indica, ser. 15, Himdlayan Fossils, vol. 1, No. 3, pp. 1-105, pls. 1-13. 1897b. The cephalopoda of the Lower Trias. Geol. Surv. India, Mem., Palaeontologia Indica, ser. 15, Himdlayan Fossils, vol. 2, No. 1, pp. 1-181, pls. 1-23. 1903. Permian fossils from the central Himalayas. Geol. Surv. India, Mem., Palaeontologia Indica, ser. 15, Himdlayan Fossils, vol. 1 pt. 5, pp. 1-204, pls. 1-10. 1904. Note on Cyclolobus Haydeni, Diener. Geol. Sur. India, Records, vol. 31, pt. 2, pp. 56-58. 1921. Ammonoidea permiana. pt. 14 (pp. 1-36) of Fossilium Catalogus I: Animalia (C. Diener, ed.), W. Junk, Berlin. 1927. Leitfossilien des marinen Perm. 5th Leiferung (pp. 1-84, pls. 1-14) Leitfossilien (Georg Giirich, ed.), Gebriider Borntraeger, Ber- in. Dixon, Joe Scott 1960. A statistical study of seven species of the Pennsylvanian-Permian goniatite, Agathiceras. M. S. Thesis, University Iowa, pp. 1-58. Dunbar, Carl Owen 1924. Phases of cephalopod adaption. Pp. 187-223 in Organic Adaption to Environment (M. R. Thorpe, ed.), Yale Univ. Press, New Haven, Conn. Emeliancev, T. 1929. Artinsk cephalopods from the Polyudovsk Ridge district in the Urals. Geol. Comm. (Leningrad). Transactions [Izvestiia], vol. 48, No. 8, pp. 145 (1229) - 152 (1236), pl. 51 [in Russian]. ’ 9? BuLieTIN 272 Foord, A. H., and Crick, G. C. 1897. Catalogue of the fossil Cephalopoda in the British Museum, Part 3. Bactritidae and Ammonoidea. pp. i-xxxviii + 1-303, London. Frebold, Hans 1932. Marines Unterperm in Ostgrénland und die Frage der Grenzzie- hung zwischen dem pelagischen Oberkarbon und Unterperm. Med- delelser om Grgnland, vol. 84, No. 4, pp. 1-33, pl. 1. Frech, Fritz 1915. Loses und geschlossenes Gehduse der tetrabranchiaten Cephalo- poden. Centralblatt Min., Geol., Palaont., Jahrg. 1915, pp. 593-606. Fredericks, George 1921. On some ammonoids of the Upper Carboniferous of the Ural Mountains. Soc. Paleont. Russia, Ann., vol. 3, pp. 73-94, pl. 1 [in Russian]. Fretier, V., and Graham, A. 1966. Reproduction. Chapter 4 (pp. 127-164) of vol. 1, Physiology of Mollusca (Karl M. Wilbur and C. M. Yonge, ed.), Academic Press, New York. Furnish, W. M. 1966. Ammonoids of the Upper Permian Cyclolobus-zone. N. Jb. Geol. Palaont., Abh., vol. 125, pp. 265-296, pls. 23-26. Furnish, W. M., and Glenister, Brian F. 1970. Permian ammonoid Cyclolobus from the Salt Range, West Pakistan. pp. 153-175. Stratigraphic Boundary Problems: Permian and Trias- sic of West Pakistan (Bernhard Kummel and Curt Teichert, ed.), University Press of Kansas, Lawrence, Kansas. Furnish, W. M., and Knapp, W. D. 1966. Lower Pennsylvanian fauna from eastern Kentucky; Part 1, Am- monoids. Jour. Paleont., vol. 40, No. 2, pp. 296-308, pl. 35. Gemmellaro, Gaetano Georgio 1887. La fauna dei calcari con Fusulina della valle del Fiume Sosio nella provincia di Palermo, Fascio I, Cephalopoda, Ammonoidea. Gior. Sci. Nat. Econ., vol. 19, pp. 1-106, pls. 1-10. 1888. La fauna dei calcari con Fusulina della valle del Fiume Sosio nella provincia di Palermo, Appendice Fascio I, Cephalopoda, Ammonoidea. Gior. Sci. Nat. Econ., vol. 20, pp. 9-36, pls. A-D. Gerth, H. 1950. Die Ammonoideen des Perms von Timor und ihre Bedeutung fiir die stratigraphische Gliederung der Permformation. N. Jb. Min., Geol., Palaont., Bd. 91, Abt. B, pp. 233-320. Gillet, S. 1937. Les Ammonites du Bajocien d’Alsace et de Lorraine. Serv. Carte Géol. Alsace et Lorraine, Mém., vol. 5, pp. 1-130. Girty, G. H. 1908. The Guadalupian fauna. U. S. Geol. Sur., Prof. Paper 58, pp. 1- 651, pls. 1-31. Glenister, B. F., and Furnish, W. M. 1961. The Permian ammonoids of Australia. Jour. Paleont., vol. 35, No. 4, pp. 673-736, pls. 78-86. Gordon, Mackenzie, Jr., and Merriam, C. W. 1961. Late Permian ammonoids in the Inyo Range, California, and their significance. U. S. Geol. Sur., Prof. Paper 424-D, pp. D-238-D-239. Grabau, A. W. 1923-1924. Stratigraphy of China, Part 1, Paleozoic and Older. China Geol. Sur., Peking, pp. 1-528, pls. 1-6. PaLeozoic AMMONOIDs: DAvis 93 Greco, Benedetto ' 1935. La Fauna Permiana del Sosio Conservata nei Musei di Pisa, di Firenze e di Padova, Palaeontographia Italica, vol. 35, pp. 101-190, pls. I-IV (12-15). Gregorio, M. A. De 1930. Sul Permiano di Sicilia. Annales de géologie et de paléontologie, No. 52, pp. 1-70, pls. 1-21. Guex, Jean 1968. Note Préliminaire sur le dimorphisme sexuel des Hildocerataceae du Toarcien moyen et supérieur de Aveyron (France). Bull. Soc. Vaudoise de Sciences Naturelles, Lausanne, vol. 70, No. 327, pp. 57-84, pls. 1-3. Haniel, C. A. 1915. Die Cephalopoden der Dyas von Timor. Abh. 6 (pp. 1-153, pls. 46- 56) of Lieferung 3 of Paldontologie von Timor (J. Wanner, ed.), Stuttgart. Haug, Emile 1894. Les Ammonites du Permien et du Trias. Remarques sur leur classi- fication. Soc. Géol. France, Bull., ser. 3, vol. 22, pp. 385-412. 1897. [Observations on Glangeaud, 1897]. Soc. Géol. France, Bull., Ser 3.2 V0len25.9 py 107. 1898. Etudes sur les Goniatites. Soc. Géol. France, Mém., Paléont., Mém. 18, pp. 1-112, pl. I. Hayasaka, Ichiro 1940. On two Permian ammonoids from the Kitakami Mountains, north Japan. Geol. Soc. Japan, Jour., vol. 47, No. 565, pp. 422-427. 1947. A Permian cephalopod faunule from Chéchiang Prov., China. Acta Geol. Taiwanica, vol. 1, No. 1, pp. 13-38, pls. 1, 2. 1963. Some Permian fossils from southern Kitakami, I1I—Ammonoidea. Japan Acad., Proc., vol. 39, No. 8, pp. 594-599. 1965. Some cephalopods in the Permian faunule of Takokura-Yama, Fukushima Prefecture, Japan. Palaeont. Soc. Japan, Trans. Proc., N.S., No. 57, pp. 8-27, pls. 2, 3. Hyatt, Alpheus 1874. Abstract of a memoir on the “Biological relations of the Jurassic ammonites”. Boston Soc. Nat. Hist., Proc., vol. 17, pp. 235-241. Jeannet, Alphonse 1948. Sur la forme de l’ouverture chez certains Nautiles mésozoiques. Schweiz. Miner. & Petrogr. Mitteil., vol. 28, fase. 1 (Festschrift P. Niggli), pp. 178-187, figs. 1-5. 1959. Ammonites Permiennes et Faunes Triasiques de Himalaya Cen- tral. Geol. Surv. India, Mem., Palaeontologia Indica, new ser., vol. 34, mem. 1, pp. 1-189, pls. 1-21. Karpinsky, A. P. 1874. Geological investigation in the Orenburgian region. Records Min. Soc., ser. 2, No. 9, pp. 212-310, pl. 12 [in Russian]. 1889. Uber die Ammoneen der Artinsk-Stufe und einige mit denselben verwandte carbonische Formen. Imp. Acad. Sci. St. Petersburg, Mem., ser. 7, vol. 37, No. 2, pp. 1-104, pls. 1-5. Kerr, J. G. 1931. Notes upon the Dana specimens of Spirula and upon certain prob- lems of cephalopod morphology. Oceanographical Reports edited by the “Dana” Committee, No. 8, pp. 1-34, pls. 1-20. Krotow, P. 1885. The Artinskian Stage. A geological-paleontological monograph of the sandstone of Artinsk. Works of the Society of Naturalists 94 BULLETIN 272 attached to the Imperial Kazan University, vol. 13, No. 5, pp. 1-312, pls. 1-4 [in Russian]. 1888. Geological investigations on the western slope of the Solikamsk and Cherdin Regions of the Urals. Works of the Geol. Comm. of St. Petersburg, vol. 6, No. 1, pp. 1-563 [in Russian]. Kummel, Bernhard, and Lloyd, R. M. 1955. Experiments on relative streamlining of coiled cephalopod shells. Jour. Paleont., vol. 29, No. 1, pp. 159-170. Lane, F. W. 1960. Kingdom of the octopus. Sheridan House, New York, pp. 1-300. Lehmann, Ulrich 1966. Dimorphismus bei Ammoniten der Ahrensburger Lias-Geschiebe. Palaont. Zeitschr., vol. 40, No. 1/2, pp. 26-55, pis. 3, 4. Mabuti, S. 1935. On the occurrence of Stacheoceras in the Kitakami mountainland, etc. Saito Ho-on Kai Mus. Bull., No. 6, pp. 143-149, pl. 1. Makowski, Henryk 1962. Problem of sexual dimorphism in ammonites. Paleont. Polonica, 12-1962, pp. 1-92, pls. 1-20. Mangold-Wirz, Katharina 1963. Biologie des Céphalopodes benthiques et nectoniques de la mer Catalane. Vie et Milieu, suppl. No. 13, pp. 1-285. pls. 1-4. Mangold-Wirz, Katharina, Lu, C. C., and Aldrich, Frederick A. 1969. A reconsideration of forms of squid of the genus Illex (Illicinae, Ommastrephidae). II. Sexual dimorphism. Canadian Jour. Zoology, vol. 47, No. 6, pp. 1153-1156, pls. 1-4. Marez Oyens, F. A. H. W. De 1938. Preliminary note on the occurrence of a new ammonoid fauna of Permian age on the island of Timor. Koninklijke Nederlandsche Akademie van Wetenschappen, Proc., vol. 41, No. 10, pp. 1122-1126. Maximova, S. V. 1935. On some new species of artinsk ammonoids. Moscow Soc. Natural- ists, Bull., Sec. Geology, vol. 13, No. 2, pp. 273-288, pl. 1 [in Russian |. McCaleb, James A. 1968. Lower Pennsylvanian ammonoids from the Bloyd Formation of Arkansas and Oklahoma. Geol. Soc. Amer., Sp. Paper 96, pp. 1- 123eeplssul=12e McCaleb, James A., and Furnish, W. M. 1964. The Lower Pennsylvanian ammonoid genus Axinolobus in the southern midcontinent. Jour. Paleont., vol. 38, No. 2, pp. 249-255, pl. 40. Mikesh, D. L., and Glenister, B. F. 1968. Solenochilus springeri (White & St. John, 1868) from the Pennsyl- vanian of southern Iowa. Iowa Acad. Sci., Proc., vol. 73, pp. 269- 278. Miller, A. K. 1933. Age of the Permian limestones of Sicily. Amer. Jour. Sci., ser. 5, vol. 26, No. 154, pp. 409-427. 1944. Permian cephalopods. pt. IV (pp. 71-127, pls. 20-45) of King, et al. Geology and paleontology of the Permian area northwest of Las Delicias, southwestern Coahuila, Mexico. Geol. Soc. Amer., Sp. Paper 52. 1945a. Some exceptional Permian ammonoids from West Texas. Jour. Paleont., vol. 19, No. 1, pp. 14-21, pls. 6-8. PaLEozoic AMMONOIDs: DAvVIs 95 1945b. - eeniae ammonoid from Sonora. Jour. Paleont., vol. 19, No. 1, 1953. Pephalnsolte Pp. 81-82, pl. 24D, figs. 21-23 of Cooper, et al. Permian fauna at El Antimonio, W estern Sonora, Mexico. Smith- sonian Misc. Coll., vol. 119, No. 2. Miller, A. K., and Cline, L. M. 1934. The cephalopods of the Phosphoria Formation of ge United States. Jour. Paleont., vol. 8, No. 3, pp. 281-302, pl. Miller, A. K., and Crockford, M. B. 1936. Permian cephalopods from British Columbia. RH Soc. Canada, Trans., 3d ser., sec. IV, vol. 30, pp. 23-28, pl. Miller, A. K., and Downs, H. R. 1950. Ammonoids of the Pennsylvanian Finis Shale of Texas. Jour. Paleont., vol. 24, No. 2, pp. 185-218, pls. 31-35. Miller, A. K., and Furnish, 'W. M. 1939. The late Paleozoic ammonoid families Adrianitidae and Aga- thiceratidae. Palaont. Zeitschr., vol. 21, No. 4, pp. 297-303. 1940a. Permian ammonoids of the Guadalupe Mountain Region and ad- jacent areas. Geol. Soc. Amer., Sp. Paper 26, pp. 1-242, pls. 1-44. 1940b. Cyclolobus from the Permian of eastern Greenland. Meddelelser om Grénland, vol. 112, No. 5, pp. 1-10, pl. 1 1957a. Ammonoids of the basal Word Formation, Glass Mountains, West Texas. Jour. Paleont., vol. 31, No. 6, pp. 1052-1056. 1957b. Permian ammonoids from Tunisia. Jour. Paleont., vol. 31, No. 4, pp. 705-712, pl. 83. Miller, A. K., Furnish, W. M., and Clark, D. L. 1957. Permian ammonoids from western United States. Jour. Paleont., vol. 31, No. 6, pp. 1057-1068, pls. 133, 134. Miller, A. K., Furnish, W. M., and Schindewolf, O. H. 1957. Paleozoic ammonoids. Pp. L11-L79 of Treatise on Invertebrate Paleontology (R. C. Moore, ed.), Geol. Soc. Amer. and Univ. Kansas Press, Lawrence, Kansas. Miller, A. K., and Parizek, E. J. 1948. A lower Permian ammonoid fauna from New Mevxico. Jour. Paleont., vol. 22, No. 3, pp. 350-358, pls. 56-58. Miller, A. K., and Unklesbay, A. G. 1943. ive siphuncle of late pal oem ammonoids. Jour. Paleont., vol. 17, No.9], pp: 1-25, spls.1- Miller, A. K., and Youngauist, Welter, 1947. emer Permian cephalopods from the Texas Colorado River Brey: Univ. Kansas, Paleont. Contrib., No. 2, art. 1, pp. 1-15, pls. 1-3. Miller, S. A., Tand Gurley, W. F. E. 1896. New species of Paleozoic invertebrates from Illinois and other states. Ill]. State Museum, Bull. No. 11, pp. 1-50, pls. 1-5. Mojsisovics von Mojsvar, E. 1873,1875. Die Mollusken-Faunen der Zlambach-und Hallstdatter-Schich- ten. K.-K. Geol. Reichsanstalt, Abhand., vol. 6, pp. 1-174, pls. 1-70. 1882. Die Cephalopoden der mediterranen Triasprovinz. K.-K. Geol. Reichsanstalt, Abhand., vol. 10, pp. 1-322, pls. 1-94. 1888. Uber einige arktische Trias- Ammoniten des Lala ag Siberien Imp. Acad. Sci. St. Petersbourg, Mem., ser. 7, vol. 36, No. 5, pp. 1-21, pls. 1-3. Morton, S. G. 1836. Appendix. Being a notice and description of the organic remains 96 BuLLETIN 272 embraced in the preceding paper. Amer. Jour. Sci., vol. 29, pp. 149-154, pls. 1-36. Mullerried, F. K. G., Miller, A. K., and Furnish, W. M. i 1941. The middle Permian of Chiapas, southernmost Mexico, and its fauna, Amer. Jour. Sci., vol. 239, No. 6, pp. 397-406, pl. 1. Nassichuk, W. W., Furnish, W. M., and Glenister, B. F. 1965. The Permian ammonoids of Arctic Canada. Geol. Sury. Canada, Bull. 131, pp. 1-56, pls. 1-5. Nikitin, S. 1884. General geological map of Russia, Sheet 56. Works [Trudy] Geol. Comm., vol. 1, No. 2, pp. 1-153, pl. 1-3 [in Russian, Ger- man summary ]. Pelseneer, P. 1926. La proportion relative des sexes chez les animaux et particuliére- ment chez les Mollusques. Acad. Roy. Belgique, cl. Sci., Mém., 2deser., vol.) 8) tascy Ihe ppyal=258: Perna, A. 1915. On life habits of the goniatites. Geological Proceedings, vol. 1, No. 1, pp. 6-14 [in Russian]. Perna, E. Ya. 1914. The ammonoids of the upper Neodevonian of the east slope of the southern Urals. Works of the Geol. Comm. of St. Petersburg, n.s., vol. 99, pp. 1-114, pls. 1-4 [in Russian, German summary ]. Plummer, F. B., and Scott, Gale 1937. Upper Paleozoic ammonites in Texas. The geology of Texas, vol. III, pt. 1; Texas Univ. Bull. 3701, pp. 1-516, pls. 1-41. Pruvot-Fol, A. 1937. Remarques sur le Nautile. Comptes Rendus du XII& Congrés International de Zoologie — Lisbonne (1935), vol. 3, pp. 1652-1663. Roever, W. P. De 1940. Description of some Permian ammonoids from F. Koekatoe, Lidak. pp. 206-210, pl. V, fig. 2, of vol. I, Geological Expedition to the Lesser Sunda Islands (H. A. Brouwer, ed.), Amsterdam. Rothpletz, A. 1892. Die Perm-, Trias- und Jura-Formation auf Timor und Rotti im indischen Archipel. Palaeontographica, vol. 39, pp. 57-106, pls. 9-14. Ruzhencev, V. E. 1933. Concerning some Lower Permian ammonoids of the Aktyubinsk Region. Moscow Soc. Naturalists, Bull., new ser. vol. 41, Sec. Geology, vol. 11(2), pp. 164-180, pls. 4, 5 [in Russian, French summary]. 1936. Paleontological notes about Carboniferous and Permian ammonites. Problems Soviet Geology, No. 12, pp. 1072-1088 [in Russian, English summary ]. 1937. The Carboniferous and Permian problem. Moscow Soc. Natural- ists, Bull., new ser. vol. 45, Sec. Geology, vol. 15(5), pp. 401-411 [in Russian, English title]. 1938. Ammonoids of the Sakmarian Stage and their stratigraphic sig- nificance. Problems Paleontology, vol. 4, pp. 187-285, pls. 1-7 [in Russian, English introductory material]. 1939. The importance of ontogeny for the natural classification of am- monites. Acad. Sci. USSR, Transactions [Izvestiia], Ser. Biol., No. 1, pp. 13-32 [in Russian, English summary]. 1940a. On the family Adrianitidae Schindewolf. Acad. Sci. USSR, Re- ports [Doklady], vol. 26, No. 8, pp. 837-840. 1940b. Ad new genus Aristoceras from the Upper Carboniferous of the Urals. Acad. Sci. USSR, Reports [Doklady], vol. 27, No. 5, pp. 524-528. PaLteozoic AMMONOIDs: Davis 97 1940c. On the question of the taxonomic position of some of the Upper Paleozoic ammonites. Acad. Sci. USSR, Reports [Doklady], vol. 28, No. 3, pp. 285-288. 1940d. An essay on the natural classification of some Late Paleozoic am- monites. Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 11, No. 3, pp. 1-134, pls. 1-6 [in Russian, English summary]. 1941. The first representative of the genus Emilites Ruzhencev in the Upper Carboniferous of the Urals. Acad. Sci. USSR, Reports [Doklady], vol. 30, No. 9, pp. 884-886. 1950. Upper Carboniferous ammonites of the Urals. Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 29, pp. 1-223, pls. 1-15 [in Russian ]. 1951. Lower Permian ammonites of the southern Urals—I. Ammonites of the Sakmarian Stage. Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 33, pp. 1-188, pls. 1-15 [in Russian]. 1952. Biostratigraphy of the Sakmarian Stage in the Aktyubinsk region of Kazakhsh SSR, Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 42, pp. 1-87, pls. 1-6 [in Russian]. 1955. About the family Cyclolobidae Zittel. Acad. Sci. USSR, Reports [Doklady], vol. 103, No. 4, pp. 701-703 [in Russian]. 1956a. Lower Permian ammonites of the southern Urals—II. Ammonites of the Artinskian Stage. Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 60, pp. 1-275, pls. 1-39 [in Russian]. 1956b. About some new genera of ammonoids. Acad. Sci. USSR, Reports [Doklady], vol. 107, No. 1, pp. 158-161 [in Russian]. 1960. Principles of systematics, system and phylogeny of Paleozoic am- monoids. Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 83, pp. 1-331 [in Russian]. 1962. Superorder Ammonoidea. The ammonoids—general part. Pp. 243- 334 of Molluscs-Cephalopods. I. Vol. (V. E. Ruzhencev, ed.) Principles of Paleontology [Osnovy] (Yu. A. Orlov, overall editor), Publishing House, Acad. Sci. USSR, Moscow [in Russian]. Sazonov, N. T. 1957. Jurassic deposits of the Central Region of the Russian Platform. Leningrad, pp. 1-155 [in Russian]. Schindewolf, O. H. 1931. Uber den Ammoniten-Sipho. Preuss. Geol. Landesanst. Sitzungsber., Heft 6, pp. 197-209, pl. 5. Shevyrev, A. A. 1965. Superorder Ammonoidea. Pp. 166-182, pl. 17-24 of Evolution and change of marine organisms at the Paleozoic-Mesozoic Boundary (V. E. Ruzhencev and T. G. Sarycheva, ed.), Acad. Sci. USSR, Works Paleont. Inst. [Trudy], vol. 108 [in Russian]. Siemiradzki, J. 1925. Podrecznik paleontologit. C:1. Paleozoologia, Warsaw, pp. 1-389. Smith, J. P. 1903. The Carboniferous ammonoids of America. U.S. Geol. Surv., Mon- ogr. 42, pp. 1-211, pls. 1-29. 1927. Permian ammonoids of Timor. Jaarboek van het Mijnwezen in Nederlandsch-Indié, Jaargang 55 (1926), Verhandelingen 1, pp. 1-90, pls. 1-16. Stenzel, H. B. 1964. Living Nautilus. Pp. K59-K93, Treatise on Invertebrate Paleon- tology (R. C. Moore, ed.), Geol. Soc. Amer. and Univ. Kansas Press, Lawrence, Kansas. Stoyanow, A. A. 1910. On the character of the boundary of Palaeozoic and Mesozoic near Djulfa. Imp. Russ. Mineralogical Soc., Mem., vol. 47, No. 1 pps 6-139. 98 BULLETIN 272 Sun, Y. C. 1939 (1947). The uppermost Permian ammonoids from Kwangsi and their stratigraphical significance. The 40th Anniv. Papers Nat. Univ. Peking, pp. 35-49, pls. 1, 2, (Contr. from Geol. Inst., Nat. Univ. Peking, No. 28, pp. 35-49, pls. 1, 2). Teichert, Curt 1944. Two new ammonoids from the Permian of Western Australia. Jour. Paleont., vol. 18, No. 1, pp. 83-89, pl. 17. Teichert, Curt, and Fletcher, H. O. 1943. A Permian ammonoid from New South Wales and the correla- tion of the Upper Marine Series. Australian Mus., Rec., vol. 21, pp. 156-163, pl. 11. Toumanskaya, O. G. 1931. Permo-carboniferous beds of the Crimea. Part I. Cephalopoda, Ammonoidea. Supreme Council of National Political Economy of the USSR, Principal Geological Prospecting Bureau, Moscow, pp. 1-117, pls. 1-8 [in Russian, English summary ]. 1935. Permian ammonoids of the River Kubergandy and their strati- graphic significance. Acad. Sci. USSR, Tajik-Pamir Expedition 1933, Works of the Expedition, Pub. 31, pp. 43-130, pls. 1-5 [in Russian, English summary ]. 1937a. About representatives of the family Adrianitidae Schindewolf. Moscow Soc. Naturalists, Bull., Sec. Geology, vol. 15, No. 4, pp. 375-378 [in Russian]. 1937b. On representatives of the new genus Crimites in Permian deposits. Yearbook of All-Russian Paleontology. General, vol. 11, pp. 146-147 [in Russian, English abstract]. 1937c. La stratigraphie du systeme pérmien d’aprés les ammonées. Inter- national Geological Congress, 17th Session, Abstracts of papers, pp. 93-94. 1938. On certain new genera of the family Popanoceratidae Hyatt. Sov. Geol., 1938, No. 12, pp. 106-108 [in Russian]. 1939a. On the correlation of the Permian deposits of the USSR with the deposits of other countries. Moscow Soc. Naturalists, Bull., Sec. Geology, vol. 17, Nos. 2, 3, pp. 17-26 [in Russian]. 1939b. Permian ammonoids of the Transalai Range and their significance for the stratigraphy of the Pamirs. Problems Paleontology, vol. 5, pp. 93-137, pls. 1-8 [in Russian, English summary ]. 1939c. Permian ammonoids of the Range of Peter I. Problems Paleon- tology, vol. 5, pp. 139-145, pl. 1 [in Russian, English summary]. 1941. On the stratigraphy of the Permian succession of the Crimea. Acad. Sci. USSR, Reports [Doklady], vol. 32, No. 4, pp. 261-264. 1949. On the Permian ammonoids of Central Asia. Moscow Soc. Natural- ists, Bull., Sec. Geology, vol. 24, No. 6, pp. 49-84, pls. 1-6 [in Russian]. Trueman, A. E. 1941. The ammonite body-chamber, with special reference to the buoyancy and mode of life of the living ammonite. Geol. Soc. London, Quar. Jour., vol. 96, pt. 4, pp. 339-378, (379-383: dis- cussion). Trimpy, Rudolf 1960. Uber die Perm-Trias Grenze in Ostgrinland und iiber die Prob- lematik stratigraphischer Grenzen. Geol. Rdsch., vol. 49, No. 1, pp. 97-103. PaLEeozoic AMMOoNoOIDs: DAvis 99 Unklesbay, A. G. 1962. Pennsylvanian cephalopods of Oklahoma. Oklahoma Geol. Surv., Bull. 96, pp. 1-150, pls. 1-19. Vaillant-Couturier-Treat, Ida 1926. Note sur le Permienne marin de Madagascar. Comptes Rendus, Acad. Sci. Paris, vol. 182, pp. 1092-1094. 1933. Paléontologie de Madagascar, XIX—Le Permo-Trias Marin. An- nales de Paleontologie, vol. 22, fasc. 2, pp. 37-96, pls. 5-10. Voinova, E. 1934. Some ammonites from the Baigendja Horizon of the Artinskian of the Southern Urals. The United Geological and Prospecting Service of USSR, Trans., fasc. 352, 55 numbered pages, pls. 1-5 [in Russian]. Waagen, William 1872. On the occurrence of Ammonites, associated with Ceratites, and Gontatites in the Carboniferous deposits of the Salt Range. Geol. Sur. India, Mem., Palaeontologia Indica, vol. 9, pp. 351-358, pl. 1. 1879. Productus Limestone fossils, 1. Pisces-Cephalopoda. Geol. Sur. India, Mem., Palaeontologia Indica, ser. 13—Salt Range Fossils, vol. 1, pp. 1-72, pls. 1-6. Wanner, J. 1932. Zur Kenntnis der permischen Ammonoideen-fauna von Timor. N. Jb. Min., Geol., Palaont., Beil.-Bd. 67, Abt. B, pp. 257-286, pls. 9-11. Wells, M. J. 1962. Brain and behavior in cephalopods. Stanford Univ. Press, Stan- ford, California, pp. 1-171. 1966. The brain and behavior of cephalopods. Chapter 15 (pp. 547-590), vol. 2 of Physiology of Mollusca (Karl M. Wilbur and C. M Yonge, ed.), Academic Press, New York. Westermann, G. E. G. 1964. Sexual-Dimorphismus bei Ammonoideen und seine Bedeutung fiir die Taxonomie der Otoitidae. Palaeontographica, Bd. 124, Abt. A, Lief. 1-3, pp. 33-73, pls. 6-9. 1969. Supplement: Sexual Dimorphism, migration, and segregation in living cephalopods. Pp. 18-20 in Sexual dimorphism in fossil Metazoa and taxonomic implications (G. E. G. Westermann, ed.), Int. Union Geol. Sci., ser. A, No. 1. White, C. A. 1891. The Texas Permian and its Mesozoic type of fossils. U. S. Geol. Sur., Bull. 77, pp. 1-51, pls. 1-4. Willey, Arthur 1902. Contribution to the natural history of the pearly nautilus. Zoological results based on material from New Britain, New Guinea, Loyalty Islands, and elsewhere, collected during the years 1895, 1896, and 1897. Pt. 6, pp. 691-830, pls. 75-86, Cambridge University Press. Zeiss, Arnold 1969. Dimorphismus bei Ammoniten des Unter-Tithon. Pp. 155-162 of Sexual dimorphism in fossil Metazoa and taxonomic implications (G. E. G. Westermann, ed.), Int. Union Geol. Sci., ser. A, No. 1. Zittel, Karl Alfred Von 1895. Grundziige der Palaeontologie. Pp. 386-435. R. Oldenbourg, Minich. 1903. Grundziige der Palaeontologic (2d edition). Abt. 1, pp. 398-468. R. Oldenbourg, Miinich. eee y a) a ~ ae eIVAU Supneee Ay rosa tA im 'F iy wrtbe, lath ager ee, tee pais» fy Alycia iad aie - pall grace MEL § ae Tb iehies Y j . Pi ee bias y anata he iat +A Wy axis hay : ng Wak ler, poet te onshi “4h ahaa) ais neti alaoba? eats. lies veg Rts Ate plat res vit ee ee ee valey ob ienmh elt Ne nts ode gp \? arsotrauny gira Aon} & An operat Label? sit hsv ee hy wy bne aes, § om we 2 ean C8, ROG es email Mea! ) bes. Fat ; fitch ce . = P iosimdn dh. of or rh Wak 19) ved Th PEAY anise, xQd00R wel ie com reiian Org ug aye nt cy, ae ws a4blc ance ey Ok aa GL ane Ay, MG TEE ae By. fo oi 5 ately comet etivhf> alban) 4 aut able J tobe Anim? hy 4 ' uy) cel etArgeuelietr beaee sant sr, Mae NL. me adbrh dence sui | i Diaia AS-i ‘aim Vorgres or \ eerie inne }) elle Mbwialy & sAdy alg \ + Oe. eee iv, ae Bait Mouliathe..detlia My i Oy } ‘ ‘ ‘ fe ov a8 easly has bow oatieabesaetapium sohug aa NN = 1. Meath 11% 2 ati-! .a¢ simoiiie? (o@Eter a) tb await) ind leit am a eeeearad Are, eheamy wo hire qui! velo igesed) Wigale we Le ca@riaya!) tortie dio f wey not simoabaohy , ( be ; 7 iF : : Th, ' | whl ny tty ee Lee bd tbo mh. (ts canetah drench Laamine : "MAL ARR ae soul otamacwtiall. ooheD wepaneenren Pe i i iit Tht atte afin wi! wn Adogy P hrerg _ Jud Lay tie oye 4 perenne eg Ge x Heue YT Often ene le. averted cn! Phe? Fs agli hak aban hm a i bs a i er eo ; : prey f) inv ihe wow vial Sickie mai?) = ” si net .@°

ph Wauh crettee he ot Se whew ont peo hact inte P tei dla an cra i ’ A wey len rhc wisi dee phan «) Aut m ’eoia « aie» Pind Pere vy toad, 7 gothrad poe WA wie adh @ od! eprylgee a9 un ver'be phe bee. a tau OLY A. han we} (OG qiatialy. bel e}\en wiatesth Sen’, nee, 7 rine dinvetlgd 5 ager ie “al £ ay Stee ee am WAL a =) Se a , Coad ia Lapa? f wit ve Bl Se wt ie caw age ead vk 4h vin gekel A ie pnw, Wad Feqwy Tt: Vege! ws ovdare ; Le 4 ‘ i of coe TY Hole) sal .¢ Teo elven) or lh Rp ae | Fartpenecny:, Plana? ’ nrgodlereaeh: 7 Fate tad jy) Cesar Wh» Win Dead wonMeradbliv-tey Gritecen, Oey @ Paedeh qa shay) cede BEY yine! ag in vely 99 5 "4 ?* PLATES The cost of reproduction of the plates has been met by a grant from the Graduate Division of the University of Cincinnati. Enlargements stated to nearest 0.1. 102 BULLETIN 272 EXPLANATION OF PLATE 3 Figure Page 1-7, ‘Adrianites'Gemmellaro, 1887. 2..005.sc¢....0..6ch2 200.0004 43 1-3. A. elegans, syntype (IGUP 85, Gemmellaro, 1887, pl. 6, figs. 14, 15), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—20% mm, X2.0; the specimen is mature; 5-7. A. elegans, syntype (IGUP 85, Gemmellaro, 1887, pl. 7, fig. 23), Sosio Limestone, Passo di Burgio, Province of Pal- ermo, Sicily, maximum diameter—21 mm, X 2.0; the specimen is mature; 4. A. isomorphus Gemmellaro, (SUI 32442), Sosio Limestone, near Palazzo Adriano, Sicily, maximum width—17 mm, x 2.0; the ultimate peristome of the dorsal shell is shown. 3:9. (Neocrimites Ruzhencev; 1940a° 1 2...00... 3... ..2.. 6503-00: ee 51 8,9. N. cancellatus (Haniel) (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969), hypotype (GIUA Drawer 55, No. 1328, zbid., pl. 3, figs. 4, 5), Maoen Mollo, Timor, xX 2.0; the specimen is mature. PLATE 3 ‘BULL. AMER. PALEONT., VOL. 62 PLATE 4 BULL. AMER. PALEONT., VOL. 62 Figure PaLeozoic AMMoNoIDs: Davis EXPLANATION OF PLATE 4 fs G.o Adrianites GemmellarOslS87. 1s. fcccecccso8%..sobteonwdtete,.s.008hede- 1-3. A. isomorphus, syntype (IGUP 86, Gemmellaro, 1888, pl. B, figs. 5,6), Sosio Limestone, Rupe di San Bene- detto, Province of Palermo, Sicily, maximum diameter —25 mm, X 2.0; the specimen is mature. (Designated lectotype by Furnish and Glenister in the explanation of plate 3 of Davis, Furnish, and Glenister, 1969). 7,8. A. isomorphus (USNM Unnumbered specimen a), Sosio Limestone, Rocca di Salomone, Province of Palermo, Sicily, & 2.5; figure 7 shows a thickening of the dorsal shell at a constriction, and figure 8 shows the ultimate peristome of the dorsal shell. 9. A. isomorphus (USNM unnumbered specimen b), Sosio Limestone, Rupe di San Cologero, Province of Palermo, Sicily, x 3.7; the figure shows the pits in the internal mold at the ultimate constriction and the spherical bodies in the shell which correspond to these pits. 4-6. Stacheoceras Gemmellaro, 1887 22.00... 4,5. S. tietzei, syntype (IGUP 71, Gemmellaro, 1887, pl. 5, figs. 1-3), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—47%4 mm, xX 1.0; the specimen is mature. 6. S. gaudryi, syntype (IGUP 59, Gemmellaro, 1888, pl. D, fig. 1), Sosio Limestone, Pietra di Salamone, Province of Palermo, Sicily, maximum diameter—34 mm, X 1.2; the speci- men is immature. 78 104 BuLLeTINn 272 EXPLANATION OF PLATE 5 Figure Page 1-8.. Adrianites, Gemmellaro, 1887) 0220.00... eee 43 1-3. Adrianites cf. A. insignis Gemmellaro, (BMNH C37654), Sosio Limestone, Province of Palermo, Sicily, maximum diameter—2144 mm, X 2.0; the specimen is mature. (This specimen is figured as pl. 3, figs. 6-8, of Davis, Furnish, and Glenister, 1969, but was referred to Neocrimites by Furnish and Glenister.) 4,5. 4. insignis, hypotype (MGPU unnumbered, Greco, 1935, pl. 3, figs. 12a,b), Sosio Limestone, Pietra di Salomone, Province of Palermo, Sicily, maximum diameter—29 mm, X 2.0; the specimen is mature. 6-8. A. kingi, syntype (IGUP 81, Gemmellaro, 1887, pl. 9, figs. 31,32), Sosio Limestone, Rocca di San Benedetto, Pro- vince of Palermo, Sicily, maximum diameter—22 mm, xX 2.0; the specimen is mature. PLATE 5 But. AMER. PALEONT., VOL. 62 BULL. AMER. PALEONT., VOL. 62 PLATE 6 PaLEeozoic AMMONOIDs: Davis 105 EXPLANATION OF PLATE 6 Figure Page 2 Neocrimites Ruzhencey.’ 194089 eR RRR a 51 1,2. N. ensifer, syntype (IGUP 82, Gemmellaro, 1887, pl. 6, figs. 11,12), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—24%4 mm, X 2.0; the specimen is immature. ao (Crimifes oe roumanskayass SOS7D) 25.3 eieshe asec sesechececesseteessnanc: 3-5. C. krotowi (Karpinsky), (SUI 5981b), Artinsk Stage, Aktasty River, Aktyubinsk District, USSR, maximum diameter—23 mm, x 2.0; the specimen is mature. 6. C. krotowi (Karpinsky), (SUI 5981a), Artinsk Stage, Aktasty River, Aktyubinsk District, USSR, maximum diameter—244%4 mm, X 2.0; the specimen is mature. io: Adrianites Gemmellaro, 1887 ...........:.....ccccsccecssesccessetvestoeetens 7,8. A. insignis, syntype (IGUP 84, Gemmellaro, 1887, pl. 6, figs. 8,9), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—27 mm, X 2.0; the specimen is mature. 43 106 BULLETIN 272 EXPLANATION OF PLATE 7 Figure Page 1-5. Neocrimites Ruzhencev, 1940a 2.0.0.0... 51 1-3. N. ensifer, syntype (IGUP 82, Gemmellaro, 1887, pl. 7, fig. 25), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—32 mm, X 2.0; the specimen is mature. 4,5. N. ensifer (IGUP 82), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—31 mm, X 2.0; the specimen is mature. BuLL. AMER. PALEONT., VOL. 62 PLATE 7 PLATE 8 62 PALEONT., VOL. BULL. AMER PaLEozoic AMMONOIDs: Davis 107 EXPLANATION OF PLATE 8 Figure Page 1-4. Epadrianites Schindewolf, 1931. ................0000. en 48 1-4. E. haueri, syntype (IGUP 75, Gemmellaro, 1888, pl. C, figs. 13,15), Sosio Limestone, Rupe de San Benedetto, Province of Palermo, Sicily, maximum diameter—66 mm, X 1.0; the specimen is mature. 108 Figure 1,2. 3-7. 8,9. BULLETIN 272 EXPLANATION OF PLATE 9 Pseudagathiceras Schindewolf, 1931 .......00...000e 1G 20ehe spinosum, holotype (YPM 16310, Miller, 1944, pl. 29, figs. 1,2), zone of Waagenoceras (beds 5, 6, and 7 of the Malascachas Section), 1200 m S17°W of Noria de Malascachas, Valle de Las Delicias, Coahuila, Mexico, maximum diameter—21 mm, xX 2.0; the speci- men is mature. Palermites Toumanskaya, 1987a oo000.0000000cccceeeececceeeeeeees 3-5. P. distefanoi (Gemmellaro), hypotype (SUI 32456, Mil- ler, Furnish, and Schindewolf, 1957, fig. 2, ill. 5a, 5b), Sosio Limestone, Palazzo Adriano, Province of Palermo, Sicily, maximum diameter—45 mm, X 1.2; the specimen is mature. 6,7. P. distefanoi, syntype (IGUP 76, Gemmellaro, 1887, pl. 9, figs. 36,37), Sosio Limestone, Rupe di San Benedetto, Province of Palermo, Sicily, maximum diameter—301%4 mm, X 1.2; the specimen is mature. Epadrianites Schindewolf, 1931) .......:05..4...2.....:.s eee 8,9. E. timorense (Boehm), hypotype (PIUB 21b, Haniel, 1915, pl. 5, figs. 7a,b), Koeafeoe, Timor, maximum diameter (fide Haniel)—30 mm, 1.2; the specimen is immature. 54 48 | Butt. AMER. PALEONT., VOL. 62 PLATE 9 BULL. AMER. PALEONT., VOL. 62 PLATE 10 Figure 1-3. 4,5. 6-8. 9,10. PaLeozoic AMMONOIDs: Davis 109 EXPLANATION OF PLATE 10 Hoffmannia Genmellaro: 1887.3 ober. oct... kone 50 1-3. H. hoffmanni, syntype (IGUP 78, Gemmellaro, 1887, pl. 7, fig. 3), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—27 mm, < 2.0; the specimen apparently is mature. Neocrimites Ruzhencev, 1940a ................000ccccccccccceccceeeeeecceees 51 4,5. N. cancellatus (Haniel) (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969), hypotype (PIUB unnumbered, Wanner, 1932, pl. 9, figs. 3a,b; Davis, Furnish, and Glenister, 1969, pl. 3, fig. 3), Basleo, Timor, maximum dimension—22 mm, xX 2.0; the specimen is mature. Pseudagathiceras Schindewolf, 1931 0.000000... 56 6-8. P. wichmanni, holotype (THD 12752, Haniel, 1915, pl. 5, figs. 15a-c), Basleo, Timor, maximum diameter— 16% mm, X 2.0; the specimen is immature. Texoceras Miller and Furnish, 1940a ..0000..0.000eee. 59 9. T. texanum (Girty), (SUI 32461 AA), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, maximum diameter—26% mm, X 2.0; the specimen is mature. 10. T. texanum (Girty), (SUI 32461 AJ), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, < 5.1; figure shows approximation and simplification of the ultimate few sutures. 110 Figure BULLETIN 272 EXPLANATION OF PLATE 11 1-5,8-10.. Sizilites ‘Toumanskaya, 1937a 20.2... 0 ee eee 1,2. S. craticulatus, syntype (IGUP 87, Gemmellaro, 1888, pl. C, fig. 16), Sosio Limestone, Rupe di San Bene- detto, Province of Palermo, Sicily, maximum diameter —1514 m, X 2.0; the specimen is mature. 3-5. S. affinis (Gemmellaro), syntype (IGUP 88, Gemmellaro, 1888, pl. D, figs. 6,7), Sosio Limestone, Rupe di San Bene- detto, Province of Palermo, Sicily, maximum dia- meter—14 mm, xX 2.0; the specimen is immature. 8-10. §. craticulatus, hypotype (MGPU unnumbered, Greco, 1935, pl. 3, figs. 13a-f), Sosio Limestone, Pietra di Salomone, Province of Palermo, Sicily, maximum diameter—1014 mm, X 2.0; the specimen is immature. 6,7,11-15. Texoceras Miller and Furnish, 1940a ..............0000000000000... 6. T. texanum (Girty), (SUI 32461 Z), Bone Spring Lime- stone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, maximum diameter—24 mm, X 2.0; the specimen is mature. 7. T. texanum (Girty), SUI 32461 M), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, maximum diameter—211%4 mm, X 2.0; the specimen apparently is mature. 11. T. texanum (Girty), (SUI 32461 AG), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, 2.0; the specimen apparently is mature. 12. T. texanum (Girty), (SUI 32461 I), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, X 2.0; the specimen is mature. 13,14. T. tex- anum (Girty), (SUI 32461 P), Bone Spring Limestone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Culberson County, Texas, maximum diameter—22% mm, X 2.0; the specimen is mature. 15. T. texanum (Girty), hypo- type (SUI 13609, Miller and Furnish, 1940a, pl. 26, figs. 1,2), Bone Spring Limestone, near Bone Springs, Guadalupe Mountains, Texas, maximum diameter— 25% mm, X 2.0; the specimen is mature. 59 Buu. AMER. PALEONT., VOL. 62 PLATE 11 N ite) 3 (eo) > et Pa (e) Q 4 < fae od je3| = < = —] (=) — Figure PaLeozoic AMMONOIDs: Davis it EXPLANATION OF PLATE 12 Page i-S= Agathiceras; Gemmellaro, 1887 > .2c22....250ic...2. 00. .2008. 00s ceeencaen 61 1-4. A. suessi, syntype (IGUP 119, Gemmellaro, 1887, pl. 6, figs. 1,2), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—35 mm, xX 1.6; the specimen is mature (designated lectotype by Furnish and Glenister in the explanation of plate 2 of Davis, Furnish, and Glenister, 1969). 5,6. A. suessi, hypotype (MGPU unnumbered, Greco, 1935, pl. 3, figs. 14a,b; Davis, Furnish, and Glenister, 1969, pl. 2, fig. 8), Sosio Limestone, Rocca di San Benedetto, Province of Palermo, Sicily, maximum diameter— 37 mm, X 1.6; the specimen is mature. 7,8. A. suessi, syntype (IGUP 119, Gemmellaro, 1887, pl. 6, fig. 4), Sosio Limestone, Passo di Burgio, Province of Paler- mo, Sicily, X 1.6; the specimen is mature. 112 BULLETIN 272 EXPLANATION OF PLATE 13 Figure Page 1-9. Agathiceras Gemmellaro, 1887 2000000... cocccoccceeeeeeeeeeeeeee 61 12a uralicum (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969), (SUI 32460 BA), Road Canyon Formation, saddle and slope W of Dugout Mountain, 0.3 mi. NNW of hill 4861 (USNM loc. 732z), Glass Mountains Uplift, Brewster County, Texas, X 1.6; the specimen is mature. 3,4. 4. uralicum (Karpinsky) (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969), hypotype (SUI 32460 BN, ibid., pl. 2, figs. 3,4), Road Canyon Formation, saddle and slope W of Dugout Mountain, 0.3 mi. NNW of hill 4861 (USNM loc. 732z), Glass Mountains Up- lift, Brewster County, Texas, maximum diameter— 19 mm, X 1.6; the specimen is mature. 5-7. A. urali- cum (Karpinsky) (fide Furnish and Glenister in Davis, Furnish, and Glenister, 1969), hypotype (SUI 32460 BE, zbid., pl. 2, figs. 1,2), Road Canyon For- mation, saddle and slope W of Dugout Mountain, 0.3 mi. NNW of hill 4861 (USNM loc. 732z), Glass Moun- tains Uplift, Brewester County, Texas, maximum diameter—32 mm, X 1.6; the specimen is mature. 8,9. A. sp., (SUI 32458), Waagenoceras—zone shale, about 1 km § of Noria de las Malascachas near a goat trail on west side of draw, Valle de Las Delicias, Coahuila, Mexico, maximum diameter—30 mm, X 1.6; the specimen is mature. PLATE 13 BULL. AMER. PALEONT., VOL. 62 | | PLATE 14 BULL. AMER. PALEONT., VOL. 62 Figure PaLeozoic AMMONOIDs: Davis EXPLANATION OF PLATE 14 AEG PPP OHINFOGMEAy Gry: 19OG 92a oc st es5p eet actospuander ep conse eee eros 1,2. P. erebus Girty, (SUI 32586), upper black limestone member of Bone Spring Limestone, about 314 mi. SSE of El Capitan on west side of US 62 just N of the bend in road where it starts into Guadalupe Pass, Culberson County, Texas, maximum diameter—18% mm, X 2.0; the specimen is mature. 3. Peritrochia n. sp., (SUI 32584), upper black limestone member of Bone Spring Limestone, about 3%4 mi. SSE of El Capi- tan on west side of US 62 just N of the bend in road where it starts into Guadalupe Pass, Culberson Coun- ty, Texas, X 2.3; the specimen is immature. 4-6. P. erebus, (SUI 32585), Cut-off Shale Member of the Bone Spring Formation, pipe line road S of El Capi- tan, Culberson County, Texas, maximum diameter— 21% mm, X 2.0; the specimen is mature. (ae Marathonites BGSeGs 199 a. ree ee sas ee eeaasaee 7. M. sp., (SUI 12301), Bitauni horizon, Bitauni, Timor, maximum diameter—29 mm, xX 1.6, (see other views on plate 21); the specimen is mature. figs. 18a-c), Bitauni, Timor, maximum diameter— 35%4 mm, X 1.6; the specimen is immature. 9. 4. sp., (SUI 12297), Bitauni horizon, Bitauni, Timor, maxi- mum diameter—37%4 mm, X 1.6; the specimen is ma- ture. 113 85 61 114 BuLLeTIN 272 EXPLANATION OF PLATE 15 Figure Page 1-7. Mexicoceras Ruzhencev, 1955 .o......cccceeceeteecseeceeeees 66 1-4. M. guadalupense guadalupense (Girty), hypotype (USNM 144423, Miller and Furnish, 1940a, pl. 41, figs. 3,4, pl. 42, fig. 6; Davis, Furnish, and Glenister, 1969, pl. 5, figs. 4,5), South Wells Limestone, about 2 mi. SE of D Ranch, South Wells, Culberson County, Texas (USGS loc. 7649), maximum diameter —48 mm, X 1.4; the specimen is mature. 5,6. M. guada- lupense thompsoni (Miller and Furnish), syntype (USNM 144419, Miller and Furnish, 1940a, pl. 25, figs. 4-6), South Wells Limestone, about 2 mi. SE of D Ranch, South Wells, Culberson County, Texas (USGS loc. 7649), maximum diameter—18 mm, X 1.4; the specimen is immature. 7. M. guadalupense guada- lupense (Girty), hypotype (USNM 144422, Miller and Furnish, 1940a, pl. 41, figs. 1,2), South Wells Limestone, about 2 mi. SE of D Ranch, South Wells, Culberson County, Texas (USGS loc. 7649), maximum diameter—30 mm, X 1.4 (see other views on Plate 17) ; the specimen is immature. PLATE 15 BuLL. AMER. PALEONT., VOL. 62 PLATE 16 BULL. AMER. PALEONT., VOL. 62 Figure PaLEozoic AMMONOIDs: Davis 15 EXPLANATION OF PLATE 16 Page 1-7. Waagenoceras Gemmellaro, 1887 20.00.0000... 69 1. W. mojsisovicsi, syntype (IGUP 32, Gemmellaro, 1887, pl. 1, figs. 1-3), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—160 mm, X 0.4; the specimen is mature (designated lecto- paratype by Furnish and Glenister in the explanation of plate 5 of Davis, Furnish, and Glenister, 1969). 2,3. W. mojsisovicsi, syntype (IGUP 34, Gemmellaro, 1887, pl. 2, figs. 1,2), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—95 mm, X 0.6; the specimen is mature (designated lecto- type by Furnish and Glenister in the explanation of plate 5 of Davis, Furnish, and Glenister, 1969). 4,5. W. stachei, syntype (IGUP 37, Gemmellaro, 1887, pl. 1, figs. 4-6), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—35 mm, < 1.2; the specimen is immature. 6,7. W. richardsoni (Plummer and Scott), hypotype (SUI 32318, Davis, Furnish, and Glenister, 1969, pl. 5, fig. 7), very top of a big channel sand just below grey limestone beds, Manzanita Member, Cherry Canyon Formation, half- way up slope some 1500 ft. ESE of Last Chance Wells, Sibley Ranch, Culberson County, Texas, maximum dia- meter—170 mm, xX 0.4; the specimen is mature. 116 Figure BULLETIN 272 EXPLANATION OF PLATE 17 1,2. iMexicoceras Ruzhencev; 1955 © ):...20..0..0....2 ee 1,2. M. guadalupense guadalupense (Girty), same specimen as Plate 15, figure 7, * 1.4; the specimen is immature. 3-8. | ‘Cyclolobus ‘Waagen: "1879" oe eee 3-5. C. walkeri Diener, hypotype (MNHN B 7517, Vaillant- Couturier-Treat, 1933, pl. 2, fig. 6), Ankitohazo, Madagascar, maximum diameter—23 mm, X 1.6; the specimen is immature. 6. “C. astrei’, holotype (UPSM unnumbered, Besairie, 1930, pl. 5, fig. 4), Ankitohazo, Madagascar, maximum diameter—45 mm, X 1.2; the specimen is immature. 7. C. walkeri Diener, hypotype (MNHN B 7520, Vaillant-Couturier-Treat, 1933, pl. 1, fig. 4; Davis, Furnish, and Glenister, 1969, pl. 5, fig. 1; Furnish and Glenister, 1970, pl. 2, fig. A), Ankitohazo, Madagascar, maximum diameter—93 mm, xX 0.6; the specimen is mature. 8. C. walkeri Diener, (BMNH C36642), Ankitohazo, Ambilobe, Madagas- car, maximum diameter—104 mm, x 0.6; the specimen is mature. | PLATE 17 BuLL. AMER. PALEONT., VOL. 62 | | BuLL. AMER. PALEONT., VOL. 62 PLATE 18 Figure Pa.Leozoic AMMONOIDs: Davis EXPLANATION OF PLATE 18 Het o-ete WaaGOMinad ISTOCOW, TOO cee ce crore cnn ese e ane vareus-ceuneveraresets 7,8. Stacheoceras Gemmellaro, 1887 7,8. S. pelagicum Gemmellaro, hypotype (MGPU_ unnum- 1,2. W. perspectivum, syntype (IGUP 66, Gemmellaro, 1887, pl. 8, figs. 12-14), Sosio Limestone, Rocca di San Benedetto, Province of Palermo, Sicily, maximum dia- meter—12 mm, X 2.0; the specimen is immature. 3,4. W. subinterrupta, (SUI 32597), upper Artinsk Stage, western slope of the southern Urals, Kyaly-Coorty River, Soonyduk-Say, USSR, maximum diameter—15%4 mm, X 2.0; the specimen is immature. 5,6. W. darae, syntype (IGUP 64, Gemmellaro, 1887, pl. 4, fig. 11), Sosio Limestone, Passo di Burgio, Province of Paler- mo, Sicily, X 0.8; the specimen is mature. 9,10. W. darae, syntype (IGUP 64, Gemmellaro, 1887, pl. 4, figs. 7,8), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—544%4 mm, X 0.8; the specimen is mature. 11-13. W. darae, syntype (IGUP 68, Gemmellaro, 1887, pl. 4, figs. 2,3), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—78 mm, 0.8; the speci- men is mature. Pietra di Salomone, Province of Palermo, Sicily, maxi- mum diameter—934 mm, X 2.3; the specimen is imma- ture. 7 78 118 Figure BULLETIN 272 EXPLANATION OF PLATE 19 1-8. Stacheoceras Gemmellaro, 1887 ........0000000ccccccecccecccceceeeereeeeee 1,2. S. mediterraneum, syntype (IGUP 62, Gemmellaro, 1887, pl. 7, figs. 11-13), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter— 1234 mm, X 2.3; the specimen is immature. 3,4. S. toumanskyae Miller and Furnish, (SUI 1364 O), con- cretionary shale (beds 5 and 7 of Difunta section), along strike between Cerro Wencelao on the south to 300 m W of El Indio on the north, Valle de Las Delicias, Coahuila, Mexico (King’s loc. 20), x 0.6; the specimen is mature. 5. §. sp. (SUI 32608 D), Tim- orites-zone shale, King’s locality 20, Las Delicias, Coahuila, Mexico, maximum diameter—85 mm, x 0.6; the specimen is mature. 6-8. S. sp., (SUI 32610 A), Timorites-zone shale, 1 km NE of Cerro El Indio, Las Delicias, Coahuila, Mexico (near King’s loc. 10), maximum diameter—107 mm, X 0.6; the specimen is mature. 9: “‘Waagenina Krotow, 1888 0000 eee 9. W. subinterrupta (Karpinsky) (Krotow), (SUI 32597), upper Artinsk Stage, western slope of southern Urals, Kyaly-Coorty River, Soonyduk-Say, USSR, maximum diameter—17%4 mm, X 2.0; the specimen is immature. 76 PLATE 19 BuLL. AMER. PALEONT., VOL. 62 - ea BULL. AMER. PALEONT., VOL. 62 Figure PaLtEozoic AMMoNnoIDs: DAvVIs 119 EXPLANATION OF PLATE 20 Page 1-8. Hyattoceras Gemmellaro, 1887 ................cc ee 82 1,2. H. turgidum, holotype (IGUP 51, Gemmellaro, 1887, pl. 2, figs. 8,9), Sosio Limestone, Passo di Burgio, Province of Palermo, Sicily, maximum diameter—23% mm, X 2.0; the specimen is mature. 3,4. H. guembeli Gemmellaro, hypotype (IGUP unnumbered, Davis, Furnish, and Glenister, pl. 4, fig. 7), Sosio Limestone, Pietra di Salomone, Province of Palermo, Sicily, maxi- mum diameter—67 mm, X 1.0; the specimen is ma- ture. 5-8. H. geinitzi, syntype (IGUP 52, Gemmellaro, 1887, pl. 8, figs. 1-3), Sosio Limestone, Rocca di San Benedetto, Province of Palermo, Sicily, maximum dia- meter—40 m, X 1.4; the specimen is mature (desig- nated lectotype by Furnish and Glenister in the ex- planation of plate 4 of Davis, Furnish, and Glenister, 1969). 120 Figure BULLETIN 272 EXPLANATION OF PLATE 21 1-5,10. Hyattoceras Gemmellaro, 1887 ..........0..0..0.0ccilieceeeeeeeeeees 6,7-9. Marathonites Bose, 1919 6. M. sp., (SUI 12305), Bitauni horizon, Bitauni, Timor, 11-13. Pseudovidrioceras Ruzhencev, 1936 11-13. P. pygmeum, syntype (IGUP 65, Gemmellaro, 1887, 1-3. H. abichi, syntype (IGUP 55, Gemmellaro, 1887, pl. 2, figs. 10-13), Sosio Limestone, Passo di Burgio, Pro- vince of Palermo, Sicily, maximum diameter—22 mm, < 2.0; the specimen is mature (designated lectotype by Furnish and Glenister in the explanation of plate 4 of Davis, Furnish, and Glenister, 1969). 4,5. H. abichi Gemmellaro, (USNM unnumbered), Sosio Limestone, Rocca di Salomone, Province of Palermo, Sicily, xX 2.0; the specimen is mature. 10. H. geinitzi Gemmellaro, hypotype (GPIT unnumbered, Davis, Furnish, and Glenister, 1969, pl. 4, fig. 3), unlabelled, but almost certainly from Sosio, < 1.4; the specimen is mature. X< 1.6; the specimen is mature. 7-9. M. sp., same speci- men as Plate 14, figure 7, * 1.6; the specimen is mature. pl. 8, figs. 15-17), Sosio Limestone, Rocca di San Bene- detto, Province of Palermo, Sicily, maximum dia- meter—1114 mm, X 3.9; the specimen is mature. 85 84 BuLL. AMER. PALEONT., VOL. 62 PLATE 21 PLATE 22 PALEONT., VOL. 62 BULL. AMER PaLEeozoic AMMONOIDs: DAvIs 121 EXPLANATION OF PLATE 22 Figure He 5-10) Marathonifes Bose, 1919) oc h.ciceiee liv eccsceccoseseceascoensoscerstevass 85 1,2. M. ganti (Smith), (SUI 17033), Graham (Wayland) Shale, 64% mi. NW of Jacksboro, Texas, maximum diameter—16 mm, X 2.0; the specimen is immature. 5-7. M. ganti (Smith), (SUI 1063), Finis Shale, 3% mi. E of Jacksboro, Texas, maximum diameter—31%4 mm, X 1.6; the specimen is mature. 8-10. M. invari- abilis Ruzhencev, (SUI 10594 A), Artinsk Stage, Aktyubinsk District, Aktasty River, USSR, maximum diameter—51¥4%4 mm, X 1.2; the specimen is mature. See Peritrocnia Girty: TOOG Ree poe vin. ee Abt issccanscscneee eee 88 3,4. P. erebus Girty, (SUI 32583 E), Bone Spring Lime- stone, road cut on the west side of US 62-180, 1.8 mi. NNE of the junction of US 54 & US 62-180, Cul- berson County, Texas, maximum diameter—11 mm, xX 2.3; the specimen is immature. ‘ ib Hibgal m .: euench tsno¥en stoma h ri Oa sf thinebye | aisles ; iraccite ath Cea. ‘ee Aalst, Mid Moy, rind i ini uinstendt ey MP Wc seige wen as hii Bini aid: oe Dh lad? aH Tt) Cte MLS Te F bE h+—nasserte th mevcrenthi ety rneg't wnodedaat ors os he” Thabo Mo OLR joruteae eb emi ode aed +O,F tive me Mantis. CA eeeOk TA): bin, cocoon Ra evil. center . ae 1) ie a al fer cwpate ayy Pha 3 4 i, a syaritsil ' : \ 4 aid sorta ‘ ian A geno tt Wie Bi wary , 4 a ao” ¢ ne ve Bit te akyte wv Uh bl AN ee A So a hii seibfisn et ii me rete oT a" dosag ih afora 1 SEAM PAP iy athe naseed ald Ay Afni ibe pr) Aad rh. i. ‘ vie is Jun mee aa t ha ao) i i i ae o “ mi } ” ay Ne INDEX Note: Light face figures refer to page numbers. Bold face figures refer to the plate numbers. A a, Marathonites krasnopolskyi forma 76 PAIDICHTAM erence. 82 abichi, Hyattoceras (Aichi)! io 21824835120 Académie Moirans (see Collignon) adamsi, Adrianites .... 52 Metacrimites .......... 52 Neocrimites ............ 52 adrianense, Waagenoceras ...... 70 Adrianites ...... 3,4, 5,6 43-46, 47, 49, 50, 51, 52, 54, 5, 102) 103: 104, 105 Adrianites (otimannia) =... 50 Adrianites (Neocrimites) .......... 52 affinis, Adrianites! 2.9)... 57 Sizilitess ee 11 57, 58, 110 Agathiceras ..12, 13, 14 33, 36, 43, 47, 49, 52, 56, 61- G5 ule: 113 Agathiceras (Doryceras”)) .2.-...-. 56 Agathiceras (Gaetanoceras) ........ 61 Agathiceras (Paragathiceras) ...... 61 Sat NOCerAS -....++..1e2 59, 61 AIS ALICeT AS Een ee 61 Alktasty River .........% 105, 121 Aktyubinsk District... 105, 121 Aildnich, Be Ay... 4. 41, 42,94 PAIMILCS. Bens ke es. 86, 87 Ambilobe, Madagascar .............. 116 AMNH — American Museum of Natural ERISUOE Vid cee ae 3: 29, 69, 71, 72, 73 Amsterdam, Geologisch Instituut der Univer- siteit van (see CIUA) anceps, Adrianites .... 61 andrussowi, Stacheoceras ............ 79 Ankitohazo, Madagascar .............. 116 antiqua (-um, -us), Arecestes) 3 2a ener! 79 Stacheoceras ............ 79, 81 applanatum, Agathicerasy 2.2.25 61 applini, Agathiceras.... 61, 62, 65 (AT COSTCS 3) eth neds 73, 79 Arcestes (Cyclolobus).. 73 argentinus, Ilex illecebrosus .............. 41, 42 Argonautal o...cteeee 42 Aricoceras .................- 44, 51, 52 Aricoceras (Metaricoceras) ........ 51, 52 Aricoceras (Neoaricoceras) ...... 44 ArkanSasiacensckc none 39 arthaberi, Stacheoceras ............ 79 Artinsk Stage 0.0.0.0... 105, 117, 118, 121 asiaticum, Agathiceras 61 asselicum, Agathiceras 61. 62 astrei, Cyclolobus .17 73, 76,116 asvmmetrica, Marathonites krasnopolskyi var. .. 76 B b, Marathonites krasnopolskyi forma 76 iBasleocerasi..3 ee 49 Basleowehimor......0e 109 benedictinum, Stacheoceras ............ 76 Waagenina .............. 76 beschui, Agathiceras .. 61 beyrichi, Agathiceras. .............: 49 Basleocerasi...........) 49 Epadrianites ............ 49, 50 biassalensis, Adrianites insignis Ae ie eee 44 Neocrimites (Sosio- crimites) insignis if fick t 5) Soe ee ey 44 bidentata, Marathonites krasnopolskyi var. .. 76 Bisaunin Limon 113, 120 123 INDEX BMNH — British Museum (Natural HIStOGY) eee 29, 46, 65, 75, 76, 83, 104, 116 bobkovae, Adrianites.. 44 bobkowi, Adrianites .. 44 bodraki, Agathiceras.. 61 boesei, Stacheoceras .. 79 Bone Springs Kimestone) . ==.) 89, 109, 110, 113, 121 Bone Springs, Texas .. 110 borissiaki, Stacheoceras ............ 79 Brewster County, TEXAS ok i ge 112 brouweri, Agathiceras 61, 65 burgensis, Adrianites (Hoffmannia) .......... 50 Hofimannia, 22 50 busterensis, Crimites. 47 Marathonites (Allmites)) -2..0.....-.- 86 Cc c, Marathonites krasnopolskyi forma 76 Campbell iG. By =. 37, 91 cancellata (-um, -us), Agathiceras ............ 52 Aricoceras (Aricoceras)) -.....--.... 52 Neocrimites ....3,10 52,54, 102, 109 Carboniferous ............ 34, 37, 39 Cerro El Indio ............ 118 Cerro Wencelao .......... 118 Cherry Canyon Hormation... a 115 Cincinnati, University of .2........ 27, 29, 101 ciscoense, Agathiceras 61, 65 Clark] Davidil. = 47, 48, 79, 81, 95 clavatum, Waagenoceras ........ ; Cline) 7 Me Sime 79, 80-81, 84, ; 85, 87, 95 clinei, Pamirites ........ 76 Waaceninagees se. 76 Coahuila 108, 112, 118 coahuila, Waagenoceras ....... 70 coindetii, Illex illecebrosus .............. 41, 42 Collignon; M20 es 29, 75, 76 collignoni, Popanoceras ............ 79 Stacheoceras ............ 79 contractum, Agathiceras .............. 61 Copenhagen, University of .......... 29, 75, 81 craticulatus, Adrianites ................ 57 Sizilites) .....:.. 283 1). 5.585420 Crick) (Gs Cy. .c.08 eee 42, 92 crimensis, Stacheo- ceras mediterraneum 79 47-48, 105 Crockford, M. B. ........ 52, 54, 95 Culberson County, TOXASH, Hee cscs 109, 110, 113, 114, 115, 121 cummingsi, Waagenoceras ........ Cyclolobus) 222... 17 33, 34, oa Cyclolobus (Krafftoceras) ........ 73 D d, Marathonites krasnopolskyi forma 76 darae, Stacheoceras .... 77 Waagenina .......... 8 77,78 417 darensis, Crimites pamiricus var. ........ 47 Dear Ws eee 54, 90 DeBlainville (see Blainville) defordi, Adrianites) 52 Neocrimites ............ 52, 54 delawareanus, Marathonites.......... 59 Delicias, Valle de Las 108, 112, 118 Denton, Eric J. ............ 30, 32 diblasii, Stacheoceras ............ 79, 80 Dierners Carlie 79 dieneri, Marathonites .......... tL Waasenina Waagenoceras ........ 52, 10; dlewe. Waagenoceras dieneris {0 see 73 Dituntae eee 118 difuntense, Pseudagathiceras .... 51a}, BY INDEX discoidale (-is), fultonensis, Agathiceras cancel- Gontatites) ic. /nes... 62 latum’ form’ .8.-.2...; 52 Surnish, W.-M: «..:.....-.. 28, 29, 31, 36, Aricoceras (Metari- 42, 43, 44, 46, coceras) cancellatum 47, 48, 50, 51, fOEMG-.. ee 52 5200, 04055 Neocrimites ............ 52, 54 56, 57, 58, 59, Stacheoceras ............ 79 60, 61, 62, 63, distefanoi, 64, 65, 66, 67, ACriAanites, <<... sce.s 68, 69, 70, 71, Palermites ............ 9 54, 55, 56 72, 73, 74, 75, 76, 78, 79, 81, djidairensis, Stacheo- 82, 83, 84, 85, ceras kussicum var. 86 86, 87, 88, 89, Dorycerase 56 91, 92, 94, 95, Downs been: tks... 64, 88, 89, 95 96, 102, 103, Dugout Mountain, 104, 108, 109, ROXAS Hc ea. 2: IOS Labs alee dubari, 114, 115, 116, Adrianites 200..0c006. 52 119, 120 Neocrimites ............ 52, 53, 54 Peritrochia .............. 84 G : Gaetanoceras .............. 61 e, Marathonites ganti, krasnopolskyi forma 76 Marathonites ...... 22 85, 86, 87, 88, El Capitan, Texas ...... 113 121 electraensis, Marathonites Marathonites .......... 86 (Marathonites) ........ 87 elegans, Popanoceras ............ 85 Adrianites .....:..:.. 3 44,45,46, gaudryi, 102 Stacheoceras .......... 4 79, 81, 103 Eleganticeras .............. 42 geinitzi, elegantulum, Hyattoceras ..20,21 82, 83,119, Eleganticeras .......... 42 120 elkoense, Crimites ...... 47 Gemmellaro, G. G. ...... TU ensifer, gemmellaroi, Adrianites ................ 52 Adrianites) 22:52. 47 Aricoceras Stacheoceras .......... 79, 80, 81 (Aricoceras) ......... 52 Waagenoceras .......... 70 Neocrimites ...... 6,7 52, 53, 54, Wanneroceras ........ 69 105,106 Gertman, Richard ...... 33, 91 Epadrianites .......... 8,9 48-50,107. girtyi, 108 Agathiceras ............ 61, 62, 65 erebus, Pseudovidrioceras .. 84, 85 Peritrochia ....14, 22 88, 89, 90, Vidrioceras .......:.:.-.. 84 11313}, RAL Waagenoceras GUGHEEI HS ® eee. 70, 73 F Glass Mountains, f, Marathonites REX ASM hh eee 64, 112 krasnopolskyi forma 76 Glenister, Brian F. .... 28, 29, 34, 43, Hinisi Shales... 121 44, 46, 50, 51, fisheri, Hoffmannia .. 50 52, 54, 56, 57, mletcher Hei: eee 52, 98 58, 61, 63. 64, frechi, Agathiceras .... 61, 62, 65 65, 69, 70, 71, fredericksi, TO aen sD, Adrianites|) 51 76, 78, 81. 82, Neocrimites............ 51, 54 83, 84, 85, 86, 125 INDEX 87, 88, 89, 91, 92, 94, 96, 102, 103, 104, 109, 111, 112, 114, 115, 116, 119, 120 globosa (-um, -us), AGrianites) es... 47 Agathiceras can- cellatum form ........ 52 Agathiceras Marini Vara es2-s:..5.0: 52, 62 Mexicoceras ............ 66 Neocrimites ............ 52, 54 Stacheoceras ............ 79 globulinum, Stacheoceras .......... 79 glomulus, Crimites .... 47 Godthaabites .............. ie GOntatIteS ie... seen. 62 gordoni, Stacheoceras 79 gracilis, Marathonites .......... 86 Grahams sAe @6....... asd 39, 42, 92 Graham (Wayland) Shale ek sie eh 121 Griocerasiees....... eat 76 gruenewaldti, Stacheoceras .......... 79 gruenwaldti, Stacheoceras ............ 79 Guadalupe Mountains, ROXAS HR ais 110 guedalupense, Mexicoceras_ ..15, 17 66, 67, 68, 69, 14, 116 Mexicoceras guadalupense 15,17 69, 114,116 Waagenoceras cummingsi var. ........ 66 Waagenoceras .......... 66 W aagenoceras guadalupense .......... 66 Guadalupe Pass, TEXAS es ee ee As guembeli, Hyattoceras ......... 20 #82. 83.119 Gurley; W.'F. Bec. 62, 64, 95 H hanieli, AGrianites- 47 Neostacheoceras .... 79 Stacheoceras ............ 79 haueri, Adrianites! 22... 49 Basleoceras .............. 49 Epadrianites .......... 8 49,50, 107 haydeni, Cyclolobus (Krafftoceras) .......... 73, 74, 75 hildrethi, Ammonites 62 Hofimannial =. 10 50-51, 109 hoffmanni, Adrianites (Hoffmannia) ........ 50 Hoffmannia .......... 10 350,51, 109 hoshanensis, Cyclolobus ..........- 74 Hyattoceras ...... 20, 21 33, 43, 82-84, 119, 120 Hyattoceras (Abichia) 82 illecebrosus, Illex ...... 41, 42 DDK Shy eee eee is 41, 42 insignis, Adrianites ......... 5, 6 44, 45, 46, 52, 104, 105 €yclolobus) 2s 73, 74, 75 Neocrimites. ............ 44, 52 Neocrimites (Sosiocrimites) ........ 44 invariabilis, Marathonites ..... 22 86, 87. 88, 121 Marathonites (Almites)) 2 87 involuta (-um, -us), Agathiceras timorense var. ........ 49 Epadrianites ............ 49 TOWalPee es eo ae 37 ircutensis, Agathi- ceras frechi var. .... 61 isomorphus, Adrianites ........ 3,4 44.45, 46, 102, 103 ITB—Institut Tekno- logi Bandung .......... 29 iwaizakiense, Stacheoceras .......... 79 J Jacksboro, Texas ........ 124 jazwae, Waagenia ...... 77 J. P. Smithi, Marathonites .......... 29, 85, 88 Stacheoceras (Marathonites) ........ 29, 85 126 INDEX K Karpinskyi, Stacheoceras ............ 79 Waagenoceras GICNEEI et hens 70, 71 katschae, Agathiceras 61 Khimshiashvili, N. G... 31, 91 kingi, Adrianites ........... 5 44, 45, 46, 104 Aricoceras (Neoaricoceras) ...... 44 kinshanense, Agathicerasi! oe. 62 kitschiensis, Agathi- ceras anceps var. .... 61 Kinapps WhroDitet...c-.c.-- 42,92 knoxense, Pseudorthoceras ...... 37 Knoxville, Iowa .......... 37 Koeafeoe, Timor ........ 108 koswae, Neocrimites ............ 52 Waagenia =~. 300..4 52 kraffti, Cyclolobus (Krafftoceras) ........ 73, 74 KeratitoO@eraS) .......6.0-.... th krasnopolskyi, Marathonites ............ 76 Popanoceras ............ 76 krotovi, Crimites ........ 47 krotowi, Agathiceras 47 Crimitesey, 6 47,48, 105 kullingi, Cyclolobus ... Tey te! Godthaabites .......... 73 kussicum (-us), Marathonites .......... 86 Stacheoceras ............ 86 Kyaly-Coorty River .... iolze, 1b ks} L Keibroviteh, 1. S: .2... 28, 46, 50, 51, 60, 61, 66, 69, MO olos das 75, 16. 10,01, 82, 83, 85, 88, 89, 90 lidacense, Waagenoceras ........ Ode WRONG ON pete 32, 34, 41 ILLITE RC ORE Opie ih gaa sobres 41, 42, 94 M macromphalus, Nautilus 22. fee ee 42 Madagascar .................. 116 madagascariensis, Cyclolobus walkeri ia Taarceeee Laced. Ska 74 Malascachas, Noria de 108, 112 Mangold-Wirz, 1963 .... 39, 41, 42, 94 Manzanita Member .... 115 Maoen Mollo, Timor . 102 marathonensis, Adrianitess....o.. 52 Neocrimites ............ 52 Marathonites 14, 21, 22 29, 43, 59, 76, 77, 84, 85-88, 31205121 Marathonites CAlmaItES)e.8 en, 86, 87 Marathonites (Pseudovidrioceras) 84, 86, 87 marcoui, Stacheoceros 79 martini, Agathiceras ........ 14 52, 61, 62, 65, 113 Martocerasivete. 76 mediterraneum, Agathiceras ............ 62 Stacheoceras ........ 19 79, 80, 81, 118 meridionale (-is), Adrianites (Neo- Crimites)) eee 52 Aricoceras (Ari- COCEraAS) eee 52 Neocrimites ............ 52 Merriam, C. W.. ............ 81, 92 Metacrimites .............. 51, 52 Metaricoceras .............. Hie? MexiCOlg ee eee. 108, 112, 118 Mexicoceras ...... 15, 17 66- 69, ta MGPU—Istituto di Geologia e Paleon- tologia dell’Univer- SitaudisPisa, soe 29, 46, 58, 65, 81, 104, 110, ib tal ealilyy Miller, ARK ®. 8s: 28, 31, 89, 96 minor, Adrianites diste- PAN OUR Aes 54 Palermites? <.:......0. 54 minutum, Waagenoceras Sh ee 70 MNHN — Muséum national d’Histoire naturelle, Paris ...... 29, 75, 76, 116 moisisovicsi, Waagenoceras ..16 69, 73,115 127 INDEX murgabensis, Crimites subkrotovi var. ........ 47 N nalivikini, Adrianites ................ 52 Neocrimites ............ 52 INautilUS ee eee SONGS 2ea3: 34, 35, 36, 41, 42 Neoaricoceras ............ 44 Neocrimites 3,6,7,10 44, 51-54, 102, 104, 105, 106, 109 Neocrimites (Metacrimites) ........ HIS? Neocrimites (Sosiocrimites) ........ 44 Neostacheoceras ....... 78, 79 newelli, Adrianites: =....-..... 52 Neocrimites ............ 52, 54 Neocrimites (Metacrimites) ........ 52 Newellites ...000000...00..8 70, 71 nikitini, Waagenoceras ........ 70 novomexicana, Peritrochia -......0.. 84 oO oblatum, Syngastrioceras ...... 39 OCtOpUSH eee. 32, 41, 42 officinalis, Sepia ........ oldhami, Cyclolobus ©..2%...... 73, 74, 75, 76 Phylloceras .............. 73 oyensi, Agathiceras .... 47 Pp Pakistan, Geological Sunveyioleeees 29, 76 Palazzo Adriano ........ : 102, 108 Palermitesi....-. 9 54-56, 108 105, 106, 107, 108, 109, 110, PALE, 118, 119, 120 pamiricus, Crimitess ee 47 Marathonites CAlmites)) eee 86 Raminitesmee 76 Paraceltitesa 36 Paragathiceras ............ 61 Raratrochiay- =e 88 Barizek, Be Jo ccc 84, 85, 89, 95 Passo di Burgio .......... 102, 103, 105, 106, 109, 111, 115) eas: 119, 120 pelagicum, Stacheoceras ........ 18 79,8 Peritrochia ........ 14, 22 84, 88-90, iais} 1PAl perglobosum, Waagenoceras Mi katina vate 70 permicus, Adrianites. 44 perspectivum, Stacheoceras ............ Waagenina ......... 18.) 77; 78107 persulcatus, Arcestes (Cyclo- LObUS) Pe eee 73 Cyclolobus 73 Phylloceras®<...........! 73 PIUB — Institut fiir Palaontologie der Rhein. Friedrich- Wilhelm Univer- Sitat; Bonn’. 2.) ...... 29, 49, 50, 54, 83, 108, 109 plana (-um, -us), Adrianites) =... 44 Agathiceras ............ 61 plummeri, Adrianitess— 52 Neocrimites ........... 52 pompilius, Nautilus .... 42 Popanoceras ................ 76; 77,79, 85. pressulus, Mara- thonites (Almites) ... 86, 87 Procyclolobus .......... 73 Pseudagathiceras 9, 10 33. 56-57, 108, 109 Pseudorthoceras si Pseudovidrioceras . 21 84-85, 86, 87, 120 pygmeum, Pseudovidrio- CeraSey er oe 21 ~=84, 85, 120 Stacheoceras ............ 84 Q quadridens, Stacheoceras ............ 79 quadridentata, Marathonites krasnopolskyi var..... 76 Quenstedtoceras ........ 35 128 INDEX R richardsoni, Newellites ................ 71 Waagenoceras ....16 70, 71, 73 115 Waagenoceras Gener ee 70 Road Canyon HoOrmatlOonue scene 43, 64, 112 romanowskyi, Marathonites CAlmaIteS) ees ccna: 86 Popanoceras ............ 86 rothi, Stacheoceras .... 79 rothpletzi, Acaunicerasmuee.s 47 Runnegar, Be ..:ccsse 54, 90 Ruzhencevy, V. E. ........ 28, 46, 50, 51, 60, 61, 66, 69, 70, 72, 73, 74, 75, 76, 78, 81, 82, 83, 85, 88, 89, 90 S Salomone, Rocca (Rietra) dies... 103, 104, 110, 117, 119, 120 San Benedetto, Rupe ROCCA)EGIe ate 103, 104, 107, 108, 110, 111, 117, 119, 120 San Cologero, Rupe di 103 sarabansis, Agathi- ceras anceps var..... 61 Schindewolf, O. H. .... 69, 72, ae schmidti, Adrianites .. 44 Sea kik CS eee 50, 51, 59, 60, 61, 64, 66, 68, 69, 70, 72, 76, 81, 83, 85, 86, 87, 89, 96 sellardsi, Marathonites 86, 87, 88 SISYOIIEY | ae SAN oe ope a 32, 34, 41 MEDION. tse ates 41 sexlobatum, Stacheoceras .... 79, 81 Sipley, Ranch. .......... 115 ICTY ec oe 102, 103, 104, 105, 106, 107, 108, 109, 110, Talk Wales alalze 118, 119, 120 singularis, Crimites ........ 47 Sizilites 2. ee 11 33, 57-58, 110 smithi, Crimites.- ee 47 Mexicoceras guadalupense .......... 66, 67 Waagenoceras guadalupense .......... 66 Solenochilust=........... 34 Soonyduk-Say, USSR... 117, 118 sosiense, Stacheoceras .......... 79 Sosio Limestone ........ 102, 103, 104, 105, 106, 107, 108, 109, 110, 1D Liye 118, 119, 120 Sosiocrimites .............. 44 South Wells Limestone ................ 114 South Wells, Texas .... 114 spathi, Crimites .......... 47 Spinosa, Claude .......... 30, 36 spinosum, Pseudagathiceras .9 56,57, 108 stachei, Waagenoceras ..16 70,73, 115 Stacheoceras 4, 18, 19 29, 76, 77, 78- 81, 84, 86, 103, 117, 118 Stacheoceras (Marathonites) ........ 85 Stacheoceros ................. 7 Stehli, Francis G. ...... 29, 65 stuckenbergi, Agathiceras ©...........:. 52 Neocrimites ............ 52 subcumminsi, Cyclolobus' .2........... 74 subgeinitzi, bvattoceras)..---.- 82, 83 subinterrupta, Wiaacenias es 76 Waagenina 18,19 76, 78, ats 8 subkrotovi, Crimites .. 47 subkrotowi, Crimites.. 47 suessi, Agathiceras ........ 12 33, 61. 62, 63, 64, 65, 111 suevi, Marathonites .......... 86 Stacheoceras ............. 86 suleatus, Marathonites 86 sundaicum, Asathieerdsi nes 61, 62, 65 Syngastrioceras .......... 129 INDEX T tegengreni, Asathiceras <....—5 62 teicherti, Cyclolobus .. 73 tepense, Stacheoceras 79 texanum, Agathiceras ............ 59 Texoceras ...... 10,11 59-61, rere eb KR or care 43, 64, 89, 109, 110, 112, 113, 114, 115, 121 Texas Tech Wniversitys —.2......--- 29,71 Texas, University of . 29, 68, 69 Texoceras’......... 10, 11 59-61, 109, 110 THD—Mineralogisch Geologisch Museum Technische Hoge- school Delft” =.....= 29, 57, 65, 109, 113 thompsoni, Mexicoceras guada- LUPENSE <.:.:8%.....:-: 15 ~=66, 69, 114 Waagenoceras guadalupense ........ 66 tietzei, Stacheoceras 4 79, 80, bc FIN TTA OTe kee ree ese eee 102, 108, 109, 113, 120 timorense, Agathiceras ............ 49 Epadrianites ......... 9 49,50, 108 Popanoceras ............ 77, 79 MUMOLUCSee ee ceeeeee 69, 70, 71 tornatum, AN SaUMICeLAS a eeceeeee 62, 65 toumanskyae, Stacheoceras ..... 19 79, 80, 81, 118 tridens, IATCOStES eee 79 Popanoceras ............ 77, 79 Stacheoceras ............ 79, 80, 81 tridentata, Marathonites krasnopolskyi var. .. 76 trimarti, Stacheoceras 79 trimurti, Stacheoceras 79 tschernyschewi, Stacheoceras ............ 79 turgidum, Hyattoceras ....... 20 82, 83, 84, 119 U undosus, Crimites ...... 47 Unklesbay, A. G. ........ 69, 72, 81, 95 UPSM—University of Paris, Sorbonne .... 29, 75, 76, 116 uralensis, Marathonites .......... 86, 87 uralica (-um, -us), Agathiceras ........ 13 61, 62, 63, 64, 65, 112 Goniatites ................ 62 Marathonites .......... 86 Stacheoceras ............ 86 Ural Mountains .......... 117, 118 USNM—tUnited States National Museum .. 29, 45, 46, 51, 55, 58, 65, 69, 76, 83, 103, 112, 114, 120 WSS yy weet es ee 105, 117, 118, 121 Vv vidriensis, Marathonites .......... 86 Widriocerasn eee 84 vinogradovi, IAdrianitese ne 44 vogti, Stacheoceras .... 79 WwW Wiaaseniay v...c5:.-3e oe 52,06 Waagenina ........ 18, 19 43, 76-78, 117, 118 Waagenoceras ........ 16 52, 66, 69-73, 115 walkeri, Cyclolobus .......... 17 73, 74, 75, 76, 116 Wanneroceras ............. 69 warreni, Adrianites) = 52 Neocrimites ............ 52 wichmanni, Agathiceras (Doryceras?) ........ 56 Pseudagathiceras 10 56, 57, 109 Wiggett, Gail .............. 33, 91 Y Youngquist, W. .......... 64, 88, 89, 95 YPM—Yale Peabody MUSCUINI eee 29, 57, 108 130 LIII. LIV. LV. AYE LVII. LVIII. LIX. LX. LXI. LXII. Volume lI. II. Il. FY. VI. VII. (Nos. 225-230). BUS UD Des 4 Gres 2e-eale, ee kN arash less aie or oie ee 18.00 Venezuela and Florida cirripeds, Antarctic forams, Lin- naean Olives, Camerina, Ordovician conodonts, Niagaran forams. (NOs tes ls2S2\ enn 42 Op Diy LON DISS. ces ceeccecenerecteenstereenesemenencrecteas 18.00 Antarctic bivalves, Bivalvia catalogue. (INGS4233-0250) ou 1S SD Die 43 eS 5) etetese weno esac tae ee eee eee 18.00 New Zealand forams, Stromatoporoidea, Indo-Pacific, Mio- cene-Pliocene California forams. (INiosi237-238) ie) 2 488tipp.p 45) Is. cascc28 cee. coces od cctcceconse rereeceeee te 18.00 Venezuela Bryozoa, Kinderhookian Brachiopods. (Nos. 239-245). SIO Dts OD |Sceeeeeeesense cent eens eee ee 18.00 Dominican ostracodes, Texan pelecypods, Wisconsin mol- lusks, Siphocypraea, Lepidocyclina, Devonian gastropods, Miocene Pectens Guadaloupe. (Nos. 246-247). HEA Toy oh (10h mi ONES ES 5: <2. ee ee an emS Se Be 18.00 Cenozoic corals, Trinidad Neogene mollusks. (Nos. 248-254). SZ) RD PA ADS syee ose ote ete es ST 18.00 American Foraminifera, North Carolina fossils, coral types, Belanski types, Venezuelan Cenozoic Echinoids, Cretaceous Radiolaria, Cymatiid gastropods. (Nos. 255-256). SOI p pee G2 al Sel es ce es Od ok glee re i 18.00 Jurassic ammonites. (Nos. 257-262). EKO Y a) ohre SIL). 0) pee eco ead te ee el Sen ne 18.00 Cretaceous Radiolaria, Cretaceous Foraminifera, Pacific Silicoflagellates, North American Cystoidea, Cincinnatian Cyclonema, new species Vasum. (No. 263). SITE To) 0 ORs eR ea RIA aie | aa ee Ue MA SI Ree 18.00 Bibliography of Cenozoic Echinoidea. (Nos. 264-267). SSIS De yO Se Pl Sey, ete eee ee eee ee Pea 18.00 Jurassic-Cretaceous Radiolaria, cirripeds, Bryozoa, paly- nology. (Nos. 268-270). BOSD De Sleep Sse ee eee ee ee 18.00 Mollusks, Murex catalogue, Cretaceous Radiolaria. ONTOS 2 0127.4 te ees coos See enn ae ree 18.00 Trace fossils, ammonoids, Silicoflagellates, microfauna. PALAEONTOGRAPHICA AMERICANA See Johnson Reprint Corporation, 111 Fifth Ave., New York, N. Y. 10003 Monographs of Arcas, Lutetia, rudistids and venerids. (Nos. 6-12). CANO 0 oS AH 1) cy ee ae eRe eee en 23.00 Heliophyllum halli, Tertiary turrids, Neocene Spondyli, Paleozic cephalopods, Tertiary Fasciolarias and Pale- ozoic and Recent Hexactinellida. (Nos. 13-25). SIS app RO Leip Stee See ae. a) ee ee Soe ae 28.00 Paleozoic cephalopod structure and phylogeny, Paleozoic siphonophores, Busycon, Devonian fish studies, gastropod studies, Carboniferous crinoids, Cretaceous jellyfish, Platystrophia and Venericardia. (Nos. 26-33). AD DARTS TM / OMT NS Cees co 75. plsty--.-a2e ee Forams, ostracods, mollusks, Carriacou, fossil plants. (Nos: 177-183) .; -448 pps, 36splss 222 a South American forams, Panama Caribbean mollusks. (No 184)... (996 spp. 1 ipl ee ee Type and Figured Specimens P.R.I. (Nos:0185-192)). S80 ppes S'Swiplsaet eee eet Forams, mollusks, carpoids, Corry Sandstone. CINog 193) 35673 pp ae 48) (plsy 5 ote ee eee eee ee Venezuelan Cenozoic gastropods. GNoss1942198) 99427 “pips 20M pl sa nice ce rere oe ee te ee Ordovician stromatoporoids, Indo-Pacific camerinids, Mis- sissippian forams, Cuban rudists. (Nos: 199-203) 4. 365; eppsi68 ‘pls: 222 eee Puerto Rican, Antarctic, New Zealand forams, Lepidocy- clina, Eumalacostraca. (No: 204) S647 spp: 6S) spss a-ha eee eons ee Venezuela Cenozoic pelecypods. (Nos::205=211). 1 409\pp:, 70) plss-2..22.n xe Forams, Crustacea, brachipods, Recent mollusks. (Nos: 212-217)... 584 pps-83) plsijn2ccs er ee ee Forams, mollusks, polychaetes, ammonites. (No.218).) 1058 pp:; Siplss) 022s es ee ee Catalogue of the Paleocene and Eocene Mollusca of the Southern and Eastern United States. (Nos: 219-224) ;.''\.671-1pps, ‘83: pls. 34.2 ee Peneroplid and Australian forams, North American car- poids, South Dakota palynology, Venezuelan Miocene mol- luska, Voluta. 16.00 16.00 16.00 16.00 16.00 18.00 18.00 18.00 BUELE TINS OF AMERICAN PALEONTOLOGY (Founded 1895) Mus. COMP. ZOOL. LIBRARY aan NOV 3 1972 No. 273 HARVARD WNIVRRSITY, UPPER CRETACEOUS AND CENOZOIC SILICOFLAGELLATES AND EBRIDIANS By HSIN YI LING 1972 Paleontological Research Institution Ithaca, New York 14850, U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION 1971 - 72 PRESIDENT 2502-5 08 oe Us een EE 53. eed ae eet a ae Os ee DANIEL B. Sass WAGES PRESIDENT) toc oc sort at se kh a Le ee ee a ee MERRILL W. HAAs SECRETARY) 2.2: ee see Nae) is 2 eee ae Ree oot eee REBECCA S. Harris DIRECTOR; GE REASURER 25) 5 eee eee ee eee KATHERINE V. W. PALMER COUN SEI eee rae aor a coe eat aa eG SC a ARMAND L, ADAMS IREPRESENTATIVE (AAAS COU NGI cre nee cee ee JoHN POJETA, JR. Trustees Resecca S. Harris (Life) DonaLp W. FISHER (1967-1973) AxeL A. OLsson (Life) MERRILL W. Haas (1970-1973) KATHERINE V.W. PALMER (Life) Puitip C. WAKELEY (1970-1973) DANIEL B. Sass (1971-1974) Cecit H. KINDLE (1971-1974) KENNETH E. CASTER (1966-1972) Vircit D. WINKLER (1969-1975) Harry S. Lapp (1971-1974) BULLETINS OF AMERICAN PALEONTOLOGY and PALAEONTOGRAPHICA AMERICANA KATHERINE V. W. PALMER, Editor Mrs. Fay Briccs, Secretary Advisory Board KENNETH E. CASTER Hans KuUGLER 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. BORE EINS OF AMERICAN PALEONTOLOGY (Founded 1895) Vol. 62 No. 273 UPPER CRETACEOUS AND CENOZOIC SILICOFLAGELLATES AND EBRIDIANS By HSIN YI LING October 18, 1972 Paleontological Research Institution Ithaca, New York 14850, U.S.A. Library of Congress Card Number: 72-86843 Printed in the United States of America Arnold Printing Corporation CONTENTS Page DANDSS E:1ck CB eee eres eee ee ee ae eee eee neeoze ee fee ee rea ceebbectoc 135 DINAN EGO ELEANOR OY ee A ee Sec ead hee ar SE SS eee ee eer 135 PN ekmonvyil CCST Sy soem ae eon enna bop Seti Aree SA en an ee ten oer 136 Samples Studied seers ccna enews eee cee ee ees ee ae 137 1Wal ara t OT yam PT OCC GUT Se eeetrs eee a ne owes wet ce cee eee er eee e ee 144 Systema tiG mill CLOpall COLO] O ay aece seesaw aera ce erence eaeaeneee 145 Briss ASH ICGpon SE Wee EC pear eRe re ae ene nee 146 bytEbridians® 245 ee, ee eee Se ee 195 ODE SC 11S S 1 Or OEP ee aE ee ee ee coe SecA es tevin Saez ape svtes deettiee 199 Eley LOH 0 Vu) meeps 2 Bee Oe ee A ee eee eee eee ee 199 pamiViedtternane anim (litaly,)me ne sito Ty eae eee ieee ne ee 202 TRAST S ESE pe A i ga ee ace ah ear te ke te hy doe oc Ree 205 Relate Siero: eee es EN 5 OE eee eye ae eS i eae 213 TEXT-FIGURE 1. Index map showing the geographic location of samples investigated .... 139 2. Distribution of silicoflagellates and ebridians in upper Cretaceous and ea COR EME: SC CEO TN yas aes a eee ce Oe nacre eee ee a ee 140 3. Distribution of silicoflagellates and ebridians in Neogene section ............ 141 4. Distribution of silicoflagellates and ebridians in experimental Mohole bier Mo Vee Sey eyer a yay Ue cere Re ae Sa a ae eh See a eae a ae emer 143 5. erminology, of the silicoflagellate skeleton) 22.222. 2...-esceccecceceeeeseceeeee-eeeeseee-s 147 Coe erminolocyaormtheeDridianm skeletons sess ee cene erence 196 7. Distribution of silicoflagellates from Neogene Mediterranean (Italy) 21 © Tipe ete seed met Ek Oe BN ANY Ee Seth ers ie) A oe Soon Ace eee eee 204 TABLE NM PmPbIStMO te SAMIPLESMSEITU LES xn cce eer ce aoc cece see oan ccaceccncccece se eankes See oeoReet Se SoR cae oo 138 aTnaATHog -T | ' A a se) Le a pdr ging? ed pibea Jere A) eeady Beep re ie oe meen ttt wo atr : + SOF oni Se edna ve] ; ~ Gielsieasteqarha 7 ae | pn at ae ee ott se at Sin lay: ogee OF GI01) Quads rl Tyg ru axel rit . beg sa va! Fetetig te aintemut O47 i Vag pil nivale of | née TTT (eal ot ee Ovtl! ma test Lake htleg et taailia lo OH . a Se wie HTien 160 cream. Aghirer shies adihirl® La@ catellegnifvadl) Jom Hndate (paws ies Ay tmeth eds fb “ix llooelhialae be galing rt ae heey it, TH a eorlath eepliogalTovliie ody te squalene ee : a ; ion, Cotghyte paitiety adi tee wate Mamet), rerree eclibel# te ait rile wahelt ghana w IE Se oS ieslt e : a NE i a St Lat tae oe? a i “ute ry eee 4 7 er! = — St tee © ating eeponcome == mies yar, oe f WD ‘ 7 : ! ' i eter, es a a od er) © ¢ ; ; iad : 74 ) —— 7 i s ti , _ > ; = } TUS ' i we + | mf i) wey a Y UPPER CRETACEOUS AND CENOZOIC SILICOFLAGELLATES AND EBRIDIANS* Hsin Yr Linc Department of Oceanography University of Washington ABSTRACT This comprehensive examination of silicoflagellates and ebridians is based on samples mainly from deep-sea sediments, including experimental Mohole drilling and Legs I-III of the Deep Sea Drilling Project as well as land outcrops, their ages ranging from the late Cretaceous (Maestrichtian) to Recent. A detailed account of systematics is given and 56 taxa are discussed with illustrations included from reference samples of type localities for these forms. Stratigraphic occurrences are compared with those of other micro- planktonic groups; planktonic Foraminifera, calcareous nannoplankton, and Radiolaria. Silicoflagellates and ebridians are grouped into seven assemblages and two horizons are additionally recognized. Mediterranean samples are also examined to evaluate the use of these microfloral assemblages in the middle latitude region of Europe. INTRODUCTION The recent upsurge of micropaleontologic research has resulted in the establishment of numerous biostratigraphic zones by means of different microfossil groups from the late Mesozoic to Recent. Coupled with the advancement of paleomagnetic stratigraphy and the method of radiometric determination, these zones have been combined (Berggren, 1969, table 2). One group of siliceous microorganic remains, silicoflagellates and ebridians, first described by Ehrenberg (1839), has not been recognized for its potentiality by biostratigraphers. One of the main reasons is that earlier investigators placed their emphasis on describing new forms rather than on investigating their stratigraphic occurrences. Hanna (1928) and more recently Stradner (1961), Mandra (1968), Bachmann and Papp (1968) suggested and attempted some zonations using land outcrops from various parts of the world; and Hays (et al., 1969) included one silicoflagellate species in their study of the Plio-Pleistocene deep-sea sediments from the equatorial Pacific which brackets the Jaramillo Event within the Pleistocene. Jousé (1963, 1969, 1971), Muhina (1963, 1966, 1969), Ling (1970), and Martini (1971b) subsequently recorded the importance of sili- coflagellates in their studies of Pacific sediments, and the author also found the same low-latitude species from mid-latitude central north Pacific sediments. The successful recovery of long cores by the Deep Sea Drilling *Contribution No. 620, Department of Oceanography, University of Washington. 136 BULLETIN 273 Project (DSDP or JOIDES) provides a unique opportunity to define the range of microfossils and to seek the phylogenic relation- ship of various microfossils. This project also coordinates the efforts of micropaleontologists in achieving accurate correlation. By com- parison with the biostratigraphic framework thus refined by other groups of planktonic microfossils, the value of silicoflagellates and ebridians as a possible biostratigraphic index can be tested. The present study is undertaken with the following objectives in mind: (1) to define the range of taxa mainly from deep-sea sedi- ments; (2) to decipher the relationship or evolutionary lineage, if any, among silicoflagellates and ebridians; and (3) if possible, to recognize assemblages based on the occurrence of these siliceous microfossils. ACKNOWLEDGMENTS The author is indebted to William R. Riedel of Scripps Institu- tion of Oceanography, University of California at San Diego, for kindly providing the samples as well as the pertinent biostratigraphic data upon which the present paper is based. Without his assistance, the work could not have been accomplished at this time. Thanks are also due to the Sample Distribution Panel of the Deep Sea Drilling Project (DSDP), who kindly made samples available from Leg I to Leg III, carried out under the financial support of the National Science Foundation. Sincere appreciation is due to Alfred Bachmann and Herbert Stradner of Austria, N. de B. Hornibrook and A. R. Edwards of New Zealand, York T. Mandra, Alfred R, Loeblich, Jr., and John W. Ruth of the United States, for their graciously providing refer- ence samples and unpublished data which are of great assistance in clarifying the taxonomic problems; to Erlend Martini of West Ger- many for his information on the unpublished data from DSDP Leg VII; and to Thomas R. Worsley of the Department of Oceanography at the University of Washington, for identifying some calcareous nannofossil assemblages, Initial phase of this study was assisted by Mrs. Carol J. Stadum, and the completion by Mrs. Linda M. McPherson and Mrs. Shirley A. Verzosa. The study was supported financially by National Science Foundation grants (GA-11308, GA-26499) and Office of Naval Re- search contract Nonr 477 (37), Project NR 083 012. SILICOFLAGELLATES AND EBRIDIANS: LING 137 SAMPLES STUDIED The deep-sea sediments and land outcrop samples used for the present study are listed in alphabetical order (Table 1) and their geographic locations are shown in Text-figure 1. For deep-sea samples from the Scripps Institution of Ocean- ography collection, the abbreviations used by the Institution are followed, and the position of the samples is the depth measured (in centimeters) from the top of the core. For designating the Deep Sea Drilling Project (DSDP) samples, the general format that appeared in the Initial Reports of the Project is here adopted; namely, hole number — core number — section number, followed by sample level (in centimeters) from the top of the section. The samples from the core sediments recovered during the experimental deep-sea drilling phase of the Mohole Project at Guadalupe site are designated by the abbreviation “EM” to conform with the original description (Riedel, et al., 1961), followed by the number of the hole — the number of the core run, and the depths of the sample, in centi- meters, below the surface sediments of the particular core. The stratigraphic positions of these samples are show in Text- figures 2 and 3, except for some DSDP samples (marked with an asterisk in Table 1) and a sample WR TR 39 H (Thyrsocyrtis bromia Zone; Riedel, personal communication) which were barren of these siliceous microfossils, to avoid an unnecessary overcrowding in the figures. The scheme proposed by Berggren (1969, table 2) relating radiometric time scale, European and West Coast (Cali- fornia) marine stages, and the Cenozoic planktonic foraminiferal zonation is adopted here, Calcareous nannoplankton zonations pro- posed by Martini (1970) and Martini and Worsley (1970), and the radiolarian zonation proposed by Riedel and Sanfilippo (1970, 1971) are included; the appropriate stratigraphic position of the samples was then decided. Despite these considerations, the sample position shown in Text- figures 2 and 3 should still be regarded as merely an approximate indication based on available knowledge. Inevitably a few difficulties are encountered, According to Riedel and Sanfilippo (1970), sample RIS 111P, 280-281 cm, belongs to Zone N.4 of planktonic Foramini- fera but is regarded as the upper part of the Theocyrtis tuberosa Zone of Radiolaria. The examination of calcareous nannoplankton microflora of the sample by Thomas R. Worsley (personal com- 138 BULLETIN 273 TABLE 1. LIST OF SAMPLES STUDIED Sample and Intervals (cm) Longitude Latitude Depth(m) AMPH 6P 17-18 128°21’W 4°52’N 4460 50-51 128°21’W 4°52’N 4460 37P 250-251 121°05’W 18°16’S 3720 350-351 121°05’W 18°16’S 3720 CAS 1144 (California Academy of Science Loc. 1144) 120°45’W 36°40’N CHUB 15 78-82 125°25’W 8°31’N 4462 EM (Experimental Mohole 117°30’W 29°59’N 3566 drilling at Guadalupe site) JYN V 16 P 231-233 149°44’W 7°44'N 5168 248-250 149°44’W 7°44’N 5168 DSDP (Deep Sea Drilling Project) 1P-1-6 40-41* 92°11’W 25°52’N 2827 2-1-3 115-116* 92°35’W 23°27'N 3572 2-2-1 130-131* 92°35’W 23°27’N 3572 2-3-1 45-46* 92°35’W 23°27'N 3572 2-3-2 100-101* 92°35’W 23°27'N 3572 2-4-2 15-16* 92°35’W 23°27'N 3572 3-5-3 62-63* 92°01’W 23°01’N 3737 3-7-1 50-51* 92°01’W 23°01’N 3737 3-10-2 45-46¢ 92°01’W 23°01’N 3737 4-4-] 10-11* 73°48’W 24°29’N 5319 5-1-1 33-34* 73°38’W 24°44’N 5361 5-1-2 73-74* 73°33’W 24°44’N 5361 6-4-1 6-8 67°39'W 30°50’N 5125 115-117 67°39'W 30°50’N 5125 6-4-2 7-10 67°39'W 30°50’N 5125 125-128 67°39'W 30°50’N 5125 6-4-3 92-94 67°39'W 30°50’N 5125 110-112 67°39'W 30°50’N 5125 6-5-1 33-35 67°39°'W 30°50’N 5125 6-6-2 1-2 67°39 W 30°50’N 5125 7-1-2 48-49* 68°18’W 30°08’N 5185 7A-3-2 51-52* 68°18’W 30°08’N 5185 9-5-1 8-9 59°12’W 32°46'N 4981 9-5-2 99-100 59°12’W 32°46’N 4981 9-5-4 117-118* 59°12’W 32°46’N 4981 10-9-2 60-61* 52°13’'W 32°52’N 4612 10-9-3 55-56* 52°13’W 32°52’N 4612 13-3-1 120-121 18°14’°W 06°02’N 4585 13A-1-1 115-116 18°14’W 06°02’N 4585 13A-2-1 90-91* 18°14’W 06°02’N 4585 13A-4-1 95-96* 18°14’W 06°02’N 4585 SILICOFLAGELLATES AND EBRIDIANS: LING 139 13A-5-1 40-41* 18°14’W 06°02’N 4585 LSDH 78P 100-101 168°02E’ 4°31’S 3208 516-517 168°02E’ 4231/5 3208 LSDA 101G 38-39 7°12 5 BoA's 2960 MP 5-1 25-30 133°07’"W 14°22’N 4700 MSN 126G 66-67 154°45'W 24°41'S 4542 MSN 149P 294-296 145°15’W 9°23’N 5100 PROA 88P 275-276 167°14’E 2°56’N 4428 RIS 111P 280-281 133°29'W 14°55’N 4770 WAH 7P 259-260 153°02’W 3°58’N 4992 516-517 153°02’W 3°58/N 4992 WR TR 11 Low (Bo. 202) WR TR 23 (K9391) WR TR 39F WR TR 39F (J.S. 1068) WR ER 39H* Hermitage Quarry, south Trinidad, B.W.I. (Bolli, 1957, p. 101) Near the Retrench trigonometrical station, Gol- conda Estate, Trinidad, B.W.I. (Bolli, 1957, p. 101; Riedel and Sanfilippo, 1970, p. 510) Lower Oligocene part of the Oceanic Formation at Bath, Barbados Oceanic Formation at Bath, Barbados Uppermost Eocene part of the Oceanic Formation at Bath, Barbados *Samples examined but were barren of silicoflagellates and ebridians, there- fore not listed in Text-figures 2 and 3. > MSN 149P JYNZI6Pe ° . WAH TP PROA 88P is *LSDH 7aP °MSN I26G RIS 11IP MP 5-1 CHUB 15 “AMPH 6P = NORTH caste. AMERICA WR TR 39F, “ap © 39F (U.S. 1068) & 39H. =I $=" WR TR | LOW(BO 202) awents 7" 23(K 9391) ° ciears DSOP 13 813A AMPH 37P . Text-figure 1—Index map showing the geographic location of samples in- vestigated. 140 BuLLETIN 273 CALCARE- Ous Pl NANNO- SAMPLES WEST COAST PLANK - EUROPEAN | (CALIFORNIA) TON RADIOLARIAN | (depth intervals STAGES STAGES ZONES ZONES in cm) [G friocontho.si triacantha Dictyocha hexacantha [Corbisemo recto recta &. antiqua (without spine) Septamesocena apiculota Corbisema bimucronata Corbisema apiculata C. triecantha vor. minor Naviculopsis biopiculata C. archangelskiana N. constricta Ebriopis crenulata L. furcula vor. minor Corbisema hostata L. simplex Lyramula furcula Vollacerta hortoni CHATTIAN Dorcadospyris (BORMIDIAN) ofeuchus ZEMORIAN LATTORFIAN RUPELIAN Theocyrtis MP 5-1 25-30 tuberoso WR TR 39F WR TR 39F (JS. 1068) —-—?-- REFUGIAN BARTONIAN DSDP 13-3-1, 120-121 a= 6-8 6-3-1. {ascii F's 7-10 6-4-2, fio6 128 Podocyrtis -94 LUTETIAN ULATISIAN chalara 6-4-3, {?3Sit2 Thyrsocyetis 6-5-1, 33-35 friocontha 6-6-2, I-2 PENUTIAN IZA-I-1, 115-126 PRIABONIAN NARIZIAN D> a te} eta] ety gee fee | yee |e EOCENIE YPRESIAN BULITIAN THANETIAN YNEZIAN VERY RARE RARE PALEOCENE MONTIAN COMMON ABUNDANT pANae “DANIAN” CAS 1144 | il MAESTRI- CHTIAN Text-figure 2.—Distribution of silicoflagellates and ebridians in Upper Cretaceous and Paleogene section. The figure is compiled based on the data of Berggren (1969), Martini (1970), and Riedel and Sanfilippo (1970, 1971). munication) indicated that the sediment is Zone NN.1 of calcareous nannoplankton, and thus is in agreement with that of Foraminifera. The sample is, therefore, placed at the base of Miocene in Text- figure 3 of this paper. The Oligocene-Miocene boundary is placed by Berggren (1969, table 2) at the Globigerinoides Datum, 1.e. 22.5 m.y. and is between N.3 and N.4 Zones of planktonic Foraminifera which falls within NN.1 Zone of calcareous nannoplankton (Martini and Worsley, 1970, p. 289). Riedel (1971) placed this boundary within N.4 planktonic Foraminifera and NN.1 calcareous nanno- planktonic Zones, and between Calocycletta virginis above and 141 LING SILICOFLAGELLATES AND EBRIDIANS S/SU@UDSSAW IDA OINGIS OC DIDYNID JOA DINGIY DYIOAJAG WwW. SNINIHD ) DIA/a YD DUaIOSay DUIDSIDUO/ JOA XN1ID SNUDYIA{SIG SAYJUDIDJIIO JOA xN4Z SNUDYTDHSIG LNVONNS8V NOWWOD (vopolp “W 3yvVYy JYVYy AYSA D{D/NDIGO IDA SNjNIWI DUBIOSAY/ Sadinua WIIUDIY{OIOG jO Usumtoads B& Jo dUaTINDII0 —b ‘4 ainsry- sojdwes 104 “(TL6T ‘ Ie, (6961) Uaissiag fo evjep uo paseq pajiduiod st ainsiz ay yz, ‘UoT}Das auas0aN Ul SURIPIIgqa pUe Sa}¥[[ade[JOOT[IS JO UOTINGIIJsSIq—E¢ IINSIF-}x9 J, DUOBDIIN IDA DINGIA DYIOK{IIG BIDINDUDJIA/ WNIYIOPOWW (D901//8 “YW =) 0240I//9 42 DUEI0Say (a) SNDADYISIWAY SNjIDOUU “ds 2) ad DINGIZ DYIOAJIIGQ JOUIL JOA DY{UDIDIL{ DWAISIGIOD 4 (Gj ig XNIIZ SNUDYDHS wnjngeds =snuDyda{sig DIUOSND DYIOA{I OY, ouwwab D/JaD 0L61) ‘uURUIaWIWaT vynbuviponb “1eA vygsoutjog vurr0sa py 182-082 ‘dill SIY eee2-l€2 ‘d9l A NAC 962-62 ‘d6b!l NSW LIG-9IG ‘di HYM 092-652 ‘d2 HVM 28-82 ‘S| 8NHO (I16E6H) “ES YL YM (202 08) MOT ‘Il YL YM 1S-OS ‘d9 HdWV 8I-LZ1| ‘do HdWY Gi-bl ‘I-2 W3, 02-69 ‘II1-8W3y Sa0/9 WNIUDIOUYIAT SIUIBIIA DUAIAIO/0D D{D{SO9 DU4{9/2AI0/0D D{D/D s/4AdSOpDos0g _ WOSSIH JOD (2) snjsouun7 9l2-S22 ‘d88 woud | SWM/NUada{UD 6¢-8¢e ‘IO! vas) ‘d82 HOS) ‘d82 HOST ISE-OSE ‘dE HdIWY IG2-OS2 ‘dl HdWV 29-99 ‘9921 NSW OO!I-66 ‘2-S-6 dasa 6-8 ‘I-S-6 dasa 2IS-9IS 101-00! (wo ul S|DAJajul YJdap) S31dWvS SN ID{OWWE ‘0ul16as30 SALOIOYWUS sojuad JASOBUOTS WnHows!s/d WNUDIOIAG S3NOZ NVI¥VOI0VY Nvizi134 NVISINI NvINHOW NVILNOW 130 NVI113d3u4 NVISNLN3A NVIY3133HM NVIT1VH 2e2N EeN S39V1LS (VWINYOSI1V9) 1isvod 1S3M JxX9T Os[e das ‘YIeUI YSTI9}Se YAM oddijiyueg pue [apery pue ‘(QZ61T) Aa[sioAq pue NVINVLINOV NVI 1Vv9ldune —NVINOLYOL NVINISS3IW NVITONVZ NVIZN39VId NVILSY NVI¥8V 1V9 S39VLS Nv3ad0un3 3N3901 -$l31d S31u3s° HO0d3 142 BULLETIN 273 Lychnocanium bipes below of the radiolarian Zones. For convenience, two samples, JYN V 16 P, 231-233 cm and MSN 149 P, 294-296 cm, are also placed at the base of the Miocene in Text-figure 3. In Text-figure 4, a combined sequence of the experimental Mohole drilling samples is shown together with the biostratigraphic subdivision of the sequence determined by means of calcareous nan- noplankton by Martini and Bramlette (1963), planktonic Foramini- fera by Parker (1964), Bandy and Ingle (1970), and diatoms by Kanaya (1971). In addition, samples from the following locations were examined, and some specimens are illustrated in the present paper for com- parison of the taxa: Oamaru Diatomite: Near Oamaru, South Island, New Zealand. A. R. Edwards kindly provided the samples from the following three sections; all the sample numbers are those of the New Zealand Geological Survey: Bain’s Farm (North of Fault) section; S 136/963-970 Forrester’s Hill section; S 136/1096, 1195 and 994 Jackson’s Paddock section; S 136/1194, 914 and 878-882. Kellogg Shale (KEL): West of Byron, Contra Costa County, California. According to John W. Ruth of the Standard Oil Com- pany of California, samples were collected by Alfred R. Loeblich, Jr., of Chevron Oilfield Research Company from the location where Mandra (1968, p. 272) sampled, and they were approximately at 4- or 5-foot intervals from the bottom (#1) to the top (#10) of the present exposure. Thus the total thickness of outcrop is slightly different from that which Mandra measured in 1948, Sidney Shale (SID): South of Antioch, Contra Costa County, California. The samples were collected by John W. Ruth from the old quarry where Mandra (0. cit.) collected his samples. The seven samples are: #1, at the base of the exposure; +2, 5 feet; #3, 60 feet; #3-A, 61 feet; 4¢4, 63 feet; #5, 65-73 feet (composite); +6, 74-83 feet (composite); #7, approximately 88 feet from the base (the top of the exposure). Austrian samples: Alfred Bachmann kindly sent me the follow- ing samples which he had examined for silicoflagellate assemblages; they are: SILICOFLAGELLATES AND EBRIDIANS: LING 143 in experi- For samples with asterisk mark, see also Text- Sadinuaj WhUDIY{010g OU'4 2 DUu0bOj20 “IDA D/NGIY DYIOAJIIG (OQNA//8 W=) ODNA//a YI DUEI0SAaY/ sn2isa0yds §=$njidouuoD (auids ynouyim) DNbyuD sisdougzZ a fl @ wi a — i [= & =I [==] —J = co |_| L— ea oO nm oO oO rm ! o = Ww —_ o a cS) o is J n cos a 3° ont = = 8 = bad 2 S oS ~ acs oS S S n 3° oO a — % o ~ a Foes! = “Fae om WAINIGDS SNUBDYDHSIQ a — a we uw SIMIOJIIOUIL JOA DINGI//9 42 DUII0SA, = Heo ass ° 4OUIWI IDA DY{UDIDI4{ DU/ASIGIOD B eda Ss a xAID_ STUDY TRIS i — ae a) aE . 5 ARRAS Salas Qs /2 rls 1/0 QP [to |] w|¢ ee = lle culaal de (Ola lols all cole] “Seo o §~ gis |P | t|Ula U9 [P15 E}P]0 Som we a ~ -| -| - z2=§ ailalo =\=|N}a ro} Fw }w}o Del tal el 5 _ 8 Sec Oe ae ie ytyaya tyetapaye i) POG PUR ter =I a=" ©||@ @}@|a|o ©|a@|a|@|o lo tp = =|=|=|= =|=|=/=|= =|=\= = 0 as} Siale Wi} | us Js Ud) Jud ud | ww )W |W $2) oY = ag = Aros swoj01g 5 [5 : ir Q +t HO TH vv? g jel <| 52 ]| a c ae 9 S ol ° ote Ore SI Oe = = o WwW O DsajiulWwOs04 & = A > eR a a DIVUOJHUDIg o— o Ese as © oN = =i (d uoNearjay) u0;yUD|GouuON snoaJD9|09 Martini 9200! alPPIW and Bramlette AUS 1: “sample G, Walbersdorf im Burgenland (Jungeren Badener Serie).” AUS 2: “Limberg bei Maissau (Luschitzer Serie).” AUS 3: “Ziegelei Ernstbrunn, Waschbergzone (Eggenburger Serie, Burdigal).” AUS 4: “Steiehang E Wallern a.d. Trattnach (Oberoligozan).” A detailed description of these samples has already been presented by Bachmann and Papp (1968). 144 BULLETIN 273 Finally a series of outcrop samples from Italy studied recently by Sanfilippo (1971) were analyzed to evaluate silicoflagellate oc- currences in the Mediterranean region (see discussion and Text- figure 7). LABORATORY PROCEDURES A sample of sediment was trated routinely with hydrogen peroxide (30%) to remove organic matter, The sediment was then treated with concentrated HCl to dissolve any calcareous micro- fossils that might mask or dilute the siliceous microfossils. The re- maining residue was then decanted and sieved through a 74-p sieve. Since silicoflagellates and ebridians are generally smaller than 74 p, this provides an easy way to concentrate and separate them from larger siliceous microfossils, such as Radiolaria and diatoms. Strewn slides were made from this residue and dried. Canada balsam was then used to adhere the cover glass of 22 x 40 mm size, Counts were made on these strewn slides to determine the rela- tive abundance of silicoflagellate and ebridian species. Measurements for an individual taxon were generally made on the major axis on the basis of at least 20 specimens. Temporary or wet slides were also prepared by removing the strewn slides from the oven before the mounting medium became completely solid. By gently applying pressure in one direction on the cover glass, specimens in the slide will rotate within the mounting medium and thus permit an observation from various orientations. The location for the illustrated specimens in the strewn slides is indicated by the sample designation (as discussed earlier), fol- lowed by the slide number, the location by the England finder read- ing as previously described (Ling and Anikouchine, 1967). All the slides examined during the present study will be de- posited permanently in the micropaleontology collection, Depart- ment of Oceanography, University of Washington, Seattle, Wash- ington. SYSTEMATIC MICROPALEONTOLOGY In spite of an apparently simple configuration in comparison with other microfossils, the systematics of silicoflagellates are not so simple as one would expect. The enormous number of variety or SILICOFLAGELLATES AND EBRIDIANS: LING 145 forma proposed by previous workers has created a large number of names, and this fact has hindered the utilization of silicoflagellates and ebridians as biostratigraphic indicators. It is here considered that these microfossils belong to plant origin (Loeblich and Tappan, 1968) and thus are discussed accord- ing to the International Code of Botanical Nomenclature adopted in Utrecht (Lanjouw, et al., 1966). In the following section, the classi- fication scheme proposed by Frenguelli (1940), Deflandre (1950a), Papenfuss (1955), Glezer (1966), and more recently by Bachmann (1970b ), is generally followed. However, genera and species of each genus are arranged in alphabetical order. Illustrations of Septa- mesocena apiculata are placed immediately next to Mesocena for the convenience of comparison, Inasmuch as many of the previously reported taxa are involved during the present study, it has become necessary to review them critically from the biostratigraphic point of view. Consideration has been given to these taxa which had been recorded by the workers as variety and forma or forma, and recognized here whenever they seem to have either stratigraphic importance or possible paleoeco- logical implication. In addition, to facilitating better understanding of previous authors’ observations, specimens from the reference materials of well-known localities are presented for comparison. A detailed analysis of microfossils from these localities is currently being undertaken by the author, and the results will be reported in later papers as the work progresses. SILICOFLAGELLATES Perhaps because of the simple configuration, the terminology of the siliceous skeletal elements of silicoflagellates has not changed much since it was first introduced by Gemeinhardt (1930). The short description prepared here and also Text-figure 5 uniformize and introduce some new terms used in the later discussion. Terminology — The typical skeleton of a silicoflagellate consists of a polygonal basal body ring with radial spines at each corner ex- tending generally horizontally. From the basal side of the polygon, basal accessory spines project down- and inwardly. In some species (such as Dictyocha fibula var. messanensis), there are short acces- sory spines at the exterior side of the basal body ring. 146 BuLLeTIN 273 The structure within or above the basal body ring is referred to as an apical structure, which may be in the form of a ring, apical ring; with an opening or openings; apical window or several apical windows; or a simple straight bar, an apical bar; or a flattened thin plate, apical plate. Occasionally short spine(s), apical accessory spine(s), are present on an apical ring or on an apical bar. The apical structure and the basal body ring are connected by J/ateral rods. The spaces delineated by the apical structure, the basal body ring and also by lateral rods are called lateral window(s) (“Basal- fenster” of Gemeinhardt, 1930, p. 21) or basal window of Glezer (1966, p. 9). Orientation — The shape of the basal body ring and the posi- tion of the apical structure serve to orient the silicoflagellate speci- mens, Except for circular or triangular forms, generally the silico- flagellate skeleton is longer in one direction; this is called the major axis, and the shorter one, the minor axis. When a silicoflagellate is orientated in such a way that the basal body ring, radial spines and lateral rods are on a plane and with the apical structure form a shape of truncated pyramid, it is called lateral view (edge view of Loeblich, III, et al., 1968; Ling, 1970); the view directly facing the apical structure is called an apical view and the opposite is termed as abapical view (Marshall, 1934; Loeblich, III, et al., 1968, p. 7). Order SIPHONOTESTALES Lemmermann, 1901a Genus CANNOPILUS Haeckel, 1887, emend. Bachmann, 1967 Remarks.— As discussed earlier Ling (1970), Loeblich, III, et al. (1968) and more recently Lipps (1970) considered that Haeckel’s name should be regarded as a junior synonym of Hali- calyptra by Ehrenberg (1847), on the basis of samples from the Barbados Island and Richmond, Virginia. Furthermore, Lipps (1970, pp. 975-976) suggested that another form, Clathropyxidella described by Deflandre (1938) also from Barbados, is probably synonymous. Three of the samples studied are from Barbados; special attention was made during the microscopic examination to find forms similar to those previously described, but the search was unsuccessful. Un- doubtedly further investigation is needed to determine the exact SILICOFLAGELLATES AND EBRIDIANS: LING 147 APICAL VIEW LATERAL VIEW — basal accessory spine — _ ; a pppical bar _-——basal body ring——W— ~~ ABAPICAL APICAL vIEW > —— view = ™~ . ~— —lateral window — —— = ~— — — lateral rod —- ——— lateral / window major axis apical accessor 7 spine x41 _7lateral window f 7 i] ; \iateral rod ~ —apical plate ~ o- P , if ‘apical window \ Text-figure 5.—Terminology of the silicoflagellate skeleton (Modified after Deflandre, 1950a) nature of these forms and to resolve this taxonomic problem, and in the present paper the long-recognized Haeckel’s name is applied. Cannopilus hemisphaericus (Ehrenberg) Pl. 23, figs. 1-5 Remarks. — As discussed earlier (Ling, 1970), the synonymy of this species has been presented by various investigators; how- ever, despite their painstaking efforts, the present species has not been satisfactorily defined. This is apparently due to the fact that some of the specimens assignable to the species demonstrate inter- mediate characteristics by possessing a basal body ring like Diste- phanus speculum; and yet the complex nature of the apical struc- ture, hemispherical outline and varying numbers of apical windows 148 BULLETIN 273 are common in the genus Cannopilus. Thus Glezer (1966) and Bach- mann (1970a, b) make a special effort to differentiate between those with the diameter of the apical structure equal to or less than that of the basal body ring as Distephanus speculum var. canopil- oides, and those with the larger diameter as Cannopilus hemi- sphaericus. As has been noted from the central north Pacific sediments (Ling, op. cit.), it is not necessary to have a larger diameter of the apical structure in order to have a hemispheric outline. It is also apparent that the number of apical windows cannot be the valid taxonomic criteria as Ehrenberg or Lemmermann once proposed; thus it is somewhat puzzling that Glezer (1966, p. 280) again con- sidered an apical structure with six or more windows as one of the criteria for Cannopilus; and the taxonomic names of Ehrenberg or Lemmermann, based on the number of apical windows, appeared recently (McManus, et al/., 1970, particularly for the description of Hole 32-34) which had already been well discussed as early as 1964 by Bachmann. Perhaps the above discussion can be elucidated by Bachmann (1970b, p. 10) at the end of his emended description of Distephanus speculum var. cannopiloides which states “Abgrenzung zum nahe verwandten Cannopilus hemisphaericus vorgenommen werden.” Therefore, following the previous central north Pacific study, the specimens showing hemispheric outline of the apical structure in the lateral view and generally possessing two or more apical windows and larger than ordinary related forms, such as Distephanus specu- lum, are all included under the present species. The only exceptions to the present taxon are those specimens with two small windows, the size of one window divided by an apical bar, and with the apical structure definitely not hemispherical but parallel to the basal body ring. These such as Dictyocha btpartita Ehrenberg (1844a; 1854), are found in Recent surface sediments from various parts of the world, including the Bering Sea and Antarctic waters. Dimensions. — Length of basal body ring, 28-40 p; of radial spine, 14-26 pu. Known geologic range. — Miocene. Occurrence. —C. hemisphaericus is found between the interval from WR TR 11, Low (Bo. 202), Globorotalia fohsi barisanensis SILICOFLAGELLATES AND EBRIDIANS: LING 149 Zone or Dorcadospyris alata Zone (Riedel and Sanfilippo, 1970) in Text-figure 3, and from EM 7-2, 6-7 cm, Luisian (Parker, 1964) or Helvetian ? (Martini and Bramlette, 1963) in Text-figure 4, to EM 8-11, 69-70 cm, N.12 planktonic foraminiferal Zone or Om- matartus antepenultimus-Cannartus (?) pettersson Zone (Riedel and Sanfilippo, of. cit.). It is interesting to note here that Mandra (1968) recorded the occurrence of the present species from Relizian and Mohnian stage samples. A sample EM 7-2, 7-10 cm, which 1s identified as Relizian by Bandy and Ingle (1970, p. 140, fig. 3; p. 167), did not yield the present species. Cannopilus picassoi Stradner Pl. 23, figs. 6, 7 Cannopilus picassoi Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 92, figs. 101-104. Cannopilus picassoi Stradner, Bachmann, 1963, in Bachmann et al., Geol. Ges. Wien, Mitt., vol. 56, No. 1, p. 153, pl. 20, figs. 74-81; pl. 22, figs. 17-19. Cannopilus picassoi Stradner, Bachmann and Papp, 1968, Giorn. di Geol., (2) iceviolei3i5saple 3,etie~ 16. Cannopilus picassoi Stradner, Hajos, 1968, Geol. Hungarica, ser. Paleont., fascs 37 ps 70M pls 6, figs 5. Cannopilus picassoi Stradner, Bachmann, 1970, im Cat. Fossil, Austriae, No. 1b, p. 14. Remarks. — When Stradner (1961) originally described the present species from the Miocene (“Unteres Torton’’) of Frattings- dorf, Austria, it seems that two morphologically different forms were included: one with well-developed apical accessory and radial spines (his figs. 101-102), and the other with both spines poorly developed, particularly the radial spines (his figs. 103, 104). The Italian specimens are the only forms found during the present study which show only the latter type; however, the general form, includ- ing numerous apical windows and the overall size, agrees with the specimens from Austria, Dimensions. — Diameter of apical structure, 30-40 p. Known geologic range. — Miocene. Occurrence. — This species is found rarely and only from Italian samples. Cannopilus sphaericus Gemeinhardt Pl. 23, figs. 8-10 Cannopilus sphaericus Gemeinhardt, 1931a, Deutsch, Bot. Ges., Ber., vol. 49, No. 2, p. 104, pl. 10, figs. 3, 4. Cannopilus sphaericus Gemeinhardt, Frenguelli, 1940, Rev. Mus. La Plata, n.s., vol. 2, Paleont., No. 7, pp. 48-51, fig. 6e. . 150 BULLETIN 273 Cannopilus sphaericus Gemeinhardt, Deflandre, 1950a, Microscopie, vol. 2, fies. 95.096, 9702). Cannopilus sphaericus Gemeinhardt, Stradner, 1961, Erdél. u. Kohle, vol. 14, No. 2, p. 92, figs. 99, 100. Cannopilus sphaericus Gemeinhardt, Bachmann, 1963, in Bachmann, et al., Geol. Ges. Wien, Mitt., vol. 56, No. 1, p. 153, pl. 20, figs. 69-73; pl. 22, fig. 16. Cannopilus sphaericus Gemeinhardt, Glezer, 1966, in Cryptogamic plants of thesUcS'SeRe vol-7pa coils plz. ties 5: Cannopilus sphaericus Gemeinhardt, Bachmann and Papp, 1968, Giorn. di Geol., ser. 2, vol. 35, fasc. 2, p. 122. Cannopilus sphaericus Gemeinhardt, Hajos, 1968, Geol. Hungarica, ser. Paleont., fasc. 37, p. 70, pl. 6, figs. 1-4, 6. Cannopilus sphaericus Gemeinhardt, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, pp. 247-248, figs. 66(?), 70. Remarks. — The present species is characterized by the presence of larger and consequently fewer numbers of apical windows than C. picassoi or C. tetraceros, and by the presence of five or six down- and outwardly directed basal radial spines. Lateral windows are frequently Jarger in size than the apical windows. Apical accessory spines at the top and the sides of the spherical apical structure are either present or absent. Dimensions. — Diameter of apical structure, 28-40 up. Known geologic range. — Miocene. Occurrence. — The specimens assigned to the present species are found only from experimental Mohole samples during the present study, and from EM 7-2, 6-7 cm to EM 8-14, 388-389 cm interval. Thus the top seems to coincide with the boundary of Helvetian? — Tortonian? in middle Miocene of calcareous nanno- fossils by Martini and Bramlette (1963); and approximately Luisian-Mohnian of planktonic Foraminifera by Parker (1964) and Bandy and Ingle (1970). On the basis of studies mainly from the land sections of California, the present species is considered as one of the indices for the Mohnian stage by Mandra (1968), but recently Ruth (1971) recorded that it ranges from middle Luisian to almost the top of middle Mchnian. Cannopilus tetraceres Bachmann and Ichikawa Pl. 23, figsyadee Cannopilus tetraceros Deflandre, 1949, nomen nudum. Cannopilus tetraceros Deflandre ex Bachmann and Ichikawa, 1962, Kana- zawa Univ., Sci. Rept., vol. 8, No. 1, p. 172, pl. 5, figs. 73-75; pl. 9, Higssoulole Remarks. — When Bachmann and Ichikawa described the pres- SILICOFLAGELLATES AND EBRIDIANS: LING 151 ent species in their investigation from the Wakura Beds (1962, p. 172), of Miocene (late) (Fuji and Bachmann, 1969), they indicated that Deflandre found a similar specimen from Moron, Spain, and, therefore, they credited the authorship to Deflandre and dated it as 1949. Until now no description or figure has been presented by De- flandre; therefore the date of 1949 should be considered as nomen nudum and as invalid. The species should be Cannoptlus tetraceros Deflandre ex Bachmann and Ichikawa or its abbreviated form as above and dated as 1962 (Lanjouw, et al., 1966, ICBN Art, 46; Recommendation 46C). Dimensions. — Diameter of apical structure, 42 p. Known geologic range. — Miocene. Occurrence. — Throughout the present study, the species is found in sample EM 8-15, 246-249 cm only. Genus CORBISEMA Hanna, 1928, emend. Frenguelli, 1940 Remarks. — The genus was first proposed by Hanna (1928); and the emended diagnosis given by Frenguelli (1940, p. 69) which was later accepted by Deflandre (1950a, p. 47/82), is followed here. Glezer (1966, p. 223; pp. 252-253) restricted the present genus to those forms in which the basal accessory spines are “on the lateral rods at the corners of apical widening,” and thus Glezer con- sidered only C. geometrica Hanna as belonging to the present genus, indicating that specimens which have basal accessory spines on the basal body ring are regarded as belonging to the genus Dictyocha. Corbisema apiculata (Lemmerman) PISZS shigss ea Dictyocha triacantha var. apiculata Lemmerman, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 259, pl. 10, figs. 19-20. Dictyocha triacantha var. apiculata Lemmermann, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 247-249, fig. 27. Dictyocha triacantha var. apiculata fa. aspera Schulz, 1928, Bot. Archiv., : vol. 21, No. 2, pp. 247-249, fig. 28. Dictyocha triacantha var. apiculata fa. late-radiata Schulz, 1928, Bot. _ Archiv., vol. 21, No. 2, p. 281, fig. 73. Dictyocha triacantha var. apiculata Lemmermann, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 41-42, fig. 30. Dictyocha triacantha var. apiculata fa. aspera Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 41-42. Dictyocha triacantha var. apiculata fa. late-radiata Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 43, fig. 32. Corbisema apiculata (Lemmermann), Hanna, 1931, Mining in California, VolaZ7a No.2. ps 198 ples ties 2: 152 BULLETIN 273 Dictyocha triacantha var. apiculata Lemmermann, Deflandres, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, fig. 32. Corbisema apiculata (Lemmermann), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12h. Corbisema apiculata (Lemmermann), Stradner, 1961, Erdé] u. Kohle, vol. 14, No. 2, p. 89, figs. 26, 27, 33. Dictyocha triacantha var. apiculata fa. apiculata Glezer, 1966, in Crypto- gamic plants of the U.S.S.R., vol. 7, pp. 228-229, pl. 6, fig. 5. Dictyocha triacantha var. apiculata fa. late-radiata Schulz, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., pp. 229-230, pl. 6, fig. 1. Corbisema apiculata (Lemmermann), Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 248, figs. 25, 30(?), 35. Remarks. — The specimens referable to the present species show a triangular basal body ring with short radial spines at three rounded apices. Basal accessory spines generally present, short or occasionally strong and distinct. Dimensions. — Length of basal body ring, 30-60 up. Known geologic ranges. — Cretaceous (late) to Eocene (late). Occurrence. — Throughout the present study, the species is found in samples from DSDP Hole 6, and in reference samples from Bain’s Farm section of Oamaru Diatomite, New Zealand, as well as from Kellogg and Sidney Shale of California. Corbisema archangelskiana (Schulz) Pl. 23; figaids Dictyocha triacantha var. archangelskiana Schulz, 1928, Bot. Archiv., vol. Ze Now 2h pp. 250-25 tig 33) a-caups Zo leehiess 7750781 (er) Dictyocha triacantha var. archangelskiana Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 45-46, fig. 37a, b(?). Corbisema archangelskiana (Schulz), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12a. Corbisema archangeskiana (Schulz), Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, fig. 25 (only). Dictyocha triachantha var. archangelskiana Schulz, Tsumura, 1963, Yoko- hama Munic. Univ., Jour., ser. C-45, No. 146, pp. 48-49, pl. 9, fig. 1; pl. 22, fig. 14. Dictyocha archangelskiana (Schulz), Glezer, 1966, in Cryptogamic plants of the UlS-.SiRs -vol.07s (pp.'232-233) spl. 8, figs» 6, 7: Remarks. — Glezer (1966) correctly assigned figure 6 from Oamaru, New Zealand, and figure 7 from the eastern slope of the Urals to the present species, but erred by referring to Gemeinhardt’s figure 34, which is Dictyocha triacantha var. inermis fa. late- radiata Schulz (= Corbisema geometrica Hanna, in this paper). The species is characterized by three elongated triangular lateral windows, sides of which are subparallel and with narrow but not pointed apices. SILICOFLAGELLATES AND EBRIDIANS: LING 153 Dimensions. — Length of basal body ring, 50 up. Known geologic range. — Cretaceous (late) to Eocene (late). Occurrence. — Found rarely and only from DSDP sample, 6-4-3, 110-112 cm. Corbisema bimucronata Deflandre Pl. 24, fig. 1 Corbisema bimucronata Deflandre, 1950a, Microscopie, vol. 2, pp. 63/82- 64/82, figs. 174-177. Dictyocha bimucronata (Deflandre), Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 50, pl. 9, fig. 6. Dictyocha bimucronata (Deflandre), Glezer, 1966, in Cryptogamic plants of the. W-S.SiR. vol. 7. ps. 253,.pi. 9x tise 2: Remarks. — This small species possesses sharply truncated apices with short spines at both edges. Basal accessory spines are short but generally present. Glezer (1966, p. 233) indicated that the early Oligocene (?) form from the Ukrainian area, the only occurrence from Russia, did not possess the basal accessory spines and she is of the opinion that “arrangement of the supporting spines (= basal accessory spines in this paper) cannot serve as the major criterion in defining the genus Corbisema as does Deflandre.” Dimensions. — Length of the basal body ring, 38 pn. Known geologic range. — Eocene to Oligocene (?). Occurrence. — Until now the species has been reported, except in Russia, only from “Radiolarite 4 Diatomées de Springfield et de Newcastle, ile de la Barbade”, and was regarded as “?Miocene in- férieur” but is now considered as Eocene by Loeblich, III, et al. (1968, p. 18). The specimens found during the present study were also from Barbados samples, WR TR 39 F (J.S. 1068) and 39 F, which are both from the Theocyrtis tuberosa Zone, and the strati- graphic position for the former is also identified as slightly above the [sthmolithus recurvus Zone (Riedel and Sanfilippo, 1970). Ap- parently the present species has a limited geologic, as well as geo- graphic distribution, because no specimen was found from other areas, including Oamaru, New Zealand, and California. Corbisema geometrica Hanna Pl. 24, figs. 2-4 Dictyocha triacantha var. inermis Lemmerman, 1901b, Deutsch. Bot. Ges., Ber vole 195 p. 259 pple, tics 2c Corbisema geometrica Hanna, 1928, Jour. Paleont., vol. 1, No. 4, p. 261, pl. _ 41, figs. 1, 2. Dictyocha triacantha var. inermis Lemmerman, Schulz, 1928, Bot. Archiv.., vol. 21, No. 2, p. 249, fig. 30a, b; p. 281, fig. 75. 154 BULLETIN 273 Dictyocha triacantha var. inermis fa. late-radiata Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 281, fig. 74. Dictyocha triacantha var. inermis Lemmermann, Gemeinhardt, 1930, iz Kryptogamen-Flora, vol. 10, pt. 2, p. 43, fig. 33. Dictyocha triacantha var. inermis fa. late-radiata Schulz, Gemeinhardt, 1930, in Kryptogamen- -Flora, vol. 10, pt. 2, p. 43, fig. 34. Dictyocha triacantha var. inermis Lemmerman, "Deflandre, 1932a, Soc. France Microsc., Bull., vol. 1, No. 1, fig. 31. Corbisema geometrica Hanna, Deflandre, 1940a, Acad. Sci. Paris, C) R., vol. 211, No. 19, p. 446, figs. 3-4, 6-8. Corbisema gceometrica Hanna, Deflandre, 1950a, Microscopie, vol. 2, pp. 53-82—54-82, figs. 134, 136-139. Corbisema archangelskiana Stradner, 1961 (not Schulz or Deflandre), Erdol u. Kohle, vol. 14, No. 2, p. 89, figs. 19, 24 (only). Dictyocha geometrica (Hanna), Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, pl. 9, figs. 4, 5; pl. 22, figs. 15-16. Corbisema geometrica Hanna, Glezer, 1966, in Cryptogamic plants of the WES:S: REV vollv/ps 2 535ipleag whiz. 7. Dictyocha triacantha var. inermis fa. inermis Glezer, 1966, in Cryptogamic plants of the W:S:S:R2 vol) 7 p. 230; pl. 8, figs; 1, 2- ply $2. tizaels Corbisema geometrica Hanna, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 248, figs. 3-5. Remarks.— The present species was described originally from Cretaceous materials of California. Careful examination of more than ten slides, including both larger and smaller than 74 » fractions made from topotypic material, CAS 1144, yielded only a few speci- mens and with apical plate only (PI. 24, fig. 2). Deflandre (1940a) illustrated that the position of basal accessory spines is variable, ranging from on the lateral rods near the hyaline apical plate to on the basal body ring. Glezer (1966), on the other hand, was of the opinion that the present species should be for those with basal ac- cessory spines on the lateral rods only, and she also reported basal accessory spines up to 10 » long. Consequently Glezer considered the present species to be the only form belonging to the present genus, and she limited the range for the genus as Cretaceous (late), while for those Dictyocha triacantha var. inermis fa. inermts, early Paleo- cene is additionally mentioned. Hanna included a specimen without hyaline apical plate as a deviated form within the present species. Apparently the inclusion of such a latter form led Deflandre to combine those described pre- viously by Lemmermann (1901b) as Dictyocha triacantha var. inermis from “Fuur in Jutland” under the present species. Unfor- tunately no such specimen was observed from the topotypic ma- terial. There is a possibility that future detailed study of Cretaceous SILICOFLAGELLATES AND EBRIDIANS: LING 155 materials from California might yield such a specimen as Mandra (1968) illustrated; therefore, Hanna’s concept is followed here. Although Deflandre (1950a, p. 54/82) indicated that Dictyocha triacantha var. archangelskiana Schulz (1928, pp. 250-251, fig. 33a-c) may also belong to the present species, and Stradner (1961) ap- parently followed such an opinion, this is not accepted in the present study. Dimensions. — Length of basal body ring, 70-90 up. Known geologic range. — Cretaceous (late) to Eocene. Occurrence. —C. geometrica as here recognized is found in Cretaceous California and middle Eocene DSDP materials. Corbisema hastata (Lemmermann) Pl. 24, fig. 5 Dictyocha triacantha var. hastata Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 259, pl. 10, figs. 16, 17. Dictyocha triacantha var. hastata Lemmermann, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 249-250, figs. 31a-c; 29b (only). Dictyocha triacantha var. hastata Lemmermann, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 43, fig. 35a-c. Dictyocha triacantha var. hastata Lemmermann, Deflandre, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, fig. 28. Dictyocha triacantha var. hastata Lemmermann, Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12c (only). Dictyocha triacantha var. hastata Lemmermann, Glezer, 1966, in Crypto- gamic plants of the U.S.S.R., vol. 7, pp. 231-232, pl. 6, figs. 6-8; pl. 7, fies, 8 pla sl, fiesyis) 9% Dimensions. — Length of the basal body ring, 24-30 uy. Known geologic range. — Paleocene (early) to Eocene (late). Numerous locations are listed for the occurrence of the present species from Russia by Glezer (1966). Occurrence. — Found from the samples of DSDP 6-6-2, 1-2 cm, Thyrsocyrtis triacantha Zone, to DSDP 13-3-1, 120-121 cm, Podo- cyrtis chalara Zone (Riedel, 1971). Corbisema recta (Schulz) Pl. 24, figs. 6, 7 Dictyocha triacantha var. recta Schulz, 1928, Bot. Archiv., vol. 21, No. 3, pi250.aties052a.0 Db: Dictyocha triacantha var. recta Schulz, Gemeinhardt, 1930, in Kryptogamen- Flora, vol. 10, pt. 2, p. 45, fig. 36. Phyllodictyocha recta (Schulz), Deflandre, 1946, Soc. Bot. France, Bull., vol. 93, No. 9, pp. 335-337, fig. 1. Phyllodictyocha recta (Schulz), Deflandre, 1950a, Microscopie, vol. 2, p. 45/82, figs. 112, 113. Dictyocha recta (Schulz), Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 49, pl. 9, fig. 2; pl. 22, fig. 8. 156 BULLETIN 273 Description. — Basal body ring, triangular either smooth or slightly convex; radial spines short at each corner; short basal ac- cessory spines at the abapical side of the basal body ring directly below where the lateral rods join with basal body ring; apical struc- ture simple, consisting of three equal lateral rods meeting at the center and in some specimens, slightly expanding to form a small apical plate. Remarks. — Deflandre’s new genus, Phyllodictyocha, with Schulz’s variety as the type species, is characterized by having a flattened and non-tubular basal body (1935, 1946), and Tsumura (1963, p. 49) stated that no lumen (or hollow structure) can be found within the basal body. The specimens found from the DSDP samples failed to show any particular flattened nature of the basal body ring and the lumen was present in contrast to illustrations by Deflandre and Tsumura; furthermore the basal accessory spines seem heavier than those shown by them. Dimensions. — Length of basal body ring, 30-38 p. Known stratigraphic range. — Eocene. Occurrence. — The present taxon is found from samples DSDP 13-3-1, 120-121 cm, Thyrsocyrtis triacantha Zone and Barbados, WR TR 39 F (J. S. 1068), Theocyrtis tuberosa Zone and is just above the top of Isthmolithus recurvus Zone (= NP.19 Zone of Martini, 1970) (Riedel and Sanfilippo, 1970). Corbisema triacantha (Ehrenberg) Pl. 24, figs. 8-13 Dictyocha triacantha Ehrenberg, 1844a, Verh. K. Preuss. Akad. Wiss. Ber- lin, Ber., Jahrg. 1844, p. 80. Not Dictyocha triommata Ehrenberg, 1845, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1845, pp. 56, 76. Not Dictyocha triommata Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 33, IN, 1S, saree all Dictyocha trigona Zittel, 1876, Deutsch. Geol. Ges., Zeitschr., vol. 28, ple 83.) plar2 ties. 6 Gae Dictyocha trigona Zittel, Riist, 1888, Palaentographica, vol. 34, No. 5/6. Joy AISI Dictyocha triacantha Ehrenberg, Lemmermann, 1901b, Deutsch. Bot. Ges., Ber, vole 195 pa258plad0s figs S: Dictyocha triacantha Ehrenberg, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 247, figs. 24, 25a. Dictyocha triacantha Ehrenberg, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, p. 40,, tigss28a (2). bi ((2)eres 29aG)e Corbisema triacantha (Ehrenberg), Hanna, 1931, Mining in California, vol. Ai, je ID) aayers ile Corbisema triacantha (Ehrenberg), Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 66, pl. n, fig. 8. SILICOFLAGELLATES AND EBRIDIANS: LING SyvA Corbisema triacantha (Ehrenberg), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12g. Corbisema hastata Frenguelli, 1940 (not Lemmermann), Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12b (only). Corbisema trigona Zittel, Deflandre, 1950a, Microscopie, vol. 2, pp. 52/82- 53/82, fig. 130. Dictyocha triacantha fa. minor Desikachary and Maheshwari, 1956 (not Schulz), Ind. Bot. Soc., Jour., vol. 35, No. 3, p. 258, text-fig. 2. Dictyocha triacantha var. triacantha fa. triacantha Glezer, 1966, in Crypto- gamic plants of the U.S.S.R., vol. 7, pp. 226-227, pl. 4, figs. 1-6; pl. 5, figs. 1-4. Corbisema triacantha (Ehrenberg), Mandra, 1968, Calif. Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 249, figs. 28, 31. Remarks. — The basal body ring of this species is triangular in shape and is on a plane, in comparison with the following taxon; and the apical plate, if present, is definitely rarely developed. Because of considerable variation in size and shape, as well as in length of radial spines, some smaller specimens with less well-developed radial spines cannot satisfactorily be differentiated from those of Dictyocha triacantha var. minor. A good example of such a case is a specimen illustrated by Schulz (his fig. 25 a) as D. t. fa. minor. It should be noted that Schulz’s figure 24 for the present species illustrates that the lumen of the basal body ring is clear at the three corners as well as in the radial spines but is lost completely at the middle of the basal ring. Gemeinhardt’s specimen (fig. 28 a) from Mors Island even shows the septal structure at the apices. Ehrenberg’s D. triommata is considered synonymous by Gemeinhardt and Glezer but is considered as D. triacantha var. minor in this paper. Gemeinhardt also in- cluded another of Ehrenberg’s species, D. trifenestra, with the present taxon, but judging from the original figure, it may be re- lated to D. fibula; therefore, D. trifenestra is excluded from the above synonymy list. Dimensions. — Length of basal body ring, 18-35 p. Known geologic range. — Cretaceous to Miocene (late). Occurrence. — The present species is recovered from middle Eocene DSDP sediments and Italian samples. From the experimen- tal Mohole section, the species is recovered from the Luisian inter- val only (Parker, 1964; Bandy and Ingle, 1970). Corbisema triacantha var. flexuosa Stradner Pl. 24, figs. 14-17 Corbisema triacantha vor. flexuosa Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, pl. 1, figs. 1-8. 158 BuLLETIN 273 Dictyocha triacantha var. flexuosa (Stradner), Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, p. 228, pl. 5, figs. 5 (?), 10 (only). Corbisema triacantha var. flexuosa fa. I1 Bachmann, 1970b, im Cat. Fossil. Austriae, No. 1b, p. 16. Remarks.— One of the samples that Alfred Bachmann pro- vided the writer is from Wallern, Austria, the type locality for the present variety and typical of such specimens is here presented with both apical and lateral views (Pl. 24, figs. 14, 15). During the present study, this taxon was found only from Italian land samples. Glezer (1966) recorded the occurrences in Russia as late Eocene to late Oligocene, but only figure 10 from Mangyshlak Peninsula of late Oligocene age seems to agree with the original concept of Stradner; while figure 5, an early Oligocene Ukrainian specimen has a dentate basal body ring, but such is never observed by Stradner nor so far by the present author from Wallern samples. Figures 6 and 8 of Glezer (op. cit.) are from the Ural-Caspian area and are of late Eocene age, but the former shows a straight triangular basal body ring with strongly crenulate (?) surface ornamentation, which is unusual for these forms. Nevertheless it is better considered as C’. triacantha var. triacantha, while the latter has short radial spines as well as a smoothly concaved basal body ring, and may be re- garded as C. t. var. minor. Therefore, some of the above-discussed questionable specimens of Glezer have been excluded from the present taxon. Dimensions. — Diameter of basal body ring, 20-30 p. Known geologic range. — Possible Oligocene (late) only. Occurrence. — Found the present taxon only from Italian out- crop samples between sample WRE 67-99 and -95 which is identified as Calocycletta virginis Zone (Sanfilippo, 1971). Corbisema triacantha var. minor (Schulz) Pl. 24, figs. 18-23 Dictyocha triacantha fa. minor Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 247, fig. 25b (only). Dictyocha triacantha fa. minor Schulz, Gemeinhardt, 1930, in Kryptogamen- Flora, vol. 10, p. 41 (not fig. 29a or b). Not Dictyocha triacantha fa. minor Schulz, Desikachary and Maheshwari, 1956, Ind. Bot. Soc., Jour.. vol. 35, No. 3, p. 258, text-fig. 2. Corbisema trigona (Zittel), Tynan, 1957, Micropaleont., vol. 3, No. Zapp: 130-131, pl. 1, fig. 1 (only). Corbisema triacantha fa. minor (Schulz), Bachmann, 1963, in Bachmann, et al., Geol. Ges. Wien, Mitt., vol. 56, No. 1, p. 151, pl. 17, figs. 28-32 (not fig. 33). SILICOFLAGELLATES AND EBRIDIANS: LING 159 Dictyocha crux Ehrenberg, Bachmann, 1964 (part), in Ichikawa, ef al., Kanazawa Univ., Sci. Rept., vol. 9, No. 1, p. 103, pl. 4, figs. 38-39 (only) (as trigonale Abwandlungen). | ' Dictyocha triacantha var. triacantha fa. minor Schulz, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, pp. 227-228, pl. 5, figs 7-9. Dictyocha crux fa. trigona Frenguelli, Bachmann, 1967, im Ichikawa et al, Kanazawa Univ., Sci. Rept., vol. 7, No. 1, p. 157, pl. 4, figs. 1-6, 8 (only). Remarks. — The above synonymy list is presented as a first approach to prepare this taxon for future possible stratigraphic use. The specimens here considered are smaller than other varieties of the species, generally with shorter radial spines, and furthermore they generally have convex sides with rounded apices showing a roundly triangular basal body ring. Apical structure consists of lateral rods forming a Y, or occasionally with a small apical plate. Basal accessory spines are short, if present. Size range and some larger specimens admittedly approach to its type C. triacantha, and in some cases the separation is difficult. Thus Schulz’s figure 25a is considered in the present paper as C. triacantha, and similar consideration is applied to some of Bach- mann’s illustrations from Austria and Japan. Schulz’s figure 26b from Mors Island clearly possesses an apical accessory spine and so far no such specimen has been observed; the specimen from Mors Island is excluded from the present taxon. Dimensions. — Length of basal body ring, 16-25 yp. Known geological range. — Eocene (early) to Miocene. Occurrence. — The latest occurrence for the present taxon in the experimental Mohole section is the same as C. triacantha, and Cannopilus sphaericus; however in the Mediterranean region, it is found slightly higher than that of C. triacantha. Genus DICTYOCHA Ehrenberg, 1839 Dictyocha ausonia Deflandre PL. 25, figs. 1-10 Dictyocha pons Ehrenberg, 1844a, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, pp. 64 (in table, name only), 80. Dictyocha pons Ehrenberg, 1854, Mikrogeologie, pl. 21, fig. 40. Dictyocha navicula var. pons (Ehrenberg), Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 258. Not Dictyocha ausonia Deflandre, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, p. 252, pl. 9, fig. 1. Dictyocha ausonia Deflandre, Hajos, 1968, Geol. Hungarica, ser. Paleont., fase. 37, pp. 65-66, pl. 3, fig. 11 (only). For others, see Ling (1970, pp. 88-90) as D. cf. ausonia Deflandre. 160 BULLETIN 273 Remarks. — The present species, Deflandre (1950a) originally described from Miocene Diatomite of Italy, and at the same time presented a series of variations. On the basis of central north Pacific deep-sea sediments, Ling (1970) discussed in detail the present taxon, as D. cf. awsonia, and expressed some hesitation in accepting completely Deflandre’s species concept mainly because no complete range of intraspecific variation was observed at that time, The present study now reveals that there is a wide range of intra- specific variation as Deflandre claimed, but radial spines on the minor axis do not disappear as readily as Deflandre illustrated. Actually, if radial spines disappear completely, it is perhaps after the gradual disappearance of two lateral windows on the minor axis (see Pl. 25, figs. 5-8). A middle Miocene species, Dictyocha pons, proposed and illustrated by Ehrenberg from Oran, Algeria, which is similiar to Plate 25, figure 7 here, is thus considered as a part of variation for the present species. Judging from the illustra- tion, the size also seems to agree with such a conclusion. On the other hand, D. regularis Carnevale (1908) is not con- sidered as conspecific with the present species, as Deflandre (1950a) indicated and Ling (1970) suggested as a possibility, because of the definitely much longer radial spines on the major axis; the species is transferred to genus Naviculopsis and discussed later. Glezer (1966) recorded the only Russian occurrence and refer- red to Deflandre’s taxon; but judging from the illustration, as well as the remarks that Sakhalin specimens possess longer radial spines on the major axis, and such is not the case for the present species, the Russian specimens are excluded from the present taxon. Dimensions. — Length of the basal body ring, 30-50 y; of radial spines, 6-14 p. Known geologic range. — Miocene. Occurrence. — Apparently the present species ranges from WAH 7P, 259-260 cm, Calocycletta virginis Zone and N.5 planktonic foraminiferal Zone (Riedel and Sanfilippo, 1970) to EM 6-2, 30-32 cm, which is the top of Delmontian and Mohnian or Mohnian (Parker 1964) and the boundary between Mohnian and Delmontian stages (Bandy and Ingle, 1970). Dictyocha fibula Ehrenberg Pl. 25, figs. 11-15 Remarks. — As in the previous investigation of central north SILICOFLAGELLATES AND EBRIDIANS: LING 161 Pacific sediments, this species encompasses the wide variation and forma previously reported by various workers from all over the world (see Mandra 1968; Glezer, 1966). Dimensions. — Length of basal body ring, 30-45 yw; of radial spine, 5-16 pu. Known geologic range. — Eocene to Recent. Occurrence. — Found from WR TR 11, Low (Bo. 202), Dorcadospyris alata Zone (Riedel and Sanfilippo, 1970), to modern sediments in many parts of the world. Dictyocha fibula var. aculeata Lemmermann Pike259 figse Gn Remarks. — The synonymy list, discussions and dimensions were presented previously by the present writer (Ling, 1970). Known geologic range. — Quaternary. Occurrence. — This variety is recovered from DSDP 9-5-2, 99- 100 cm, N.22 planktonic foraminiferal Zone (Blow, 1970, pp. 357, 360) to Recent. Dictyocha fibula var. messanensis (Haeckel) Pl. 25, figs. 18, 19 Remarks.— The detailed taxonomic consideration was pre- sented by the author (Ling, 1970). Known geologic range. — Quaternary. Occurrence. — Like D. f. var. acwleata, this variety is recovered from DSDP 9-5-2, 99-100 cm to Recent. Dictyocha fibula var. octagona Tsumura PIN2Z6 figs: 152 Not Dictyocha octonaria Ehrenberg, 1844b, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, p. 201. Not Dictyocha octonaria Ehrenberg, Deflandre, 1950a (part), Microscopie, vol. 2, fig. 37 (only). Dictyocha fibula var. Tsumura, 1959, Yokohama Munic. Uniy., Bull., vol. 11, Nat. Sci., No. 1, p. 66, pl. 4, figs. 47-49 (fide Tsumura, 1963). Dictyocha fibula var. octagona Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 55, pl. 10, figs. 11-13; pl. 23, figs. 8-10 (as D. octagona on p. 55). Remarks. — The illustrated specimens agree with the species proposed by Tsumura from Tsubaki, Sado Island, Niigata Prefecture of Japan. Tsumura questionably correlated his present species with Ehrenberg’s D. octonaria, but in the original description, Ehrenberg indicated its close relationship with another form, D. ornamentum, 162 BULLETIN 273 which in turn is related to Distephanus speculum. Tsumura also correlated his specimen with one (fig. 37) of Deflandre’s Dictyocha octonaria, but judging from the illustration, Deflandre’s specimen possesses small apical accessory spines on an apical bar, lateral rods, and basal accessory spines, and no such specimen has been found during the present study; therefore, both Ehrenberg’s and De- flandre’s species are excluded from the present vartety. Dimensions. — Length of basal body ring, 20-30 pw; of radial spines, 10-14 p. Known geologic range.— Listed only as fossil, according to Tsumura. Occurrence. — This variety is found from AMPH 6P, 50-51 cm, Dorcadospyris alata Zone and N.11 planktonic foraminiferal Zone (Riedel and Sanfilippo, 1970), to EM 7-1, 14-15 cm, N.12 planktonic foraminiferal Zone, according to Riedel and Sanfilippo (o. cit.). Martini (1971b) indicated his Dictyocha octagona horizon from the Deep Sea Drilling Project Leg VII in the equatorial Pacific region, but did not list it in another article (1971a). Dictyocha hexacantha Schulz Pl, 263fig73 Dictyocha hexacantha Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 255, fig. 43. Dictyocha hexacantha Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 55-56, fig. 46. Dictyocha hexacantha Schulz, Hanna, 1931, Mining in California, vol. 27, | No. 2; p. 9198; pl. D; fig: 7: Dictyocha deflandrei fa. hexacantha, Frenguelli, 1940, Rev. Mus. La Plata, n.s., vol. 2, Paleont., No. 7, p. 65, fig. 14g (only). Corbisema hexacantha (Schulz), Deflandre, 1950a, Microscopie, vol. 2, pp. 65/82-66/82, figs. 183-187. Dictyocha hexacantha Schultz, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, p. 239, pl. 10, fig. 12. Description. — Basal body ring, triangular with convex side; three radial spines, short, at the apices; apical structure simple, consisting of three lateral rods that meet near the center and ex- tend the distal ends beyond the basal body ring, thus showing six radial spines in apical or abapical view; basal and apical accessory spines absent, Remarks. — Schulz (1928) described and illustrated the present species from Oamaru, and a specimen here presented (Pl. 26, fig. 3) is from sample S136/964, Forrester’s Hill section of Oamaru Diatomite, New Zealand. ‘al SILICOFLAGELLATES AND EBRIDIANS: LING 163 Results of the preliminary observation so far made, including some Eocene samples from California and New Zealand, reveal that the shape of the present species is better considered basically as triangular rather than hexagonal. The so-called six radial spines from which the name of the present species was apparently derived actually are three radial spines at the three apices and three exten- sions of lateral rods of apical structure that intersect approximately at the middle of the basal body ring. Thus, it may not be surprising that the apical structure and such distal extension are similar to “propeller-like structure” that Mandra (1969, lower-right figure on p. 173) observed from Antarctic deep-sea samples. Dimensions. — Length of basal body ring, 20-26 u. Known geologic range. — Eocene to Oligocene (early ?). In addition to Schulz’s finding from Oamaru Diatomite, Hanna (1931) reported the present species from Kreyenhagen Shale (Eocene) of California. Although Mandra (1968) failed to find the present species during his study, this author found the present species from Sidney Shale during preliminary examination. Deflandre (1950a) added the Springfield, Barbados occurrence, which is now regarded as Eocene age (Loeblich, III, et al., 1968, p. 18), and not Miocene (early ?) as indicated by Deflandre (op. cit.) or Glezer (op. cit., p. 239). The “early Oligocene (?)” occurrence is reported by Glezer from Ukrainian, Russian. Occurrence. — This species is recovered only from DSDP 6-4-1, 6-8 cm, upper part of the Globigerapsis kugleri Zone (Ewing, et al., 1969) and the Thyrsocyrtis triacantha Zone (Riedel, 1971), The species is observed in the reference samples from Oamaru Diatomite, New Zealand, and Sidney Shale, California. Dictyocha sp. Pl. 26, figs. 4-8 Dictyocha fibula var. fibula fa. rhombica Glezer, 1966 (not Schulz, Lemmer- mann nor Ling), im Cryptogamic plants of the U.S.S.R., vol. 7, p. 249, DieelSs figss 5,07) (in) =) 9s onlys Description. — Basal body ring, rhombic with almost straight sides; radial spines present, two on the major axis always longer, sometimes longer than those on the minor axis; apical bar along the minor axis like D. ausonia; four lateral windows of approxi- mately similar size or two on the minor axis slightly smaller but so far never disappearing as D. ausonia. Basal accessory spines, 164 BuLLETIN 273 either present on abapical side of junction of lateral rods and basal body ring, or slightly to the side of the junction, or sometimes absent. Remarks. — Because of the nature of radial spines, particularly those on the major axis, the shape of skeleton is extremely variable, but the basal body ring is definitely rhomboid. A similar silicoflagellate was discussed as D. fibula var. rhom- bica by Schulz (1928, fig. 37) and Ling (1970), and D. fibula var. rhombus by Lemmermann (1901b), but none of them are related to the forms illustrated here. Glezer (1966) recorded a few Russian specimens that seem to be conspecific, but it is believed that Glezer erred by referring to Schulz’s or Lemmermann’s species. Further- more Glezer’s figure 4, which is from Mondaino (?), Italy, seems to belong to D. ausonia; therefore, comparison with Russian ma- terial will be definitely necessary before the new name can be established for the present species. Another Russian Eocene form, D. fibula var. fibula fa. eocaenica Krotov, according to Glezer (0. cit., p. 249, pl. 15, fig. 6; pl. 32, fig. 5), is synonymous with D. fibula fa. rhombica Schulz sens Gemeinhardt, fig. 40a (only) but has dentate surface and is larger than the present taxon. Dimensions. — Length of basal body ring, 26-40 y; of radial spine 6-20 np. Occurrence. — This species is found in samples ranging from WR TR 11, Low (Bo. 202), in many Mohole samples to LSDH 78 P, 516-517 cm, Spongaster pentas Zone (Riedel and Sanfilippo, 1970). Genus DISTEPHANUS Stohr, 1880 Distephanus crux (Ehrenberg) Pl. 26, figs. 9-16 Remarks. — As in previous studies (Ling, 1970, 1971), wide intra- and infraspecific variation is recognized under the present species, except those varieties recognized below, Dimensions. — Length of basal body ring, 24-36»; of radial spines, 8-24 p. Known geologic range. — Eocene to Miocene (late). Pliocene (?), Quaternary (?). Late Miocene to Pliocene occurrence recorded by Glezer (1966, p. 262) from Noto Peninsula and Kanzawa area, SILICOFLAGELLATES AND EBRIDIANS: LING 165 Honshu Island, Japan, is more likely to be Miocene (late) only. Quaternary occurrences reported by Glezer (op. cit.) from inter- moraine layer, Ladoga area, Raukhiala, Russia, and interglacial de- posits from Finland need to be reexamined. Occurrence. — This species is found during the present study from sample WR TR 23, (K9391), Calocycletta costata Zone (Riedel and Sanfilippo, 1970), to EM 6-2, 10-11 cm which is con- sidered as Delmontian by Bandy and Ingle (1970) or upper Mio- cene by Martini and Bramlette (1963). Mandra (1968) reported the Californian occurrence for the present species from Relizian, Mohnian and Delmontian stages. Distephanus crux var. longispina Schulz Pl. 26, figs. 17-19 Distephanus crux fa. longispina Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 256, fig. 44. Distephanus crux var. longispina Schulz, Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 92, fig. 56 (only). Dictyocha crux fa. longispina (Schulz), Bachmann and Ichikawa, 1962, Kanazawa Univ., Sci. Rept., vol. 8, No. 1, p. 169, pl. 2, figs. 16, 17 (?), 18, 19 (only). Dictyocha crux fa. longispina (Schulz), Bachmann, 1963, in Bachmann et al., Geol. Ges. Wien, Mitt., vol. 56, No. 1, p. 148, pl. 16, fig. 16. Dictyocha crux Ehrenberg, Hajos, 1968 (part), Geol. Hungarica, ser. Paleont., fasc. 37, p. 65, pl. 3, figs. 8, 9 (only). Dictyocha crux var. longispina (Schulz), Bachmann, 1970a, Verh. Geol. B.-A., Jahrg. 1970, No. 2, p. 287, pl. 4, figs. 15-17; pl. 5, figs. 1-9. Distephanus crux var. longispina Schulz, Bachmann, 1970b, in Cat. Fossil. Austriae, No. Ib, p. 9. Remarks. — The present variety is characterized, as Bachmann described (1970a, p. 287), by the relatively long radial spines along the major axis, relatively large apical ring, and above all, by a highly arched apical structure which is in turn supported by high-angled lateral rods (see Pl. 26, fig, 17). The sudden and common appearance of this variety in the ex- perimental Mohole section is significant. With the consideration that Schulz’s original figure for his forma came from Santa Monica, California, which is considered as Helvetian stage by Loeblich, IIT, et al. (1968), the specimens from Mohole sediments are assumed to be identical with that of Schulz. Dimensions. — Length of basal body ring, 28-36 y; of radial spines, 16-28 up. Known geologic range. — Miocene, Occurrence. — Throughout the present study, the specimens re- 166 BULLETIN 273 ferred to the present taxon are found only from experimental Mohole samples, from EM 8-15, 505-506 cm, to EM 8-11, 69-70 cm, the latter of which is recorded as Ommatartus antepenultimus - Cannartus (?) petterssoni Zone and N.15 planktonic foraminiferal Zone (Riedel and Sanfilippo, 1970). Distephanus crux var. octacanthus Desikachary and Maheshwari Pl. 26, figs. 20-22 Distephanus crux var. octacanthus Desikachary and Maheshwari, 1956, Ind. Bot. Soc., Jour., vol. 35, No. 3, pp. 260-261, text-figs. 10, 12, 13; pl. 13, figs. 8, 9. Remarks. — As discussed by Desikachary and Maheshwari from upper Miocene samples of Nicobar Island, the present taxon is char- acterized by an octagonal basal body ring; and two radial spines on the major axis are much longer than the other six. The specimens found during the present study agree with the above original descrip- tion and illustrations. Apparently the size and shape demonstrated during the present study show limited infraspecific variation. Glezer (1966, p. 263) included the present variety within a part of Distephanus stauracanthus (Ehrenberg), but they are different morphologically and should be regarded as separate taxa (compare with Ling, 1970, pl. 19, figs. 7, 8). Dimensions. — Length of basal body ring, 24-30 »; of radial spines, 8-16 uw Known geologic range. — Miocene. Occurrence. — Martini (197la, b) noticed the limited occur- rence of the present taxon in the DSDP Leg VII samples and placed his Dictyocha octacantha horizon near the top of his Cor- bisema triacantha Zone. This horizon, according to him, is time equivalent with the middle of NN.6 calcareous nannoplankton, ap- proximately at the bottom of N.12 planktonic foraminiferal and middle part of Dorcadospyris alata radiolarian Zones. Throughout the present study this variety has occurred in the experimental Mohole samples, interval between EM 7-2, 6-7 cm and EM 7-1, 14- 15 cm. Distephanus speculum (Ehrenberg) PI. 26, figs. 23, 24; Pl. 27, figs. 1, 2 Remarks. — As pointed out in previous studies from the central north Pacific deep-sea sediments and Shinzan diatomaceous member, SILICOFLAGELLATES AND EBRIDIANS: LING 167 Akita Prefecture, Japan (Ling, 1970, 1971), the synonymy for the present species has been presented by numerous workers on this subject. Dimensions. — Length of basal body ring, 18-40; of radial spines, 6-30 yp. Known geologic range. — Eocene to Recent. Occurrence. — D. speculum is found from sample WAH 7P, 516- 517 cm, N.4 foraminiferal and Calocycletta virgins - Lychnocamum bipes Zones (Riedel and Sanfilippo, 1970), throughout many of the Mohole and Mediterranean samples to LSDA 101G, 38-39 cm sam- ple, which is N.17 or 18 foraminiferal and Spongaster pentas radio- larian zones (Riedel and Sanfilippo, 1970). Occurrence of the present species is recognized in various parts of the world by many investi- gators. Distephanus speculum var. pentagonus Lemmermann | 5) DY a 00S Distephanus asteroides Haeckel, 1887, Rept. Voy. Challenger, Zool., vol. 18, p. 1564. Distephanus speculum var. pentagonus Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 264, pl. 11, fig. 19. Distephanus speculum var. pentagonus Lemmermann, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 263-264, fig. 57. Distephanus speculum var. pentagonus Lemmermann, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 65-67. Dictyocha speculum Ehrenberg, Stradner, 1961 (part), Erdél u. Kohle, vol. 14, No. 2, p. 92, figs. 72, 73 (only). Dictyocha speculum fa. pentagona (Lemmermann), Bachman, 1963, iz Bach- mann et al., Geol. Ges. Wien, Mitt., vol. 56, No. 1, p. 150, pl. 21, fig. 3. Distephanus speculum var. pentagonus Lemmermann, Glezer, 1966, in Cryp- togamic plants of the U.S.S.R., vol. 7, pp. 267-268, pl. 21, figs. 1-5. Distephanus speculum var. pentagonus Lemmermann, Bachmann, 1970b, in Cat. Fossil. Austriae, No. Ib, p. 10. Remarks. —In contrast to the previous work from the central north Pacific deep-sea sediments (Ling, 1970), an attempt was made during the present study to examine the biostratigraphic distribution of the present variety by recognizing it as an inde- pendent taxon. At least in the experimental Mohole samples, the present variety has a limited stratigraphic occurrence (see below). Haeckel (1887) proposed the new species from Challenger sta- tion 272 but did not give any illustration. As the sample contains numerous Tertiary Radiolaria (Riedel, 1957), and judging from the size, it seems that the species named by Haeckel may be considered synonymous and, therefore, it is included here. Apparently Glezer 168 BULLETIN 273 regarded the present variety in a broader sense by including Lem- mermann’s Distephanus speculum var. pentagonus fa. armata (1901b, pp. 264-265, pl. 11, fig. 20) which possesses apical accessory spines on the apical ring. So far no such specimen has been recovered in the present study; hence the forma of Lemmermann’s is not included, Glezer (1966) also synonymized a part of Hanna’s Distephanus variabilis (1931, pl. E, fig. 8 only), but the size for the latter is much bigger and the basal body is much thicker than for the present species. Eocene samples from California need to be studied in the future, and therefore, Hanna’s species name is ex- cluded from the present taxon at this time. Dimensions. — Length of basal body ring, 20-26 y; of radial spine, 8-16 pu. . Known geologic range. — Eocene to Neogene, Quaternary (?). Occurrence for the variety reported by Glezer (1966) from the inter- moraine layer of Ladoga area needs to be reexamined. Occurrence. — During the present study, specimens identified as the present taxon are found only in samples from experimental Mohole drilling material from EM 8-12, 94-95 cm to EM 8-11, 322- 323 cm. Thus from the analysis of the Mohole samples, they are recovered from the middle (Parker, 1964) or lower (Bandy and Ingle, 1970) Mohnian stage. Whether such limited stratigraphic occurrence is a local phenomenon needs to be examined in the future in other areas. Mandra (1968) observed the California land occur- rence only from Delmontian samples. Distephanus speculum var. pseudocrux Schulz Pay tics 5-0 Distephanus speculum fa. pseudocrux Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 263, fig. 52a, b. Distephanus speculum fa. pseudocrux Schulz, Gemeinhardt, 1930, in Krypto- gamen-Flora, vol. 10, pt. 2, p. 64, fig. 55. Distephanus speculum fa. pseudocrux Schulz, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 63, pl. 11, figs. 2, 3. Distephanus japonicus fa. pseudofibula Glezer, 1966 (part), in Cryptogamic plants of the U.S.S.R., vol. 7, p. 276, pl. 25, figs. 1, 3, 5 (?) (only). Distephanus speculum (Ehrenberg), Mandra, 1968 (part), Calif. Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 262, fig. 76 (only). Remarks. — The figure (see Pl. 27, fig, 5) illustrated here agrees with the form originally described by Schulz. Similar apical structure can be found also in specimens with a pentagonal basal body ring but rarely, while another figure (see Pl. 27, fig. 6) is SILICOFLAGELLATES AND EBRIDIANS: LING 169 considered as an example of morphological variation for the present variety. Glezer (1966) combined the present and the following taxon as Distephanus japonicus (Deflandre), which possesses the charac- teristic apical accessory spine(s) according to original species diag- nosis but no such specimen was encountered during the present study. Furthermore as can be seen from the distribution chart (Text-figure 4), the two varieties are not always found together, such as in the eastern Bering Sea margin samples (see below); therefore, they are considered as separate taxa in the present study. Dimensions. — Length of basal body ring, 24-30 yp; of radial spine, 8-12 un. Known geologic range. — Neogene, most likely only Miocene. Occurrence. — The present taxon is found only from the Mohole samples interval between EM 8-10, 78-79 cm, and EM 8-9, 148-149 cm. The age of this part is identified as upper Mohnian by Bandy and Ingle (1970), Delmontian and Mohnian or Mohnian by Parker (1964), and upper Miocene by Martini and Bramlette (1963). Distephanus speculum var. pseudofibula Schulz Pl. 27, figs. 8-13 Distephanus speculum fa. pseudofibula Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 262-263, fig. 51a, b. Distephanus speculum fa. pseudofibula Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 64, fig. 54. Distephanus speculum fa. pseudofibula Schulz, Deflandre, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, fig. 46. Dictyocha pseudofibula (Schulz), Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, pp. 55-56, pl. 11, figs. 1-3; pl. 24, fig. 2. Dictyocha pseudofibula var. complexa Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, pp. 56-57, pl. 11, fig. 4; pl. 24, fig. 1. Distephanus japonicus fa. pseudofibula Schulz, Glezer, 1966 (part), in Cryptogamic plants of the U.S.S.R., vol. 7, p. 276, pl. 24, figs. 4, 6-8, 10. Remarks. — As indicated under the preceding taxon, the com- bination by Glezer (op. cit.) seems undesirable as well as mislead- ing; therefore, Glezer’s usage is not followed in this study. This variety is described originally by Schulz from San Pedro and Redondo, California, Abashiri of Japan, and Ngemegy of Hun- gary, and all are fossil forms, Tsumura found his var. complexa from a Modern sea sample near Japan, and it is the only Quaternary record. Recently Hopkins (et al., 1968) reported the variety (as Dicty- 170 BULLETIN 273 ocha pseudofibula) from the eastern margin of the continental slope of the Bering Sea. By courtesy of David W. Scholl of the U.S. Geological Survey at Menlo Park, the TT-2 and -4 samples (TT18- 02 and TT18-04 respectively) were examined, and they are illus- trated here (PI. 27, figs. 11-13) for comparison. Dimensions. — Length of basal body ring, 26-32 yp; of radial spine, 7-14 un. Known geologic range. — Miocene to Quaternary (?). Occurrence. — Throughout the present study, the present var- iety 1s found only from experimental Mohole samples, and the interval between samples of EM 8-10, 78-79 cm, and EM 6-2, 10-11 cm, upper Mohnian to Delmontian. Martini (1971la, b) recognized his Dictyocha pseudofibula horizon from the DSDP Leg VII, which is correlated with NN.10 calcareous nannoplankton, N.16 fora- miniferal and lower part of Ommatartus antepenultimus radio- larian Zones. Judging from the stratigraphic position, it is possible that occurrence within the Mohole section is time-equivalent with that of the above western equatorial Pacific. The Bering Sea dredge haul samples are, therefore, regarded as of late Miocene age rather than late middle Miocene as previously assumed (op. ctt., p. 1475). Genus LYRAMULA Hanna, 1928 Remarks. — Since the genus and two species were first described by Hanna (1928), the exact nature of the forms has remained uncertain. Thus, Gemeinhardt (1930) and Frenguelli (1940) ex- cluded the genus, and Lipps (1970) regarded them as questionable silicoflagellates and suggested their possible affinities as “the setae of several species of Chaetoceros-like diatoms, from which the frus- tule has been dissolved.” This may be possible because of selective dissolution, the delicate frustules of Chaetoceros are rarely found in bottom sediments despite the fact that they are abundant in plank- ton both in numbers of species and individuals (Kanaya and Koizumi, 1966). However Chaetoceros frustule with setae, but not the setae alone, have been reported from deep-sea sediments and Tertiary deposits by several diatom researchers; such as Koizumi (1968), Kozlova (1964), Jousé (1962), Sheshukova-Poretzkaya (1967), and the author has also found such specimens from surface sediments of various parts of the world oceans. Therefore, the forms SILICOFLAGELLATES AND EBRIDIANS: LING 171 illustrated here from Cretaceous materials under the present genus Lyramula are too distinctive to be considered as a part of diatoms at present, At the same time, microfossils similar to the Lyramula species have been described by Tsumura (1963) as L. tenwpertica Kokubo et Tsumura (pp. 30-31, pl. 3, fig. 3; pl. 16, fig. 5) from Japan and L. tenwipertica var. laevis Tsumura (p. 31, pl. 3, fig. 5; pl. 16, fig. 3) from California. Recently Hopkins (et al., 1969, p. 1477) re- corded the occurrence of L. tenuipertica from the dredge haul of TT18-3 (as TT-3) from the continental margin of the Bering Sea. Numerous specimens were observed similar to Tsumura’s species during the present study, and an example is shown here. One specimen is from a sample, DSDP 9-5-2, 99-100 cm, identified as belonging to the N.22 planktonic foraminiferal Zone (Blow, 1970), and possessing the surface structure of “roughly an alter- nate scalariform” (Tsumura, 1963, p. 30). Under careful examina- tion, the specimen does not show the hollow structure of the rods like the Lyramula species from Upper Cretaceous, and such differ- ence is apparent under phase contrast microscopy (compare PI. 27, figs. 14, 15 vs. 16, 17). The affinity of Lyramula tenuipertica remains uncertain, and therefore, is excluded from the present paper. Lyramula furcula Hanna Pl. 27, figs. 16-18 Lyramula furcula Hanna, 1928, Jour. Paleont., vol. 1, No. 4, p. 262, pl. 41, figs. 4, 5. Lyramula furcula Hanna, Deflandre, 1940b, Acad. Sci. Paris, C. R., vol. 211, No. 21, p. 509, figs. 1-4. Lyramula furcula Hanna, Deflandre, 1950a, Microscopie, vol. 2, p. 61/82, figs. 163, 165, 167, 169. Lyramula furcula Hanna, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., vol. 1, p. 43, pl. 1, figs. 1-2 (fide Tsumura, 1963). Lyramula furcula Hanna, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-44, No. 146, pp. 29-30, pl. 1, figs. 1; pl. 3, figs. 1-2; pl. 16, figs. 1-2. Lyramula furcula Hanna, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 256, figs. 7, 8, 13. Lyramula furcula Hanna, Glezer, 1966 (part), in Cryptogamic plants of the WES SAR, Vile snp caleople 2 figs: 3.05—7- Remarks. — Deflandre (1950a, figs. 167-169) illustrated speci- mens with one or more lateral rods as a premutant form of the present species, but the topotypic sample, CAS 1144, did not yield such specimens. 172 BuLueTIN 273 Dimensions. — Length of lateral rods (from the base of Y), 45-55 uw. Known geologic range. — Cretaceous (late) to Paleocene (early), Glezer reported the early Paleocene occurrence from west- ern Siberia, Russia. Occurrence. — The species is found to be abundant but only in the topotypic material from California, Therefore, Mandra (1968, p. 242) concluded that the present species seems to be restricted stratigraphically to the late Cretaceous, at least from California. Lyramula furcula var. minor Deflandre Pl. 27, figs. 19-21 Lyramula furcula var. minor Deflandre, 1940b, Acad. Sci. Paris, C. R., vol. 211, No. 21, p. 509, figs. 7-10. Lyramula furcula Deflandre, 1950a, Microscopie, vol. 2, pp. 62/82-63/82, figs. 170-173. Lyramula furcula Hanna, Glezer, 1966 (part), in Cryptogamic plants of the WS:S:Reavoly 74p.22t Remarks. — Similar to the preceding taxon except that the present variety is smaller in size (approximately one-half), and frequently has a third lateral rod; thus the three rods are approxi- mately 120° apart (see Pl. 27, fig. 21). Glezer (1966) considered that the present small size is within the range of variation of the type. Dimensions. — Length of lateral rods (from the base of Y), 28-35 up. Known geologic range. — Cretaceous (late). Occurrence. —L. furcula var, minor is found only from the CAS locality 1144 and rarely. Mandra studied a sample which came from nearby this locality but failed to find the variety. Lyramula simplex Hanna Pl. 28, fig. 1 Lyramula simplex Hanna, 1928, Jour. Paleont., vol. 1, No. 4, p. 262, pl. 41, fig. 6. Lyramula simplex Hanna, Deflandre, 1940b, Acad. Sci. Paris, C. R., vol. 211, No. 21, p. 506, figs. 5, 6. Lyramula simplex Hanna, Deflandre, 1950a, Microscopie, vol. 2, pp. 62/82- 62/82, figs. 164, 165. Lyramula simplex Hanna, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., vol. 1, p. 46, pl. 1, fig. 4 (fide Tsumura, 1963). Lyramula simplex Hanna, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 31, pl. 1, fig. 2; pl. 3, fig. 4; pl. 16, fig. 4. Lyramula simplex Hanna, Glezer, 1966, in Cryptogamic plants of the WES SERS voll 75 ps 22d ipler2. figs 2.4. Lyramula simplex Hanna, Mandra, 1968, Calif. Acad. Sci., Proc., ser. 4, vol. 36, No. 9, pp. 256-257, figs. 9, 10. SILICOFLAGELLATES AND EBRIDIANS: LING IW Remarks. — Specimen referred to here has thicker rods than the L. furcula and clearly possesses fine surface ornamentation, as Hanna (1928) originally described. Dimensions. — Length of rods (from base of U), 82-90 ux. Known geologic range. — Cretaceous (late). Occurrence. —So far the present species is recovered rarely from CAS 1144, the type locality for the present species. Genus MESOCENA Ehrenberg, 1839, emend. Deflandre, 1950a Remarks. — In a previous article, Ling (1970) discussed in de- tail the taxonomic problems involved for a species, Mesocena cf. elliptica. At that time, the observation was based only on deep-sea sediments from the central north Pacific and also on the illustra- tions of the reference, Since then the study has been expanded by including many reference samples, and it is now possible to present additional data of the detailed investigation. The occurrence of a silicoflagellate form referable to Mesocena was first described by Ehrenberg (1839, p. 129), and the figure was illustrated by Ehrenberg (1854, pl. 22, fig. 41) as Dictyocha triangula from Caltanisetta, Sicily. It was Stradner who noticed in 1956 and 1961 for the first time that some of the Mesocena specimens possess septa (“Scheide- wand” of Stradner) in the basal body ring. The structure can be detected if the specimen is carefully examined under the micro- scope but it is more easily detected and clearly illustrated by utiliz- ing a phase contrast attachment. Stradner further stated that Mesocena with septa (Mesocena septatae) were derived from the genus Corbisema, while those without septa (Mesocena aseptatae) came from Dictyocha. Bachmann (1970b), then proposed the new genus Septamesocena for the former. Mesocena apiculata (Schulz) Pl. 28, figs. 2-4 Mesocena oamaruensis var. apiculata Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 240, fig. 11. Mesocena polymorpha var. triangula Lemmermann, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 28, fig. 12a (only). Mesocena apiculata Schulz, Hanna, 1931, Mining in California, vol. 27, No. Zaple Distious: Not Mesocena apiculata (Schulz), Deflandre, 1932c, Soc. Bot. France, Bull., vol. 79, Nos. 5, 6, p. 499, figs. 34, 35. Not Mesocena apiculata (Schulz), Tynan, 1957, Micropaleont., vol. 3, No. 2 ps 154. plata 10: 174 BULLETIN 273 Not Mesocena apiculata (Schulz), Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, figs. 28, 29, 32. Not Mesocena apiculata (Schulz), Bachmann, 1962, Geol. B.-A., Verh., Jiahre? 19625 Nos 2, p: 379; fisss Osa: Not Mesocena apiculata (Schulz), Bachmann, 1963, in Bachmann, et al., Geol. Ges. Wien, Mitt., p. 152, pl. 19, figs. 60-62. Not Mesocena apiculata (Schulz), Bachmann, 1964, im Ichikawa, et al., Kanazawa Univ., Sci. Rept., vol. 9, No. 1, p. 107, pl. 4, fig. 36. Mesocena aff. apiculata (Schulz), Glezer, 1966 (part), im Cryptogamic plants of the US.S.R., vol. 7, p. 282, pl. 28, fig. 5 (?); pl. 33, fig. 7, (not pl. 29, fig. 9). Not Mesocena apiculata (Schulz), Hajos, 1968, Geol. Hungarica, ser. Paleont., fasc. 37, p. 67, pl. 4, fig. 3. Not Mesocena apiculata (Schulz), Bachmann and Papp, 1968, Giorn. di Geol., ser. 2, vol. 35, fasc. 2, pl. 3, figs. 1, 2. Not Mesocena apiculata (Schulz), Bachmann, 1970a, Geol. B.-A. Verh., Jahrg. 1970, pp. 280, 282, 284. Remarks. — The above synonymy list is prepared to record that the various forms were referred to this species by numerous workers from many parts of the world. VW. apiculata is differentiated from another species, Septamesocena apiculata Bachmann, which will be discussed later, by the absence of septal structure at the apices. Dimensions. — Diameter of basal body ring, 36-46 »; of radial spines, 2-6 yp. Known geologic range. — Paleocene (?), Eocene, Miocene (?). The type locality for the present species is Oamaru Diatomite, New Zealand, of Eocene. The oldest occurrence, Paleocene, is reported by Glezer (1966) from the eastern slope of the Ural region, and it possesses a dentate basal body ring (pl. 28, fig. 5); such a specimen has not yet been observed from samples of Oamaru Diatomite. An- other Paleocene specimen (pl. 33, fig. 7) from the same Russian location has a smooth basal body ring, but the structure at the three apices is obscured. It is conceivable that previous students of silicoflagellates may have overlooked the septal structure, and oc- currence of the present species may be limited only to the Eocene age. Occurrence. — M. apiculata is not found in the deep-sea sedi- ments examined during the present study. The specimens here illustrated are from Bain’s Farm (PI. 28, figs. 2, 3) and Jackson’s Paddock (PI. 28, fig. 4) sections of Oamaru Diatomite, New Zea- land, for comparison with similar forms, particularly with Septa- mesocena apiculata. SILICOFLAGELLATES AND EBRIDIANS: LING 175 Mesocena circulus Ehrenberg Pl. 28, figs. 5, 6 Dictyocha (Mesocena) circulus Ehrenberg, 1840, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., p. 208. Mesocena circulus Ehrenberg, Ehrenberg, 1844a, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., p. 65. Dictyocha circulus Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 19, fig. 44. Not Mesocena circulus Ehrenberg, Lemmermann, 1901b, Deutsch. Bot. Ges. Bers volet9s ps 2517. Not Mesocena circulus Ehrenberg, Schulz, 1928, Bot. Archiv., vol. 21, No. 2; p. 242, fig. 14. Not Mesocena circulus Ehrenberg, Gemeinhardt, 1930, in Kryptogamen- Flora, vol. 10, pt. 2, p. 33, fig. 18. Mesocena circulus Ehrenberg, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 41 (not pl. 7, fig. 1). Not Mesocena circulus Ehrenberg, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, pp. 285-286, pl. 29, fig. 8. Remarks. — This species is characterized by a circular to oval- shaped basal body ring with one series of radial spines generally in a plane. Confusion about the present species has resulted from the be- ginning when Ehrenberg gave the original description of the present species as “D. cellula unica circulari margine dentata Diam. - 1/48. Fossils in marga Graeciae.” The first illustration given by Ehren- berg (1854) came from upper Miocene, Aegina, Greece, and the margin can be interpreted as either coarsely dentate or as possess- ing about 17 short radial spines, The diameter of the specimen is over 50 » according to Loeblich, III (et al., 1968, p. 217, fig. 20). Lemmermann (1901b) added the Barbados and Caltanisetta (Sicily) as additional localities, and although referring to Ehren- berg’s description and figure, he indicated the species as “Gehiuse kreisrund, 20-30 » gross, glatt oder am dussern Rande schwach gezahnt.” It is thus apparent that Lemmermann’s specimens are about 1% the size of Ehrenberg’s. Schulz (1928) followed Lemmer- mann’s description, and the figure given from Mors Island is oval- shaped. Schulz at the same time observed that a specimen from Kusnetzk, Russia, has only a 14 p» diameter. Gemeinhardt (1930) followed Lemmermann’s and Schulz’s concept. Tsumura (1963) also recorded the present species, but his specimen (pl. 7, fig. 1) seems to possess two series of radial spines and should be transferred to M. circulus var. apiculata. Glezer (1966) also referred a specimen from the Ural (pl. 29, fig. 8) to the present species, but it shows a finely dentate margin and not radial spines. A similar form is 176 BULLETIN 273 reported by Hajos (1968) and classified as M. elliptica var. circulus which is later followed by Bachmann (1970b). Dimensions. — Diameter of basal body ring, 68-72 y; of radial spines, 3-6 p. Known geologic range. — Eocene to Miocene. Occurrence. — The present species is recovered from two samples, EM 8-12, 26-28 cm, and EM 8-11, 69-70 cm only which are within Mohnian age by Parker (1964), Bandy and Ingle (1970), and Tortonian (?) of middle Miocene by Martini and Bramlette (1963). Mesocena circulus var. apiculata Lemmermann Pl.-28; figs: 57,0 Mesocena circulus var. apiculata Lemmermann, 1901b, Deutsch Bot. Ges., Ber., vol. 19, p. 257, pl. 10, figs. 9, 10. Mesocena circulus var. apiculata Lemmermann, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 242-243, fig. 15a, b, c. Mesocena circulus var. apiculata Lemmermann, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 33-34, fig. 19. Distephanus polyactis fa. mesocenoidea Deflandre, 1932c, Soc. Bot. France, Bull., vol. 79, Nos. 5, 6, fig. 41 (only). Mesocena circulus var. apiculata Lemmermann, Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 65, fig. 5. Paradictyocha polyactis fa. mesocenoidea (Deflandre), Frenguelli, 1940, Rev. Mus. La Plata, n.s., vol. 2, Paleont., No. 7, p. 53, fig. 8b, d, e (?) (only). Paradictyocha apliculata Lemmermann, Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, p. 53, fig. 7h. Mesocena circulus var. apiculata Lemmermann, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., No. 1, p. 55, pl. 2, figs. 19-21 (fide Tsumura, 1963). Mesocena circulus var. apiculata Lemmermann, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 41, pl. 6, figs. 7, 8; pl. 20, figs. 1-2. Mesocena circulus Ehrenberg, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 41, pl. 7, fig. 1. Paradictyocha polyactis fa. mesocenoidea Frenguelli, Glezer, 1966, in Cryp- togamic plants of the U.S.S.R., vol. 7, p. 278, pl. 28, fig. 1. Remarks. — Ling (1971) discussed the present taxon in detail on the basis of Japanese Miocene specimens. Frenguelli’s Para- dictyocha apiculata from Sendai, Japan, seems likely to belong to the present taxon judging from the illustration. Dimensions. — Diameter of basal body ring, 64-74 yp; of radial spines, 3-5 p. Known geologic range. — Eocene to Miocene. Schulz (op. cit., fig. 15c) described the only Eocene form for the present variety SILICOFLAGELLATES AND EBRIDIANS: LING 177 from Oamaru, New Zealand. Examination of Oamaru Diatomite by the author so far has failed to recover such a specimen. Occurrence. — Specimens identified as belonging to the pres- ent variety were found only from experimental Mohole samples from EM 7-1, 35-36 cm, to EM 6-2, 10-11 cm, with their occur- rence apparently limited to only middle and late Miocene. Mesocena cf. elliptica Ehrenberg Pl. 28, figs. 9-15; Pl. 29, figs. 1-3 Remarks. — As discussed by Deflandre (1932c), Glezer (1966), and Ling (1970), the taxonomy of the present species is one of the most uncertain among silicoflagellates. On the one hand, differ- ent taxonomic names were proposed, based on the number of radial spines (Ehrenberg, Lemmermann); and on the other hand, all these forms are grouped in only one species (Deflandre, Glezer). Be- cause of this and because of the limited number of samples ob- served at that time, Ling (1970, 1971) referred to these forms as M. cf. elliptica. It is extremely unfortunate that Hajos (1968) and later Bachmann (1970b) proposed a new combination and grouped them as M. elliptica, apparently following Deflandre’s prac- tice (1932c), but then proposed WM. e. var. quadrangula Bachmann and Ichikawa (1962) in place of M. e. var, elliptica (see Lanjouw, et al., 1966, ICBN, Art. 25). Furthermore inclusion of M. circulus as one of the variety within this species also seems undesirable. During microscopic examination, an effort was made to seek the biostratigraphic occurrences of the taxa even by recognizing separately those distinguished on the basis of the number of radial spines (see Text-figs. 3, 4, 7). The following is apparent from the present study: 1. No specimen with three radial spines that may be refer- able to Dictyocha triangula and not M. apiculata or Septamesocena apiculata has been found. 2. The four-spine form, “MV. elliptica”, stratigraphically appears earlier and ends slightly later than the two-spine “MM. diodon”, 3. Only one specimen assignable to M. hexagona Haeckel (see Ling, 1971) is found from sample EM 8-13, 49-51 cm (“h” in Text- fig. 4). 4. Only a single specimen similar to MV. polymorpha var. quad- 178 BULLETIN 273 rangula Lemmermann (1901b) is found from sample WR TR 11, Low (Bo. 202) (“q” in Text-fig. 3). As in previous articles, a wide range is considered for the present taxon. Dimensions. — Length of basal body ring, 43-70 pn. Known geologic range. — Eocene to Pleistocene Occurrence. — In the Mediterranean section of Italy (see Text- figure 7), the initial appearance of so-called “M. elliptica” starts with the beginning of the Calocycletta costata radiolarian Zone (Sanfilippo, 1971), and apparently this seems the earliest for this form so far recognized during the present investigation. From other samples, the first occurrence is noticed from Trinidad sample, WR TR 11, Low (Bo. 202), which is assigned to the Dorcadospyris alata Zone by Riedel and Sanfilippo (1970). The highest strati- graphic occurrence of the four-spine form is in LSDA 101G, 38-39 cm which is N.17 or 18 foraminiferal Zone or Spongaster pentas Zone (Riedel and Sanfilippo, 1970). On the other hand, the two-spine form (“M. diodon’’) is found only from the Mohole samples, the interval between EM 8-15, 505-506 cm, to EM 6-2, 30-32 cm, ranging fom Luisian to Mohnian. Mandra (1968) indicated the range of his M. crenulata var. diodon from Valmonte Diatomite (Mohnian) to Buttle Diatomite (Del- montian), The specimen of the “M. hexagona’ is found in a sample of the lower Mohnian stage, but Mandra found his specimens from the Buttle Diatomite (Delmontian) of California, Mesocena cf. elliptica var. minoriformis Bachmann and Papp Pl. 29, figs. 4-7 Mesocena elliptica minoriformis Bachmann and Papp, 1968, Giorn. di Geol., sera 2-vole 55 plo sips 121. tig: Mesocena elliptica var. minoriformis Bachmann and Papp, Bachmann, 1970b, zz Cat. Fossil. Austriae, No. 1b, p. 13. Remarks. — Bachmann kindly sent the author possible topo- typic material from Ernstbrunn, Austria (Aus. 3 in this paper). The author agrees that the size of the present variety is definitely smaller than that of M. cf. elliptica, and also accepts that the present variety has “relativ starken Basalringteile wesentlich von der geo- logisch jiingeren Art .. .” M. cf. elliptica was also found in the SILICOFLAGELLATES AND EBRIDIANS: LING 179 sample Bachmann sent, although he did not indicate such occur- rence in his table. Dimensions. — Diameter of basal body ring, 28-50 up. Known geologic range.— Miocene (Burdigalian). Occurrence. — Similar to M. cf. elliptica, this Bachmann’s var- iety is found earlier in Italian samples of the Calocycletta virginis Zone than in another part of the area of the present study, WR TR 23 (K9391), which is the Calocycletta costata Zone (Riedel and Sanfilippo, 1970) from Trinidad. The highest occurrence is from sample EM 8-13, 125-126 cm which is lower Mohnian according to Bandy and Ingle (1970) and Parker (1964) or lower part of Tor- tonian (?) by Martini and Bramlette (1963). Mesocena oamaruensis Schulz Pl. 29, figs. 8-10 Mesocena oamaruensis Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 240, fig. 10a, b. Mesocena oamaruensis Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 34, fig. 20. Mesocena oamaruensis Schulz, Deflandre, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, fig. 11. Corbisema oamaruensis (Schulz), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, p. 64, fig. 13c. Mesocena oamaruensis Schulz, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., No. 1, p. 56, pl. 2, fig. 22 (fide Tsumura, 1963). Not Mesocena oamaruensis Schulz, Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, figs. 30, 31. Not Mesocena oamaruensis Schulz, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 42, pl. 7, fig. 2; pl. 21, fig. 12. Not Mesocena oamaruensis Schulz, Bachmann, 1964, in Ichikawa ef al., Kanazawa Univ., Sci. Rept., vol. 9, No. 1, pl. 4, fig. 37. Mesocena oamaruensis Schulz, Glezer, 1966, in Cryptogamic plants of the WES SHR EViOlNa/. eps 2ooe Dla ZSnetion se Remarks. — One of the forms illustrated here (Pl. 29, fig. 8) is from sample $136/1096 of the Forrester’s Hill section of Oamaru Diatomite, New Zealand. It is apparent that the basal body ring is smooth, without either radial spines or accessory spines. Lumen is apparent in the specimen but no septa. The specimens from Kellogg and Sidney Shales of California (see Pl. 29, figs. 9, 10) beyond any doubt are conspecific with that of Oamaru Diatomite, except that the Californian specimens are slightly smaller in size. Stradner’s form is illustrated as having septa as also does Bachmann’s specimen from the Hojuji diatomaceous mudstone of Japan; therefore, they are excluded from the present species (see 180 BULLETIN 273 below). Tsumura also described specimens from Jackson’s Paddock, Oamaru, New Zealand, but his illustration (pl. 7, fig. 2) can be interpreted as having septa, and another specimen (pl. 21, fig. 12) as having spines at the radial corners; therefore they are excluded from the present species. Dimensions. — Length of basal body ring, 60-90 up. Known geologic range. — Eocene (late), Oligocene (early ?). As discussed by Loeblich, III (et al., 1968, p. 18) and is accepted here, several localities or sections from the so-called Oamaru Dia- tomite are now considered as late Eocene age. The only Oligocene but questionable record for the present species is reported by Glezer (1966) from Dnepropetrovsk of European Russia. Thus it is con- ceivable that the present species has limited stratigraphic range of only late Eocene. Occurrence. — During the present study, no specimen referable to the present species was recovered from the deep-sea sediments. The present species is discussed here and illustrated for comparison purposes to differentiate it clearly from the very similar form, Septamesocena apiculata, that previous workers assigned erron- eously. Genus NAVICULOPSIS Frenguelli, 1940 Remarks. — The silicoflagellate with naviculoid basal body ring was named by Ehrenberg (1839) as Dictyocha navicula from Miocene sediments of Zante, Greece. The detailed structure of these specimens was discussed by Frenguelli (1940, p. 60), who first noticed that in some specimens the middle part of the basal body ring where the apical structure joins is sometimes transformed into a thin flattened form thus losing the general tubular nature; there- fore, in either apical or abapical view, the tubular skeleton is suddenly narrowed to capillary form in the middle of the basal body ring. Deflandre (1950a) later concurred in this opinion, although both Frenguelli and Deflandre failed to mention that the middle of the basal body ring frequently shows some constriction. Schulz observed such a phenomenon and described it as Dicityocha navicula var. constricta. As can be seen in the illustrations of different taxa within the present genus, such constriction is found rather com- monly. SILICOFLAGELLATES AND EBRIDIANS: LING 181 Another important point that deserves attention for its taxo- nomic significance has been neglected, In 1950, Deflandre (p. 36/82) indicated that in rare cases there are some specimens that show flattening of the two apices of the major axis, and he indicated that he found such forms in samples from Zante, Greece and Saint- Laurent-La Vernede, France, but only those from Zante were illus- trated under the name of Naviculopsis navicula (Ehrenberg) (his figs. 241-243). Later Stradner (1956, 1961) also noticed this struc- ture, called “Endflichen”, which exhibits small projections or spines from both sides of the plates (see 1961, abb. 1 A; figs. 46, 47). Bachmann (1970a) also illustrated such specimens from his Ernst- brunn, Austria sample. Note that in these specimens, no radial spines were observed. The taxonomic significance of such flattened nature of the apices is apparent and should not be confused with the small flattened hyaline area found between the tubular basal body ring of the apices as discussed by Glezer (1966, p. 254) for N. foliacea. Finally it should be pointed out here that in some naviculoid forms these two transformations just described never take place and thus the tubular nature is preserved completely throughout the basal body ring. These three different types within the genus of Naviculopsis may suggest different phylogenic lineages. However, the author pre- fers to await further study of these forms, particularly examination of Eocene samples from New Zealand and California. Naviculopsis biapiculata (Lemmermann) Pl. 30, figs. 1-4 Dictyocha navicula var. biapiculata Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 258, pl. 10, figs. 14 (?), 15. Dictyocha navicula var. biapiculata Lemmermann, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 244-245, figs. 18, 19. Dictyocha navicula var. biapiculata fa. aspera Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 246, fig. 20a, b Dictyocha navicula var. biapiculata Lemmermann, Gemeinhardt, 1930, _ in Kryptogamen Flora, vol. 10, pt. 2, pp. 36-37, fig. 24a (only). Dictyocha (?) biapiculata Lemmermann, Hanna, 1931, Mining in California, vol. 27, No. 2; pl. D; figs. 5 (?). 6. Dictyocha navicula var. biapiculata Lemmermann, Deflandre, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, figs. 15-17 (not fig. 18). Not Dictyocha navicula var. biapiculata Lemmermann, Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 65, fig. 6. Naviculopsis biapiculata (Lemmermann), Frenguelli, 1940, Rev. Mus., La (aa n.s., vol. 2, Paleont., No. 7, p. 60, fig. 11c, d (as fa. normal) only). 182 BULLETIN 273 Dictyocha navicula var. apiculata Lemmermann, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci, No. 1, p. 58, pl. 3, figs 24-26 (fide Tsumura, 1963). Dictyocha navicula var. biapiculata Lemmermann, Tsumura, 1963, Yoko- hama Munic. Univ., Jour., ser. C-45, No. 146, p. 45, pl. 8, figs. 1-3; pl. 2ieetigs: 7-9: Naviculopsis biapiculata var. biapiculata Glezer, 1966, im Cryptogamic plants of the U.S.S.R., vol. 7, pp. 255-256, pl. 16, figs. 2, 4-5. Naviculopsis biapiculata (Lemmermann), Mandra, 1968 (part), California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 264, figs. 20, 21 (only). Remarks. — As described and illustrated in his original figure 15, when Lemmermann (1901b) proposed this species, he indi- cated that the apical structure was in the form of an apical bar (“Kieselbalken”). Although no reference samples are available from Dolje, Yugoslavia, Fuur Island or Kusnetzk, Russia, the localities from which Lemmermann’s new taxon was proposed, samples from Jackson’s Paddock section of the Oamaru Diatomite are here illus- trated (PI. 30, figs. 1, 2) in lateral view to show the nature of the transition of the basal body ring to the apical bar, Also as will be demonstrated later, the basal body ring of the specimens be- longing to the present genus always remains on the same plane of the radial spines in lateral view, and is never warped or curved upward as Lipps (1970, fig. 3, bottom figure) illustrated. The above synonymy is prepared by adhering to the original definition. Thus, Gemeinhardt, although referring his specimen to that of Lemmermann’s, described the apical structure of his as “kleineren mitunter besonders breit, bandartig, nach der mitte zu schmalerwerdend.” Therefore, his figure 24b, which clearly shows such a broad apical structure is excluded from the present species. One of Mandra’s specimens (1968, fig. 22) is also excluded on the same basis and is referred to as N. foliacea. In addition, as Deflandre (1950a) indicated, Schulz’s fa. aspera is included as a morpho- logic variation of the present species. Dimensions. — Length of basal body ring, 40-54 »; of radial spine, 34-50 p. ; Known. geologic range. — Eocene to Oligocene (early ?). Pos- sible early Oligocene occurrence is reported by Glezer (1966) from several locations of western Siberia. Occurrence. — The present species is found rarely and from DSDP 6-6-2, 1-2 cm, upper part of Hantkenina aragonensis plank- tonic foraminiferal Zone (Ewing, et al., 1969), or Thyrsocyrtis tri- SILICOFLAGELLATES AND EBRIDIANS: LING 183 acantha Zone (Riedel, 1971) and WR TR 39 F (J.S. 1068) from Barbados, which is the Theocyrtis tuberosa Zone (Riedel and San- filippo, 1970). Naviculopsis constricta (Schulz) Pl. 30, figs. 5-8 Dictyocha navicula var. biapiculata fa. constricta Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 246, fig. 21. Dictyocha navicula var. biapiculata fa. constricta Schulz, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, p. 38, fig. 25. Naviculopsis constricta (Schulz), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 11a, b. Not Naviculopsis constricta (Schulz), Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, pl. 2, figs. 49-52. Not Dictyocha var. biapiculata fa. constricta Schulz, Tsumura, 1963, Yoko- hama Munic. Univ., Jour., ser. C-45, No. 146, p. 46, pl. 8, fig. 8. Naviculopsis biapiculata var. constricta (Schulz), Glezer, 1966, in Crypto- gamic plants of the U.S.S.R., vol. 7, pp. 257-258, pl. 17, fig. 4. Description. — Basal body ring, oval, frequently constricted at the middle where the apical structure joins; two long radial spines at each end of the major axis; apical structure in the form of an arched band with more or less uniform width throughout except broadened slightly where connected with the basal body ring; no apical nor basal accessory spines present. Remarks. — Schulz (1928) indicated when he proposed his new fa. contricta that the middle part of the basal body ring is, in either apical or abapical view, constricted. As already noted by Frenguelli (1940) when he discussed the present genus, such a phenomenon is common among the naviculoid silicoflagellates be- cause of transformation of the basal body ring from tubular to flattened nature. The present species can be recognized by the band-form apical structure and generally shows uniform width throughout; thus it can be differentiated from those either with an apical bar like N. biapiculata or with a foliated apical plate such as N. foliacea. Depending on the width of the apical band, the size of lateral windows is variable. Dimensions. — Length of basal body ring, 26-34 »; of radial spines, 18-36 u. Known geologic range. — Eocene (late). Glezer listed the age of Kreyenhagen Formation of California and Oamaru Diatomite, New Zealand as “late Eocene or early Oligocene” but they are now regarded as Eocene (see Loeblich, III et al., 1968, p. 18). Therefore, the geologic range for the present species seems limited to middle and late Eocene. 184 BULLETIN 273 Occurrence. — Like the preceding taxon, this species is found only from samples of DSDP and Barbados. Naviculepsis foliacea Deflandre Pl. 30, figs. 9-11 Dictyocha (?) biapiculata Lemmermann, Hanna, 1931 (part), Mining in California, vol. 27, No. 2, pl. E, fig. 10 (only). Dictyocha (?) biapiculata Lemmermann, Clark and Campbell, 1945 (part), Geol. Soc. Amer., Mem. 10, p. 3, pl. 5, fig. 8 (not others). Naviculopsis foliacea Deflandre, 1950a, Microscopie, vol. 2, pp. 76/82-77/82, figs. 235-240. Naviculopsis foliacea Deflandre, Stradner, 1961, Erd6él u. Kohle, vol. 14, No. 2p. 89 ities 3: Naviculopsis foliacea Deflandre, Glezer, 1966, in Cryptogamic plants of the WAStS Reaviole 7, ps 2585 wDlea7ette. 5. Naviculopsis biapiculata (Lemmermann), Mandra, 1968 (part), Calif. Acad. Sci., Proc., ser. 4, vol. 36, No. 9, p. 264, fig. 22 (only). Remarks.— The specimens found during the present study from the Deep Sea Drilling Project (Pl. 31. fig. 11) agree with the description and illustration originally given by Deflandre from Barbados. Although no sample is available from the Kreyenhagen Shale where Hanna apparently described the present species, speci- mens from the Kellogg Shale and Sidney Shale of California are illustrated (PI. 31, figs. 10, 11). The nature of the foliated apical plate and the size variation of the apical plate in contrast to that of basal body ring can be seen in these figures. Note here also that in DSDP samples, there is a flattened hyaline area between the basal body ring at the apices which is not evident in specimens from California. Therefore, Glezer is of the opinion that the present species should be limited to those with the flattened area. As indicated earlier, however, the significance of such a flattened area should not be confused with that of the completely flattened end plate found in N. navicula. It is the au- thor’s opinion that the presence of the foliated apical plate, from which the name of the present species is apparently derived, is characteristic; and the value of the flattened area needs to be confirmed in the future after more specimens are studied, The California specimens are, therefore, included in the present species. Dimensions. — Length of basal body ring, 40-56 u; of radial spine, 30-36 yp. Known geologic range. — Eocene. The age of “Diatomo-radio- larite de Springfield, Ile de la Barbade,” which was considered as “Oligocéne-Miocéne ?” by Deflandre (1950a, p. 76/82) and which SILICOFLAGELLATES AND EBRIDIANS: LING 185 is followed by Glezer (1966), is now regarded as Eocene by Loeblich, DD (et al3 1968, p. 18>): Occurrence. — N. foliacea here discussed is found in several DSDP samples of middle Eocene age. With consideration of the Californian specimens, this species has the highest occurrence at the top of Eocene or bottom of Oligocene from the Barbados sample WR TR 39 F (J.S. 1068). Naviculopsis lata (Deflandre) Pl. 30, figs. 12-16 Dictyocha biapiculata var. lata Deflandre, 1932c, Soc. Bot. France, Bull., vol. 79, p. 500, figs. 30, 31. Dictyocha navicula var. biapiculata Lemmermann, Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 65, pl. n, fig. 6. Naviculopsis lata (Deflandre), Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, p. 61, fig. 11h (?). Dictyocha ausonia var. regularis Carnevale, Deflandre, 1950a, Microscopie, vol. 2, pp. 68/82-69/82, fig. 197 (only). Naviculopsis robusta Deflandre, Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, pl. 2, figs. 39-41, 43-45 (not fig. 42). Naviculopsis robusta Deflandre, Bachmann and Papp, 1968, Giorn. di Geol., ser. 2, vol. 35, fasc. 2, p. 119, pl. 3, figs. 3, 4. Naviculopsis lata (Deflandre), Bachmann, 1970a, Verh. Geol. B.-A., Jahrg. 1970, No. 2, pp. 278-279, pl. 2, figs. 1-20; pl. 3, figs. 1-15. Remarks. — As discussed in detail by Bachmann (1970a), the present species is apparently similar to another species, Naviculopsis robusta, from the Eocene Diatomite of Singhiliewski, Russia, but the latter is characterized by possessing a small triangular, foliated lateral plate where the basal body ring and apical bar meet. So far in this study, a specimen with this structure as Deflandre (1950a) and Glezer (1966) illustrated has not been seen; therefore, it is agreed that N. robusta has a limited biogeographic distribution. Some of the present species show a slight constriction in the middle of the basal body ring where an apical bar forked and merged, and such a phenomenon can be observed easily from the abapical view, particularly under phase contrast (Pl. 30, fig. 14), but in no case does the basal body ring show a flattened nature. Apparently Deflandre (1950a), by considering the wide range of variation for Dictyocha ausonia, regarded the specimen of the present species as within its variation. As discussed earlier, the varia- tion of a gradual narrowing and the disappearance of radial spines on the minor axis is not so readily as shown by Deflandre for Dictyocha ausonia (figs. 194-196) or D. mutabilis (figs. 203-208). 186 BULLETIN 273 Dimensions. — Length of basal body ring, 42-52 p; of radial spine, 10-16 p. Known geologic range. — Oligocene (late). Occurrence. — During the present study, NV. lata is found only from Mediterranean Italian samples ranging from near the bottom of Calocycletta virginis Zone to the highest available samples of Calocycletta costata Zone (Sanfilippo, 1971). Naviculopsis navicula (Ehrenberg) Pl. 30, figs. 17-19; Pl. 31, fig. 1 Dictyocha navicula Ehrenberg, 1839, K. Preuss. Akad. Wiss. Berlin, Abh., Jahrg. 1838, p. 129. Dictyocha ponticulus Ehrenberg, 1844c, Verh. K. Preuss. Akad. Wiss. Ber- lin; Ber., p. 267- Dictyocha ponticulus Ehrenberg, Bailey, 1845, Amer. Jour. Sci. Arts., vol. 48, No. 2, p. 328, pl. 4, fig. 21. Dictyocha navicula Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 20, No. 1, fig. 43. Dictyocha navicula Ehrenberg, Haeckel, 1887, Rept. Voy. Challenger, Zool., vol. 18, p. 1559. Dictyocha navicula Ehrenberg, Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, pp. 257-258, pl. 10, figs. 12-13 (only). Dictyocha navicula Ehrenberg, Lemmermann, 1903, in Nordisches Plankton, Bot. No: 21, p: 27, fig. 90: Dictyocha navicula Ehrenberg, Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 243, fig. 16b (only). Dictyocha navicula Ehrenberg, Gemeinhardt, 1930, in Kryptogamen-Flora, vol. 10, pt. 2, pp. 35-36, fig. 22. Not Dictyocha navicula (Ehrenberg), Deflandre, 1932a, Soc. France, Mi- crosc., Bull., vol. 1, No. 1, fig. 13. Not Corbisema apiculata fa. naviculoidea Frenguelli, 1940, Rev. Mus., La Plata, n.s., vol. 2, Paleont., No. 7, fig. 12i. Not Corbisema apicuata var inermis Lemmermann, Deflandre, 1950a, Micro- scopie, vol. 2, fig. 88. Naviculopsis navicula (Ehrenberg), Deflandre, 1950a, Microscopie, vol. 2, p. 77, figs. 241-243. Naviculopsis navicula (Ehrenberg), Stradner, 1961, Erdé] u. Kohle, vol. 14, No. 2, p. 89, fig. 47 (only). Dictyocha navicula var. naviculopsis (Deflandre), Tsumura, 1963, Yoko- hama Munic. Univ., Jour., ser. C-45, No. 146, p. 44, pl. 7, fig. 5. Not Dictyocha navicula Ehrenberg, Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, pp. 233-235, pl. 9, figs. 4, 5. Naviculopsis navicula (Ehrenberg), Bachmann, 1970a, Verh., Geol. B.-A., Jahrg. 1970, No. 2, fig. 2b (only). Remarks. — The specimens recovered from Northern Italy agree in general with the first figure for the present species illustrated by Ehrenberg from Zante, Greece, except that they are slightly smaller in size. In the illustration of Deflandre (1950a), the flattened struc- ture at the apices of the major axis and the rudimentary spines SILICOFLAGELLATES AND EBRIDIANS: LING 187 are seen for the first time. As shown here the degree of development of such a structure differs among the specimens but can be found only after careful examination (see Pl. 30, fig. 19). Therefore, it is the author’s opinion that such a structure perhaps escaped notice by previous workers particularly prior to 1950. The above synonymy is prepared with this in mind. In addition to listing the fossil locations, Haeckel reported (1887, p. 1559) the present species “living in the Atlantic, Stations 352, 354 and off Bermuda, surface”; and later workers such as Lemmermann and Gemeinhardt, apparently followed these records. Judging from geological occurrence of the present species (see be- low), it seems likely that the above record of living forms for the present species has been either reworked from nearby land deposits or may be outcrops of Tertiary deposits at the ocean bottom. Glezer referred Russian specimens all to Eocene, but her illus- trations clearly show they are different from the present taxon by possessing the basal accessory spines, as well as a much wider basal body ring along the minor axis. Dimensions. — Length of basal body ring, 18-24 up. Known geologic range. — Miocene. Occurrence. — The specimen referable to the present N. navi- cula is found, in the present study, only from the Italian samples and only from WRE 67-77 and -76 samples of the Calocycletta costata Zone. Apparently this species has a limited biogeographic as well as stratigraphic range, Naviculopsis quadrata (Ehrenberg) Pest. figs 2 Dictyocha quadrata Ehrenberg, 1844c, Verh. K. Preuss. Akad. Wiss. Berlin, _ Ber., Jahrg., 1844, pp. 258, 267. Dictyocha quadrata Ehrenberg, Bailey, 1845, Amer. Jour. Sci. Arts, vol. 48, _ No. 2, p. 328, pl. 4, fig. 22. Dictyocha quadrata Ehrenberg, Haeckel, 1887, Rept. Voy. Challenger, Zool., _ vol.18; (p. 1559. Dictyocha quadrata Ehrenberg, Lemmermann, 1901b, Deutsch. Bot. Ges., Ber., vol. 19, p. 259. Dictyocha quadrata Ehrenberg, Lemmermann, 1903, in Nordisches Plankton, ‘ Bot., No. 1, p. 27. Dictyocha navicula var. rectangulare Schulz, 1928 (part), Bot. Archiv., vol. _ 21, No. 2, pp. 243-244, fig. 17a (only). Dictyocha navicula var. rectangulare Schulz, Gemeinhardt, 1930 (part), in Kryptogamen-Flora, vol. 10, pt. 2, p. 36 (not fig. 23). Naviculopsis rectangularis (Schulz), Frenguelli, 1940, Rev. Mus., La Plata, _ ns., vol. 2, Paeont. No. 7, p. 60, fig. 11), k. Dictyocha biapiculata (Lemmermann) var. iberica Deflandre, Colom, 1940, Las Ciencias, vol. 5, No. 2, p. 351, fig. 9 (fide Deflandre, 1950a). 188 BuLLeETIN 273 Naviculopsis iberica Deflandre, 1950a, Microscopie, vol. 2, pp. 74/82-76/82, figs. 231-234. Naviculopsis rectangularis (Schulz), Stradner, 1961, Erdél u. Kohle, vol. 14, No. 2, p. 89, pl. 2, fig. 48. Dictyocha navicula var. rectangularis Schulz, Tsumura, 1963, Yokohama Munic, Univ., Jour., ser. C-45, No. 146, pp. 45-46, pl. 7, figs. 8-10; pl. 2s figs =3r Naviculopsis rectangularis (Schulz), Bachmann, 1970a, Verh, Geol. B.-A., Jahrg. 1970, No. 2, p. 284, abb. 3, figs. a-f. Naviculopsis rectangularis (Schulz), Bachmann, 1970b, im Cat. Fossil. Aus- triae, No. 1b, p. 17. Remarks.— The present species is described by Ehrenberg (1844c) from “Bermuda-Inseln” and is illustrated by Bailey (1845) from “Bermuda.” These locations are now regarded as actually from Nottingham, Maryland, and the age as Helvetian stage ac- cording to Loeblich, III (et al., 1968, pp. 16-17). These, however, have escaped the attention of previous investigators. Thus Schulz in 1928 when he proposed his Dictyocha navicula var. rectangulare from the same locality, failed to mention Ehrenberg’s description or Bailey’s illustration, and Schulz’s name has been adopted by various students since that time. It should be mentioned here that Schulz included two morphologically different forms under his name. The form considered here is only that with a rectangular- shaped basal body ring (fig. 17a only). It is possible that NV. tberica described by Deflandre (1950a) from Spain and Majorca is a somewhat irregular shape of the present species but still within the range of intraspecific variation and, therefore, is considered as synonymous. Another specimen illustrated by Schulz at the same time (fig. 17b) has a elongated oval basal body ring which was erroneously referred to recently as N. iberica by Bachmann (1970a, Abb. 1, fig. Gh dink.) Dimensions. — Length of basal body ring, 36-52 ,»; width, 24-30 p; radial spine, 6-8 yp. Known geologic range. — Miocene. Occurrence. —Only from Mediterranean Italian outcrop samples, WRE 67-78 to -76, the Calocycletta costata radiolarian Zone (Sanfilippo, 1971) are the present species recovered. Naviculopsis regularis (Carnevale) Pl..31, figs; 35 Dictyocha regularis Carnevale, 1908, R. Inst. Veneto, Sci. Lett. Arti, Mem., vol. 28, No. 3, p. 35, pl. 4, fig. 28. SILICOFLAGELLATES AND EBRIDIANS: LING 189 Dictyocha ausonia var. regularis Carnevale, Deflandre, 1950a, Microscopie, vol. 2, pp. 68/82-69/82, fig. 198 (only). Remarks. — This lenticular-shaped species possesses relatively longer radial spines, and the size seems to agree with the middle Miocene form originally described by Carnevale from Bergonzano, Reggio Emilia, Italy. Deflandre considered the present species as within the range of variation for his Dictyocha ausonia, but as discussed earlier, it is hard to conceive that two radial spines on the major axis can become longer, while the other two on the minor axis diminish (compare PI. 31, figs. 3-5 with Pl. 25, figs. 1-8). The present species also resembles the preceding species, NV. lata, by showing some constriction at the middle of the basal body ring, but is generally smaller in size, and has a slender basal body ring and no small lateral windows as found in the JN. Jata. Dimensions. — Length of basal body ring, 33-38 uw; width, 19-24 yw; radial spines, 14-22 yp. Known geologic range. — Miocene. Occurrence. — N. regularis is found from the Italian samples whose age has been identified as Calocycletta virginis and C. cos- tata Zones (Sanfilippo, 1971). Naviculopsis sp. Pls fig 6 Naviculopsis navicula Stradner, 1961 (not Ehrenberg), Erdél u. Kohle, vol. 14, No. 2, p. 89, fig. 46 (only). Naviculopsis navicula Bachmann and Papp, 1968 (not Ehrenberg), Giorn. _ di Geol., ser. 2, vol..35, fasc. 2, pl. 3, fig. 5S. Naviculopsis navicula Bachmann, 1970a (not Ehrenberg), Verh. Geol. B.-A., Jahrg. 1970, No. 2, abb. 2, figs. a, c-f (not b). Remarks. — Although the present species is similar structurally to NV. navicula, because it possesses the “Endflaichen” (Stradner, 1961), it differs in that the apices on the major axis are sharply truncated, and it has two short spines at both corners of the plate. The specimen illustrated here is from Ernstbrunn, Austria, the pos- sible type locality of Stradner’s specimen for comparison. Dimensions. —No complete specimen was observed. Known geologic range. — Miocene (early). Occurrence. — The specimen assignable to the present taxon is found only from Ernstbrunn, Austria, and has not been found in the deep-sea sediments, 190 BULLETIN 273 Naviculopsis trispinosa (Schulz) Pl. 31, figs. 7, 8 Dictyocha navicula var. trispinosa Schulz, 1928, Bot. Archiv., vol. 21, No. 2, pp. 246-247, fig. 23a, b. Dictyocha navicula var. trispinosa Schulz, Gemeinhardt, 1930, im Krypto- gamen-Flora, vol. 10, pt. 2, p. 40, fig. 27. Dictyocha navicula var. trispinosa Schulz, Deflandre, 1932a, Soc. France, Microsc., Bull., vol. 1, No. 1, fig. 24. Naviculopsis biapiculata fa. trispinosa Schulz, Frenguelli, 1940, Rev. Mus., La Plata, nis:, vol. 2, Paleont., No. 7, fig: lle. Dictyocha navicula var. trispinosa Schulz, Tsumura, 1963, Yokohama Mu- nic. Univ., Jour., ser. C-45, No. 146, p. 46, pl. 8, figs. 4-6. Naviculopsis trispinosa (Schulz), Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, pp. 258-259, pl. 17, fig. 7. Remarks. — Apparently the present species occurs rarely, and during the present study, no specimen was found. The specimen here illustrated is for reference purpose and particularly to present the lateral view. Dimensions. — Length of basal body ring, 24 yu; of radial spines, 25 pe Known geologic range. — Eocene. Occurrence. — No specimen belonging to N. trispinosa has been found in the present study. The representative specimen presented here is from a reference sample, $136/966, Bain’s Farm section, Oamaru Diatomite, New Zealand. Genus PARADICTYOCHA Frenguelli, 1940 Paradictyocha polyactis (Ehrenberg) Pl. 31, figs. 9-11 Dictyocha polyactis Ehrenberg, 1839, K. Akad. Wiss. Berlin, Abh., Jahrg. 1838, p. 129. Dictyocha polyactis Ehrenberg, Ehrenberg, 1844a, Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, p. 80. Dictyocha polyactis Ehrenberg, Ehrenberg, 1854, Mikrogeologie, pl. 22, fig. 50. Distephanus speculum var. octonaria fa. polyactis (Ehrenberg), Jorgensen, 1899, Bergens Mus. Aarbog 1899, No. 6, pt. 2, p. 50. Distephanus speculum var. polyactis (Ehrenberg), Lemmermann, 1901b (part), Deutsch. Bot. Ges., Ber., vol. 19, pp. 265-266, pl. 11, fig. 17. Distephanus speculum var. polyactis (Ehrenberg), Lemmermann, 1903, in Nordisches Plankton, Bot., pt. 21, p. 31, fig. 106. Not Distephanus speculum var. polyactis (Ehrenberg), Gemeinhardt, 1931b, Deutsche Stidpolar-Exped., vol. 20 (Zool. vol. 12), p. 241, pl. 42, fig. 7. Distephanus polyactis Deflandre, 1932c, Soc. Bot. France, Bull., vol. 79, Nos. 5-6, pp. 501-502, fig. 40 (only). Distephanus speculum var. polyactis fa. decagona Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 71, pl. n, fig. 47. Distephanus speculum var. polyactis fa. dodecagona Zanon, 1934, Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, p. 71, pl. n, fig. 48. Paradictyocha polyactis (Ehrenberg), Frenguelli, 1940, Rev. Mus., La Plata, n:s., vol. 2) Paleont, No: 7, p: 52) fig: 7£ 2 1(?) sp. 54. fis) Sa (only)e SILICOFLAGELLATES AND EBRIDIANS: LING 191 Paradictyocha polyactis fa. polyactis Glezer, 1966, in Cryptogamic plants of the U.S.S.R., vol. 7, p. 277, pl. 24, figs. 7-11. , Paradictyocha polyactis (Ehrenberg), Mandra, 1968 (part), California Acad; Sct., Proc.,, ser. 4, vol. 36, No. 9, p. 264. Remarks. — The examination of related forms such as Meso- cena circulus var. apiculata from various localities convinced the author that: (a) the present species actually occurs only rarely; (b) so far no intermediate forms have been found during the present study demonstrating the morphologic variation of the gradual disappearance of the apical structure as indicated by Fren- guelli (1940) or the gradual enlargement of the apical ring to fuse with the basal body ring indicated by Deflandre (1950a); and (c) the diameter of the specimen is relatively larger than those of re- lated forms frequently referred to as Distephanus speculum. As shown previously (Lemmermann, 1901b; Ling, 1971), in lateral view, Mesocena circulus var. apiculata has two series of di- vergent radial spines on the exterior side of the basal body ring. Thus, should the disappearance of the apical ring as claimed by Frenguelli or fusion of the apical ring according to Deflandre ac- tually be the case, at least one series of the radial spines should point either inwardly or perpendicular to the basal body ring on apical view, and so far this is definitely not the case, Thus perhaps it is advisable to limit the present species to the form that is close to Ehrenberg’s original figure or only to the complete specimen of Frenguelli (1940, fig. 8a). It is possible that Mandra found the present species during his California study, but his figures are not like the present species and, therefore, they are excluded. Lemmermann (1901b, 1903) illustrated a form, but without mentioning whether it is a fossil or modern form. Jorgensen (1899) recorded the present species from plankton samples of the west coast of Norway but without illustration. Gemeinhardt (1931b) referred to a single specimen from the Atlantic Ocean (0°18’N, 16°1YW), but as the basal diameter is approximately only 25 un, (less than one-half that of the specimen found during the present study — about 60 » here), and as Gemeinhardt himself illustrated in the same paper that there are wide variations in the number of spines of Distephanus speculum in the Atlantic, it is concluded that Gemeinhardt’s specimen is related closely to Distephanus specu- lum; therefore it is excluded from the present species. 192 BuLLETIN 273 Dimensions. — Diameter of basal body ring, 60-66 yp; of radial spine, 4-8 pz. Known geologic range.— Miocene. Glezer (1966, p. 277) described the Russian occurrence as Neogene. Occurrence. — P. polyactis thus recognized is found, during the present study, only in one sample, EM 8-15, 36-37 cm, which is Luisian, according to Parker (1964), Bandy and Ingle (1970) or Helvetian according to Martini and Bramlette (1963). Genus ROCELLA Hanna, 1930 Remarks. — The present genus was proposed by Hanna (1930) with Rocella gemma as the type by monotypy, and until recently, this unusual siliceous microfossil has not been recovered. The exact nature or affinity of these remains is still uncertain. Hanna (1930) indicated that he was in favor of placing them within or closely related to silicoflagellates over the wheel-like plate of holothuridae, radiolarians, sponges, and diatoms, or the possi- bility of calcite replaced by amorphous silica. Recently Lipps (1970, p. 981) suggested that they were small valves of a diatom from which the silica had been dissolved from the “pores.” The present author has studied deep-sea sediments from various parts of the world including the equatorial Pacific, but until now diatoms indicating such a possibility have never been encountered. Therefore, despite the nature of the genus still remaining un- known, there is a good possibility of its being considered a bio- stratigraphic index for deep-sea sediments, and thus it is included in the present study. Rocella gemma Hanna Pl. 31, figs. 12-15 Rocella gemma Hanna, 1930, Jour. Paleont., vol. 4, No. 4, pp. 415-416, pl. 40, figs. 8-18. Remarks. — The specimens found during the present study agree with the original description and illustration given by Hanna from the San Gregorio Formation (possible Helvetian) near Purris- sima, California, which Loeblich, III (et al., 1968) regarded as Baja California, Mexico. The present species was recovered from Core 17 of the DSDP Hole 34 at Lat, 39°28.21’N.; Long. 127°16.54’W., and its age 1s con- SILICOFLAGELLATES AND EBRIDIANS: LING 193 sidered as “Coccolithus bisectus — Triquetrorhabdulus carinatus Subzone;” but whether the sample is autochthonous is questioned (McManus, et al., 1970, pp. 114-115). Core 16 sample from the same hole, which is regarded as the same age as that of Core 17, was identified by Bukry and Bramlette (1970, p. 490) as upper Oligo- cene to lower Miocene from its nannofossil assemblage. Dimensions. — Diameter, 50-70 p. Known geologic range. — Miocene. Occurrence. — The present species is found abundantly in sam- ples of MSN 149P, 294-296 cm, and rarely in JYN V 16P, 231-233 cm, and these samples are considered here as the base of the Mio- cene agreeing with the above observation. Therefore, it is considered that the above DSDP specimens are likely not reworked. Genus SEPTAMESOCENA Bachmann, 1970b Septamesocena apiculata (Deflandre) Pl. 29, figs. 11-15 Not Mesocena oamaruensis var. apiculata Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 240, fig. 11. Mesocena polymorpha var. triangula Lemmermann, Gemeinhardt, 1930 (part), iz Kryptogamen-Flora, vol. 10, pt. 2, p. 28. Mesocena polymorpha var. triangula fa. glabra Gemeinhardt, 1930 (not Schulz), in Kryptogamen-Flora, vol. 10, pt. 2, p. 28, fig. 12b (only). Not Mesocena apiculata (Schulz), Hanna, 1931, Mining in California, vol. Zi Nowe2 sp 198; ple Dy tics 3 ink Mesocena apiculata (Schulz), Deflandre, 1932c, Soc. Bot. France, Bull., vol. 79, Nos. 5-6, p. 499, figs. 34 (?), 35. Mesocena apiculata (Schulz), Tynan, 1957, Micropaleont., vol. 3, No. 2, p. 134, pl. 1, fig. 10. Mesocena apiculata (Schulz), Stradner, 1961, Erdél u. Kohle, vol. 14, No. 7 vs OSE eeh AE AS ey Mesocena apiculata (Schulz), Bachmann, 1962, Verh. Geol. B.-A., Jahrg. 1962, No. 2, p. 379, figs. 10, 11. Mesocena apiculat (Schulz), Bachmann, 1963, in Bachmann, ef al., Geol., Ges. Wien, Mitt., vol. 56, No. 1, p. 152, pl. 19, figs. 60-62. Mesocena oamaruensis Schulz, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 42, pl. 7, fig. 2; pl. 21, fig. 12. Mesocena apiculata (Schulz), Bachmann, in Ichikawa, ef al., 1964, Kan- azawa Univ., Sci. Rept., vol. 9, No. 1, p. 107, pl. 4, fig. 36. Mesocena oamaruensis Schulz, Bachmann, in Ichikawa, ef al., 1964, Kan- azawa Univ., Sci. Rept., vol. 9, No. 1, pp. 107-108, pl. 4, fig. 37. Mesocena aff. apiculata (Schulz), Glezer, 1966, in Cryptogamic plants of the U.S:SIR-: vols 7;ips282, pl28, fig. 54(2))3 pl> 29, fig. 9: Mesocena apiculata (Schulz), Bachmann and Papp, 1968, Giorn. di Geol., ser: 2, vol. -35, ‘pl. 3, figs: 1, 2: Mesocena apiculata (Schulz), Hajos, 1968, Geol. Hungarica, ser. Paleont., fase: 3/7, sp. (67,1 pla 4a tis. 3? Mesocena apiculata (Schulz), Bachmann, 1970a, Verh. Geol. B.-A., Jahrg. 1970, No. 2, pp. 280, 282, 284, pl. 5, figs. 10-16; pl. 6, figs. 1-5. Septamesocena apiculata (Schulz), Bachmann, 1970b, in Cat. Fossil. Aus- triae, No. 1b, pp. 13-14. 194 BULLETIN 273 Remarks. —In 1928, Schulz, recognized a silicoflagellate form with a smooth basal body ring but without septa from Hungarian sediments and established a M. polymorpha var. triangula fa. glabra. Gemeinhardt (1930) found the Schulz’s forma unnecessary, but in his figure 12 b, he illustrated the presence of septa. The above syn- onymy is prepared after close examination of the figures illustrated by previous students of silicoflagellates. The new genus, Septameso- cena, was proposed by Bachmann for the Mesocena with a septal structure, Stradner (1961) referred the present species to the form described originally by Schulz as Mesocena oamaruensts var. apicu- lata from Oamaru, New Zealand, and such practice was followed by Deflandre, Hanna, and others and until as recently as the early part of 1970 by Bachmann, The samples from the Oamaru Diatomite are currently under detailed examination; however, as already shown here (PI. 28, figs. 2-4) for comparison, so far specimens from Oamaru which correspond with Schulz’s original figure, have no septa. Glezer recorded specimens ranging from early Paleocene to late Eocene in Russia. The early Paleocene specimen from the eastern slope of the Urals has no septal structure (pl. 28, fig. 5); the late Eocene form (pl. 29, fig. 9) from the Ural-Caspian area possess discontinuous lumen and can be interpreted as being due to septal structure, but it has a dentate basal body ring. Dimensions. — Length of basal body ring, 42-58 p; of radial spines, 2-3 p. Known geologic range. — Eocene (late) to Miocene. Occurrence. — The present species is found only in DSDP 13-3-1, 120-121 cm and Italian outcrop samples. Examination of more Tertiary California samples is required before worldwide distribution of the present species can be discussed in more detail. Genus VALLACERTA Hanna, 1928 Vallacerta hortoni Hanna Pl..32) figssslees Vallacerta hortoni Hanna, 1928, Jour. Paleont., vol. 1, No. 4, pp. 262-263, pl. 41, figs. 7-11. Dictyocha siderea Schulz, 1928, Bot. Archiv., vol. 21, No. 2, p. 284, fig. Sillaeb: Dictyocha siderea Schulz, Gemeinhardt, 1930, in Krytogamen-Flora, vol. 10, pt2, pe 56, fey 47. Vallacerta hortoni Hanna, Deflandre, 1940a, Acad. Sci. Paris, C. R., vol. 211, No. 19, p. 446, figs. 1, 5. SILICOFLAGELLATES AND EBRIDIANS: LING 195 Vallacerta hortoni Hanna, Deflandre, 1940c, Acad. Sci. Paris, C. R., vol. Diie Now 235 ps 5985) tgs Le Vallacerta hortoni Hanna, Deflandre, 1950a, Microscopie, vol. 2, pp. 57/82- 58/82, figs. 144-149. Dictyocha siderea Schulz, Tsumura, 1959, Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., vol. 1, p. 66, pl. 4, fig. 52 (fide Tsumura, 1963). Dictyocha siderea Schulz, Tsumura, 1963, Yokohama Munic. Univ., Jour., ser. C-45, No. 146, p. 59, pl. 11, fig. 12. Vallacerta hortoni Hanna, Glezer, 1966, in Crytogamic plants of the U.S.S.R., voll 70p.\ 219, pli, fighacs plisiy fig. si: Vallacerta hortoni Hanna, Mandra, 1968, California Acad. Sci., Proc., ser. 4, vol. 36, No. 9;-p.'267, tgs. 11, 12; 19: Remarks. — A literature survey reveals that Hanna’s article was published in January, while Schulz’s article was dated in June of the same year; Hanna’s name, therefore, has priority, Although Schulz (1928) also proposed a quadrangular form as Dictyocha siderea var. quadrata from Prussia, no such variety is found in the topotypic sample, CAS 1144, from California. Dimensions. — Diameter of pentagonal plate, 35-45 yw; length of spines, 5-8 yp. Known geologic range.—Cretaceous (late) to Paleocene (early). The Paleocene occurrence is reported from Russia by Glezer (1966). Occurrence. — The present species is recovered only from the topotypic material from California. Mandra (1968, p. 242) indicated that the present species (together with Lyramula furcala) is found only from Upper Cretaceous. Ebridians Terminology. — Morphologic terms used herein are those com- monly employed and summarized by Deflandre (1951) and are shown in Text-figure 6. Order STEREOTESTALES Lemmermann, 1901a Genus AMMODOCHIUM Hovasse, 1932 Ammodochium rectangulare (Schulz) Pl. 32, figs. 3-5 Remarks. — For the synonymy, refer to Ling (1971). Known geologic range. — Paleocene to Miocene. Dimensions. — Length, 18-24 up. Occurrence. — From the samples studied, this species is found from WR TR 11, Low (Bo. 202), Dorcadosypris alata radiolarian 196 BULLETIN 273 Zone (Riedel and Sanfilippo, 1970) to EM 6-2, 10-11 cm, late Mio- cene. Genus EBRIOPSIS Hovasse, 1932a Ebriopsis antiqua (Schulz) Pl. 32, figs. 6-12 Remarks. — For the synonymy of the present species, also refer to Ling (1971). Since the present species was first reported by Schulz, wide range of variation has been recognized by earlier in- vestigators: surface ornamentation of skeletal elements is smooth or crenulate; with or without anterior and posterior axial spines, “corne axiale anterieure” and “corne axiale posterieure” of Deflandre (1951) (see Text-figure 6B). A B Text-figure 6.— Terminology of ebridian skeleton. A. Ammodochium rectangulare, B. Ebriopsis antigua; a = actine, ca = anterior axial spine, cp = posterior axial spine, o — opisthoclade, p = proclade, r = rhabde, sa = anterior synclade, sp = posterior synclade, t = triaene, T = triode (Modified after Deflandre, 1951). Deflandre (1950b) noticed that in Paleocene Ebriopsis valida, both the rhabde and one of the opisthoclades are on the same plane of symmetry, but in Eocene form, E. mesnilt (=E. crenuata in this paper, see below), there is an angle between the two skeletal elements, beginning from 12° to between 35° to 50° in the late Eocene (not Oligocene) Oamaru samples from New Zealand. At the time of Miocene form, FE. antiqua, the opisthoclade 02 is ap- proximately on the same plane with one of the actines, Deflandre, SILICOFLAGELLATES AND EBRIDIANS: LING 197 therefore, proposed the phylogenic lineage of E. valida - E. mes- nit - E. antiqua. Although no samples nor specimens from Paleocene sediments are available for the present study to confirm Deflandre’s observa- tion, lineage between FE. crenulata - E. antiqua seems agreeable. In addition to his observation, the following are obvious from the present investigation: 1. Surface ornamentation is strongly coarse and crenulate in the middle Eocene specimens of FE. crenulata, and also the skeletal elements are generally broader than those from the higher horizon. 2. A gradual size increase is noticed from specimens of middle Eocene to Miocene form. 3. Although forms without anterior and posterior axial spines are found from middle Eocene samples, the specimens with these spines occur mostly throughout Miocene and also possibly late Eocene, but the specimens with such well-developed spines are rather commonly found in Miocene samples and are also reported from various parts of the world. Dimensions. — Diameter, 28-40 p. Known geologic range. — Paleocene to Miocene. Occurrence. — The earliest occurrence of this species in the present study is from DSDP 6-6-2, 1-2 cm, and the latest is found in EM 6-2, 10-11 cm which is considered upper Miocene by Mar- tint and Bramlette (1963) or Delmontian by Bandy and Ingle (1970). Ebriopsis crenulata Hovasse Pl. 32, figs. 13-18 Podamphora mesnili Deflandre, 1932b, Acad. Sci. Paris, C. R., vol. 194, No. 24, p. 2172, figs. 6, 7. nom. nud. Ebriopsis crenulata Hovasse, 1932b, Soc. Zool. France, Bull., vol. 57, No. 4, p. 281, fig. 4 I, Il. Podamphora mesnili Deflandre, Deflandre, 1933, Soc. Zool. France, Bull., ViOls 517, NOmGsIpp A 516s O19 e522, tiess 11266 113) Ebriopsis mesnili (Deflandre), Deflandre, 1950b, Acad. Sci. Paris, C. R., vol. 230, No. 19, p. 1684, figs. 3-7. Ebriopsis mesnili (Deflandre), Deflandre, 1951, Biol. France, Belgique., Bull., vol. 85, fasc. 1, p. 64, figs. 23-29, 50-54. Ebriopsis mesnili (Deflandre), Hajos, 1968, Geol. Hungarica, ser. Paleont., fascsa7, pawl eples 60 tigw £2: Remarks. — As clearly discussed by Loeblich, III (et al., 1968, p. 51), the name Podamphora mesnili appeared in 1932b, but was a nomen nudum and only validated by a later article dated Decem- 198 BULLETIN 273 ber 13 of the same year, but actual date of publication for the particular issue was February 15, 1933. However, Hovasse in the meantime published Ebriopsis crenulata on June 14, 1932, and, therefore, has priority over Deflandre’s name. The specimen of this species is characterized by a smaller size than the preceding species, coarsely crenulated surface ornamenta- tion and broader skeletal parts. No anterior or posterior axial spines are found. Dimensions. — Diameter, 24-32 » Known geologic range. — Eocene. Occurrence. —Hovasse described the present species from Oamaru, New Zealand, and one specimen with a lorica. A specimen from Jackson’s Paddock section, $136/914, of the Oamaru Dia- tomite, New Zealand, is here illustrated as a reference (PI. 32, figs. 13, 14). Genus PARATHRANIUM Hovasse, 1932c Remarks.— The present genus was proposed by Hovasse (1932c, p. 465) with P. tenuipes as the type species. Loeblich, III (1965, p. 189) discussed Dicladia (Ehrenberg, 1844a, p, 73), and designated D. ? clathrata (Ehrenberg, 1944a, pp. 70, 79; 1854, pl. 18, fig. 100) as the type, and by so doing indicated that Dicladia has priority over Parathranium. This is later followed by Loeblich, III (et al., 1968, pp. 32, 62). Recently, Deflandre (1971) rejected these opinions. It should be pointed out here, however, that Ehrenberg’s speci- men from Richmond, Virginia, illustrated by him shows only two opisthoclades instead of three, and furthermore the exact nature for the portion of the proclades is not clear. Further study, particu- larly from the sample in the vicinity of Richmond, Virginia, is neces- Sary in order to recognize the characters of Dicladia ? clathrata; thus at the present time Parathranium Hovasse is used. Parathranium tenuipes (Hovasse) Pli32, figs 219-25 Thranium tenuipes Hovasse, 1932a, Soc. Zool. France, Bull., vol. 57, No. 2, p. 123, fig. 5. Thranium tenuipes Hovasse, Deflandre, 1932d, Soc. Zool. France, Bull., vol. 57, No. 4, pp. 309-311, figs. 31-33. Parathranium tenuipes (Hovasse), Hovasse, 1932c, Soc. Zool. France, Bull., vol. 57, No. 2, pp. 465-466. SILICOFLAGELLATES AND EBRIDIANS: LING 199 Parathranium clathratum Deflandre, 1951 (not Ehrenberg), Biol. France, Belgique., Bull., vol. 85, fasc. 1, p. 77, figs. 5, 172. Parathranium clathratum Deflandre (not Ehrenberg), Hajos, 1968, Geol. Hungarica, ser. Paleont., fasc. 37, p. 72, pl. 6, figs. 16, 17. Remarks. — The Californian specimens agree well with the previous records. Dimensions. — Length of opisthoclade, 18-22 uy. Known geologic range. — Miocene. Occurrence. — The present species was recovered only from Mohole samples during the present study and ranges from EM 7-1, 14-15 cm, N.12 planktonic foraminiferal Zone (Riedel and San- filippo, 1970) to EM 8-9, 148-149 cm; thus it encompasses most of the Luisian and all the Mohnian stages by Parker (1964), Bandy and Ingle (1970), and Kanaya (1971). DISCUSSION (a) General Having examined in detail the numerous silicoflagellates and ebridian taxa, it is now possible to investigate from the samples studied, their occurrences since Maestrichtian time. The stratigraphic occurrences of the taxa are shown in Text- figures 2, 3, and 4 with the inclusion of the 28 experimental Mohole samples. The sample coverage throughout the Neogene section is considered adequate, strongly contrasting to the Paleogene interval, where available samples examined during the present study were clustered in a few stratigraphic age intervals and hence are admit- tedly inadequate for establishing a definite zonation. However, the following general statement can be made in ascending order: Lyramula furcula - Vallacerta hortont assemblage: At least a part of the Maestrichtian or uppermost Cretaceous section repre- sented by sample CAS 1144 is characterized by these unique silico- flagellates. DSDP samples 4-4-1, 13A-2-1, 13A-4-1 and 13A-5-1 are of Cretaceous age (Ewing, et al., 1969; Maxwell, et al., 1970) but were unfortunately barren of these siliceous microfossils. Neither the lower nor upper limit of this assemblage, therefore, can be de- termined from the present study. Naviculopsis foliacea assemblage: The middle Eocene interval, particularly its lower part, is characterized by the presence of various forms of Navicwopsis and Corbisema species, Occurrence of 200 BULLETIN 273 Ebriopsis crenulata is also limited in this assemblage in the present study. Although the upper and lower limit of these taxa found in this interval cannot be decided at this time, preliminary examina- tion of Oamaru Diatomite (Runangan Stage, NP.17 - NP.18 of calcareous nannoplankton Zones) and Kellogg Shale and Sidney Shale samples indicate that they would extend their occurrences to the upper Eocene and, therefore, sample WR TR 39F (1068), which is considered slightly below the Oligo-Eocene boundary, may indi- cate the highest occurrence for these forms. There is a good possi- bility that the interval could be subdivided in the future. Rocella horizon: Occurrence of Rocella gemma at the base of the Miocene, in this paper, or possibly the top of the Oligocene, according to others, may be a good time marker. As discussed earlier, it was only last year that R. gemma was found for the second time since the species was proposed, and for the first time it was found from deep-sea sediments, Core 17 of the Deep Sea Drilling Project Hole 34 near California. The sample was interpreted as upper Oligocene to lower Miocene. However, whether the sample was of autochthonous origin was questioned at that time. The present finding from samples JYN V, 16 P, 231-233 cm, and MSN 149 P, 294-296 cm, agrees with the above strati- graphic occurrence, and, therefore, this species may be a reliable time indicator. From this horizon to the next assemblage, several known but long-range silicoflagellates make their first appearance, such as Distephanus crux, D. speculum, and Dictyocha ausonia, but further investigation is needed to establish the assemblage. Dictyocha fibula var. octagona assemblage: The interval is de- fined by the range of D. f. var. octagona. The initial appearance of so-called Mesocena elliptica, Cannopilus hemisphaericus, and Am- modochium rectangulare is slightly below the base of assemblage, while the top of assemblage is marked by the latest occurrence of Distephanus crux var. octacanthus. Within this interval Dictyocha sp., Ebriopsis antiqua (with spine form), and Mesocena circulus var. apiculata appear. From the upper part of this assemblage to the uppermost Mio- cene, numerous experimental Mohole samples were studied as shown in Text-figure 4. Dictyocha fibula and Parathranium tenuipes show SILICOFLAGELLATES AND EBRIDIANS: LING 201 initial appearance at the top of this assemblage. As indicated earlier, judging from the relationship with other microfossils, particularly with the radiolarians, this is the interval that Martini (1971a, b) recognized as his Dictyocha octacantha (Distephanus crux var. octacanthus in this paper) horizon from Deep Sea Drilling Project Leg VII of the western equatorial Pacific. Cannopilus sphaericus assemblage: The top of the underlying Dictyocha fibula var. octagona assemblage to the latest occurrence of Cannopilus sphaericus defines the assemblage. The base of the assemblage is also marked by the earliest occurrence of Distephanus crux var. longispina, so-called “Mesocena diodon’”, and also coincides with the initial occurrence of the radiolarian species, Cannartus (2) petterssoni, according to Sanfilippo and Riedel (1970). The top of the assemblage is also the highest occurrence of Corbisema triacantha, C. t. var. minor; therefore, it is conceivable that the upper limit of Corbisema triacantha Zone of Martini is here. Oc- currence of Paradictyocha polyactis also falls within this assemblage. The boundary between this and overlying assemblages seems to agree well with the Helvetian? — Tortonian? boundary of Mar- tini and Bramlette (1963), and the Luisian — Mohnian boundary of Parker (1964) and Bandy and Ingle (1970). Distephanus crux var, longispina assemblage: The interval from above the underlying Cannopilus sphaericus assemblage to the last appearance of Distephanus crux var. longispina is considered as the present assemblage. The top thus defined coincides also with the latest occurrence of Cannopilus hemisphaericus and likely also with that of Mesocena circulus. The limited appearance of Distephanus speculum var. pentagonus, and the highest stratigraphic occurrence of “Mesocena elliptica” in Mohole samples are also found within this assemblage. The top of this assemblage coincides with the top of middle Miocene of Martini and Bramlette (1963) and is ap- proximately in agreement with the top of the Mohnian stage of Parker (1964) and the lower and upper Mohnian boundary of Bandy and Ingle (1970). Distephanus speculum var. pseudofibula assemblage: The as- semblage is defined by the range of Distephanus speculum var. pseudofibula in the Mohole section which also coincides with the interval from the top of the underlying previous assemblage to the 202 BuLLeTIn 273 highest occurrence of the silicoflagellates and ebridians in the ex- perimental Mohole samples. Within this interval, limited occur- rence of Distephanus speculum var. pseudocrux, last occurrence of Dictyocha ausonia, Ammodochium rectangulare, “Mesocena diodon”, and Parathranium tenuipes are observed, and they may mark the Mohnian-Delmontian boundary according to the study made by Bandy and Ingle (1970), and Kanaya (1971). The highest sample bearing silicoflagellates and ebridians from Mohole, EM 6-2, 10-11 cm, is recognized as Delmontian by Bandy and Ingle (op. cit.), and Kanaya (op. cit.) and is apparently in agreement with late Miocene age of Martini and Bramlette (1963). It is likely that the present assemblage is correlative with the Dictyocha pseudofibula horizon of Martini (197la, b) from the western equatorial Pacific. Above this assemblage, throughout the Pliocene to part of the Pleistocene interval, silicoflagellates are found sporadically during the present study, and no distinct assemblage can be recognized until the next and the last assemblage, Dictyocha fibula var. aculeata assemblage: The beginning of modern forms, such as Dictyocha fibula var. aculeata, D. fibula var. messanensis provides the last and the latest assemblage recognized during the present study. Within this assemblage, one horizon can be recognized by the recurrence of Mesocena cf. elliptica, which brackets the Jaramillo Event of Matuyama Reversed Epoch, about 0.79 million years in the eastern equatorial Pacific (Hays, et al., 1969); a similar occurrence is recognized by Jousé (1969) and Muhina (1969). Ling (1970) also observed such an occurrence from the central north Pacific sediments and also added that the latest occurrence of Dictyocha subarctios and D. cf. ausonia is found at the same horizon. (b) Mediterranean (Italy) region The investigation thus far carried out on silicoflagellates and ebridians from deep-sea sediments of the Pacific and Atlantic oceans and some land outcrops demonstrates that there are much diversi- fied taxa showing limited geological occurrence since late Cretaceous time in the low-latitude area. Reports from the midlatitude of the western Pacific (Ling, 1971) and the central north Pacific bottom sediments (Ling, 1970) also agree with such findings. SILICOFLAGELLATES AND EBRIDIANS: LING 203 Previously, workers such as Ehrenberg, Zanon, and Deflandre recorded the occurrence of these siliceous microfossils from the Medi- terranean region, but stratigraphic information about these samples was often vague, and the exact range of the taxa cannot be deduced from the existing data. Samples from Italian localities were here examined in order to seek the stratigraphic occurrence of taxa in Italy, to compare the results with those from the present deep-sea sediments of low lati- tude, and at the same time to cross-correlate with the radiolarian zones from these samples recognized by Riedel and Sanfilippo (1971) and Sanfilippo (1971). The results of the present stratigraphic occurrence are sum- marized in Text-figure 7, and the following microfloral boundaries are noted in ascending order: 1. The earliest occurrence of Naviculopsis lata, together with that of Distephanus speculum and Corbisema triacantha, marks the boundary between samples WRE 67- (in the following discussion the prefix WRE 67- will not be repeated) 107 and 112, The boun- dary of radiolarian zones, Lychnocanium bipes below and Calo- cycletta virginis above, is drawn between 106 and 107 and thus is slightly below the present silicoflagellate boundary. 2. The first appearance of Mesocena cf. elliptica and Navt- culopsis quadrata occurs between samples 95 and 78. The boundary also marks the highest occurrence of Naviculopsis regularis and Corbisema triacantha and C. triacantha var. flexuosa. This boundary thus seems to agree with that of radiolarian zones, Calocycletta virginis below and C. costata above. Although minor microfloral changes are recognized between the interval of samples 112 and 95, and of 78 and 76, the Italian sam- ples thus can be grouped into three assemblages and thus boundaries are generally in agreement with the radiolarian results. Perhaps the most interesting and significant phenomenon found in the Italian samples in comparison with the low- and midlatitudes of Pacific and Atlantic deep-sea sediments is the abundance of Naviculopsis specimens throughout the Italian samples here exam- 204 BULLETIN 273 ined. Apparently some taxa are limited in their biogeographic distri- bution to the Mediterranean region and are within a part of the European continent only. However their value as a stratigraphic index is promising for the European Tertiary section. M. elliptica) SILICOFLAGELLATES FROM ITALY Mesocena cf elliptica ( Naviculopsis lata Dictyocha ausonia Noviculopsis quadrata Cannopilus picasso/ Distephanus crux | evicutopsis reguiaris =a 8 RADIOLARIAN 3 ZONES S (Sanfilippo, é 1971) Ez Septamesocena apiculatu WRE 67-76 EA Calocycletta “77 Li costara gall -78 i -95 i eal Calocycletra virginis VERY RARE RARE COMMON a bipes Text-figure 7.— Distribution of silicoflagellates from Neogene Mediter- ranean (Italy) region. For detail study of the samples, see Sanfilippo (1971). SILICOFLAGELLATES AND EBRIDIANS: LING 205 REFERENCES ann, A. 4 pie co Eine neue Mesocena-Art (Silicoflagellidae) aus dem Kalifornischen Eozan. Verh. Geol. [Bundesanstalt] B.-A. Wien, Jahrb. 1962, No. 2, pp. 378-383, pl. 1. 1963. Silicoflagellidae. In Bachmann, A. et al., Mikropaldontologische Studien im “Badener Tegel” von Frattingsdorf N. O. Geol. Ges., Wien, Mitt., 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. Kanazawa Univ., Sci. Rept., vol. 9, No. 1, pp. 87-118, pls. 1-7, figs. 1-20. 1967. Part II. Silicoflagellidae im lida Diatomit. In Ichikawa, W. et al., Fossil silicoflagellates and their associated uncertain forms in lida Diatomite, Noto Peninsula, Kanazawa Univ., Sci. Rept., vol. 12, No. 1, pp. 149-172, pls. 2-9. 1970a. Silicoflagellaten aus dem oberésterreichischen Egerien (Oberoli- gozan). Verh. Geol. B.-A., Jahrg. 1970, No. 2, pp. 275-305, pls. 1-7. 1970b. Flagellata (Silicoflagellata). In Catalogus Fossilium Austriae, Ed. by H. Zapfe, No. 1b, pp. 1-28. Bachmann, A., and Ichikawa, W. 1962. The silicoflagellides in the Wakura Beds, Nanao City, Prefecture Ishikawa, Japan. Kanazawa Univ., Sci. Rept., vol. 8, No. 1, pp. 161-175, pls. 1-10, figs. 1-4. Bachmann, A., and Papp, A. 1968. Vorkommen und Verbreitung der Silicoflagellaten im Neogen Osterreichs. Comm, Mediterranean Neogene Stratigraphy, Proc., 4th Sess., Bologna 1967, Giornale di Geologie, ser. 2, vol. 35, fasc. 2, pp. 117-126, pl. 3. Bailey, J. W. 1845. Notice of some new localities of Infusoria, fossil and Recent. Amer. Jour, Sci. Arts, vol. 48, No. 2, pp. 321-343, pl. 4. Bandy, O. L., and Ingle, J. C., Jr. 1970. Neogene planktonic events and radiometric scale, California. In Radiometric dating and paleontologic zonation, Ed. by O. L. Bandy, Geol. Soc. Amer., Spec. Paper 124, pp. 131-172. Berggren, W. A. 1969. Cenozoic chronostratigraphy, planktonic foraminiferal zonation and the radiometric time scale. Nature, vol. 224, No. 5224, pp. 1072-1075. Blow, W. H. 1970. Deep Sea Drilling Project, Leg. 2, Foraminifera from selected samples. In Peterson, M. N. A., et al., Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, vol. 2, pp. 357-365. Bolli, H. M. 1957. Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.1I. U.S. Nat. Mus., Bull., No. 215, pp 97-123, pls. 22-29. Bukry, D., and Bramlette, M. N. 1970. Deep Sea Drilling Project, Leg 5, Coccoliths age determinations. In McManus, D. A., et al., Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, vol. 5, pp. 487-494. 206 BULLETIN 273 Carnevale, P. 1908. Radiolarie e silicoflagellati de Bergonzano (Reggio Emilia). R. Ist. Veneto Sci. Lett. Arti. Mem., vol. 28, No. 3, pp. 1-46, pls. 1-4. Clark, B. L., and Campbell, A. S. 1945. Radiolaria from the Kreyenhagen Formation near Los Banos, California. Geol. Soc. Amer., Mem. 10, pp. 1-66, pls. 1-7. Colom, G. 1940. Arqueomonadineas, Silicoflagelados, Discoasteridos fosiles de Espana. Las Ciencias, vol. 5, pp. 343-356, figs. 1-11. Deflandre, G. 1932a. Les Silicoflagellés des terres fossiles a Diatomées. Soc. France Microsc., Bull., vol. 1, No. 1, pp. 10-20. 1932b. Sur le genre Podamphora et ses relations avec les Ebriacées- Acad. Sci. Paris, C. R., vol. 194, No. 24, pp. 2171-2173, figs. 1-8. 1932c. Sur la systématique des Silicoflagellés. Soc. Bot. France, Bull., vol. 79, Nos. 5-6, pp. 494-506, figs. 1-42. 1932d. Remarques sur quelques ebriacées. Soc. Zool. France, Bull., vol. 57, No. 4, pp. 302-315, figs. 1-40. 1933. Enkystement et stade loriqué chez les Ebriacées. Soc. Zool. France, Bull., vol. 57, No. 6, pp. 514-523, figs. 1-13. 1935. Sur un Silicoflagelle aberrant, Dictyocha recta (Schulz), a squelette non tubulaire. Soc. France, Microsc., Bull., vol. 3, No. 4, pp. 115-118, figs. 1-5. 1938. Sur deux microfossiles siliceux énigmatiques (Silicoflagellidées?). Soc. Bot. France, Bull., vol. 7, No. 3, pp. 90-96, figs. 1-25. 1940a. Sur les affinités et la phylogenese du genre Vallacerta, Silico- flagellidée du Crétacé supérieur. Acad. Sci. Paris, C. R., vol. 211, No. 19, pp. 445-448, figs. 1-8. 1940b. L’origine phylogénétique des Lyramula et l’évolution des Silico- flagellidées. Acad. Sci. Paris, C. R., vol. 211, No. 21, pp. 508-510, figs. 1-12. : 1940c. Sur une structure reticulée méconnue du squelette des Silico- flagellidées. Acad. Sci. Paris, C. R., vol. 211, No. 23, pp. 597-599. 1946. Phyllodictyocha nov. gen. Silicoflagellidées et formes affines du Miocéne de Hongrie. Soc. Bot. France, Bull., vol. 93, No. 9, pp. 335-337, figs. 1-5. 1950a. Contribution a Pétude des Silicoflagellidés actuels et fossiles. Microscopie, vol. 2, 82 pp., figs. 1-240. 1950b. Sur l’évolution des Ebriediens. Interprétation du genre Ebriopsis. Acad. Sci. Paris, C. R., vol. 230, No. 19, pp. 1683-1685, figs. 1-8. 1951. Recherches sur les Ebriediens. Paléobiologie, Evolution, Systéma- tiqgue. Biol. France, Belgique., Bull., vol. 85, fasc. 1, pp. 1-84, figs. 1-238. 1971. Rejet du genre Dicladia Ehrenberg (Diatomée) introduit fallacie- usement dans les Ebriédiens. In II Planktonic Conf., Proc., Roma, 1970, Ed. by A. Farinacci, vol. 1, pp. 349-353, pl. 1. Desikachary, T. V., and Maheshwari, C. L. 1956. Fossil silicoflagellates from Colebrook and Nancoori Islands. Indian Bot. Soc., Jour., vol. 35, pp. 257-264, figs. 1-19, pl. 13. Ehrenberg, C. G. 1839. Uber die Bildung der Kreidefelsen und des Kreidemorgels durch unsichtbare Organismen. K. Akad. Wiss. Berlin, Abh., Jahrg. 1838, pp. 59-147, pls. 1-4, 1 table. 1840. . . . 274 Blatter von ihm selbst ausgefiihrter Zeichnungen von ebenso vielen Arten. . .. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1840, pp. 197-219. 1844a. Uber 2 neue Lager von Gebirgsmassen aus Infusorien. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, pp. 57-97. SILICOFLAGELLATES AND EBRIDIANS: LING 207 1844b. Resultate seiner Untersuchungen der ihm von der Siidpolreise des Captain Ross, so wie von den Herren Schayer und Darwin zugekommenen Materialien tiber das Verhalten des kleinsten ‘Lebens in den Oceanen und den gréssten bisher zugdnglichen Tiefen des Weltmeers. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, pp. 182-207. 1844c. Untersuchungen iiber die kleinsten Lebensformen im Quellenlande des Euphrats und Araxes, so wie tiber eine neuen Formen sehr reiche marine Tripelbildung von den Bermuda-Inseln vor. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1844, pp. 253-275. 1845. Neue Untersuchungen iiber das kleinste Leben als geologisches Moment. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1845, pp. 53-87. 1847. Ueber die mikroskopischen kieselschaligen Polycystinen als mdach- tige Gebirgsmasse von Barbados und iiber das Verhdltniss der aus mehr als 300 neuen Arten besthenden ganz eigenthiimlichen Formengruppe jener Felsmasse zu den jetzt lebenden Thieren und zur Kreidebildung. Verh. K. Preuss. Akad. Wiss. Berlin, Ber., Jahrg. 1847, pp. 40-60. 1854. Mikrogeologie. Leopold Voss, Leipzig; pp. 1-374, pls. 1-40. Ewing, M., Worzel, J. L., Beall, A. O., Berggren, W. A., Bukry, D., Burk, C.A., Fischer, A. G., and Pessagno, E. A. Jr. 1969. Initial Reports of the Deep Sea Drilling Project. U.S. Government Printing Office, Washington, vol. 1, i-xx + 1-672 pp. Frenguelli, J. 1940. Consideraciones sobre los silicoflagelados fésiles. Rev. Mus. La Plata, n.s., vol. 2, Paleont. No. 7, pp. 37-112, pls. 1-4. Fuji, N., and Bachmann, A. 1969. Silicoflagellaten in Tijiritkawa-Schichten. Kanazawa Univ., Fac. Educ., Natural Sci., Bull., No. 18, pp. 79-94. Gemeinhardt, K. 1930. Silicoflagellatae. In MRabenhorst, L., Kryptogamen-Flora von Deutschland, Osterreich und der Schweiz. Akademische ie aes gesellschaft, Leipzig, vol. 10, pt. 2, pp. 1-87, figs. 1-69, pl. 1931a. Organismenformen auf der Grenze zwischen eee und Flagellaten. Deutsch. Bot. Ges., Ber., vol. 49, No. 2, pp. 103-110, pl. 10. 1931b. Die Silicoflagellaten der Deutschen Siidpolar-Expedition 1901- 1903. Deutsche Siidpolar-Exped., vol. 20 (Zool. No. 12), pp. 221- 258, pls. 42-43. Glezer, Z. |. 1966. Silicoflagellatophyceae. In Cryptogamic plants of the U.S.S.R., Ed. by M. M. Gollerbakh, Akad. Nauk. SSSR, Botanicheskii Institut IM V. A. Komarova. (Translated from Russian by Israel Program for Scientific Translations Ltd., Jerusalem, 1970), vol. 7, pp. i-iv + 1-330, pls. 1-33, figs. 1-28. Haeckel, E. 1887. Report on the Radiolaria collected by H.M.S. Challenger during the years 1873-1876. Rept. Voy. Challenger, Zool., vol. 18, pp. i-clxxxviii + 1-1803, pls. 1-140. Hajos, Marta 1968. Madtraalji Miocene Uledekeinek Diatomi (Die Diatomeen der Miozdnen Ablagerungen des Mdtravorlandes). Geologica Hungar- ica, ser. Paleontologica, fasc. 37, pp. 1-401, pls. 1-63. Hanna, G. D. 1928. Silicoflagellates from the Cretaceous of California. Jour. Paleont., vol. 1, No. 4, pp. 259-264, pl. 41. 208 BULLETIN 273 1930. A new genus of Silicoflagellates from the Miocene of Lower Cali- fornia, Jour. Paleont., vol. 4, No. 4, pp. 415-416. 1931. Diatoms and silicoflagellates of the Kreyenhagen Shale. Mining in California. California Div. Mines Rept., State Mineralogist, vol. 27, pp. 187-201, pls. A-E. Hays, J. D., Saito, T., Opdyke, N. D., and Burckle, L. H. 1969. Pliocene-Pleistocene sediments of the equatorial Pacific: Their paleomagnetic, biostratigraphic and climatic record. Geol. Soc. Amer., Bull., vol. 80, No. 8, pp. 1481-1513, figs. 1-16, pl. 1. Hopkins, D. M., et al. 1969. Cretaceous, Tertiary, and Early Pleistocene rocks from the con- tinental margin in the Bering Sea. Geol. Soc. Amer., Bull., vol. 80, No. 8, pp. 1471-1480, figs. 1-2, pls. 1-2 Hovasse, R. 1932a. Note préliminaire sur les Ebriacées. Soc. Zool. France, Bull., vol. 57, No 2, pp. 118-131, figs. 1-12. 1932b. Second note sur les Ebriacées. Soc. Zool. France, Bull., vol. 57, No. 4, pp. 278-283, figs. 1-6. 1932c. Troisiéme note sur les Ebriacées. Soc. Zool. France, Bull., vol. 57, No. 5, pp. 457-476, figs. 1-27. Jorgensen, E. 1899. Protophyten und Protozoen im Plankton aus der norwegischen W estkiiste. Bergens Museums Aaarbog, No. 6 (pt. 2), pp. 1-112, pls. 1-4, tables 1-1xxxii. Jousé, A. P. 1962. Stratigraphic and paleogeographic researches in the northwestern part of the Pacific Ocean. Izd. Inst. Okeanologii, Akad. Nauk SSSR, Moscow, pp. 1-258, pls. 1-80, tables 1-31. 1963. Problems in stratigraphy and paleogeography of the northern part a the Pacific Ocean. Okeanologia, Akad. Nauk SSSR, vol. 3, No. 6, pp. 1017-1028, figs. 1-2. 1969. Silicoflagellates in bottom sediments of Pleistocene and late Plio- cene in the Pacific Ocean. In Micropaleontology and organogenous sedimentation in the Oceans, Ed. by A. P. Jousé, Nauka, Moscow, pp. 105-114, figs. 1-4. 1971. Diatoms in Pleistocene sediments from the northern Pacific Ocean. In The Micropaleontology of Oceans, Ed. by B. M. Funnel] and W. R. Riedel, Univ. Press, Cambridge, pp. 407-421, pls. 31.1- 31.3, figs. 31.1-31.7 Kanaya. T. 1971. Some aspects of Pre-Quaternary diatoms in the oceans. In The Micropaleontology of Oceans, Ed. by B. M. Funnell and W. R. Riedel, Univ. Press, Cambridge, pp. 545-565, pls. 40.1-40.6. Kanaya, T. and Koizumi. I. 1966. Interpretation of Diatom thanatocoenoses from the North Pacific applied to a study of core V20-130 (Studies of a deep-sea core V20-130, pt. 4) Tohoku Univ., Sci. Repts., ser. 2 (Geol.), vol. 37, No. 2, pp. 89-130, figs. 1-6 Koizumi, I. 1968. Tertiary diatom flora of Oga Peninsula, Akita Prefecture, North- east Japan. Tohoku Univ., Sci. Repts., ser. 2 (Geol.), vol. 40, No. 3, pp. 171-240, pls. 32-35, figs 1-15. Kozlova, O. G. 1964. Diatoms of the Indian and Pacific sectors of the Antarctic. 1z- datel’stvo, Nauka, Inst. Oceanology, Akad. Nauk SSSR. (Trans- lated by Israel Program for Scientific Translations, Ltd., Jeru- salem, 1966), pp. 1-191, pls. 1-6. SILICOFLAGELLATES AND EBRIDIANS: LING 209 Lanjouw, J. (Chairman), et al. 1966. International Code of Botanical Nomenclature adopted by the tenth International Botanical Congress, Edinburgh, August 1964. Kemink en Zoom N. V. Utrecht, Netherland, pp. 1-402. Lemmermann, E. 1901la. Beitrdge zur Kenntniss der Planktonalgen. Deutsch. Bot. Ges., Ber., vol. 19, pp. 85-95. 1901b. Silicoflagellatae. Deutsch. Bot. Ges., Ber., vol. 19, pp. 247-271, pls. 10-11. 1903. Klasse Silicoflagellatae. In Nordisches plankton, Ed. by K. Brandt and C. Apstein. (Botanischer Teil), No. 21, pp. 25-32, figs. 89-108. Ling, H. Y. 1970. Silicoflagellates from central north Pacific core sediments. Bull. Amer. Paleont., vol. 58, No. 259, pp. 85-129, pls. 18-20. 1971. Silicoflagellates and Ebridians ‘from the Shinzan diatomaceous mudstone member of the Onnagawa Formation (Miocene), North- east Japan. In 11 Planktonic Conf., Proc., Roma, 1970, Ed. by A. Farinacci, vol. 2, pp. 689-703, pls. 1, 2, figs. 1-3. Ling, H. Y., and Anikouchine, W.A. 1967. Some spumellarian Radiolaria from the Java, Philippine, and Mariana Trenches. Jour. Paleont., vol. 41, No. 6, pp. 1481-1491, pls. 189-192, text-figs. 1-5. Lipps, J. H. 1970. Ecology and Evolution of Silicoflagellates. North American Pale- ont. Convention, Proc., pt. G, pp. 965-993. Loeblich, A. R., Jr., and Tappan, H. 1968. Fossil Phytoflagellates. Geol. Soc. Amer. Spec. Paper No. 101, paelZ5: Loeblich, A. R., III. 1965. Type designations for Dicladia (Ebriaceae), Periptera (Baccillario- pee aey: Gymnocella, Phaeodactylis and Phaeosphaera (Radio- laria). Proc. Biol. Soc. Washington, vol. 78, pp. 189-192. Loeblich, A. R., Ill, Loeblich, L. A., Tappan, H., and Loeblich, A. R., Jr. 1968. Annotated index of fossil and Recent, stlicoflagellates and ebridians with descriptions and illustrations of validly proposed taxa. Geol. Soc. Amer, Mem. 106, pp. i-xl7-1-319, pls. 1-53. McManus, D. A., et al. 1970. Initial Reports of the Deep Sea Drilling Project. U.S. Government Printing Office, Washington, vol. 5, pp. i-xxi -+ 1-827. Mandra, Y. T. 1968. Silicoflagellates from the Cretaceous, Eocene, and Miocene of California, U.S.A. California Acad. Sci., Proc., ser. 4, vol. 36, No. 9, pp. 231-277, figs. 1-83, tables 1-7. 1969. Silicoflagellates: A new tool for the study of Antarctic Tertiary Climates. Antarctic Jour. U.S., vol. 4, No. 5, pp. 172-174. Marshall, S. M. 1934. The silicoflagellata and Tintinnoinea. Sci. Rept. Great Barrier Reef Exped., vol. 4, No. 15, pp. 623-662. Martini, E. 1970. Standard Paleogene calcareous nannoplankton zonation. Nature, vol. 226, No. 5244, pp. 560, 561. 1971a. Standard Tertiary and Quaternary calcareous nannoplankton. In II Planktonic Conf., Proc., Roma, 1970, Ed. by A. Farinacci, vol. 2, pp. 739-785, pls. 1-4, tables 1-6. 1971b. Neogene Acne: from the equatorial Pacific. In Winterer, E. L., et al., Initial Reports of the Deep Sea Drilling Project, US: Government Printing Office, Washington, vol. 7, pp. 1695- 1708, figs. 1-3, tables 1-4. 210 BULLETIN 273 Martini, E., and Bramlette, M. N. 1963. Calcareous nannoplankton from the Experimental Mohole Drill- ing. Jour. Paleont., vol. 37, No. 4, pp. 845-856. Martini, E., and Worsley, T. R. 1970. Standard Neogene calcareous nannoplankton zonation. Nature, vol. 225, No. 5229, pp. 289-290. Maxwell, A. E., et al. 1970. Initial Reports of the Deep Sea Drilling Project, U.S. Govern- ment Printing Office, Washington, vol. 3, pp. i-xx + 1-806. Muhina, V. V. 1963. Biostratigraphic correlation of bottom deposits at station 3802 in the Equatorial zone of the Pacific. Okeanologiia, vol. 3, No. 5, pp. 861-869, figs. 1-3. 1966. The boundary between sediments of Quaternary and Tertiary age in the Pacific (on the basis of diatom analysis). Oceanology, vol. 6, No. 1, pp. 99-110, figs. 1-5. 1969. Biostratigraphy of sediments and some questions of paleogeogra- phy of the tropical region of the Pacific and Indian Oceans. In Micropaleontology and organogenous sedimentation in the Oceans, Ed. by A. P. Jousé, Nauka, Moscow, pp. 52-84, figs. 1-10. Papenfuss, G. F. 1955. Classification of the algae. In Miller, R. C. (chairman), A cen- tury of progress in the natural science. California Acad. Sci., San Francisco, pp. 115-224. Parker, F. L. 1964. Foraminifera from the experimental Mohole drilling near Guada- lupe Island, Mexico. Jour. Paleont., vol. 38, No. 4, pp. 617-636, pls. 97-102, tables 1-3. Riedel, W. R. 1957. Radiolaria: a preliminary stratigraphy. Swedish Deep-Sea Exped., Rept., vol. 6, fasc. 3, pp. 61-96, pls. 1-4. 1971. Radiolarians from Atlantic Deep-Sea Drilling. In I1 Planktonic Con., Proc., Roma, 1970, Ed. by A. Farinacci, vol. 2, pp. 1057- 1065, figs. 1-8, tables 1, 2. Riedel, W. R., and Sanfilippo, Annika 1970. Radiolaria, Leg 4, Deep Sea Drilling Project. In Bader, R. G., et al., Initial Reports of the Deep Sea Drilling Project, U.S. Govern- ment Printing Office, Washington, vol. 4, pp. 503-575, pls. 1-15. 1971. Cenozoic Radiolaria from the western tropical Pacific, Leg 7. In Winterer, E. L., et al., Initial Reports of the Deep Sea Drilling Project, U.S. Government Printing Office, Washington, vol. 7, pp. 1529-1672, pls. 1-8, figs. 1-3, tables 1-8. Riedel, W. R., Ladd, H. S., Tracey, J. I., and Bramlette, M. N. 1961. Preliminary drilling phase of Mohole Project: Summary of coring operations (Guadalupe Site). Amer. Assoc. Petr. Geol., Bull., vol. 45, No. 11, pp. 1793-1798. Rust, D. 1888. Beitrage zur Kenntnis der fossilen Radiolarien aus Gesteinen der Kreide. Palaeontographica, vol. 34, pp. 181-213. Ruth, J. W. 1971. Late Tertiary diatoms and silicoflagellates of the California coastal area. Geol. Soc. Amer., Cordilleran section (abstract), p. 188. Sanfilippo, Annika 1971. Neogene radiolarians of the Mediterranean and western Pacific. In II Planktonic Conf., Proc., Roma, 1970, Ed. by A. Farianacci, vol. 2, pp. 1121-1127, figs. 1, 2. SILICOFLAGELLATES AND EBRIDIANS: LING Abt Sanfilippo, Annika, and Riedel, W. R. 1970. Post-Eocene “closed” theoperid radiolarians. Micropaleont., vol. 16, No. 4, pp. 446-462, pls. 1-2. Schulz, P. 1928. Beitrdge zur Kenntnis fossiler und rezenter Silicoflagellaten. Bot. Archiv., vol. 21, No. 2, pp. 225-292, figs. 1-83. Sheshukova-Poretzkaya, V. S. 1967. The Neogene marine Diatomaceae of Sakhalin and Kamchatka. Izd. Leningrad Univ., pp. 1-327, text-figs. 1-8, tables 1-19, pls. 1-50. Stohr, E. 1880. Die Radiolarienfauna der Tripoli von Grotte Provinz Girgenti in Sicilen. Palaeontographica, vol. 26, pp. 69-124, pls. 1-7. Stradner, H. 1956. Uber fossile Silicoflagelliden aus dem Tertiar Osterreichs. Univ. Wien, Dissertation (unpublished). 1961. Uber fossile Silicoflagelliden und die Méglichkeit ihrer Verwen- dung in der Erdélstratigraphie. Erdél. u. Kohle, vol. 14, No. 2, pp. 87-92, pls. 1-3, fig. 1. Tsumura, K. 1959. Komentariita figuraroj de silikoflageluloj. Yokohama Munic. Univ., Bull., vol. 11, Nat. Sci., No. 1, pp. 35-90, pls. 2-4. 1963. A systematic study of silicoflagellatae. Yokohama Munic. Univ., Jour., ser. C-45, No. 146, pp. 1-84, pls 1-28. Tynan, E. J. 1957. Silicoflagellates of the Calvert formation (Miocene) of Maryland. Micropaleont., vol. 3, No. 2, pp. 127-136, pl. 1, figs. 1-3. Zanon, D. V. 1934. Silicoflagellate fossili Italiane. Acta Pont. Acad. Sci. Nov. Lincei, vol. 87, pp. 40-82, figs. 1-3, pl. 1 Zittel, K. A. 1876. Uber einige fossile Radiolarien aus der norddeutschen Kreide. Deutsche Geol. Ges. Zeitschr., vol. 28, pp. 75-86, pl. 2. iN ae pan bela 9 HHA Mate ibe rie ereent | a | a We tooth htt salina ¢ mT] Naor atte nape li i Hith Pre hy SA" eee Ath peer ta ; Fal! pda yi wok yates ha. ypertabrsatt puis yi : aay ‘ i " ite A ee ER zt Wet omaha BAD taViieol apieay® we pale = 7 ; heey i ois be toktte a ear aap Condit . ek Gi. aa * Lt ee i ie of. shien wai’ ph ewer om es hw Ve vavierraas) abide, aesaah 4 AVS er -< ein Mik ) eb ogl! Pda Gabinete ot cy Vii der AL OMe i, iy Vonpe v9 Bi ’ » Met We RE het we wy A 2 id ine ee | 7 I ethan od 1 ee elven, Ay Way Dae eri ai Cyn bis 8) Ng Bur} } Voile FRR Petal ded ae ake 2 rid 5 wel ne ao Menlo well yD wari ake ‘ 14 pial wht Ve oie Hisyatheut ue "a wr: ao pois BAY OFti- bt, na A Oe & bay eer vagestie ‘ AG, 1) Wes - Ah, ADD eit | ae a te atl anoint, Heed hull awlle ATL } iy fee gil -0e aq Ae tov, bs Ris oe) ANWVA ieee i AL Ga pms Minion lioas\ yerat a hae ee BERS ag’ 0S aBtengeiga ae ead) | jisiee ws pat aty hain 5 — 50 i ee y' ma ri i a. we iM. a, y ete 9 Pv dd ee J wea @ j » Pires nd ta? in one Ae wT aie Oe Acin Pave = : an 2 in th tis § Pes: ha fy We | ee x | woes KY ites y “a HOAMAGT, vl Vi ; Vue rer | wil 4 - ee ith s ee ANTE m nua, & wis” VS, fut hob 7 bt ipo wn hate MPO RP Gere ace yi Seen ea ice hei ea Lily a “a dois al x faye rie Se L PPA ia ite Pia 7 id ¥ an thee ve my ida } “vr PLATES 214 Figure 1-5. 6,7. 8-10. 11, 12. 13-17. 18. BuLweTIn 273 EXPLANATION OF PLATE 23 All figures 500 unless otherwise indicated. Cannopilus hemisphaericus (Ehrenberg) ........................00000.. 148 1. EM 7-1, 14-15 cm, L-2 (V42/0); 2, 3. Different focus levels, EM 7-1, 14-15 cm, L-2 (E37/3); 4. EM 7-1, 14-15 cm, L-2 (R27/0); 5. EM 8-12, 94-95 cm, L-2 (018/1). Cannopilus picassoi Stradmer ....................ccccccecteenereeeenes 149 6. WRE 67-77, R-2 (C43/1); WRE 67-77, L-7 (N27/3). Cannopilus sphaericus Gemeinhardt .................0...cccees 150 8. EM 7-2, 6-7 cm, L-2 (L18/4); 9. EM 8-15, 505-506 cm, L-2 (E33/0); 10. EM 8-14, 388-389 cm, L-2, (042/0). Cannopilus tetraceros Bachmann and Ichikawa ........................ 151 11, 12. Different focus levels, EM 8-15, 246-249 cm, L-2 (V24/4). Corbisema apiculata (Lemmermann) .. .................0......ccccees 152 13. $136/964, L-2 (U30/4); 14. SID 1, R-1 (E7/1); 15. KEL 9, R-1 (M23/3); 16. DSDP 6-6-2, 1-2 cm, R-1 (V34/4) ; 17. DSDP 6-6-2, 1-2 cm, L-2 (H18/3). Corbisema archangelskiana (Schulz) ate tee 152 18. DSDP 6-4-3, 110-112 cm, L-4 (G29/3) BuLL. AMER. PALEONT., VOL. 62 PLATE 23 BULL. AMER. PALEONT., VOL. 62 PLATE 24 14-17. 18-23. SILICOFLAGELLATES AND EBRIDIANS: LING 215 EXPLANATION OF PLATE 24 All figures 500 unless otherwise indicated. Corbisema bimucronata Deflandre ....... 1. WR TR 39F (J.S.1068), L-2 (C41/4). Corbisema’ .geometrica) Hanna. £2... 22... J.ccc0.5sksc.--deccscecesaveectessovnees 154 2. CAS 1144, R-5 (D30/1); 3. DSDP 6-6-2, 1-2 cm, R-2 (K17/4), X400; 4. DSDP 6-6-2, 1-2 cm, R-2 (J36/3), 400. Corbisema hastata (Lemmermann) 5. DSDP 12-3-1, 120-121 cm, L-2 (P18/1). Corbisemayrectan(Schulz)e..2 0 ee re te cess ate 155 6. DSDP 13-3-1, 120-121 cm, L-2 (U18/0); 7. DSDP 13-3-1, 120-121 cm, L-2 (P40/0). Corbisema triacantha Ehrenberg ....00.00.0...0...ccccccccceecececceee 156 8, 9. Different focus levels, KEL 10, R-1 (J48/0); 10. KEL 7, L-2 (K37/0); 11. WRE 67-99, L-2 (M37/0); 12. WRE 67-99, L-3 (D22/0); 13. AMPH 6P, 50-51 cm, L-2 (L22/3). Corbisema triacantha var. flexuosa Stradner 14. AUS 4, L-2 (W17/0); 15. Lateral view, AUS 4, L-2 (W25/0); 16. AUS 4, L-3 (K26/0); 17. WRE 67-96, L-2 (F26/0). Corbisema triacantha var. minor (Schulz) .... ..................... 158 18. EM 8-15, 246-249 cm, L-2 (S7/0); 19. WRE 67-96, L-2 (K2273) e205 Keb 9s e-2) (12/2) 21D SDP 6-4-2, 7=10 cm, L-2 (R32/0); 22. DSDP 6-4-3, 110-112 cm, L-2 (Z32/2) ; 23. DSDP 6-6-2, 1-2 cm, R-2 (M39/4). 216 Figure 1-10. 11-15. 16,17. 18, 19. BuLLeTIN 273 EXPLANATION OF PLATE 25 All figures 500 unless otherwise indicated. Dictyocha ausonia Deflandre 2.0.02... ccceceee cette 160 1. WRE 67-77, L-7 (R18/2); 2. WRE 67-99, L-2, 019/0; 3. WAH 7P, 259-260 cm, L-2 (Y13/4); 4. WAH 7P, 259-260 cm, L-2 (Q10/2); 5. EM 8-9, 148-149 cm, L-2 (D19/2); 6-10. WR TR (K9391), L-2 (U47/4); 7. WR TR 23 (K9391) L-2 (M17/4); 8. WR TR 23 (K9391), L-2 (N23/2); 9. WR TR 23 (K9391), L-2 (H10/4); 10. WR TR 23 (K9391), L-2 (N28/0). Dictyocha fibula Ehrenberg ............... ete: PE Reson: Gi 11. WR TR 11, Low (Bo. 202), L-2, (W34/1); 12. WR TR 11, Low (Bo. 202), L-2 (K33/4); 13 PROA 88P, 275-276 cm, L-2 (H28/1); 14. EM 6-2, 30-32 cm, L-2, (Y18/0); 15. AMPH 6P, 17-18 cm, L-2 (N17/2). Dictyocha fibula var. aculeata Lemmermann ...................... 161 16. DSDP 9-5-2, 99-100 em, L-2 (U29/3); 17. DSDP 9-5-1, 8-9 cm, L-2 (L23/0). Dictyocha fibu'a var. messanensis (Haeckel) | .........0...0........ 161 18. DSDP 9-5-2, L-2, 99-100 cm, L-2 (Y32/4); 19. DSDP 9-5-2, 99-100 cm, L-2 (016/2). PLATE 25 BULL. AMER. PALEONT., VOL. 62 uw oo aT, wt ty Oey PLATE 26 Bulut. AMER. PALEONT., VOL. 62 Figure I, 24, 17-19. 20-22. 23, 24. SILICOFLAGELLATES AND EBRIDIANS: LING 217 EXPLANATION OF PLATE 26 All figures <500 unless otherwise indicated. Page Dictyocha fibuia var. octagona Tsumura ............ treats SGI 1. AMPH 7P, 17-18 cm, L-2 (P7/3); 2. EM 7-1, 35-36 cm, L-2 (W8/4). Dictyocha jhexacanthacochulz 4 iv...cnulugete...2ceeelso)...8 162 3. $136/964, L-2 (D10/0). Diciyocha sp. ... sie «ile ee RE 164 4. AMPH 6P, 17-18 cm, L-2 (W9/0); 5. EM 8-15, 505-506 cm, L-2 (L12/4); 6. EM 8-11, 322-323 cm, L-2 (S8/0) ; 7. EM 8-11, 69-70 cm, L-2 (B33/4); 8 EM 8-11, 69-70 cm, L-2 (S14/2). Distephanus crux (Ehrenberg) 1b RAE eR OP ces LOD 9. EM 8-11, 421-423 cm, L-2 (G8/4); 10. EM 8-12, 94-95 cm, L-2 (E17/1); 11. AMPH 6P, 17-18 cm, L-2 (¥9/0); 12. EM 6-2, 30-32 cm, L-2 (N46/2); 13. $136/880, L-2 (N30/4) ; 14. WRE 67-77, L-4 (N49/2); 15. WRE 67-77, L-7 (Z36/2) ; 16. WRE 67-77, L-7 (G32/0). Distephanus crux var. longispina Schulz ................... LOD 17. Oblique lateral view, EM 8-14, 388-389 cm, L-2 (P31/4) ; 18, 19. Different focus levels, EM 8-13, 125-126 cm, L-2 (M19/0). Distephanus crux var. octacanthus Desikachary and Maheshwari ........ A eee eed | el 66 20. EM 7-2, 6-7 cm, L-2 (G17/2); 21. EM 7-1, 35-36 cm, L-2 (V24/1); 22. EM 7-1, 14-15 cm, L-2 (U25/4). Distephanus speculum (Ehrenberg) .....000......00000.0cceccceceeeeeeeeee. 167 23. WAH 7P, 516-517 cm, L-2 (N14/0); 24. WRE 67-112, L-2°(¥17/0). 218 Figure 152: 3, 4. 5-7. 8-13. 14, 15. 16-18. 19-21. BuLLeTIN 273 EXPLANATION OF PLATE 27 All figures 500 unless otherwise indicated. Distephanus speculum (Ehrenberg) ....................0::cccccceescceteeeees 167 1. EM 8-12, 26-28 cm, L-2 (J41/1); 2. EM 6-2, 10-11 cm, W-2 (W31/0). Distephanus speculum var. pentagonus Lemmermann ........ 167 3. EM 8-11, 322-323 cm, L-2 (F11/0); 4. EM 8-11, 322-323 cm, L-2 (G35/4). Distenphanus speculum var. pseudocrux Schulz .................... 168 5. EM 8-9, 148-149 cm, L-2 (D45/4); 6. EM 8-9, 148-149 cm, L-2 (V29/0); 7. EM 8-9, 148-149 cm, L-2 (L44/0). Distephanus speculum var. pseudofibula Schulz .................... 169 8, 9. Different focus levels, EM 8-10, 383-384 cm, L-2 (G26/3) ; 10, (EM. ‘6-2, 10-11 “cm, L-2 (J40/0); 11: EE! 18-020 Rs (G30/0); 12, 13. Different focus levels, TT 18-02, R-1 (N23/0). Lyramula tenuipertica Kokubo et Tsumura ............................ 171 14. DSDP 9-5-2, 99-100 cm, L-2 (U14/4); 15. the same specimen of figure 14 under the phase contrast photomicro- graph. Lyramula furcula Hanna ......0.:....6.cecc100005. See ee 171 16. CAS 1144, L-2 (C24/1); 17. the same specimen of figure 16 under the phase contrast photomicrograph; 18. CAS 1144, L-3 (G26/4). Lyramula furcula var. minor Deflandre | .................000...000....... 172 19. CAS 1144, L-3 (J21/0); 20. CAS 1144, L-3 (Q23/3); 21. CAS 1144, L-3 (Q23/3). BULL. AMER. PALEONT., VOL. 62 PLATE 27 BuLL. AMER. PALEONT., VOL. 62 PLATE 28 5, 6. a8. 9-15. SILICOFLAGELLATES AND EBRIDIANS: LING 219 EXPLANATION OF PLATE 28 All figures 500 unless otherwise indicated. Page Eyramulae simplex: Hannas forte: eee ee 172 1. CAS 1144, L-2 (Q36/4). Mesocena apiculata (Schulz) ..............0.....cccccceccceseseceeseeeseneeeees 173 2. $136/966, L-2 (L13/0); 3. the same specimen of figure 2 under the phase contrast photomicrograph; 4 §$136/880, L-2 (R5/4). Mesocena circulus Ehrenberg 2...............0.cccccccccccccceeeeeceeeeeeeeeeeees 175 5. EM 8-11, 69-70 cm, R-1 (S43/4) 400; 6. EM 8-11, 69-70 cm, L-2 (F17/2). Mesocena circulus var. apiculata Lemmermann ................... 176 7. EM 8-12, 94-95 cm, L-2 (L13/2); 8 EM 8-15, 246-249 cm, R-1 (N43/3). Mesocena cf. elliptica Ehrenberg |......0.00.0.0000000..0000.0cc eee atzte/ 9. EM 6-2, 30-32 cm, L-2 (D10/2); 10. EM 8-11, 69-70 cm, L-2 (L32/3), 400; 11. EM 8-15, 505-506 cm, L-2 (W26/4) ; 12. AMPH 6P, 50-51 cm, L-2 (D13/2); 13. AMPH 6P, 50-51 cm, L-2 (J31/3); 14. WRE 67-77, L-2 (026/1); 15. WRE 67-76, L-2 (M13/1). 220 Figure 1-3. 4-7. 8-10. 11-15. BuLLeETIN 273 EXPLANATION OF PLATE 29 All figures 500 unless otherwise indicated. Mesocena cf. elliptica Ehrenberg ........00.0...........0.:cceeeseeeeees 177 1. LSDA 101G, 38-39 cm, L-2 (E44/1); 2. EM 8-13, 49-51 cm, L-2 (C8/3); 3. WR TR 11, Low (Bo. 202), L-2 (E42/2). Mesocena cf. eliiptica var minoriformis Bachmann and Papp 178 4. AUS 3, L-2 (08/4); 5. AUS 3, L-2 (G16/4); 6. EM 8-13, L-2 (R37/1); 7. EM 7-2, L-2 (D18/2). Mesocena oamarvensis SchulZ ..................cccccceccccccecccceceeveeeeeeeeess 179 8. S$136/1096, L-2 (J11/0), 400; 9. KEL 6, R-2 (S23/2); 10.SID 3, R=1) (J50/2). Septamesocena apiculata Bachmann |... cee 193 13. WRE 67-99, L-3 (S41/4); 14. the same specimen of figure 13 under the phase contrast photomicrograph; 15. DSDP 13-3-1, 120-121 cm, L-2 (S10/2). BuLL. AMER. PALEONT., VOL. 62 PLATE 29 PLATE 30 BULL. AMER. PALEONT., VOL. 62 Fs ites aero. rigs tn = ya Fv oan Figure 1-4. 9-11. 12-16. 17-19. SILICOFLAGELLATES AND EBRIDIANS: LING 2a EXPLANATION OF PLATE 30 All figures 500 unless otherwise indicated. Naviculopsis biapiculata (Lemmermann) 2.0.0.0... 181 1, 2. Different focus levels, lateral view, S136/914, L-2 (R31/4); 3. DSDP 6-6-2, 1-2 cm, L-3 (Q17/0); 4. WR TR 39F (J.S.1068), L-3 (R40/1). Naviculopsis constricta (Schulz) ..0..000000....000....... ea el oS 5. S136/878, L-2 (N48/0); 6. Lateral view, S136/1096, L-2 (C23/0); 7. KEL 9, R-1 (E46/3); 8. DSDP 6-6-2, 1-2 cm, R-2 (W46/0). Naviculopsis foliacea Deflandre ........0.............50ccceeecceetteee es 184 9. Lateral view, KEL 3, R-1 (V47/3); 10. Oblique abapical view, KEL 8, R-1 (G13/0); 11. DSDP 6-6-2, 1-2 cm, L-2 (G33/3). Naviculopsis; latan (Deflandre) ie rrr caer ee 185 12. AUS 4, L-3 (U36/3); 13. the same specimen of figure 12 under phase contrast photomicrograph; 14. Abapical view, under the phase contrast photomicrograph, WRE _ 67-100, L-2 (034/2); 15. AUS 4, L-3 (X31/3); 16. WRE 67-76, L-4 (W16/3). Naviculopsis navicula (Ehrenberg) ..............000....00...c cece 186 17. WRE 67-77, L-4 (K49/0); 18. WRE 67-77, L-2 (C29/0); 19. a part of the same specimen of figure 18 with higher magnification, 1250. 222 Figure 12-15. BULLETIN 273 EXPLANATION OF PLATE 31 All figures <500 unless otherwise indicated. Page Naviculopsis nmavicula (Ehrenberg) .....000................000ccccceceeee 186 1. WRE 67-77, L-6 (W39/2). Naviculopsis quadrata Ehrenberg ......0.00000......0...ccceeccccecece ees 187 2. WRE 67-77, L-6 (W40/0). Naviculopsis regularis (Carnevale) .....000....0000...cccc eee 188 3. WRE 67-95, L-2 (G12/); 4. WRE 67-112, L-2 (037/0); 5. WRE 67-99, L-4 (K32/1). Naviculopsis, Sp* 2.20.6. S80 ee... eee 189 6. AUS 3, L-2 (M22/0). Naviculopsis trispinosa (Schulz) oo....000.0..ccccccccccccceeeeeceeeeeeees 190 7, 8. Different focus levels, lateral view, $136/966, L-2 (Q26/0). Paradictyocha polyactis (Ehrenberg) (0 ooo...cccccceccee 190 9. EM 8-15, 36-37 cm, L-2 (R45/1); 10. EM 8-15, 36-37 cm, L-3 (E16/0); 11. EM 8-15, 36-37 cm, L-4 (R9/0). Rocella gemma Hanna PRR R kN en Ee 192 12. JYN V 16 P, 231-233 cm, L-2 (L48/0); 13. MSN 149P, 294-296 cm, L-2 (Y16/2); 14. MSN 149P, 294-296 cm, L-2 (P27/4); 15. MSN 149P, 294-296 cm, L-2 (C19/3). BULL. AMER. PALEONT., VOL. 62 PLATE 31 BULL. AMER. PALEONT., VOL. 62 PLATE 32 Figure IP 3-5. 6-12. 13-18. 19-21. SILICOFLAGELLATES AND EBRIDIANS: LING 223 EXPLANATION OF PLATE 32 All figures 800 unless otherwise indicated. Page Wallacerfarhortonii blanma se tie oo eee tee te a cate nese eearee nce 194 1. CAS 1144, L-3 (N34/4), 500; 2. CAS 1144, L-3 (N18/3), < 500. Ammodochium rectangulare (Schulz) .....00.0..0.0000..c. 195 3, 4. Different focus levels, EM 7-1, 35-36 cm, L-2 (C10/0) ; 5. $136/880, L-2 (M7/4). Ebriopsis antiqua (SCHULZ). ees cee ee cee . 196 6, 7. Different focus levels, EM 6-2, 10-11 cm, L-2 (C38/0) ; 8. EM 7-1, 36-36 cm, L-2 (S33/3) ; 9. EM 8-9, 148-149 cm, L-2 (G28/1); 10. EM 8-15, 505-506 cm, L-2 (W32/0) ; 11, 12. Different focus levels, DSDP 6-6-2, 1-2 cm, R-1 (R11/0). Ebriopsis crenulata HOvasse ooo.........cccccceecccee ee ceeeceeeeees 197 13, 14. Different focus levels, $136/914, L-2 (U23/0); 15-17. Different focus levels, DSDP 6-6-2, 1-2 cm, L-2 (H11/2); 18. DSDP 6-4-3, 110-112 cm, L-5 (X20/2). Parathranium tenuipes HovaSsSe_ ..............0....0cc0ccccccceeeeeeeeeeeeeeeeeeee 198 19, 20. Different focus levels, EM 8-9, 148-149 cm, L-2 (J29/1) ; 21. EM 8-15, 505-506 cm, L-2 (V17/1). INDEX Note: Light face figures refer to page numbers. Bold face figures refer to the plate numbers. A var. aculeata, Dictyocha fibula 25 161, 202, 216 alata, Dorcadospyris.. 149, 161, 162, 166, 178, ae Algerian jfpecereeses 60 Ammodochium .......... 195, 196 Antanrcticiwmc 148 antepenultimus, Ommatartusee. 149, 166, 170 antiqua, Ebriopsis ..32 196, 197, a, apiculata, Corbisema .......... 23 151, 152, 214 Mesocena _............ 28 173, 174, 177, 193, 219 Paradictyocha ........ 176 apiculata, Septamesocena ..29 145, 174, 177, 180, 193, 220 forma apiculata, Dictyocha triacan- tha var. apiculata .. 152 var. apiculata, Dictyocha navicula.. 182 Dictyocha triacantha ............ 151, 152 Mesocena CiGCULUS) 22... 28 175, 176, 191, 200, 219 Mesocena oamaruensis ........ 173, 193, 194 aragonensis, Hantkenina ............ 182 archangelskiana, Corbisema .......... 23 152, 154, 214 Dictyochawe 152 var. archangelskiana, Dictyocha tiacantha ee 152, 155 forma armata, Diste- phanus speculum var. pentagonus .... 168 aseptatae, Mesocena .. 173 forma aspera, Dictyocha navicula var. biapiculata ...... 181, 182 Dictyocha triacantha var. apieulata, ....0.008 151 asteroides, Distephanus ............ 167 PRET ENIC Rs ioe ee 191, 203 ausonia, Dictyocha 25 159, 163, 164, 185, 189, 200, 202, 216 cf. ausonia, Dictyocha 159, 160, 202 Austria (or Austrian).. 142, 149, 158, 159, 178, 181, 189 B Bain’s Farm section .. 142, 174, 190 Bat DAGOS) Foc sen kaart 139, 146, 153, 163, 175, 183, 184, 185 barisanensis, Globoro- taliaetonsivee nso: 148 Bering Sa) ..-fe4 ee 148, 169, 170, 171 Bermudaneseest.. ee 187 biapiculata, Dictyocha (7?) ........ 181, 184 Naviculopsis _...... 30 181, 182, 183, 184, 221 var. biapiculata, Dictyocha navicula 181, 182, 185 Naviculopsis biapiculata .......... 182 bimucronata, Corbisema _.......... 24 153, 215 Dictyochay =. oee 154 bipartita, Dictyocha .. 148 bipes, Lychnocanium.. 142, 167, 203 bisectis, Coccolithus .. 193 bromia, Thyrsocyrtis.. 137 Buttle Diatomite ........ 178 Cc California (or Californian) 72. 142, 153, 154, 155, 163, 165, 168, 169, 171, 172, 173, 178, 181, 184, 185, 191, 192, 194, 195, 199, 200 California Academy of Science (CAS) .... 138, 154, 171, 172, 173, 195, 199 Cannopilusie 146, 148 var. cannopiloides, Distephanus SPEGulun | -ce.. cat 148 224 INDEX carinatus, Trique- trorhabdulus’ =... 193 Chaetoceros_................ 170 chalara, Podocyrtis .... 155 circulus, Dictyochal ys 175 Mesocena ......... 28 175, 176, 177, 201, 219 var. circulus, Meso- cena elliptica .......... 176 clathrata, Dicladia ?.. 198 clathratum, Parathranium _........ 199 Clathropyxidella ........ 146 var. complexa, Dictyo- cha pseudofibula .... 169 constricta, Naviculopsis ........ 30 183, 221 forma constricta, Dic- tyocha navicula var. biapieulata™ .20..4.2.. 183 var. constricta, Dictyocha Naviculasee ee 180 Naviculopsis biapiculata —2....- 183 Corbisema’-2=....2.0 32 151, 153, 199 costata, Calocycletta 20... 165, 178, 179, 186, 187, 188, 189, 203 crenulata, Ebriopsis °2..))).. 32 196, 197, 198, 200, 223 crux, Mictyocha. .......0 159, 165, 169 Distephanus ....... 26 164, 200, 217 forma decagona, Dis- tephanus speculum Var spolyactis) .......... Deep Sea Drilling Project (DSDP) 190 i. 135, 136, 137, 138, 153, 155, 156, 157, 161, 162, 166, 171, 182, 184, 185, 192, 193, 194, 197, 199, 200, 201 Spssaynbet sos 160, 165, 168, 170, 178, 197, 202 Delmontian Dicladian =. ee 198 Dichvoehawe ee: 151, 159 diodon, Mesocena ...... Wiis LitosreOue 202 var. diodon, Meso- cena crenulata ....... 178 Distephanus! 2. 164 forma dodecagona, Dis- tephanus speculum var. polyactis ....... 190 E I DTIODSISsa ee cee eee 196 elliptica, Mesocena .... 177, 178, 200, 201 cf. elliptica, Mesocena ....... 28, 29 173, 177, 178, 179, 202, 203, 219, 220 var. elliptica, Meso- cena elliptica .......... 177 forma eocaenica, Dic- tyocha fibula Vite, IACI, cessonsgnenne 164 experimental Mohole (EM) (or Mohole) .. 135, 137, 138, 142, 149, 150, 15 573159; 160, 162, 165, 166, 167, 168, 169, 170, 176, Wiel S819) 192, 196, 197, 199, 200, 201, 202 F fibula, Dictyocha .25 157, 160, 200, 216 Painilan dagen s =. fee. 165 var. flexuosa, Corbisema triacantha ....... 24 157, 158, 203, 215 Dictyocha ftiacantha 158 foliacea, Naviculopsis _...... 30 181, 182, 183, 184, 199, 221 Forrester’s Hill SGCtiOniie 32 3...04eeee! 142, 162, 179 lergcha(ec ae). pe nee 181 furcula, Lyramula 27 171, 172, 173, 195, 199, 218 BuUreSland ses ae 182 225 INDEX G gemma, Rocella ...31 192, 200, 222 geometrica, Corbisema ........... 24 151, 152, 153, 154, 155, 215 forma glabra, Meso- cena polymorpha var. triangulaliies:.. 193, 194 Globigerinoides DAtuIMG ree 140 GreCCe eo ececs teetsee- 3s 175, 181, 186 H Halicalyptraly -..-----:- 146 hastata, Corbisema..24 155, 157, 215 var. hastata, Dictyo- cha triacantha 155 TSIGIRVEUTEI, socennspaecceeeoeee 149, 150, 165, 188, 192, 201 hemisphaericus, Cannopilus _.......... 23 147, 148, 200, 201, 214 hexacantha, Corbisema _............-.. 162 Dichyochay. .eese.. 26 162, 217 forma hexacantha, Dictyocha deflandrel | ............. 162 hexagona, Mesocena .. 143, 177, 178 Hojuji diatomaceous mudstones |.)......-.---- 179 hortoni, Vallacerta ........... 32 194, 195, 199, 223 JERTROERIAY ssa pecedeansesece 169, 194 I iberica, Naviculopsis ............ 188 var. iberica. Dictyo- cha biapiculata ...... 187 forma inermis, Dictyo- cha triacantha Vat INeGMIS ese. 154 var. inermis, Corbisema apiculata 186 Dictyocha triacant has... ee 153, 154 Italy (or Italian) ........ 149, 157, 158, 159, 164, 178, 179, 186, 187, 188, 189, 202, 203, 204 J Jackson’s Paddock Sectlonue ee ates 142, 174, 180, 182, 198 Japan 2: | ees 159, 161, 165, 167, 169) 176; 176 japonicus, Distephanus) 222. 169 Jutland 2...382eoe 154 K Kellogg Shale ............ 142, 152, 179, 183, 184, 200 Kieselbalken: ...............: 182 Kreyenhagen Shale .... 163, 184 kugleri, Globigerapsis .......... 163 L WadOa: tse nce 168 var. laevis, Lyramula tenuipertica ............ 171 lata, Naviculopsis .30 185, 186, 189, 203, 221 var. lata, Dictyocha biapieulatal -se-core 185 forma late-radiata, Dictyocha triacan- tha var. apiculata 151,152 Dictyocha triacan- tha var. inermis .. 152, 154 forma longispina, Dictyocha crux ...... 165 Distephanus crux .. 165 var. longispina, Distephanus crux 26 165, 201, 217 TAU STAN ee ee 149, 150, 157, 178, 192, 199, 201 loyramiulay ae eee 170, 171 M Miryam died essences 188 Matuyama Reversed EypoOchiae ee 202 Mediterranean ............ 159, 167, 202, Pu 203, 204 mesnili, IE DRIOpSISHee ee 196, 197 Podamphora ............ 197 Mesocena 2.2... 145, 173, 194 226 INDEX forma mesocenoidea, Distephanus polyactis ....... 176 Paradictyocha polyactis ........ 45 176 var. messanensis, Dictyocha fibula 25 145, 161, mie IMGXIGOMLS Soke ; 192 forma minor, Corbisema triacantha 158 Dictyocha triacantha .... 157,158 Dictyocha triacantha var. iracanihale- 159 var. minor, Corbisema triacantha ...... 24 158, 201, 215 Dictyocha friacanthal 22.2. 157 Lyramula furculave. er, 172, 218 minoriformis, Meso- cena elliptica .......... 178 var. minoriformis, Mesocena elliptica .. 178 Mesocena cf. elliptica ........... 29 178, 220 Mohnian, -2..22.08...) 149, 150, 160, 165, 168, 169. LOS Ge S: 179, 199, 201, 202 Moron) Spain®s............ 151 Morsi sland ........:....<. 157, 159 mutabilis, Dictyocha.. 185 N navicula, Dictyocha 7-4... ‘ 180, 186 Naviculopsis 30, 31 181, 184, 186, 187, 189, 221, 222 Naviculopsis .....:........ 160, 180, 181, 199, 203 forma naviculoidea, Corbisema apiculata 186 var. naviculopsis, Dictyocha navicula. 186 Nicobar Island ............ 166 INOGEWAYE o)c:eo 191 re) Oamaru (or Oamaru Diatomite) ....... oamaruensis, Corbisema ... Mesocena ...........29 octacantha, Dictyocha var. octacanthus, Dis- tephanus crux ...26 octagona, Dictyocha .. var. octagona, Dictyo- cha shibulas. 26 octonaria, Dictyocha . ornamentum, Dictyocha Pacific Paradictyocha Parathraniume 2. forma pentagona, Dictyocha speculum var. pentagonus, Distephanus speculum 27 pentas, Spongaster .... petterssoni, Cannartus (?) picassoi, Cannopilus .......... 23 Phyllodictyocha ......... polyactis, Dictyochaws Distephanus ............ Paradictyocha .. 31 forma polyactis, Distephanus specu- lum var. octonaria Paradictyocha polyactis =... var. pOlyactis, Diste- phanus speculum . 227 142, 152, 153, 162, 163, 174, 177, 179, 180, 182, 183, 190, 194, 196, 198, 200 179 179, 193 166, 201 166, 200, 201, 217 161, 162 161, 200, 201, 17 161, 162 161 135, 148, 162, 166, 167, 170, 173, 192, 201, 202, 203 190 198 167 167, 201, 218 164, 167, 178 156 190, 191, 192, 201, 222 190 191 190, INDEX pons, Dictyocha 159, 160 var. pons, Dictyo- cha naviculale. 159 ponticulus, Dictyocha 186 forma pseudocrux, Distephanus speculum) =)... 168 var. pseudocrux, Distephanus Speculum! 22-72 27 168, 202,218 pseudofibula, Dictyocha 22... 169, 170, 202 forma pseudofibula, Distephanus Japonicusn.....4e.2 168, 169 Distephanus speculum) se. 169 var. pseudofibula, Distephanus speculum ....... 27 169, 201, 218 Q var. quadrangula, Mesocena elliptica.. 177 Mesocena polymorpha ........ 141, 177, 178 quadrata, Dichyoenay 4... 187 Naviculopsis ........ 31 187, 203, 222 var. quadrata, Dictyo- cha siderea .............. 195 recta, Corbisema ............ 24 155, 215 Dictyochae..t- 155 Phyllodictyocha . 155 var. recta, Dictyocha tracanthase 155 rectangulare, Ammodochium. ... 32 195, 196, 200, 202, 223 var. rectangulare, Dictyocha navicula.. 187, 188 rectangularis, Naviculopsis .......... 187, 188 recurvus, Isthmolithus ............ 153, 156 regularis, Dictyocha ........... 160, 188 Naviculopsis _... 31188, 189, 203, 222 var. regularis, Dictyo- cha ausonia Relizian 185, 189 149, 165 forma rhombica, Dictyocha fibula var. fibula 163, 164 var. rhombica, Dictyocha fibula .... 164 var. rhombus, Dictyocha fibula .... 164 robusta, Naviculopsis 185 ROCA te 35 eee 192, 200 Russia (or Russian) .. 153, 155, 158, 160, 164, 165, iPr Ges als), 180, 182, 185, 187, 194, 195 S Septamesocena .......... 173, 193, 194 septatae, Mesocena .... 173 Siberag 2 eee 182 Sicily? bie ee Itsy, les siderea, Dictyocha ... 194, 195 sidney, ‘Shales... 142, 152, 163, 179, 184, 200 simplex, Lyramula 28 172, 219 Siphonotestales .......... 146 SDAIN fa. eee eee 188 speculum, Dictyocha, 222... 167 Distephanus . 26, 27 147, 148, 162, 166, 167, 168, 191, 200, 203, PAL, PA: sphaericus, Cannopilus ......... 23 149, 150, 159, 201, 214 stauracanthus, Distephanus ........... 166 Stereotestales ............ 195 subarctios, Dictyocha.. 202 T tenuipes, Parathranium ... 32 198, 200, 202, 223 Thranivm ee 198 tenuipertica, lbyramulal eee 27 171, 218 tetraceros, Cannopilus ..........23 150, 151, 214 Mortontanieren cee 149, 150, 176, 179, 201 228 INDEX triacantha, Corbisema ............ 24 156, 157, 159, 166, 201, 203 Dictyocha,=— 4... 156 HV ESOCYLLISM see 155, 156, 163, 182, 183 forma triacantha, Dictyocha triacan- tha var. triacantha.. 157 var. triacantha, Cor- bisema triacantha .. 158 triangula, Dictyocha . Ilgey, Lee/z var. triangula, Meso- cena polymorpha 173, 193 trifenestra, Dictyocha 157 trigona, Corbisemas- 158 Dietyochay 156, 157 forma trigona, Dictyocha crux ..... 159 Atreab aN Gl, Ve cey ee ee cane 139, 178, 179 triommata, Dictyocha 156, 157 trispinosa, Naviculopsis ....... 31 190, 222 forma trispinosa, Naviculopsis bpliapiculata =o... 190 var. trispinosa, Dic- tyocha navicula z 190 tuberosa, Theocyrtis.. 137, 153, 156, 183 V valida, Ebriopsis . 196, 197 Vallacertameee- ine 194 Valmonte Diatomite . 178 variabilis, Distephanus .... 168 WATERED co sccmosncceepseccatcote 146, 198 virginis, Calocycletta ....... .. 140, 158, 160, 167, 179, 186, 189, 203 WwW Wakura Beds .............. 151 229 a) At ay n , a) 1 hae of A 4 aiioags ps ae ALi Pies ine nema "a ht } a mits) Ged) aeore whh hve WU phaneay HSollmatele? eaAceiuay Pyrat nile ival AN , oti als: WP tH at br: at PON eT Ani PiybE Ww til sball ata bi ‘ | : a) i dh ‘ ry ee | es | wie mrt iat 1 abe » f Ay iy hoy planta ee w wilder oe het eh 2 aon f ee ; hi ee iy, hiik ‘ Ne i jl Te Sey au) BY ud Lae git f pie ogyyd c : ad perl, we 4g) - ter nies - & L. LI LI. LIII. LIV. LV. LVI. LVII. LVIII. LXI. LXII. Volume lI. II. Il. IV. V. VI. (INos'9225-2350) 5, CSUSiapp. [42> plaiis.2 oe coe eos cee cre eee rceeeses 18.00 Venezuela and Florida cirripeds, Antarctic forams, Lin- naean Olives, Camerina, Ordovician conodonts, Niagaran forams. (Nos2sle232)en ) AZO pps, 10) play oie rere ese 18.00 Antarctic bivalves, Bivalvia catalogue. (Nigar 255-280 Nes (SE Teas Oa UMS estes apres an en aonc eacn seve 18.00 New Zealand forams, Stromatoporoidea, Indo-Pacific, Mio- cene-Pliocene California forams. (NG@aesc-coG) ao | FOS SDD ig 1451 PUR oat ret Seas cata cesmac cents 18.00 Venezuela Bryozoa, Kinderhookian Brachiopods. A) PIE 8 Sey a SP 2 2 rn 18.00 Dominican ostracodes, Texan pelecypods, Wisconsin mol- lusks, Siphocypraea, Lepidocyclina, Devonian gastropods, Miocene Pectens Guadaloupe. (Nos. 246-247). 6S DP LOO DiS swe eee ee ee eee Ae Bee 18.00 Cenozoic corals, Trinidad Neogene mollusks. (INs$9248°254)) 91572 spp 4 Op sine ree cree ee eo nacteeees 18.00 American Foraminifera, North Carolina fossils, coral types, Belanski types, Venezuelan Cenozoic Echinoids, Cretaceous Radiolaria, Cymatiid gastropods. (Nos. 255-256). Eve Way of eA fol hse eit ek ena ee 18.00 Jurassic ammonites. (Nos. 257-262). CUS ip oy oe CIC Tayo) Lah 9 ee ee emo as 18.00 Cretaceous Radiolaria, Cretaceous Foraminifera, Pacific Silicoflagellates, North American Cystoidea, Cincinnatian Cyclonema, new species Vasum. (No. 263). SILAS ID Dap ees: eee ee MN ee AMES: § 18.00 Bibliography of Cenozoic Echinoidea. (Nos. 264-267). S35 cps aOS PLS sce eee 18.00 Jurassic-Cretaceous Radiolaria, cirripeds, Bryozoa, paly- nology. (Nos. 268-270). SSD pene sleepless ee cee e terse ees 18.00 Mollusks, Murex catalogue, Cretaceous Radiolaria. (Ul. fe Bf 4 IE © yrs Ma aoe ee ee Eee 18.00 Trace fossils, ammonoids, Silicoflagellates, microfauna. PALAEONTOGRAPHICA AMERICANA See Johnson Reprint Corporation, 111 Fifth Ave., New York, N. Y. 10003 Monographs of Arcas, Lutetia, rudistids and venerids. (Nos. 6-12). CT 018A 7 03 eee ee nee eee A ee Re 23.00 Heliophyllum halli, Tertiary turrids, Neocene Spondyli, Paleozic cephalopods, Tertiary Fasciolarias and Pale- ozoic and Recent Hexactinellida. (Nos. 13-25). Bessey tee. CTU 0) Ci Me Ue LS oR Een area aan 28.00 Paleozoic cephalopod structure and phylogeny, Paleozoic siphonophores, Busycon, Devonian fish studies, gastropod studies, Carboniferous crinoids, Cretaceous jellyfish, Platystrophia and Venericardia. (Nos. 26-33). CMe ay ee EY Ah) CE nce ecetr canter oleate art -eee ater ara 28.00 Rudist studies Busycon, Dalmanellidae Byssonychia, De- vonian lycopods, Ordovican eurypterids, Pliocene mol- lusks. (Nos. 34-47). a SEN L OM plSay ces eee eee eee ee ee 32.00 Tertiary Arcacea, Mississippian pelecypods, Ambonychiidae, Cretaceous Gulf Coastal forams. (Nos. 38-41). EO PRR 0) C5 See eae 2 2F ee ee 35.00 Lycopsids and sphenopsids of Freeport Coal, Venericardia, Carboniferous crinoids, Trace fossils. VII. (Nos. 42-45). 257G Nps 58 aD Sain ee ee ee nen 23.50 Torreites Sanchezi, Cancellariid Radula, Ontogeny, sexual dimorphism trilobites, Jamaician Rudists. BULLETINS OF AMERICAN PALEONTOLOGY Vols. I-XXIII. See Kraus Reprint Corp., 16 East 46th St., New York, XXIV. XXV. XXVI. XXVII. XXVIII. XXIX. XXX. XXXII. XXXII. =IN- Y¥. 100175-U:S-A: (Nos.,80-87))., 334 pps)27- pls eee Mainly Paleozoic faunas and Tertiary Mollusca. (Nos;. 88-94B).7'306.*ppy. 30 pls.) 2:20, 0h ee oe eee Paleozoic, Mesozoic, and Miocene fossils. (Nos. 95-100). 420) pp.) 58- pls: tek ee eee Florida Recent, Texas and South America Cretaceous, Cenozoic fossils. (Nos! 1012108). 2°376 opp. 36-pls.. 22.202 3) 2 ee ee Tertiary mollusks, Paleozoic Venezuela, Devonian fish. (Noss 1092114) e412) pps k34iplsss cece ee seceeee ee Paleozoic cephalopods, Cretaceous Eocene, forams. CNost 1152116) 7738 pps 52 4plse ccc kece Bowden forams and Ordovician cephalopods. (No. 117). 563 pp., 65 pls. Jackson Eocene mollusks. @Nosiel182128) 4558 spp. 27 pls ee ee Mollusks, crinoids, corals, forams, Cuban localities. (Nos. 129-133). 294 pp., 39 pls. Silurian cephalopods, crinoids, Tertiary forams, Mytilarca. @Nos:..134=139) = 44:3pp:,: 51! ips) 2 eee ee ee Devonian annelids, Tertiary mollusks, Ecuadoran strati- graphy paleontology. (Nos: 140-145) 5400 ‘pp. 19 pls) 2 eee Forams, cephalopods, ostracods, conularid bibliography. (Nos. 146-154). 386 pp., 31 pls. Forams, cephalopods, mollusks, ostracods. Nos; 155-160). 412epp.) 53h plsy 4 ee Forams, Eocene fish, rudists. (Nos: 161-164). 486) pp:,737o pls: 2 ee Antillean Cretaceous Rudists, Canal Zone Foraminifera, Stromatoporoidea. (Nos. 165-176): 447 \pp.;°53" pls... ee Forams, ostracods, mollusks, Carriacou, fossil plants. (INos),177-183), 448) ppa3i6 pls.jes ee ee South American forams, Panama Caribbean mollusks. (No. 184). 996 pp., 1 pl. Type and Figured Specimens P.R.I. (Nos, 185-192), 388) pp. 35: piss 4.2 eee Forams, mollusks, carpoids, Corry Sandstone. (No. 193). 673 pp., 48 pls. Venezuelan Cenozoic gastropods. (Nos o3194-198 5-427 pp seo pss: pace Ordovician stromatoporoids, Indo-Pacific camerinids, Mis- sissippian forams, Cuban rudists. (Nos. 199-203). 365 pp., 68 pls. Puerto Rican, Antarctic, New Zealand forams, clina, Eumalacostraca. (No. 204). 564 pp., 63 pls. Venezuela Cenozoic pelecypods. (Nos:205-21) 4191) pps 70) pl Sep arcs rece ee Forams, Crustacea, brachipods, Recent mollusks. (Nos. .212-217).5) ¢584-pp.083) pls: 2 ee ee Forams, mollusks, polychaetes, ammonites. (No.'218). 1058S) ppsnsupls: 23 ee eee eee Catalogue of the Paleocene and Eocene Mollusca of the Southern and Eastern United States. (Nos; 219-224)... 671: ppg (83 pls. ee Peneroplid and Australian forams, North American car- poids, South Dakota palynology, Venezuelan Miocene mol- luska, Voluta. Lepidocy- 12.00 Res 14.00 14.00 14.00 18.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 16.00 18.00 16.00 16.00 16.00 18.00 18.00 18.00 BUEREE TINS OF AMERICAN PALEONTOLOGY (Founded 1895) MUS. COMP. ZOOL mea ote LIBRARY Vol. 62 = R 9 19/3 No. 274 FE HARVARD UNIVERSITY SILURO-DEVONIAN MICROFAUNAL BIOSTRATIGRAPHY IN NEVADA By W. A. McCLeLLAN 1973 Paleontological Research Institution Ithaca, New York 14850, U.S.A. PALEONTOLOGICAL RESEARCH INSTITUTION 1972 - 73 PRESIDENT ie ctecocesocsse eee ae ee ee ee ee Se DANIEL B. SAss VIGE=PRESIDENT coo oe eo ae Rk ane mae See MERRILL W. HAAS SECRETARY Joh ccc ck eS Pe Ree eee ee PHILIP C. WAKELEY (ASSISTANT SEGRE TARY: 6 soem te fog eae ha Pee Maa REBECCA S. HARRIS DIRECTOR; “TP IREASURER Messer Sere ee ne okt Ee ee ee KATHERINE V. W. PALMER COIN SE ae eee re a ae Be enh aes ee ARMAND L. ADAMS IREPRESENTA TIVE, CAV AVA GH COUIN GET: cesses eee een ee cee ee JOHN POJETA, JR. Trustees Resecca S. Harris (Life) Ceci, H. KINDLE (1971-1974) AXEL A. Otsson (Life) Harry S. Lapp (1971-1974) KATHERINE V. W. PALMER (Life) DANIEL B. Sass (1971-1974) DonaLp W. FIsHER (1967-1973) Vinci, D. WINKLER (1969-1975) MERRILL W. Haas (1970-1973) KENNETH E. CASTER (1972-1975) Puitip C. WAKELEY (1970-1973) D. Hoye EArGLe (1972-1975) 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. BWIREEATINS OF AMERICAN PALEONTOLOGY (Founded 1895) Vol. 62 No. 274 SILURO-DEVONIAN MICROFAUNAL BIOSTRATIGRAPHY IN NEVADA By W. A. McCLeLLan January 29, 1973 Paleontological Research Institution Ithaca, New York 14850, U.S.A. Library of Congress Card Number: 72-86844 Printed in the United States of America Arnold Printing Corporation CONTENTS Page JéN| OSL S| cee PRs Tap as Ae ES ng A Ue ee Be PE naa TE 235 PACK OW GG SIL e Its fae eeees were ee eee ee ae ee eee ce Sn eee 235 Tin tO GUC et orig cee a ee oO Rl rE sca MeLct jenna een eee 235 Stratignapliy: | a 08 ie wees Se ee ie Be A ie eae Repeat) 238 Balleontol ogynctetcee ee ee ee ee ee Pies ees) A LRN ee 246 LEE SESE) (Yo ia aE ee Bet tn SR AN EE BRE Mit Poa 252 PESTO SE REN Tc EY pe cn ee RE RR bee ce ea nN ih Seago cde degaieseeee 257 Systematicmp alle on tol o pry ge eee see ee tee ec ee cates a oe 2 2a ons Wetec zan as ee 275 MoLaminite rida cee etn eee eee ee ee SO er WS Ae 275 (QELS ETO IE ee ek Ae eee A A en ee 320 WG Gallntiygpnte OSte tye sees tae ce ese eet eee ear ees, eee ee NR ete ea te heats eA td 345 References @ite digests 5 tke Minis Binary cele eh A Aes tle as Sono Si ca Seer eh aa cPoaseeanaete 351 Plates scans ree rR ue ben ee ipo: | Petey WIR Sewn, pit eee 7 eet desc ie 357 TABLES Table Page 1. Extended geographic distribution of known Silurian genera .................. 249 2. Extended stratigraphic range of known SpeCies ..............-..--.c--ccssccsecsesesee-s 249 Sa CON OC OMS yg ee ce areata tec ht re NEM ee 5 OE DE 252 4. Family Astrorhizidae, abundance and stratigraphic range ......................- 259 5. Subfamily Psammosphaerinae, abundance and stratigraphic range ...... 259 6. Subfamily Saccammininae, abundance and stratigraphic range ................ 260 7. Subfamily Hemisphaerammininae, abundance and stratigraphic range .. 260 8. Additional families, abundance and stratigraphic range _.........................- 263 oe Order Laleocopidaystraticraphicy range) ese eee ee ere ere eee eee eee 264 1OsOxdersPodocopidawstratignaphic ran ce mses. cece eee eee 264 11. Stratigraphic occurrence of species at March Spring ....................::..:--+-- 265 12. Stratigraphic occurrence of species at Ikes Canyon .......................---.------- 266 13. Stratigraphic occurrence of species at Rabbit Hill ......................:......-00 267 14. Stratigraphic occurrence of species at Copenhagen Canyon ................-...-- 268 15. Stratigraphic occurrence of species at Lone Mountain ......................--.---- 268 16. Stratigraphic occurrence of species at Wood Cone ....................-::--::-00ee0--0-- 269 Wee otratioraphic occurnence Of species) at. Gatecl ithe es esses eececccaceseeoeesceoeeeeee 269 18. Stratigraphic occurrence of species at Pete Hanson Creek .....................-.. 270 19. Stratigraphic occurrence of foraminifers at Willow Creek ..................4 271 20. Stratigraphic occurrence of ostracodes at Willow Creek ....................... 272 21. Stratigraphic occurrence of species at Coal Canyon ..............2..---:::--00------ 273 22. Stratigraphic occurrence of species at Cortez Canyon ........................0.-.---- 274 ILLUSTRATIONS Figure Page iy dindex map) of centrall Neva die eee cee cee tes cee cee srens coe = pee c cee sc eeccecrecen cco cceecceeesnen=s 237 2. Stratigraphic relationships of Silurian and Lower Devonian EORINE ACTON Sealine CE MG all RIN ayced Cl elec ea ete eo ene ae 239 3. Siluro-Devonian Lithosomes in central Nevada ........ Bde cess t cwate tebe aaustaae 240 Roraminiteralimassemb laren Zz OMe si eee es ceree cerca eens cee cee cee arenes eee 258 ah a AWAITS i +f i E ss ‘f ‘ , ? } j - an ’ f j - ’ i e.1o4 ery , ° > ei) 2 7 ib odes vie ton ee _ ‘ pm) ein, i @ SALUT PE Ye ayi > Sere “ayo. Aa DA (00 9 ete 1 ee er ees ee: ‘ines veil A Re —s, vest! fore eet ale es i) yi i | es obu wll) Felis wl ereremin,? tr@me tenes ery | te4i ole: Svdiv tet py re Ohara olen Tdi3t 9 v heb oe het biey aati ' RL! ay «| TRL Ase | ~~ A abl yt | ey 4 all Pye i" eeeg) (Lived) (err ‘uy eet oF oak 0 ty peo fel"G i qieng y hy eng _— ite = rian geires 7h hangeep jadi SILURO-DEVONIAN MICROFAUNAL BIOSTRATIGRAPHY IN NEVADA W. A. McCLeELLAN ABSTRACT From a regional microfossi] study of Silurian and Lower Devonian strata in central Nevada, a large and diversified fauna of Foraminiferida and Ostracoda is described in detail for the first time. The foraminifers consist of 22 genera and 45 species. Two of the genera, Anictosphaera and Atelika- mara, and the following species are new: Anictosphaecra progressa, Asche- monella bastillensis, Atelikamara incomposita, Haplophragmoides antiquus, Hemisphaerammina bipatella, Sorosphaera compacta, Sorosphaera inflata, Storthosphaera malloryi. Recognition of Haplophragmoides antiquus in the Lower Devonian of central Nevada is the earliest record of the family Lituo- lidae. The ostracode fauna contains 29 genera and 20 identifiable species. Of these, Longiscapha is a new genus, and Aechmina cortezensis, Longiscapha nevadensis, Rudderina mutaspina, Thlipsura bispinosa, Ulrichia obesita, and Winchellatia fragilis are new species. The Foraminiferida recorded here have been combined with previously known Silurian species from the Midwest to establish a tentative series of assemblage zones for the Silurian and Lower Devonian of North America, which are based on dominance of the different subfamilies. The Nevada fauna represents the Upper Silurian, characterized by the Psammosphaerinae, and the Lower Devonian, characterized by the Astrorhizinae and Hemi- sphaerammininae. The Lower and Middle Silurian assemblages, best known in the Midwest, have been divided into the following three zones: 1) Albion — Hippocrepininae, Rhizammininae, Ammodiscinae; 2) lower Niagaran — Sac- cammininae, Ammodiscinae; 3) middle Niagaran — Hippocrepininae, Psam- mosphaerinae, Hemisphaerammininae. In general, there is not sufficient evi- dence for widespread correlations on the basis of the ostracodes recognized here, though several genera and species of the Nevada fauna compare closely with those known from Appalachian strata of uppermost Silurian and Lower Devonian age. The physical environment shows local variances with time which are recognized regionally as lithosomes. Association of the foraminifers with the several lithosomes suggests overall similarity to associations in other parts of North America. Associations between ostracodes and the various lithosomes remain uncertain due to their sporadic and limited occurrence. ACKNOWLEDGMENTS The writer wishes to especially thank Dr. V. S. Mallory for his critical review and suggestions on several important points in this study, Dr. John Kepper also assisted in many ways. The Atlantic Richfield Company generously contributed field expenses and research facilities. Additional contributions for field expenses were made by Humble Oil and Refining Company. The University of Nevada, Las Vegas, provided research funds for scanning electron microscopy. The Paleontological Museum of the University of Cin- cinnati in Cincinnati, Ohio, provided type specimens for study. INTRODUCTION Paleontological studies of Silurian and Lower Devonian rocks in the Cordilleran region have been mostly centered around the 236 BULLETIN 274 brachiopod faunas. Detailed microfossil reports have dealt exclu- sively with conodonts, though recent progress has been made with chitinozoans. Analysis of the combined brachiopod, conodont, and graptolite faunas has made possible the faunal subdivision of these strata, and certain of the elements have proven useful for inter- regional correlations. Foraminiferal studies of Middle Paleozoic rocks have never been made west of Oklahoma. The work of Ireland (1939) from that area is the only detailed study of the Upper Silurian and Lower Devonian. The only report of ostracodes from these strata in Nevada is that of Berdan in Gilluly and Masursky (1965). Foraminiferida and Ostracoda are reported here in detail for the first time from Nevada. In addition to the systematic description of species, the fauna has been applied as a biostratigraphic tool, and the age relation- ships of the formations, previously established on macrofossils or other bases, are re-examined in a regional framework throughout central Nevada, (Text-fig. 1). At this time the microfauna cannot be applied biostratigraphically in as refined a manner as the brachiopods and graptolites. The physical stratigraphic record is represented by a series of lithologically distinct bodies (lithcsomes) which persisted, or were recurrent, over an area for a considerable time. Lithosomes are recognized and presented here for two reasons. First, they demonstrate the changing depositional patterns across the region, an understanding of which is necessary to correctly interpret and correlate the various formational units. Second, they represent the environment which must be related to the biota for ecologic in- terpretations, All microfossils which are figured or otherwise recognized as identified material have been deposited in the micropaleontology collections of the Geology and Paleontclogy Division, Thomas Burke Memorial Washington State Museum, at the University of Washington in Seattle. Locality numbers are designated by the prefix UWA, and a description of each locality is given in the Locality Register. SILuRO-DEVONIAN MiIcroFAUNA: McCLELLAN ree eh W INNEMUCCA | hy BATTLE CARLIN ee ROUNTAINE— 23 BEOWAWE MITCHELL - CREEK TIELEGRAPH - NORTHUMBERLAND: : CANYON : = Limits of Study = Town = Major Section . = Other Sections Fig.1: INDEX MAP OF CENTRAL NEVADA 237 238 BULLETIN 274 STRATIGRAPHY Silurian and Lower Devonian rock units in Nevada comprise the major part of the Tippecanoe Sequence as demonstrated by Smith (1966) in his study of this sequence throughout western North America. Within the boundaries of the present study (Text- fig. 1) these rocks have been preserved in considerable thicknesses beneath the Wallbridge Discontinuity (Wheeler, 1963). They pre- sent a complete lateral series of marine rock types, from back-reef dolomites to reefoid units, fore-reef carbonates and shales, and finally the eugeosynclinal cherts, black shales, and quartzites. The various formational units (Text-fig. 2) are briefly outlined here and then considered, as applicable, in a presentation (Text-fig. 3) of the lithosomal units. The lithosomes more accurately illustrate the important lithic variables of the physical environment, which may be then related to the biological variables in the discussion of paleoecology. Previous workers have discussed the formations, and the purpose here is to develop an integrated picture of the Silurian and Lower Devonian environment. Correlations (Text- fig. 2) are based primarily on this integrated picture and the Foraminiferida and Ostracoda. FORMATIONS AND AGES The first recognition of rocks of Silurian age was by Hague (1892) who included all carbonates in the region ranging from Upper Ordovician through Silurian time as the Lone Mountain Limestone. He referred to those rocks, believed to be Devonian in age, as the Nevada Limestone. Subsequent work has resulted in several restrictions of these units as originally defined, as well as nomenclatural additions, In recent years relative agreement has been reached on the nomenclature by most workers. Merriam (1940) restricted the name Lone Mountain to a massive dolomite unit representing Late Silurian and possibly earliest Devonian sedimentation. To the east, outside of this area, the Lone Moun- tain Dolomite, thus restricted, merges with several other dolomite formations which have different lithologic characteristics. The Lone Mountain Dolomite has been demonstrated by Winterer and Mur- phy (1960) to be a dolomitized reefoid complex cropping out in a band striking north-northeast through east-central Nevada. The reef grew in a westerly direction during Silurian time and _ per- sisted into the early Devonian. SILuRO-DEVoNIAN MicroFAuNA: McCLELLAN 239 West Fast FROUAPUPUAUAHAD LRGRDURAPUDRDAPUDGATRAARINORADRRDAADOD S | | | McColley Canyon € D a fe) 5 . sy) 8 et ® = oe ee McMonnigal Rabbit tS o . : x Hill ° Lone | Mountain i Dolomite | | | | ! z Masket | £& fore Ss H = Shale | a c | | Roberts Mountains | 5 | E | | v | | ' = Uv © = Bastille | or Diana | i | > | | > | | = Gatecliff Hanson Creek to} { en te ee eee Fig. 2: STRATIGRAPHIC RELATIONSHIPS OF SILURIAN AND LOWER DEVONIAN FORMATIONS IN CENTRAL NEVADA cia) maa My bf AD a. i074 By Mo 8 “ad | : v, j = A eaten on : NE rar 8 zt ACEH : : 0 we pe---*--- =O 7) — = == »| Pe te SS Whatate ai : Pa os 507 ea ar a na | fj gS Pee Le Soe AD Ne ara4y Hoe cabal Spr. e> Gop eprasas#®.. Cy PPLE GP ag | AY ab! = sans abel EAC ACTRESS oo. ek LH ——a. SECECEACE RT : SRT | tal \ i Ne a : LW N LHL J \ aed i i aysiu : a Mi MA : 4 2 ; ni REE : ae ] / aT = Siena | [| E ae A l ge q nha ST ee COPENHAGEN CAMYON < (a) < = Zz WwW | 3 1 iP Astrorhizinae (1) Hemisphaerammininae (2) DEVONIA HELDERBERG GEDINNIAN ie = =) — t a —S Psammosphaerinae (2) | = | { | | | | | =i a | a | = Sipe phassle Wy aks ie im | oO > Hemisphaerammininae (2) f eeevhal, ies ee ee er Psammosphaerinae (2) | | | Hippocrepininae (1) ree | Saccammininae (2) Lid = eri Ammodiscinae (3) f=) | } ae i —— = eee | Ammodiscinae (3) | | ALBION | | Rhizammininae (1) | iF Hippocrepininae (1) Fig.4: FORAMINIFERAL ASSEMBLAGE ZONES TAB Bs 4 f SILURIAN LOWER t DEVONIAN Family ASTRORHIZIDAE Abundance and Stratigraphic Range Hyperammina casteri Hyperammina constricta Hyperammina curva =a Marsipella torta =] ery bifurcata ee Rhabdammina cylindrica | ———_—_}—s__1 V7 BBtersc PA Rhabdammina major =| Rare; 1-2 (——) Common: 6-10 (gma) Uncommon: 3-5 (c™-) Abundant: over 10 (cum) DEVONIAN Subfamily PSAMMOSPHAERINAE Cayuga (Helderberg) Abundance and Stratigraphic Range Ludlow Anictosphaera progressa TTATTA___} Ceratammina cf. C. cornucopia Psammosphaera cava Psammosphaera laevigata Raibosammina aspera Sorosphaera compacta Sorosphaera confusa Sorosphaera inflata Sorosphaera osgoodensis Stegnammina contorta Seem cre Storthosphaera malloryi | W777] V7T/I 3 Rare: 1-2 ( ) Common: 6-10 (waz) Uncommon: 2-5 (ct) Abundant: over 10 ( gmp) TABLE: 6 LOWER DEVONIAN SILURIAN (Helderberg) Subfamily SACCAMMININAE Abundance and Stratigraphic Range Sorostomasphaera waldronensis Stomasphaera brassfieldensis : a eae Rare: 1-2 (——) Common: 6-10 (gza) Uncommon: 3-5 (t=) Abundant: over 10 (dag) TABLE: SILURIAN LOWER DEVCNIAN Subfam. HEMISPHAERAMMININAE {Helderberg) Abundance and Stratigraphic Range Atelikamara incomposita Hemisphaerammina coronata Hemisphaerammina discoidea? Metamorphina gibbosa Metamorphina tholus Webbinelloidea hattini Webbinelloidea hemispherica Webbinelloidea atf W. nodosa Webbinelloidea ventriquetra Rare: 1-2 (——) Common: 6-10 (Zz) Uncommon: 3-5 (t=) Abundant: over 10 ( gm) Stturo-DeEvontan MicroFaAuNnA: McCLeLLan 261 nammina Moreman (1930) species and Anictosphaera progressa characterize the very latest Ludlovian strata and Helderbergian strata. The Hemisphaerammininae appear to be much more im- portant in the Lower Devonian, especially Webbinelloidea Stewart and Lampe (1947). An exception to this is Hemisphaerammina bradyi which is most common in the Upper Silurian. Though not as clearly defined as the Hemisphaerammininae, the family Astrorhizidae is also better represented in the Lower Devonian. However, nearly all of the astrorhizid species are known elsewhere from all levels within the Silurian. Pursuant to the above discussion, an informal zonation of the Silurian and Lower Devonian in central Nevada is shown on Text- fig. 4. The assemblage zones defined here are combined with those characteristic of Llandovery strata to lower Wenlock strata in southern Indiana. Further studies on the Upper Silurian in other areas may provide a refinement of the assemblages evident in Nevada. Little work has been done on Devonian foraminifers, making it difficult to establish any consistent relationship patterns. Ireland (1939) reported several Silurian species from the Lower Devonian Haragan Shale of Oklahoma, In addition he considered Ceratam- mina cornucopia, Metamorphina bipartita, and Psammonyx max- wells as restricted to the Lower Devonian. Other species, similarly restricted, have since been found in the Silurian. Ceratammina cf. C. cornucopia was found in Nevada in the latest Silurian; the other species were not encountered, The Haragan foraminifers, and those from Helderbergian beds here, have many characteristic Silurian species. It appears that a gradual transition occurs, with introduction of more and more Devonian species. The subfamily Hemisphaeram- mininae is the dominant group. Middle Devonian foraminifers are well known only in Ohio (Stewart and Lampe, 1947; Summerson, 1958). Two widely ranging Silurian species, Psammosphaera cava Moreman and Sorosphaera osgoodensis Stewart and Priddy occur commonly in these beds. Hemtsphaerammina Loeblich and Tappan (1964) and Webbinel- loidea Stewart and Lampe (1947) are the dominant genera how- ever. The Devonian species Hemtsphaerammina discoidea (Sum- merson) has been reported in the Silurian Waldron Shale by Mc- 262 BULLETIN 274 Clellan (1966, p. 487) and questionably recognized here in the Rab- bit Hill (Table 13). Webbinelloidea hemispherica Stewart and Lampe, also known in the Silurian is more common in the Devonian, Table 7 shows the increasing abundance and number of species of these two genera in the younger strata of this study. There is still a more marked difference between the Lower Devonian species of Nevada and the Middle Devonian of Ohio than between any rocks in the Silurian. Perhaps the most characteristic feature of the foraminiferal fauna is the stratigraphic limitation of Stegnammina Moreman (1930) and Fairliella Summerson (1958), As presently known, the several species of Stegnammina are restricted to strata no younger than Lower Devonian, and those of Fairliella occur only in the Middle Devonian. Because the earliest Silurian sediments studied here are Wen- lock in age and the Waldron Shale in Indiana is lower Wenlockian, there is only a small overlap between the two areas. There are several species which characterize the overlap. Sorosphaera con- fusa Brady which occurs sporadically throughout the Silurian, is present in similar quantities in both Indiana and Nevada. Psam- mosphaera laevigata White is common in the Lower Silurian and only present in the lowest strata in Nevada. Similarly, Glomospira Rzehak (1885), characteristic of the Lower Silurian, is represented in Nevada by G. stluriana which occurs rarely in the same units as Psammosphaera laevigata White. The only Silurian records of Aschemonella Brady (1879) are an unnamed species found in the Waldron Shale (Hattin, 1960, p. 2016) and A. bastillensis McClel- lan found here in the Bastille Limestone of early Wenlockian age. The total stratigraphic range of the ostracodes is shown on Table 9 and Table 10, each representing one of the two orders to which the species belong. Most of the species were found only in strata of Helderbergian age. One of the most commonly occurring species Phlyctiscapha keslingi Copeland has a greater stratigraphic range than previously known. It is likely that many other species would also prove to be more long lived if additional material were studied in detail. The restricted ranges in Table 9 and Table 10 should be used with caution for that reason. Winchellatia fragilis McClellan is the youngest known species of the Sigmoopsidae, an Ordovician family, and its uppermost Silurian occurrence here may StturRo-DEVONIAN MicroFAuNA: MCCLELLAN 263 SILURIAN LOWER TABLE; 8 DEVONIAN Additional Families (Helderberg Abundance and Stratigraphic Range Wenlock Ammodiscidae Glomospira siluriana Toloypammina tortuosa Hormosinidae Aschemonella bastillensis Lituolidae Haplophragmoides antiquus Endothyridae Nanicella dainae? Rare: 1-2 (—) Uncommon: 3-5 (C—) Common: 6-10 (mz) Abundant: over 10 ( umm) be stratigraphically useful. Limbinaria Swartz in Swartz and Whit- more, 1956 is restricted to upper Ludlow and lower Helderberg strata in eastern North America and has a similar occurrence here. Local stratigraphic distribution of the foraminifers and ostra- codes is shown on Tables 11-22, including columnar sections and sample localities, From these distributions the previously discussed composite range charts were compiled. It is evident that the oc- currences are locally discontinuous for the most part. This may be due in part to transportation of dead specimens, with the resultant faunule thus representing a thanatocoenose for most of the species. This is possible for some of the sample localities in the Willow Creek Section (Table 19). The ostracodes are even more locally restricted which clearly limits their biostratigraphic use without detailed study, TABLE: 9 SILURIAN Order PALEOCOPIDA DEVONIAN Stratigraphic Range Lidlow Helderberg BEYRICHICOPINA Aechmina cortezensis Aechmina equilateralis Aechmina longior Aechmina aff, A. phantastica | Bolbiprimitia teressaccula t Hollinella sp. | Kloedenia aparchoides L imbinaria sp. Myomphalus? sp. Phlyctiscapha keslingi a ea ee a fcewentes necturie | | =] Ulrichia obesita Cia Ea frees abeynei oe [Welleropsiejersevensie | mene een Poa KLOEDENELLOCOPINA Eukloedenella aff. E. dalhousiensis areal ene rel a Parahealdia aff, P, pecorella eS ass TABLE: 10 Order PODOCOPIDA SILURIAN DEVONIAN Stratigraphic Range Wenlock Ludlow Helderberg PODOCOPINA | ae, Acanthoscapha aff,A. navicula iz —- | Berounella sp. Bythocypris aff. B. alcocki Bythocypris? sp. Longiscapha nevadensis METACOPINA Birdsallella sp. Thlipsura bispinosa Tubulibairdia cf,T. chaleurensis 1 T. aff. T. chaleurensis | Tubulibairdia sp. [Rios | =. 265 SILURO-DEVONIAN MicroFAUNA: McCLELLAN jbulisay ees aed x ePplsajluilweuo4 \ Cee /OOL O Buluds youew i | | ny im HHH "| INI i | it | | | = O = E O O = = U STRATIGRAPHIC OCCURRENCE OF SPECIES AT MARCH SPRING Table 11: BULLETIN 274 266 "ds Ze1yasAaqijan Byisaqo e1ydidin SISUadNAa|eYd “| “ye elpalequjnqny Puldsejnw eulsappny "ds sayiiisend (Burjsay eydeasiyoKiyd SISUaISNOUl|ep “FZ “Jye ej jauapaod|ynq ‘ds gsiadAo0uyAg yoo e “g “sye Siid 2pode4}sQ Pdsaydsiway eaplojjauiqqam eyenose PUlWwWeiny{ ~TAsO; [ew esaeydsouys0jys jueWIOW PUlWWweUba,s éeysaqay eulwweubays edipuljAD eulwWeuUbays ®}40}U09 eulwweUba}S ‘ds exsaeudsoios PJE;JUL eLaeYdsSouOS esnjyuod esaeydsoios ediipuljAd eulwwepgeyy edadse eulwwesoqiey eaed esaeyudsowwesd 2}914}SU09 PUlWWwesadAH peig eulwwesaeydsiway Ppyiajlulweso4 {OOL O uoKkueg say| iE R| RI CIR yaxSeW mo|pny yoo, uaM common Cc uncommon, U rare, R STRATIGRAPHIC OCCURRENCE OF SPECIES AT IKES Table 12: CANYON 267 SILURO-DEVONIAN MicroFAuNA: McCLELLAN Erno Ye nO OG ee PolJaydsiway eaplojjaulqqam fUI}}eY4 Caplo|jaulqqom |>. iAsO]JewW esaeydsoyjyso0}S ej0ju09 eulwweubays ies ae epliajiulweso4 | aye oIeeraeRrS | i i H il il HH IItH ¥1qqey abundant A Cc rare U= R , O E = O Ut uncommon, Table 13: STRATIGRAPHIC OCCURRENCE OF SPECIES AT RABBIT HILL ‘ds eydeosiyIAlUd "ds e|/auapao|,0aNn TED eulmwweubays common epliajlulweso4 uncommon, C 0001 fo) uleyUNOW au0y rare, U R BuLLETIN 274 iKpeag Pienaar Pplsajylulwmeio4 ommon, = 5979 uy HT tit TL ivaatt i neath 6 , HH ii i ne HHH stat ttdiataiet vit Tr tReath uoKkuey) uabeyuadog R=rare, othe mojpny 268 OCCURRENCE OF SPECIES AT Table 15: STRATIGRAPHIC LONE MOUNTAIN Table 14: STRATIGRAPHIC OCCURRENCE OF SPECIES AT COPENHAGEN CANYON 269 SItuRo-DeEvontan MicroFAuna: McCLettan SISUaPjaljsseig eraeydsewo}s | « eiadse PulmWwesoqgiey PAPD PLAPUCGSOWWeS, epliaji ulweso4 ——— ‘ OL JJl]Ia}eO & o BARD PlaeUdsOWWeSY epliajiulweso4 aUu0) poom ule}UNOW au0] Table 17; STRATIGRAPHIC OCCURRENCE OF SPECIES AT GATECLIFF Mo|pny i nce Table 16: STRATIGRAPHIC OCCURRENCE OF SPECIES AT WOOD CONE BULLETIN 274 270 Eeyeinqnjyispenb eulwweisnu, Ssluejnbueipenb eulwweubays Zeysaqay eulWweuba}s S1SUapoobso esaeyudsosos edlspuijAd PUlMWepqgeuYy EIR ae UEC SOUS Ee a evo | me conn UO UE Be nm \Apeiq eulWwWwesaeydsiway common Pplsajlulweso4 6002 "6003 6004 O i oO ls is [@) 0) (e 5 H] HHH HHI : Hal i ays q q 7 Ot ; HHH HH iH IE}UNOW S}saqoy (oS SS 100G O U yaad UosSUeH ajad =rare, R STRATIGRAPHIC OCCURRENCE OF SPECIES AT PETE HANSON CREEK Table 18: 271 McCLELLAn S1LtuRO-DEVONIAN MICROFAUNA erjanbisjuan eSopou “M ‘sje edijaydsiway 1U1}}eU 49 Ze UE euES ay epliajluimeso4 ABO MRO oeaOno HAA ods 0 wnt! Sv DSHenTHGOgn HANA Hebets st 49a49 MOIIIM ~ c uo U ie >} O a S common, A R=rare, U=uncommon, STRATIGRAPHIC OCCURRENCE OF FORAMINIFERS AT Table 19: WILLOW CREEK BuLLeETIN 274 chaleurensis . B. alcocki le Willow Creek Ostracoda erditia? sp. airdia sp. erounella sp. Saccarchites saccularis Winchellatia fragilis Tubulibairdia cf. Roberts Mountains = |/5]/52i|= X|X|—1X|X]X]| XTX] XI] xX Table 20: STRATIGRAPHIC OCCURRENCE OF OSTRACODES AT WILLOW CREEK DAS: McCLeLLAn Stturo-DEVONIAN MICROFAUNA Sisuakassal sisdoisajjam Sijesayejinba eulwyodey B}911}SU0D BUulwwedad Ppliajlulweso4 SSS ,00S ) uokuey jeoy ae s cn Wnt in mo|pny yO; UaM ~ = oO 5e) [= 2 Oo ia) A : C=common uncommon, U rare, R STRATIGRAPHIC OCCURRENCE OF SPECIES AT COAL Table 21 ANYON r ~ BULLETIN 274 ©5980 °598I uncommon 274 SiSuadnajeyd “| “Jye elpsleqijnaqny x x x Xx =i aes x| xX] Xx] - DANG ae S| eles PjNDIAeU “YW “Jye EYdedsouUedY Ppliojlulwedso4 | Table 22: STRATIGRAPHIC OCCURRENCE OF HHH EIU Ae ea | ,OOL O ul a THEE uoAuey Za}109 rare, R SPECIES AT CORTEZ CANYON S1LtuRO-DEVONIAN MicroFAUNA: McCLELLAN 275 SYSTEMATIC PALEONTOLOGY Order FORAMINIFERIDA Eichwald, 1830 Suborder TEXTULARIINA Delage and Herouard, 1896 Superfamily AMMODISCACEA Reuss, 1862 Family ASTRORHIZIDAE Brady, 1881 Subfamily ASTRORHIZINAE Brady, 1881 Genus RHABDAMMINA MM. Sars in Carpenter, 1868 1869. Rhabdammina M. Sars in Carpenter, Royal Soc. London, Proc., vol. 18 (1868), No. 114, p. 61. Type species. — Rhabdammina abyssorum M. Sars (1869, zbid., poly), Description. — Test free, tubular, straight or branching with elongate arms, wall agglutinated, usually well cemented, apertures at open ends of tubular arms. This primitive genus, whose species are straight or branching tubes, is similar to several other genera. The most closely related is Astrorhiza Sandahl (1858) which also branches but differs in possessing a central chamber. Linear species of Rhabdammina, such as R. linearis Brady or R. cylindrica Glaessner, have often been misidentified, usually as Bathysiphon Sars (1872) species. This is especially true in studies of Paleozoic foraminifers because of poor test preservation. Bathysiphon should be partly defined, however, on the basis of a wall structure consisting of an inner layer of cemented sponge spicules covered by an outer layer of sand grains, or other mineral matter, with calcareous or siliceous cement. This wall structure was well illustrated by Cushman (1910, p. 32) in his discussion of Recent species of Bathysiphon. The wall structure of Rhabdammina is clearly shown by the scanning electron micro- graphs on Plate 33. A related third genus, Marsipella, uses sponge spicules, sand grains, or other foraminifer tests indiscriminantly in forming its tests. In contrast, Rhabdammina exclusively employs mineral grains, such as quartz, in the construction of its test. It is, therefore, probable that many identifications of Bathysiphon, based on completely arenaceous structured material, should be referred to Rhabdammina. 276 BULLETIN 274 Rhabdammina bifurcata Browne and Schott Pl. 33, figs. 8, 9; Pl. 39, fig. 4 1963. Rhabdammina bifurcata Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 198, pl. 48, figs. 4, 5. Description. — Test free, consisting of three nearly straight, branching, tubular arms united in a single plane to form a Y-shaped test, lower arm of the Y normally being longer than the other two; wall finely arenaceous and well cemented; apertures at open ends of tubes. Measurements. — Dimensions of figured hypotypes as follows: Test Length Diameter Short Arm Long Arm 34682 0.22 mm 0.07 mm 0.11 mm 0.18 mm 34683 indet. 0.11 mm 0.21 mm indet. Occurrence. — This species was found only at locality UWA 5991, where it is a rare element of the fauna. Its only other known occurrence is in the Osgood Formation of Indiana of Llandovery, or lowest Niagaran age, and its presence in Nevada extends the range of the species to the lowest Devonian. Rhabdammina cylindrica Glaessner Pl. 33, figs. 10, 11; Pl. 40, fig. 4 1937. Rhabdammina cylindrica Glaessner, Moscow Univ. Lab. Paleont., Prob. Paleont., vol. 2-3, p. 354. 1941. Bathysiphon exiguus Moreman, Stewart and Priddy, Jour. Paleont., vol. 15, No. 4, p. 370, pl. 54, fig. 7. 1942. Bathysiphon exiguus Moreman, Dunn, Jour. Paleont., vol. 16, No. 3, p. 322, pl. 42, fig. 27. 1961. Bathysiphon exiguus Moreman (in part), Mound, Indiana Dept. Con- serv., Geol. Sur., Bull. No. 23, p. 36, pl. 3, figs. 17-20. 1963. Bathysiphon exiguus Moreman (in part), Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 232, pl. 52, fig. 7, 8. 1966. Bathysiphon exiguus Moreman, McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 462, pl. 36, figs. 1-5; pl. 40, figs. 1-5. Description. — Test apparently free, straight cylindrical tube; wall finely arenaceous, poorly to well cemented; aperture at open ends of tubular test. Measurements. — Hypotype 34684 diameter 0.09 mm, length 0.84 mm; 34685 diameter 0.11 mm, length 0.67 mm. Occurrence. — Widespread throughout the area; present in varying degrees of abundance at all stratigraphic horizons within the several limestone formations. Figured specimens from UWA 5973. Discussion.—The species Bathysiphon exiguus Moreman SILURO-DEVONIAN MicroFAuNA: McCLELLAN Bt (1930) has frequently been applied to specimens having a straight, cylindrical or tubular test consisting of apparently arenaceous material. Moreman’s description (p. 46) of this species mentioned the character of a slightly tapering test. Possibly Moreman’s speci- mens should also be referred to the genus Rhabdammina on the basis of wall material. If so, they would be distinct from the species R. cylindrica Glaessner (1937) by virtue of the slight taper of the test. The species named by Glaessner is limited to cylindrical, non- tapering forms. Subsequent authors have identified material, which is cylindrical and nontapering, as Bathystphon exiguus. Mound (1961) and Browne and Schott (1963) included a variety of forms under the latter species, some of which can be referred to the former R. cylindrica. McClellan’s (1966) material contained one specimen (U.C. 37783) which is properly a Bathysiphon but should be assigned to another species due to the constrictions present on the test. Rhabdammina major de Folin IAL OB y. 30 0h al| 1887. Rhabdammina major de Folin, Naturaliste, Paris, vol. 9, No. 2, p. 127 (fetae). Description. — Test free, large, cylindrical, twisted, branching tube; wall composed of single layer of fine to medium sand grains with moderate cement; apertures at open ends of branching tubes. Measurements. — Hypotype 34686 length 1.63 mm, diameter 0.33 mm, branch length 0.37 mm, Occurrence. — This species is present only at locality UWA 6022 in shaly limestones. It has not previously been reported from the Silurian. Discussion. — The Y pattern of branching in Rhabdammina bifurcata is distinctive from the type of branching in R. major, and the twisted nature of most specimens of the latter is also a distinc- tive characteristic. Previously, R. major has been recorded as a Recent species, but it is found here in rocks of Middle Ludlow age. Subfamily RHIZAMMININAE Rhumbler, 1895 Genus MARSIPELLA Norman, 1878 1878. Marsipella Norman, Ann. Mag. Nat. Hist., ser. 5, vol. 1, p. 281. Type species. — Marsipella elongata Norman (1878, ibid., pl. 16). 278 BULLETIN 274 Loeblich and Tappan (1964, p. 186) redescribed the genus as follows: Test free, consisting of undivided tubular, cylindrical, or elongate- fusiform chamber, which may be slightly twisted; wall of agglu- tinated sand, sponge spicules, or tests of other foraminifers; aper- tures at open ends of tube. The above description is more in keeping with modern generic concepts than the original of Norman which appears to be re- stricted to the type species. An important feature is the variety of wall material allowable in this primitive foraminifer. While Mar- stpella elongata used sand grains and sponge spicules, several species, including those in the Paleozoic, used only the sand grains, This suggests a close relationship to Rhizammina Brady (1879) which uses the same materials in two layers, but whose test is not com- monly twisted and fusiform. Bathysiphon Sars (1872) shows more specialization, consistently having an inner layer with spicules and an outer one of sand grains. Marsipella torta Stewart and Priddy Pl33ietien7 1941. Marsipella? torta Stewart and Priddy, Jour. Paleont., vol. 15, No. 4, p. 370, pl. 54, fig. 4. Description. — Test free, cylindrical, twisted tube, tapering toward apertural end; wall thin, medium to finely arenaceous, mod- erately cemented; aperture terminal at end of tube, additional apertures not presently known from incomplete specimens. Measurements. — Length of the figured hypotype 34673 is 1.16 mm; larger diameter 0.30 mm, smaller, apertural diameter 0.18 mm. Occurrence. — This species occurs rarely at two localities repre- senting a time span from middle Ludlow to Helderberg age. It has previously been reported from the Osgood Formation of Indiana, which is earliest Niagaran, or middle Llandovery. Hypotype from locality UWA 6022. Discussion. — Stewart and Priddy, in discussion of the generic position of this species, believed that it was more twisted than nor- mal for the genus, and that it lacked sponge spicules in the test. Because the wall structure is known to be variable, their generic classification seems correct. Specimens recovered from the Nevada material are somewhat damaged so that no example adequately demonstrates the complete variability of the species. The tapering SILURO-DEVONIAN MicroFAUNA: MCCLELLAN 279 test is characteristic and serves to separate specimens from un- branched examples of Rhabdammina major. Marsipella sp. Ply soy tiga Description. — Test free, subcylindrical, moderately contorted, tubular; wall fine to medium sand grains poorly cemented; aper- tures at ends of tube though poorly defined due to damaged tests. One end with narrow lip at aperture. Measurements. — Length of figured specimen 34674 is 1.09 mm, diameter of undamaged portion 0.12 mm. Occurrence. — Rarely present at locality UWA 5973 in strata of Helderbergian age. Similar individuals referred to this genus have been reported from the Middle Silurian Waldron Shale in Indiana by Hattin (abstract, 1960, p. 2016). Discussion. — The two specimens recovered here both have one end of the test flattened, apparently by external forces, so that the original form is indeterminate. The test is less contorted than that of M. torta, the wall composition less consistent, and there is little cement. What appears to be minute openings of the test surface may be due to the poor cementation. Subfamily HIPPOCREPININAE Rhumbler, 1895 Genus HYPERAMMINA Brady, 1878, emend. Conkin, 1961 1878. Hyperammina Brady, Ann. Mag. Nat. Hist., ser. 5, vol. 1, pp. 433-434. Type species. —Hyperammina elongata Brady (1878, ibid., pl. 20s tig. Zab). The generic concept of Hyperammina that Conkin first dis- cussed (1954, pp. 167-168) and later (1961, p. 254) proposed as an emended description is that which is followed herein. Description. — Test free, arenaceous; with an elongate tubular, singular or branching second chamber, which may be nontapering, may taper toward the proloculus, or in a few species taper toward both the aperture and proloculus; aperture open or constricted slightly to strongly; interior smooth; exterior rough, may be marked by transverse constrictions of varying strength. Hyperammina casteri Conkin Pl. 33, figs. 2, 6 1961. Hyperammina casteri Conkin, Bull. Amer. Paleont., vol. 43, No. 196, p. 260, figs. 6, 7; pl. 20, figs 1-18; pl. 26, figs. 7, 8. 280 BULLETIN 274 Description. — ‘Test free, proloculus shape variable, usually oblate to spherical, followed by straight second chamber which expands gradually from constriction near proloculus to diameter greater than the proloculus; wall thin to thick, finely arenaceous, well cemented; aperture terminal on second chamber. Microspheric forms have a small, pointed proloculus and rapidly expanding second chamber giving the test the appearance of an elongated cone. Measurements. — Microspheric specimen 34670 has a_ test length of 0.58 mm, proloculus diameter of 0.06 mm, apertural end diameter of 0.16 mm. Specimen 34669 has broken second chamber and indeterminate length, but proloculus diameter is 0.18 mm. Occurrence. — This species is poorly represented here in Mid- dle Silurian strata at only two localities in the northern Roberts Mountains (UWA 5989, UWA 6024). Discussion. — Megalospheric forms of H. casteri are similar to those of H. glabra Cushman and Waters (1927), but the proloculus diameter is larger in relation to the second chamber than in the latter species. Conkin (1961, pp. 261-263) presented a thorough discussion of the affinities of H. casteri to other species with which the writer is in agreement. This species was first reported from earliest Mississippian strata where it is abundant in dark shales, silts, and calcareous shales. McClellan (1966, p. 460) found it to be dominant in lower energy environments of the Waldron Shale. In the present material it occurs in argillaceous and cherty lime- stone beds. Hyperammina constricta Gutschick and Treckman Pl. 33. fig. 4 1959. Hyperammina constricta Gutschick and Treckman, Jour. Paleont., vol. 33, Now2:5ps 237, pls 34, figs. 117-19) text fig. lamin: Description. — Test free, proloculus spherical; second chamber long, straight or slightly curved, bearing regularly spaced, slight constrictions; wall thin, finely arenaceous, well cemented; aperture terminal opening on second chamber. Microspheric stage not present in this material. Measurements. — Figured hypotype 34671 has length of 0.76 mm, maximum diameter 0.13 mm, minimum diameter 0.10 mm at constrictions. S1LURO-DEVONIAN MicroFAuNA: McCLELLAN 281 Occurrence. — Present only in rocks of lowest Devonian age at localities UWA 5974 and UWA 5985. Discussion. — Previously this species has been known only locally from Silurian and Mississippian rocks in Indiana. Its presence in Nevada indicates a wider geographic occurrence. In every case it is found in relatively clean limestones indicative of a preference for higher energy conditions than those of some hyperamminids, such as H. casteri which preferred a quiet, muddy environment, and H. rockfordensis (Conkin, 1961, pp. 270-272). Hyperammina curva (Moreman) Pim3o. figs 5 1930. Bathysiphon curvus Moreman, Jour. Paleont., vol. 4, No. 1, p. 45, pl. Seatipsee9 pelOs 1961. Hyperammina curva (Moreman), Mound, Indiana Dept. Conserv., Geol: Sur., Bull. No, 23, p: 35, pl. 3, figs. 13-16. Description. — Test free, with megalospheric proloculus small and bluntly rounded, microspheric pointed; second chamber long, gently tapering, and slightly curved with no constrictions; wall thin, finely arenaceous, well cemented; terminal opening of second chamber serves for an aperture. Measurements. — Specimen 34672 has a broken second cham- ber; remaining length is 0.44 mm, diameter 0.15 mm. Occurrence. — This is the most common Hyperammina species known from these rocks in Nevada. It was recovered from several horizons, indicating a presence throughout the entire sequence of strata studied here. The stratigraphic range of H. curva is here extended at least into the lowest Devonian by its occurrence in the Rabbit Hill Limestone. Figured specimen from locality UWA 6024. Discussion. — The original type specimens have the proloculus missing, hence Moreman’s mistaken identification as a species of Bathysiphon. However, they are well tapered as in Hyperammina. Mound (1961, p. 35) recovered a large number of specimens from the Brassfield Limestone of Indiana which compared closely with Moreman’s types and also possessed proloculi. Both of these collections are from rocks of Llandovery age in which the species is more abundant than in the younger rocks of central Nevada. Ecologically the Brassfield is probably similar to the silty limestone and argillaceous limestone of the Roberts Moun- tains Formation and Rabbit Hill Formation. Other occurrences of 282 BULLETIN 274 H. curva (Ireland 1939; Dunn, 1942), in the Illinois Basin, are in more pure carbonates, but the abundance of the foraminifer is not stated in these instances. Family SACCAMMINIDAE Brady, 1884 Subfamily PSAMMOSPHAERINAE Haeckel, 1894 Genus PSAMMOSPHAERA Schulze, 1875 1875. Psammosphaera Schulze, Komm. Untersuch. deutsch. Meere in Kiel, Jahresber., vol. 1872-73, p. 113 (fetae). Type species. —Psammosphaera fusca Schulze (1875, zbid.). Cushman’s (1918, p. 34) redescription is given below: Test free or attached, single chambered, usually spherical, no definite aperture, the pseudopodia making their way out through the interstitial openings between the elements of the test; wall of sand grains, mica flakes, sponge spicules, or other foraminiferal tests firmly cemented. This genus, with its simple, nonspecialized form, is one of the most primitive foraminifers known and is a common constituent of arenaceous foraminiferal faunas from the Middle Ordovician to Recent. It is found in almost every environment which agglutinated foraminifers have inhabited. In the Silurian and Lower Devonian of Nevada Psammosphaera has been found in rocks with lithologies varying from calcareous, dark, organic shales to reefoid dolomites. In several instances it is the only foraminiferal genus represented. This situation may be incurred by specimen transport into a thanatocoenose, but tubular and polythalmous, spherical genera would also be subject to the same transportation if such were the case. It appears more likely that Psammosphaera was more primitive and able to tolerate a greater variety of ecologic conditions. At the same time, the genus is often the most abundant one in a well- developed, diversified faunule. A possible explanation for this situation may be a lack of intensive competition among the foram- inifers due to the small number of individuals present. Psammosphaera cava Moreman Pl. 34, fig. 21 1930. Psammosphaera cava Moreman, Jour. Paleont., vol. 4, No. 1, p. 48, pl. (Gh, tier, TA Description. — Test free, spherical; wall thick to thin, outer layer of medium to coarse sand grains and inner pseudochitinous layer, well cemented but not an excess on the surface; no apparent aperture. SILURO-DEVONIAN MicroFAuNA: MCCLELLAN 283 Measurements. — Hypotype 34679 has a diameter of 0.25 mm. Occurrence. — Widespread, generally abundant relative to other foraminifers in these rocks. Specimen 34679 at locality UWA 6010. Discussion. — Spherical test shapes with a single arenaceous layer over an inner pseudochitinous one, such as P. cava, are prone to deformation after death of the animal, Therefore, a wide range of variation in shape may result, all of which represent the same species. Several new species have been erected by authors for these shapes. McClellan (1966, pp. 468-470) reviewed the synonymies which are referable to Psammosphaera cava. Psammosphaera laevigata White Pl. 34, fig. 26; Pl. 39, fig. 1 1928. Psammosphacra laevigata White, Jour. Paleont., vol. 2, No. 3, p. 183, pl. 27, figs. 1a,b. Description. — Test free, spherical, wall finely arenaceous with abundant cement, surface appearing smooth and silky; no aperture apparent, other than small, interstitial pseudopodia openings. Measurements. — The diameter of the figured specimen is 0.24 mm. Occurrence. — This species has been recorded as a minor faunal element from the Lower Silurian of Indiana and is similarly present here in the lower part of the Roberts Mountains Formation at locality UWA 6031. Discussion. — White’s type material appears to have been flat- tened. This flattening is not uncommon with Paleozoic species of Psammosphaera, but the examples here do not show similar distor- tion. The fine wall texture and abundant cement makes them readily distinguishable from specimens of P. cava, Genus ANICTOSPHAERA McClellan, n. gen. Type species. — Anictosphaera progressa McClellan, n. sp. Description. — Test free, multilocular, globular to spherical chambers closely appressed to loosely joined, broad openings be- tween chambers; wall consists of single layer of agglutinated sand grains, well cemented; no definite aperture. The most important feature of this genus is the presence of broad internal openings between the chambers, hence the origin of the name (Greek, anictos = open). The test has several cham- 284 BULLETIN 274 bers and no aperture, features which characterize many Psam- mosphaerinae. Other members of the subfamily which are poly- thalmous have no visible openings between the chambers. There is some indication of multilocular development in Storthosphaera Schulze (1875) indicated by the outward projections from the cen- tral chamber, which give the appearance of incipient chambers formed by an infolding of the test wall. Such “pseudochambers” are not evident on Antctosphaera; instead, well-developed chambers bearing recognizable sutures are readily observable. Arenosphaera Shchedrina (1939) appears similar to the type species Anictosphaera progressa, but close inspection reveals the multiple apertures between the agglutinated grains of the wall. Thus, Shchedrina’s genus belongs in the subfamily Saccammininae. All other characters of the two genera point to a close phylogenetic relationship. Anictosphaera progressa McClellan, n. sp. Pl. 34, figs. 1-5 Description. — Test free, multilocular, subspherical chambers tightly appressed with rectilinear boundary bearing a generally deep suture; presently known only as bilocular forms which have one chamber larger than the other; internal opening between cham- bers wide and circular; wall thin, medium to finely arenaceous, well cemented; no aperture known. Measurements. — Diameters of the smaller chamber varies from 0.08 mm to 0.19 mm. Larger chamber diameter ranges from 0.22 mm to 0.27 mm. The ratio of diameters between the cham- bers is most often approximately 2:1. Wall thickness is fairly constant at 0.02 mm. Small Larger Pl. 34 Spec. Number Chamber Chamber Rig, 1 34651 paratype 0.19 mm 0.27 mm Fig. 2 34652 paratype 0.08 mm 0.17 mm Fig. 3 34653 paratype 0.14 mm 0.27 mm Fig. 4 34654 holotype 0.10 mm 0.24 mm Fig. 5 34655 paratype 0.11 mm 0.22 mm Occurrence. — This species is present in rocks from the middle Roberts Mountains Formation to Rabbit Hill Formation. This SILURO-DEVONIAN MiIcrRoFAUNA: McCLELLAN 285 represents a range of middle Upper Silurian (Ludlow) to lowest Devonian age. Specimen 34651 from locality UWA 6020; 34652 and 34653 from UWA 6010; 34654, and 34655 from UWA 6009. Discussion. — The 2:1 ratio between the two chambers occurs commonly but might represent microspheric individuals, The para- type 34651, has a ratio of 3:2 that may indicate a megalospheric form. It is believed that this represents a particularly robust in- dividual, and there is insufficient material available to seriously consider the possibilty of dimorphism. No. 34653 does not have a strong suture between the chambers, but this is most probably only an individual variant in this respect, though it was first believed to be a dimorphic form. The most common occurrence of Anictosphaera progressa is in thin-bedded argillaceous limestones, but it is also present in the more nearly pure carbonates as well, From the known occurrences and associations it does not appear that any significant ecologic interpretations can be made. Genus CERATAMMINA Ireland, 1939 1939. Ceratammina Ireland, Jour. Paleont., vol. 13, No. 2, p. 194. Type species. —Ceratammina cornucopia Ireland (1939, ibid., p. 196, figs. A-31, 32). The description given by Ireland (p. 194) is as follows: Test free, horn-shaped; wall composed of fine sand grains; surface smooth; aperture not apparent. Ceratammina cf. C. cornucopia Ireland Pl. 34, fig. 25 Description. — Test free, near horn-shaped but only slightly curved, apparent constriction near larger end of horn; wall thin, finely arenaceous, well cemented; no apparent aperture. Measurements. — Length of figured specimen is 0.26 mm, larger diameter 0.17 mm, smaller diameter 0.11 mm. Occurrence. — This species is rarely present at locality UWA 6017 of uncertain stratigraphic position in the Upper Silurian. Ire- land (1939, p, 196) reported it as a distinctive Lower Devonian form. Discussion. — The referred specimen is not well preserved, showing a fracture along one side of the test. The constriction near the larger end may be externally induced, and also be partly re- 286 BULLETIN 274 sponsible for the indistinctness of the horn shape. Because of this damage the specimen cannot be definitely determined as a Cera- tammina cornucopia. Genus Raibosammina Moreman, 1930 1930. Raibosammina Moreman, Jour. Paleont., vol. 4, No. 1, p. 50. Type species. — Raibosammina aspera Moreman (1930, 1bid., pl. 6, figs. 13-15), designated lectotype. The genus, as originally designated, included forms which have subsequently been considered as species of Stegnammina Moreman (1930), including the original type R. mica Moreman. Loeblich and Tappan (1964, p. 196) included all Razbosammuna species within Stegnammina. McClellan (1966, p. 474) discussed the rela- tionships of these genera and suggested that Raibosammina aspera might well be better considered as generically separate from other Stegnammina species. It is, therefore, necessary to emend the original description of Moreman which did not restrict the genus to only branching forms. The following emendation is considered necessary: Test free, subcylindrical, chamber may be crooked, irregularly branch- ing; wall of variable thickness, arenaceous, poorly to well cemented, no aperture apparent. As thus described the genus is monotypic and Ratbosammina aspera is, therefore, designated as typical. Raibosammina is closely related to Stegnammina which has several similar subcylindrical species, but it differs from the latter in having a branching test. The only other species previously identi- fied as a Raibosammina is Stegnammina mica (Moreman), a sub- cylindrical, nonbranching, monothalmous form, Raibosammina aspera Moreman PI-33, fis, 125°Pi-- oo) tee 1930. Raithosammina aspera Moreman, Jour. Paleont., vol. 4, No. 1, p. 50, figs. 13-15. 1964. Stegnammina aspera (Moreman), Loeblich and Tappan, Treat. Invert. Paleont., Pt. C, Protista 2, vol. 1, p. 196 Description. — Test free, subcylindrical and branching, ends bluntly terminated; wall of poorly sorted sand grains, moderately cemented; no apparent aperture, numerous pseudopodia openings on surface. S1LtuRO-DEvVoNIAN MicroFAuNA: McCLeELLAn 287 Measurements. — Figured hypotype 34681 has diameter of 0.29 mm and length of 0.71 mm. Occurrence. — Uncommon at localities UWA 5985 and UWA 5996. Discussion. — This species has been recognized in rocks from Upper Ordovician to Lower Devonian age. It does not appear to have obvious habitat preferences nor to occur in abundance at any time during its known geologic range. It has a fairly wide geographic distribution, being present in faunas from Indiana, Oklahoma, and Nevada. Genus SOROSPHAERA Brady, 1879 1879. Sorosphaera Brady, Quart, Jour. Micr. Sci., vol. 19, new ser., pp. 28-29. Type species. — Sorosphaera confusa Brady (1879, ibid., pl. 4, fras. 18% 19 )t Brady’s original description follows: Test free, irregular; consisting of a number of convex or spheroidal chambers, either discrete or more or less embracing, irregularly crowd- ed together. Walls thin, loosely arenaceous in texture. General aper- ture, none. Long diameter of large specimens, 1/6 inch (4.5 mm.) Several species of this genus have been erected on the basis of differing number of chambers. It can readily be demonstrated that these species are all within the expected range of variation of a single species. The difference in number of chambers may be due to breakage and separation, or ontogeny. Grubbs (1939, p. 544) suggested the former and Hattin (personal communication) found a complete ontogenetic sequence of the genus which suggests the latter, in the Waldron Shale. The writer concurs with these opinions and has here considered two and three chambered forms as frag- ments or neanic individuals of species having a greater number of chambers, In the case of an isolated chamber it is impossible to recognize Sorosphaera from Psammosphaera cava unless a frag- ment of a second chamber is present. Sorosphaera confusa Brady Pl. 34, fig. 24 1879. Sorosphacra confusa Brady, Quart. Jour. Micr. Sci., vol. 19, new ser., oe Ay Rk Ze sitery ain ai) Description. — Test free, multilocular, consisting of a variable number of subspherical chambers connected closely in a random manner with adjoining walls somewhat appressed, entire test having 288 BULLETIN 274 a massive appearance; wall thin, usually finely arenaceous, well cemented; no apparent aperture. Measurements. — Chamber diameters of the hypotype 34687 are 0.29 mm, 0.43 mm. Occurrence. — Infrequently present at several localities and stratigraphic levels. Hypotype from locality UWA 6030. Discussion. — Sorosphaera confusa has been previously recog- nized throughout strata of Silurian age, and here is found in rocks of lowest Devonian age. None of these occurrences are in abundance. Though typically occurring in argillaceous or silty limestones, it has also been found in dolomitic limestones. Sorosphaera osgoodensis Stewart and Priddy Pl. 34, figs. 15, 16; Pl. 39, fig. 6 1930. Sorosphaera tricella Moreman, Jour. Paleont., vol. 4, No. 1, p. 49, pl. 5, figs. 12, 14. 1932. Sorosphaera tricella Moreman, Croneis, et al., Science, vol. 75, No. 1935, pl. 138. 1941. Sorosphaera osgoodensis Stewart and Priddy, Jour. Paleont., vol. 15, No. 4, p. 371, pl. 54, fig. 11. 1942. Sorosphaera bicella Dunn, Jour. Paleont., vol. 16, No. 3, p. 325, pl. 42, figs. 17, 18. 1942. Sorosphaera multicella Dunn, ibid., p. 325, pl. 42, figs. 19a, b. 1942. Sorosphaera tricella Moreman, Dunn, ibid., p. 324, pl. 42, fig. 15. 1947. Sorosphaera bicelloidea Stewart and Lampe, Jour. Paleont., vol. 21, No. 6, p. 534, pl. 78, fig. 6. 1958. Sorosphaera bicella? Dunn, Summerson, Jour. Paleont., vol. 32, No. 3, Pao sieepla Si, figs 13. 1958. Sorosphaera bicelloidea Stewart and Lampe, Summerson, ibid., p. 81, fig. 14. 1961. Sorosphaera bicella Dunn, Mound, Indiana Dept. Consery., Geol. Sur., Bull. No. 23, p. 33, pl. 3, figs. 4-6. 1961. Sorosphaera tricella Moreman, Mound, ibid, p. 34, pl. 3, figs. 7-10. 1963. Sorosphaera bicella Dunn, Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 211, pl. 49, fig. 16. 1963. Sorosphaera tricella Moreman, Browne and Schott, ibid., p. 212, pl. 49, fia oe 1966. Sorosphaera bicella Dunn, McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 472, pl. 37, 41, figs. 7-9. 1966. Sorosphaera tricella Moreman, McClellan, ibid., pl. 37, 41, fig. 10. Description. — Test free, multilocular, consisting of any num- ber of spherical to subspherical chambers, usually joined and always in a single plane which may be somewhat distorted; wall thin, fine to coarsely arenaceous, moderately cemented; no apertures ap- parent, infrequent minute and poorly defined pseudopodia openings present. StLtuRO-DEVONIAN MicroFAuNA: McCLeELLAN 289 Measurements. — Four-chambered figured specimen 34688 has chamber diameters of 0.15 mm, 0.15 mm, 0.16 mm, 0.13 mm. Speci- men 34790 has diameters of 0.15 mm, and 0.13 mm. Occurrence. — This species, though not widespread or abundant in Nevada, is present at several horizons. In Silurian rocks and Devonian rocks of other areas from which it has been reported, it also occurs in modest numbers. Hypotypes from locality UWA 6018. Discussion. — The several synonymous species listed above con- sist of individuals described as having two or three chambers and are here considered invalid. The figured specimens show that breakage readily occurs by separation between chambers. Speci- men 34688 has four complete chambers and a large part of a fifth preserved. Specimen 34790 has only a small part of a third chamber remaining, The writer concludes that such accidental breakage is responsible for the several species names applied by previous authors. The inclusion of two-chambered and three-chambered forms in the species S. osgoodensis is sometimes difficult to accomplish be- cause the chambers are attached in a single plane. This is especially true with two-chambered specimens when there are few individuals in a sample. S. osgoodensis specimens having only two chambers may be confused with S. irregularis Grubbs (1939) or S. subcon- fusa Dunn (1942). There presently is some doubt as to the validity of the latter two species, and they may well be S. osgoodensis. The chart below illustrates their relationships. S. osgoodensis S. irregularis S. subconfusa 1) Loosely joined, Chambers closely Closely joined, spherical chambers joined, spherical subspherical chambers 2) Growth-planar Growth-irregular Massive, irregular appearance 3) Well cemented Very well cemented Well cemented (this feature has questionable specific validity) 290 BULLETIN 274 Sorosphaera inflata McClellan, n. sp. Pl. 34, figs. 11, 12; Pl. 40, fig. 1 Description. — Test free, multilocular, chambers subspherical, presently known only as bilocular with one chamber two or three times larger than the other, chamber wall appressed where closely joined, with external suture moderate to deep, no openings between chambers; wall thin, medium to finely arenaceous, poor to well cemented; no aperture known. Measurements. — Paratype 34689 has smaller chamber diameter 0.15 mm, larger chamber 0.30 mm, and wall thickness 0.05 mm. Holotype 34690 with smaller chamber diameter 0.08 mm, larger chamber 0.27 mm, wall thickness 0.02 mm. Occurrence. — This species is rare, occurring at locality UWA 5976 and locality UWA 5987. Both localities are probably of latest Ludlovian age. Discussion. — The distinctive feature of Sorosphaera inflata is the pronounced inequality of size between the two chambers with subequal diameters. Loeblich and Tappan (1964, p. 196) included Arenosphaera perforata Shchedrina (1939) as a species of Soro- sphaera. This, then, would appear to be a closely related species because it has similar inequality in chamber size. However, A. perforata has an opening between chambers and multiple openings in the test wall, and thus actually should be considered a genus in the Saccammininae. If this is true, S. inflata, which has no recog- nizable openings between chambers or in the exterior wall, would have no known close relatives. Only two-chambered forms are currently known, but it is likely that specimens with more chambers may be found in the future. Although ecologic considerations of this new species must of necessity be limited by the quantity of material and its limited geographic extent, the two occurrences are in medium-bedded, fine- grained limestones. One of these bears common crinoidal fragments. The lack of argillaceous material might suggest somewhat higher energy conditions. Sorosphaera compacta McClellan, n. sp. PI. 34, figs. 13, 14; Pl. 40, fig. 2 Description. — Test free, massive, multilocular, subrounded to subangular, chambers closely packed in an irregular mass and nearly indistinct externally, adjoining chambers tightly appressed Situro-DEVONIAN MicroFAuNA: McCLeELLAaNn 291 with linear sutures faint to nonexistent; wall thin, medium to finely arenaceous, moderately cemented; no apparent apertures. Measurements. — Holotype 34691 has chamber diameters of 0.18 mm, 0.19 mm, 0.14 mm. Paratype 34692 has diameters of 0.11 mm, 0.13 mm, 0.17 mm. Occurrence. — This species is present in the Lone Mountain Formation and Roberts Mountains Formation, with a stratigraphic range through the Upper Ludlow. Holotype 34691 from locality UWA 5974 and 34692 from locality UWA 5992. Discussion. — Sorosphaera confusa is the most closely related species to S. compacta, but the latter is more massive in appearance and has more closely joined chambers. In the holotype, chambers can only be recognized because of the broken test. The figured para- type has a slightly depressed suture separating one of the three chambers. The chambers can also be externally recognized on an unfigured paratype, 346791 which has two partially damaged cham- bers. Sorosphaera compacta was recovered from samples without silt or mud. This would seem to indicate a preference for relatively higher energy conditions. Associated invertebrates include brachio- pods, Bryozoa, corals and crinoids in abundance. The microfauna is usually quite diversified and includes ostracodes, conodonts and, in one instance, tentaculitids. This fauna has been preserved in limestones and limey dolomites suggestive of well aerated waters having bottom currents. Sorosphaera sp. Pl. 34, fig. 20 Description. — Test apparently free, multilocular, chambers subspherical where not badly damaged, overall test configuration indeterminate; wall thin, composed of fine sand grains well cemented; aperture unknown. Measurements. — Diameter of measurable chamber 0.11 mm, other chamber diameter is indeterminate. Occurrence. — Present only at locality UWA 5985. Discussion. — Though the specimen is partially broken and one chamber much distorted, this species is not referable to S. confusa which also occurs at the same locality, for the well-developed cham- ber is more nearly spherical and discrete than those of that species. 292 BULLETIN 274 S. confusa and this species are the only sorosphaerids present in the McMonnigal Limestone. Genus STEGNAMMINA Moreman, 1930, emend. McClellan, 1966 1930. Stegnammina Moreman, Jour. Paleont., vol. 4, No. 1, p. 49. Type species. — Stegnammina cylindrica Moreman (1930, tbid., pHAgs pli tie; a2): The emended description of McClellan (1966, p. 475) is given below. Test free, monothalmous, cylindrical to angular, straight to curved; wall thin to thick, agglutinated, poorly to well cemented; aperture not apparent. Stegnammina contorta McClellan Pl. 34, fig. 22 1966. Stegnammina contorta McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 476, pls. 36, 40, figs. 17, 18a, b. Description. — Test free, monothalmous, cylindrical and twist- ed, ends rounded, chamber tubular and narrow; wall thick, fine to medium arenaceous grains, poorly cemented; no aperture apparent. Measurements. — Length of figured hypotype 34696 is 0.57 mm and diameter 0.12 mm. Occurrence. — Present in small numbers at several localities representing a general Ludlow age. Specimens at locality UWA 6010, which is very near the probable Silurian-Devonian boundary, are the latest known occurrence for the species. Hypotype 34696 is from locality UWA 6024. Discussion. — Stegnammina contorta evidently has no strong preference for a particular energy level of its habitat. It has most frequently been recovered from sediment consisting of mixed argil- laceous and calcareous material, The species is also present in lime- stones with little argillaceous material, though there is some indica- tion that this is not the preferred environment. Stegnammina cylindrica Moreman Pl. 34, fig. 18 1930. Stegnammina cylindrica Moreman, Jour. Paleont., vol. 4, No. 1, p. 49, yoNk: i, sated. 1. 1942. Stegnammina cylindrica brevis Dunn, Jour. Paleont., vol. 16, No. 3, 1. 325, pl. 42, fig. 25. Description. — Test free, monothalmous, cylindrical, ends flat- tened; wall thin, finely arenaceous, well cemented; no definite aper- ture, but smal] pseudopodia openings present on test surface. StLtuRo-DEvoNIAN MIcRoFAUNA: MCCLELLAN 293 Measurements. — Figured specimen 34697 measures 0.22 mm in length and 0.13 mm in diameter. Occurrence. — This species was found at several localities in the middle Roberts Mountains Formation, or its equivalent, repre- senting middle Ludlow time. Though well known elsewhere from older Silurian strata it has not been recognized in the older units within this area. Presence of this species at locality UWA 5978 lends paleontological support to the assignment of these beds to the Roberts Mountains Formation rather than to the Hanson Creek, as suggested in the stratigraphic discussion previously. The figured hypotype is from locality UWA 6017. Discussion. — The length of Stegnammina cylindrica has been shown by Mound (1961, p. 25) to range from 0.17 mm to 0.50 mm. The subspecies, S. cylindrica brevis Dunn supposedly varies from Moreman’s type in being only half as long. However, it is still well within the range determined by Mound for S. cylindrica specimens. The occurrence noted above is the youngest yet known for the species sensu stricto. Mound (1961, p. 25) and Browne and Schott (1963, p. 210) considered Stegnammina elongata Ireland (1939) as synonymous with S. cylindrica. The writer believes that S. elongata presently is not well enough known to be so placed taxonomically. The main reason concerns the use of length-width ratios in the two species. McClellan (1966, p. 475) suggested the likelihood of a fairly constant 2:1 ratio between these dimensions for S. cylindrica. Measurements made on specimens recovered here agree with that ratio. The ratio in S. elongata, if similarly constant, would be much greater, but no measurements have been made for a comparison. The only reported occurrence of Stegnammina cylindrica in the Devonian is that by Mound (1961) and Browne and Schott (1963). Following the above discussion of that species and S. elongata, as considered herein the specimens at locality UWA 6010 represent the youngest occurrence of S. cylindrica. Stegnammina hebesta? Moreman Pl. 34, fig. 19 1930. Stegnammina hebesta Moreman, Jour. Palecnt., vol. 4, No. 1, p. 50, pl. 7, fig. 13. Description. — Test free, subcylindrical, robust, ends rounded, diameter about two-thirds the length; wall thin, finely arenaceous and well cemented; no apparent aperture. 294 BULLETIN 274 Measurements. — Length of the figured specimen is 0.21 mm and diameter 0.14 mm. Occurrence. — Hypotype 34698 is from the McMonnigal Lime- stone at locality UWA 5985. Forms referred to this species are also present at locality UWA 6000. Both localities are of Helderbergian age, Discussion. — The type specimen of Moreman is more robust than any of those in the present material, having a diameter about three-fourths the length. This feature is one of the main reasons for separating S. hebesta from the less robust species S. cylindrica. The material at hand is poorly preserved for the most part, and the thin test walls are fragile, making measurement of the length- diameter ratio difficult. The figured specimen, though slightly de- formed, seems typical, however, and has a ratio of 3:2 which is between S. cylindrica and S. hebesta. The consistency found within examples of the former species precludes the identification of this material with them. Therefore, it has been referred to S. hebesta with some question. Ecologically this species had a preference for a higher energy environment as indicated by its occurrence in nearly pure carbonate rocks. In contrast, Stegnammina cylindrica was found in rocks indicative of quieter conditions as well as consistently occurring at lower stratigraphic horizons. Stegnammina moremani (Dunn) Pl 3s4 tig V7 Pi soe thica? 1942. Thekammina moremani Dunn, Jour. Paleont., vol. 16, No. 3, p. 326, pl. 42, fig. 22. 1961. Thekammina moremani Dunn, Mound, Indiana Dept. Conservy., Geol. Sum, Bulli Nos 23, ps 26) ple i, fiz: 29: 1964. Stegnammina moremani (Dunn), Loeblich and Tappan, Treat. Invert. Raleont., Pt. ©) Protistay2) vol. 1) ps 196. Description. — Test free, triangular in outline, slightly de- pressed; wall thin, finely arenaceous, well cemented; no aperture apparent, except minute openings on test surface. Measurements. — Length of hypotype 34699, measured from triangle apex to opposite side is 0.21 mm for each side. Occurrence. — This is a rare species, present only at locality UWA 5985 in the McMonnigal Limestone. The only previous re- port of S. moremani is from the Lower Silurian Brassfield Limestone in Missouri and Indiana. StturRO-DEVvoNIAN MicroFrAuna: McCLeLian 295 Discussion. —Loeblich and Tappan (1964 p. 196) included species of Ratbosammina Moreman (1930) and Thekammina Dunn (1942) within the generic limits of Stegnammina stating that “modifications of chamber shape are not regarded as generic in importance”. Because Thekammina had been erected on the basis of its angular test shape it falls within the species limits set by them. Stegnammina quadrangularis (Dunn) P34 tes load 1942. Thekammina quadrangularis Dunn, Jour. Paleont., vol. 16, No. 3, p. 326, pl. 42, fig. 23. 1961. Thekammina quadrangularis Dunn, Mound, Indiana Dept. Conserv., Geol. Sur., Bull. No. 23, p. 25, pl. 1, fig. 28. 1963. Thekammina quadrangularis Dunn, Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 210, pl. 49, figs. 13, 14. 1964. Stegnammina quadrangularis (Dunn), Loeblich and Tappan, Treat. Invert. Paleont., Pt. C, Protista 2, vol. 1, p. 196. Description. — Test free, boxlike with planar sides; wall thin, fine to coarsely arenaceous, poor to moderately cemented; no aper- ture apparent. Measurements. — Hypotype 34700 has length 0.44 mm and width 0.42 mm. Hypotype 34701 has length 0.64 mm and width 0.31 mm. Occurrence. — Specimen 34700 is from locality UWA 5992 and 34701 from locality UWA 6019, both in the Lone Mountain Dolomite. The species is also uncommonly to rarely present at several other localities from Ludlow to Lower Helderberg age. Discussion. — For the same reasons as those presented in the discussion of S. moremant, this species belongs within the limits of Stegnammina and the generic name Thekammina should be sup- pressed as a junior synonym. The test shape of S. quadrangularts varies substantially from nearly square to elongate, always with the boxlike form. Most specimens here were nearly square. The height of the test is usually indeterminate because the thin, fragile wall is so easily damaged and distorted. This species occurs most frequently in silty and shaly lime- stones indicating a probable preference for quieter water. How- ever, the two hypotypes are from a distinctly different environment, the reefoid conditions in the Lone Mountain Dolomite. It is one of the few foraminifers found in this environment, and its presence 296 BULLETIN 274 here is the only known occurrence in such conditions as well as its youngest stratigraphic position, Genus STORTHOSPHAERA Schulze, 1875 1875. Storthosphaera Schulze, Komm. Untersuch. deutsch. Meere iz Kiel, Jahresber, vol. 1872-73, p. 113. Type species. —Storthosphaera albida Schulze (1875, ibid., pl. 2). Description. — Test free, monothalmous, irregular chamber, wall finely arenaceous, poorly to well cemented, aperture indefinite. The surface of the test wall may be irregular with protuber- ances of various configurations but not possessing any aperture. The interior, despite the irregularities of the test which suggest incipient chambers, lacks a definite indication of subdivision that might sug- gest Sorosphaera. Storthosphaera malloryi McClellan, n. sp. Pl. 34, figs. 6-10; Pl. 40, fig. 3 Description. — Test free, irregular, globular chamber appears lumpy on exterior; wall thin, very finely arenaceous, well cemented; no aperture apparent. Measurements. — Maximum test size for the figured speci- mens averages 0.26 mm. Pl. 34 Spec. Number Test Size Fig. 6 34703 holotype 0.29 mm Big. /, 34704 paratype 0.19 mm Fig, 8 34705 paratype 0.22 mm Fig. 9 34706 paratype 0.26 mm Fig. 10 34707 paratype 0.33 mm Occurrence. — Present throughout the stratigraphic interval at several localities. Holotype 34703 from locality UWA 5985; para- types 34704, 34705 at UWA 5985; 34706 at UWA 5976; and 34707 at UWA 6010. Discussion. — This species varies considerably from the type, S. albida, which has an irregular wall thickness and heterogeneous development of ridges and protuberances on the surface. In con- trast, S. malloryi has a thin wall and a lumpy, or globular, surface appearance. The lumpy nature actually resembles chambers but SILURO-DEVONIAN MiIcROFAUNA: MCCLELLAN 297 smaller lumps make up most of the surface of these pseudochambers. Interiorly there is no indication of subdivision into a multilocular growth, hence this is regarded as a species of Storthosphaera. Previously Storthosphaera has been known only from the Recent and generally from cold waters. In the present material it ranges from the Middle Silurian to Lower Devonian. There seems not to be any preference for a particular environment other than not being found in the high energy condition of the reefoid dolomites. Subfamily SACCAMMININAE Brady, 1884 Genus SOROSTOMASPHAERA McClellan, 1966 1966. Sorostomasphaera McClellan, Bull. Amer. Paleont., vol. 50, No. 230, pp. 478, 479. Type species. — Sorostomasphaera waldronensis McClellan, (1966, zbid., pls, 37, 41, figs. 1-5). The original description of McClellan (1966, p. 478) is as follows: Test free, multilocular, consisting of a variable number of globular to spherical chambers irregularly attached to each other; chambers may be loosely connected or appressed where adjoined; wall thin, finely arenaceous, well cemented; single, rounded aperture on each chamber, no openings between chambers. Sorostomasphaera differs from Sorosphaera Brady (1879) in possessing apertures, and from Saccamminoides Geroch (1955) in having consistent chamber diameters each with an aperature. Sorostomasphaera waldronensis McClellan Pl. 35, figs. 7,8 1966. Sorostomasphaera waldronensis McClellan, Bull. Amer. Paleont., vol. 50, No. 230, pp. 479-80, pl. 37, 41, figs. 1-5. Description. — Test free, multilocular, variable number of chambers which are subspherical, chambers loosely or firmly joined, wall thin, very finely arenaceous, well cemented; single circular aperture on each chamber. Measurements. — Diameter of single chamber is 0.30 mm on hypotype 34694. Diameter of 34695 is 0.29 mm. These measurements compare closely with the original types (McClellan, 1966, p, 480). Occurrence. — Rarely present at two localities, UWA 6028 (hypotypes) and UWA 6025 in the Willow Creek section. The stratigraphic interval is Wenlockian to lower Ludovian, in the lower and middle Roberts Mountains Formation. 298 BULLETIN 274 Discussiton.— The presence of this species here extends its stratigraphic range, but it is significantly absent from localities in younger strata which indicate quite similar physical environment conditions. McClellan (1966, p, 379) stated that the genus was not particularly specialized ecologically, and its occurrence in Nevada is similar to that discussed by him. Thus it is possible that Sorostomasphaera waldronensis is biostratigraphically a_ useful species restricted to rocks of middle and upper Niagaran age, Genus STOMASPHAERA Mound, 1961 1961. Stomasphaera Mound, Indiana Dept. Conserv., Geol. Sur., Bull. No. S35 Oy Cade Type species. —Stomasphaera brassfieldensis Mound (1961, thid., pl. 2, figs. 9-13, text fig. 3). Mound’s (p. 28) generic diagnosis is as follows: Wall rough, thick to thin, medium to coarsely arenaceous, grains poorly to well cemented; test free, subangular to spherical, most com- monly subspherical or spherical; aperture single, round or oval. This is a common Lower Silurian genus in Indiana but rare from younger rocks, It occurs rarely in central Nevada no higher than lower Ludlovian, or uppermost Niagaran. Stomasphaera brassfieldensis Mound Pl. 36; fig. 7 1961. Stomasphaera brassfieldensis Mound, Indiana Dept. Conserv., Geol. Sur., Bull. No. 23, p. 28, pl. 2, figs. 9-13, text fig 3. Description. — Test free, monothalmous, subspherical, slightly produced around aperture; wall thin, medium to finely arenaceous, well cemented; single, round aperture. Measurements. — Hypotype 34702 diameter is 0.62 mm and aperture 0.14 mm. Occurrence. — The figured specimen is from locality UWA 6022 in the Roberts Mountains. The species is also present at locality UWA 5983 in the Bastille Limestone. Rare at both localities. Discussion. — The similarity between S. brassfieldensis and Saccammina Sars (1869) species is close except for the aperture. Saccammina species have the aperture at the end of a short neck which is lacking on the well-preserved Stomasphaera brassfieldensis in the Bastille strata and Roberts Mountains strata. Sorostoma- sphaera waldronensis also has affinities with Stomasphaera brass- fieldensis, but is consistently more nearly spherical, has no modi- SILURO-DEVONIAN MicroFAUNA: MCCLELLAN 299 fication of the test in the apertural area, and has a thinner and more finely arenaceous wall. These features allow identification even of isolated chambers. Genus THURAMMINA Brady, 1879 1879. Thurammina Brady, Quart. Jour. Micro. Sci. new ser., vol. 19, pp. 45-47. Type species. —Thurammina papillata Brady (1879, sbid., p. 45) subsequently designated, Cushman, 1910, p. 57. Brady (1879) failed to provide a generic diagnosis and Cush- man (1910, p. 57) subsequently described the genus and designated the type species. Test typically free, usually nearly spherical, but in some species com- pressed, chamber single and undivided in typical species; wall thin, composed of fine sand with more or less chitin; apertures several to many at the end of nipple-like protuberances of the surface, occasional- ly wanting. There are a number of lower Paleozoic species of Thurammina but seldom is any one of them abundant. The material studied herein has each of the species sparsely present at only one or two localities. McClellan (1966, p. 481) did not find the genus to be generally useful as an environmental indicator. Certain species may nonetheless be ecologically restricted in the Siluro-Devonian sedi- ments of central Nevada. Thurammina arcuata Moreman Pl. 35, fig. 18 1930. Thurammina arcuata Moreman, Jour. Paleont., vol. +, No. 1, p. 54, pl. Geties. 2. 3. Description. — Test free, monothalmous, arcuate, inflated poly- gonal outline; wall thin, finely arenaceous, well cemented; aper- tures several, at ends of short, broad protuberances. Measurements. — Width of hypotype 34708 is 0.37 mm. Aper- ture neck length 0.04 mm, Occurrence. — Uncommon, figured specimen from _ locality UWA 6018, in the McColley Canyon Formation. Also present in the McMonnigal Limestone at locality UWA 5985. Both forma- tions are of Lower Devonian age. Discussion. — The specimens recovered here are more robust than Moreman’s figured types, and the short nodes bearing the apertures are better developed. The polygonal and arcuate outline is consistent with both Moreman’s (1930) specimens and those of Browne and Schett (1963). 300 BULLETIN 274 Thurammina arcuata has previously been recorded from Lower and Middle Silurian argillaceous limestone strata. McClellan (1966, p. 460) listed this species as one limited to lower energy environ- ments in the Waldron Shale of Indiana. The specimens from cen- tral Nevada were found in less argillaceous carbonates, suggestive of higher energy conditions. Thurammina quadritubulata? Dunn Pl 3b tigao 1942. Thurammina quadritubulata Dunn, Jour. Paleont., vol. 16, No. 3, p. 334, pl. 43, fig. 22. Description. — Test free, monothalmous, spherical; wall thin, composed of medium-sized sand grains, moderately cemented; four apertures at ends of short, broad tubules arranged in pairs on dif- ferent planes. Measurements. — Diameter of hypotype 34709 is 0.51 mm; aperture necks 0.035 mm. Occurrence. — This species is rarely present at locality UWA 6004 in the Roberts Mountains Formation. Discussion. — The apertures of the specimens studied herein show a variation in arrangement from that described by Dunn as normal for the species. He described the apertures (p. 334) as: four blunt tubular necks arranged in opposite pairs, the horizontal plane of one pair cutting the vertical pair of the other at right angles. Viewed from above, however, the four tubes do not lie in vertical planes through the center of the sphere but are offset on opposite sides of perpendicular vertical central planes. These specimens have one pair of apertures arranged at opposite poles. The other pair does not form a plane normal to the first pair, because one aperture is at an angle of less than 90 degrees. It is believed that the above arrangement only represents a variation, though positive identification of the specimens as T. quadritubulata was not possible because comparison with the holotype could not be made. Thurammina trituba Dunn P1.\35, fig: 17 1942. Thurammina tributa [sic] Dunn, Jour. Paleont., vol. 16, No. 3, p. 334, pl. 43, fig. 26. Description.— Test free, monothalmous, triangular outline slightly inflated; wall thin, finely arenaceous, well cemented; aper- tures number three, at ends of short nodes forming corners of tri- angular test outline. StLtuRO-DEVONIAN MicroFauna: McCLeLLan 301 Measurements. — Lengths of the three sides from aperture to aperture are 0.30 mm, 0.30 mm, 0.35 mm on figured hypotype 34710. Occurrence. — Rarely present in the Gatecliff Dolomite at locality UWA 5998. Discussion. — The specimen described here is slightly more ro- bust than characteristic for the species. Its occurrence in the Gate- cliff Dolomite compares well stratigraphically with the occurrence in the Osgood Limestone reported by Dunn (1942, p. 334). Kay and Crawford (1964, p. 438) suggested a Llandovery age for the Gatecliff on the basis of the graptolite fauna and the Osgood is in nearly the same stratigraphic interval. Because the species is only rarely present and has been reported only from Missouri and central Nevada, too much importance should not be placed on its bio- stratigraphic occurrence. Thurammina tubulata Moreman IDL, Bh), sake, ay) 1930. Thurammina tubulata Moreman, Jour. Paleont., vol. 4, No. 1, p. 52, jl Op sakes fh Description. — Test free, monothalmous, spherical, wall thin, finely arenaceous, abundant cement; apertures at ends of variously positioned tubes. Measurements. — Diameter of figured specimen 34711 is 0.22 mm and aperture neck is 0.04 mm long. Occurrence. — This species occurs rarely at locality UWA 6015 only. Discussion. — The single specimen recovered here has several of the tubules mostly broken off leaving only the bases. Those which are intact are long and definitely indicate the specimen to be a T. tubulata rather than T. papillata which has shorter, nodular pro- jections. Subfamily HEMISPHAERAMMININAE Loeblich and Tappan, 1961 Genus HEMISPHAERAMMINA Loeblich and Tappan, 1957 1904. Webbinella Rhumbler, Archiv. Protistentkunden, vol. 3, pt. 1, p. 228. 1957. Hemisphaerammina Loeblich and Tappan, U.S. Nat. Mus., Bull. 215, pp. 223, 224. 1958. Fairliella (in part) Summerson, Jour. Paleont., vol. 32, No. 3, pp. 5519, 556; Type species.— Hemisphaerammina batalleri Loeblich and Tappan (1957, ibid. p. 224, pl. 72, fig. 3). 302 BuLLeETIN 274 The redescription given by Loeblich and Tappan (1964, p. 202) is as follows: Test attached, consisting of single hemispherical chamber; may have bordering flange; wall agglutinated, with considerable cement; no apparent aperture. This genus was established by Loeblich and Tappan (1957) for those agglutinated species of Webbinella Rhumbler (1901) which were excluded when the type W. hemispherica was recognized as a polymorphinid. Certain species of Fairliella Summerson (1958) can also be allotted to Hemisphaerammina. F. dicantha Summerson and F. clitellata Summerson are retained in that genus as distinctly different from Hemtsphaerammina, following the decision of McClel- lan (1966, pp. 484, 485). Hemisphaerammina bradyi Loeblich and Tappan Pl. 35,. fig. 1; Pl) 36; hex 1957. Hemisphaerammina bradyi Loeblich and Tappan, U.S. Nat. Mus., Bull. 215, ps 224, pl? 72) figs 3. Description. — Test attached, monothalmous, hemispherical, highly convex with side wall forming a sharp angle at junction with base; dorsal wall thickness greater than the ventral, finely arenaceous, well cemented; no apparent aperture. Measurements. — Figured hypotype 34663 has diameter of 0.31 mm and height of 0.28 mm. Occurrence. — The hypotype is from locality UWA 6018. The species is common at all stratigraphic intervals in the area. Discussion.— The most favorable environment for H. bradyi appears to have been that in which well-bedded limestones were deposited from waters bearing little argillaceous material, It is commonly found in samples with a diversified foraminiferal and invertebrate faunule, that implies relatively higher energy condi- tions. The only previous Paleozoic record of this species is in the Waldron Shale of Indiana (McClellan, 1966, p. 485) where it is in calcareous shales, but again, is associated with a diversified faunule of a type similar to that of central Nevada. Hemisphaerammina? cf. H. bradyi Loeblich and Tappan PI. 35, fig. 2 Description. — Test attached, monothalmous, hemispherical, moderately convex; wall thin, finely arenaceous, base thinner than convex dorsal wall, well cemented; no apparent aperture. StturRo-DEVONIAN MIcROFAUNA: MCCLELLAN 303 Measurements. — Specimen 34664 has diameter of 0.28 mm and height of 0.13 mm. Occurrence. — Present at locality UWA 6028 associated with typical specimens of Hemisphaerammina brady. Discussion. — Hemisphaerammina bradyi is typically hemi- spherical and highly convex, the test being nearly as high as it is broad. Variants with partially collapsed tests can usually be readily recognized. This form is questionably referred to the genus Hemi- sphaerammina because of the abnormally low convexity which seems not to be caused by collapse. A closely related genus, Webbinelloidea Stewart and Lampe (1947), has several species which also have low convexity but differ from Hemisphaerammina in the manner of junction between the dorsal and ventral walls (see generic discussion of Webbinelloidea). Hemisphaerammina coronata (Ireland) Pl. 35, fig. 4; Pl. 38, fig. 4 1939. panes lle coronata Ireland, Jour. Paleont., vol. 13, No. 2, p. 198, fig. -11. Description. — Test attached, monothalmous, elongate hemi- spherical, broad flange with projecting spines; wall thin, finely arenaceous, well cemented; no aperture apparent. Measurements. — Test length of figured specimen 34665 is 0.15 mm, width 0.13 mm, height 0.11 mm, wall thickness 0.01 mm, width of flange 0.02 mm. Occurrence. — Only a single specimen was recovered from locality UWA 6004 in the midlde Roberts Mountains Formation. Discussion. — This specimen is much smaller than Ireland’s holotype, whose length is 0.87 mm, and probably represents a neanic individual. A scanning electron micrograph shows the dorsal wall having the grains arranged in concentric layers, a pattern not pre- viously recognized in other specimens. Only a small part of the diagnostic basal flange is preserved but Hemisphaerammuina casteri McClellan (1966), the only other species with a broad flange, has a very thick flange with no spines, and, therefore, cannot be con- fused with H. coronata. Hemisphaerammina discoidea? (Summerson) PIF35) figs"3 1958. Fairliella discoidea Summerson, Jour. Paleont., vol. 32, No. 3, p. 557, pl. 82, fig. 20, text figs. 6a, b. 304 BULLETIN 274 1966. Hemisphaerammina discoidea (Summerson), McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 486, pls. 38, 42, figs. 2a, b, 3. Description. — Test attached, monothalmous, slightly ovoid, strongly biconvex, dorsal and ventral surface joined along highly sinuous line which is sharply defined with thickened test wall; flange questionably present as wedge edge of sinuous junction line; wall thin to thick, medium to coarsely arenaceous, poorly cemented; no apparent aperture. Measurements. — Width of figured specimen is 0.26 mm and height is 0.22 mm. Occurrence. — Rarely present only at locality UWA 6010, of earliest Devonian age. Discussion. — This species has previously been reported from the Columbus Limestone (M. Devonian) of Ohio, and Waldron Shale (M. Silurian) of Indiana. The specimen here differs from those of earlier reports in the configuration of the junction line between the dorsal and ventral surfaces. The Devonian forms (Summerson, 1958, p. 557) possess a straight to slightly sinuous junction line, while those from the Silurian (McClellan, 1966, p. 486.) show more variation, Specimens from both of these occur- rences have a definite wedge-shaped flange. Specimen 34666 has a much more highly sinuous junction line and may be lacking the wedge-shaped flange. Unfortunately the flange is difficult to rec- ognize and for this reason identification of the species was ques- tioned. The actual configuration of the junction line probably is not constant for the species. The varying curvature of the line could readily be a function of the attaching surface. Those specimens with a highly sinuous line have correspondingly highly convex ven- tral and dorsal walls. Hemisphaerammina bipatella McClellan, n. sp. Ply 35) figs) 56> Ply 38 etissoaD Description. — Test attached, monothalmous, dorsal side mod- erately convex and elliptical, ventral side slightly convex and hemi- spherical; heavy flange at contact of upper and lower surfaces is wide adjacent to long axis of the dorsal ellipse of the chamber and narrow to absent along short axis giving overall test a circular outline, flange merges gently into chamber surface without suture SILURO-DEVONIAN MIcRoFAUNA: MCCLELLAN 305 and is indistinct from ventral portion of chamber; wall thick, medium to finely arenaceous, grains may be arranged in concentric layers; poorly to moderately cemented; no aperture apparent. Measurements. — Holotype 34668 has chamber length 0.30 mm, width 0.18 mm, total diameter 0.31 mm, height 0.15 mm; flange width 0.05 mm, thickness 0.04 mm, Paratype 34667 cham- ber length is 0.20 mm, width 0.12 mm, total diameter 0.20 mm, height 0.11 mm; flange width 0.04 mm, thickness 0.03 mm. Occurrence. — Present only at locality UWA 5990 in the basal beds of the Roberts Mountains Formation. Discussion. — Hemisphaerammina bipatella is most closely re- lated to H. casteri McClellan (1966), both species characterized by a broad, thick marginal flange. It is also closely related to H. coronata (Ireland, 1939) in showing a tendency to develop the test with concentric layers of sand grains, but the latter species has a much thinner flange. H. discoidea (Summerson, 1958) has a biconvex test much like H. bipatella, but a narrower flange and more variable shape. All the specimens recovered here closely re- semble the holotype though some are less well preserved. Isolated chambers of the multilocular Metamorphina imbricata McClellan (1966) look somewhat similar to H. bipatella in their thick, broad flange and moderate convexity, The chamber is hemi- spherical, the bordering flange shows a constant width around it, and the ventral surface is planar rather than convex. H. bipatella can- not be a Metamorphina species because that genus is only known to have a planar surface of attachment, is multilocular, and is not known to have wall material arranged in an orderly manner. None of the specimens here show any evidence of multilocularity. Interpretations of ecology must remain inconclusive until the species has been recognized more widely. It was found as a common constituent of a limited foraminiferal faunule, lacking associated in- vertebrates. It occurs in an argillaceous, cherty limestone, suggest- ing a rather quiet bottom habitat with low circulation. Genus ATELIKAMARA McClellan, n. gen. Type species. — Atehkamara incomposita McClellan, n. sp. Description. — Test attached, inflated dorsally, ventral sur- face planar to angular; interior incompletely divided into incipient chambers by walls which may be slightly developed to semicom- 306 BULLETIN 274 plete; wall thin to thick, composed of poorly sorted sand grains, well cemented; aperture indefinite. The distinguishing feature of this genus is the incipiently de- veloped chambers, hence the origin of the name: Greek atelis = incomplete, kamara = chamber. Storthosphaera Schulze (1875) resembles Atelikamara externally in the irregular shape, but the latter differs in being attached, and, therefore, belongs in the Hemi- sphaerammininae. The same difference separates this new genus from Anictosphaera n. gen. which has incomplete walls dividing the chambers of a free test, Atelikamara does not have definite chambers like multilocular genera in the same subfamily. In comparison with unilocular gen- era, none of them has any suggestion of division into chambers. Thus, Atelikamara is distinct in its character of the partial test subdivision. The degree to which subdivision takes place is appar- ently quite variable, as partially developed walls may be present as well as only very slightly developed partitions on the same specimen. Often the partial chambers are separated by a depression in the exterior test wall, such that they present the appearance of nodes on the surface of the test. Atelikamara incomposita McClellan, n. sp. Pl. 36, figs. 1-3, 6; Pl. 40, figs. 5a,b Description. — Test attached, irregular outline, conical to ir- regularly inflated dorsally, ventral surface usually planar, may be angular; interior subdivisions incomplete to nearly lacking; ex- terior surface may haye nodular appearance with slight depressions corresponding to interior subdivisions; wall thin to thick, basal wall unknown, composed of poorly sorted sand grains, abundant cement; no apparent aperture, scattered pseudopodial openings be- tween grains on dorsal surface. Measurements. — Dimensions of the type specimens suggest two distinct sizes, but the differences are caused by grain sizes in the wall construction. Pi 36 Specimen Length Height Wall Fig. 1 34658 holotype 0.63mm 0.38mm 0.04mm Fig. 2 34793 paratype 0.67mm 0.45mm 0.04mm Fig. 3 34657 paratype 0.34mm 0.15mm 0.015mm Fig. 6 34659 paratype 0.37mm 0.14mm 0.015mm SILURO-DEVONIAN MicroFAuNA: McCLELLAN 307 Occurrence. — Holotype 34658 and paratype 34793 are from locality UWA 6022 where the species is common, Paratype 34657 is from locality UWA 6004, and paratype 34659 from locality 6007. All localities are in the middle and upper parts of the Rob- erts Mountains Formation. Discussion. — The external form of this species is distinctive by its irregularity. In the holotype the lumpy appearance only moderately suggests the internal form, The paratypes have a more globulose surface suggesting corresponding internal partial sub- division but actually have little development of the partial chamber walls. Several unfigured specimens from the type locality lack sur- face expression of the incipient chamber development inside. The basal surface is completely lacking in every specimen and likely con- tained no agglutinated material, and, therefore, it has not been preserved. It is apparent from specimen 34793 that the surface of attachment was variable and partially responsible for the form of the entire test. This individual was attached in a narrow crevice, evidenced by the sharp angularity of the base, and was, therefore, restricted in growth to a less spreading habit than specimens at- tached to a flat surface. There are two distinct sizes suggested in the measurements of the figured specimens. Other foraminifers from locality UWA 6022 have utilized coarser grains than normal in constructing their tests. The large size and thick wall of Atelikamara incomposita specimens at this locality has resulted from use of coarse sand grains in the test wall. Examples from other localities all used finer grains resulting in a thin wall and smaller test size. Since all the foraminifers recovered from locality UWA 6022 have used larger grains than normal, it is clear that the grain size was determined by the coarseness of available material rather than a preference of the organism. For this reason the size differences of A. incom- posita do not represent two species, because grain size alone, in a primitive foraminifer, is not of specific value. Atelikamara incomposita occurs commonly only in the upper- most beds representing the argillaceous and cherty limestone litho- some. It occurs rarely in thick-bedded limestones slightly lower stratigraphically. All these occurrences are in the Roberts Moun- tains Formation where it is approximately uppermost Niagaran 308 BULLETIN 274 age, The argillaceous and cherty limestones suggest a preference by the organism for low energy, quiet water conditions. Genus METAMORPHINA Browne, 1963 1963. Mctamorphina Browne, in Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 223. Type species. — Webbinella tholus Moreman (1933, Jour. Pal- eont., vol. 7, No. 4, p. 395, pl. 47, figs. 8, 10). Following is the generic diagnosis given by Browne im Browne and scnott (1965, p: 223): Test attached, plano-convex, varying in outline from circular to oval to linear; often surrounded by a marginal flange; single chambered to multichambered; wall of fine sand grains, smooth to roughly finished with the basal wall thin and frequently missing; aperture not apparent. This genus is characterized by its thin basal wall and marginal flange. Hemisphaerammina differs from Metamorphina in being single chambered often having an orderly arranged wall material, and having higher dorsal convexity. The type species M. tholus (Moreman) was formerly considered a Webbinella until Loeblich and Tappan (1957, p. 224) reevaluated the latter genus (see gen- eric discussion of Hemisphaerammina). Metamorphina was erected for those arenaceous, multilocular forms of Webbinella, subse- quently, Metamorphina tholus (Moreman) Pl. 35; figs 133) P1939), Hees 1933. Webbinella tholus Moreman, Jour. Paleont., vol. 7, No. 4, p. 395, pl. 47, figs. 8, 10. 1963. Metamorphina tholsus (sic) (Moreman), Brown and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 225, pl. 51, figs. 1-9. Description. — Test attached, plano-convex with low convexity widening to the basal plane, may have marginal flange; number of chambers variable, closely appressed with rectilinear contact and well-developed suture; wall of fine or poorly sorted sand grains, well-cemented, basal wall thin and often missing; aperture not apparent. Measurements. — Hypotype 34676 has test length of 0.35 mm and width of 0.22 mm. Chambers are each 0.18 mm long and small, third chamber length is 0.07 mm. Occurrence. — Rare, only at locality UWA 6010. Discussion. —M, tholus is a common species of the Lower Silurian but has not been reported from younger rocks except in SILURO-DEVONIAN MiIcrRoFAUNA: MCCLELLAN 309 the Mississippian Lodgepole Limestone of Montana (Gutschick, Weiner and Young, 1961, p. 1205). In Nevada it presently is known only at one locality, but further study, especially in the argillaceous limestones in which it most often occurs in other areas, should reveal a more widespread occurrence in this region. The specimen figured here has less well sorted wall material than is customary for the species, In addition, the wall dividing the two chambers does not extend to the base as is normal, (best seen on PI. 39, fig. 5). An interesting feature of the specimen is the small third cham- ber which apparently was only partially developed. Metamorphina gibbosa (Ireland) Plead, figs 16 1939. Webbinella gibbosa Ireland, Jour. Paleont., vol. 13, No. 2, p. 198, figs. B-23, 24. 1963. Metamorphina gibbosa (Ireland), Browne and Schott, Bull. Amer. Paleont., vol. 46, No. 209, p. 224, unfigured. 1966. Metamorphina gibbosa (Ireland), McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 490, pl. 38, figs. 4a, b, 5; pl. 42, figs. 4a, b, 5. Description. — Test attached, polythalmous, plano-convex, mar- ginal flange narrow, may be incomplete, chambers closely joined with faint suture defining contact plane; wall thin, basal wall very thin and commonly absent, finely arenaceous, well cemented; no aperture apparent. Measurements. — Hypotype 34675 has test length of 0.44 mm, chambers 0.24 mm, 0.18 mm, and 0.13 mm; test height 0.18 mm. Occurrence. — Present in rare numbers only at locality UWA 6030 in the lower Roberts Mountains Formation of Wenlockian age. Discussion.— The diagnostic features of this species are the very narrow marginal flange and faint, slightly depressed, dorsal sutures between chambers. M. tholus (Moreman) may also have only a narrow flange, but its sutures are more prominent and de- pressed. An additional feature, which appears with relative consis- tency, is the high convexity of M. gibbosa compared to other species, such as M. tholus and M. imbricata. McClellan (1966, p. 492) considered these three species to represent a phylogenetic lineage with M. gibbosa the most primitive and M. imbricata the most advanced. The former species has been recorded from the Lower and Middle Silurian of several areas, while the latter is known only from the Middle Silurian of Indiana. 310 BULLETIN 274 If A. gibbosa is more primitive and characteristic of the Lower Silurian, then its stratigraphic position in central Nevada may be significant. The one locality at which it occurs has a foraminiferal faunule quite similar to that found in the Waldron Shale of south- eastern Indiana (McClellan, 1966). These comparative faunal ele- ments from the Waldron are species commonly found in Lower Silurian rocks elsewhere. This evidence suggests correlation between the Waldron Shale and basal units of the Roberts Mountains For- mation based on the foraminifers, M. gibbosa and Glomospira sluriana (see discussion of that species) are probably the most diagnostic species. Genus WEBBINELLOIDEA Stewart and Lampe, 1947 1947. Sorosphaeroidea Stewart and Lampe, Jour. Paleont., vol. 21, No. 6, p. 534. 1947. Webbinelloidea Stewart and Lampe, ibid., pp. 534, 535. Type species. — Webbinelloidea similis Stewart and Lampe, (1947, tbids.p:535, pl. 78, tig:-8)- Description. — Test attached, multilocular, usually plano-con- vex, chambers hemispherical, globular, to subangular and usually highly convex; junction of base and sides forms an obtuse angle; wall thick to thin, well cemented, finely to coarsely arenaceous; no apparent aperture. This genus resembles Metamorphina Browne (1963) in general form and habit but lacks the marginal flange and thin basal wall of that genus. Single chambered specimens differ from Hemz- sphaerammina Loeblich and Tappan (1957) on three counts: firstly, many examples of the latter species have a marginal flange like that of Metamorphina; secondly, Webbinelloidea joins the basal, or ventral, wall to the dorsal with a contact that forms a rounded, bluntly obtuse angle often greater than 90 degrees. A comparable feature on Hemisphaerammina forms a sharp, V-shaped angle of not more than 90 degrees. Thirdly, several species of Hemisphaer- ammuina have test wall material oriented in a regular, layered man- ner, while species of Webbinelloidea have yet been found to only randomly place grains in the test wall. Sorosphaeroidea Stewart and Lampe (1947) differs only in the polygonal outline of the chambers, This genus, therefore, differs in traits which seem to be only of specific character. A more de- Stturo-DeEvonian MicroFauna: MCCLELLAN Si tailed discussion has been presented by Conkin and Conkin (1970, p. 4). The material here recovered and referred to Webbinelloidea is so placed in accordance with the generic description of Stewart and Lampe (1947) and Summerson (1958). Recently Conkin and Conkin (1970) have restudied the type material of the former au- thors plus new material from the Devonian of Ohio. As a result they have revised the genus and emended the description, provid- ing four morphological groups all within the type species W. similis. They also have demonstrated that Webbinelloidea contains an aper- ture on the dorsal surface. Hence the genus would properly be in the subfamily Saccammininae. Of the Nevada species, only W. hemispherica has been revised by Conkin and Conkin, the others not being included in their study. The material recovered here does not show any evidence of an aperture even under scanning electron microscopy (Pl. 38, figs. 1, 2). Therefore the original generic con- cept of Webbinelloidea is followed here, though it is recognized that more, well-preserved material may necessitate future revision. In view of Conkin and Conkin’s discoveries (1970) the entire re- lationship of Webbinelloidea, Metamorphina, and Hemisphaeram- mina should be closely studied for probable phyletic revisions. Webbinelloidea hattini McClellan Ple3sbs tie. 12 1966. Webbinelloidea hattini McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 495, pls. 38, 42, figs. 10, 11. Description. — Test attached, one- or two-chambered forms known, plano-convex with high conical convexity of upper surface, junction of basal surface forms rounded angle, suture between chambers deep, rectilinear; wall thin to thick, fine to coarsely arenaceous, moderately cemented; no apparent aperture. Measurements. — Hypotype 34713 has diameter of 0.31 mm and height of 0.26 mm. Occurrence. — The figured specimen is from locality UWA 6025. Also present at locality UWA 6009, which gives a range of upper Wenlock to lower Helderbergian age in Nevada. Discussion. — The high conical convexity of the dorsal sur- face is characteristic for the species. Multilocular specimens are further characterized by the deep, rectilinear suture between cham- 312 BULLETIN 274 bers. Webbinelloidea similis Stewart and Lampe (1947) is similarly multilocular but has a less conical form and the chambers are more loosely connected. Webbinelloidea hemispherica Stewart and Lampe Pl. 35, figs. 9,10; Plessiaigad 1947. Webbinelloidea hemispherica Stewart and Lampe, Jour. Paleont., vol. Zi eNos6. ps 555siplaeoyetiosyelansp: Description. — Test attached, apparently monothalmous, cham- ber hemispherical and strongly convex, basal edge slightly rounded; wall thick, moderately to coarsely arenaceous, well cemented; no apparent aperture. Measurements. — Hypotype 34714 has a diameter of 0.21 mm and height of 0.11 mm. Hypotype 34715 diameter is 0.25 mm and height 0.16 mm. Occurrence. — Hypotype 34714 is from locality UWA 5990 and 34715 from locality UWA 6010, also present at several other locali- ties and stratigraphic horizons. Discussion. — This species differs from W. hattini on its lesser convexity. Stewart and Lampe (1947, p. 535) separated this species from W. similis on the basis of its unilocularity, and in the posses- sion of a thicker basal wall and higher convexity. The first charac- ter was probably due to an insufficient number of specimens. None of the material studied here shows any definite evidence of being other than single chambered, and, therefore, is all referable to W. hemispherica. W. similis presently is only known from the Middle Devonian of Ohio, whereas W. hemispherica is known at horizons ranging from Middle Silurian to Middle Devonian. W. hemispherica specimens recognized here do not compare adequately with those of Conkin and Conkin (1970) to be similarly considered a W. similis as revised by them. Webbinelloidea aff. W. nodosa Summerson Pl 35, figs: 117 15; Pl) 36, tice2 1958. Webbinelloidea nodosa Summerson, Jour. Paleont., vol. 32, No. 3, p. 555, pl. 82, fig. 12. Description. — Test attached, apparently monothalmous, square outline, ventral surface planar, dorsal surface highly convex with vertical sides; upper surface divided into subequal quadrants by rectilinear sutures and each quadrant is convex forming a node; wn StturRo-DEVONIAN MiIcroFAUNA: MCCLELLAN 3] junction between dorsal and ventral surfaces forms rounded right angle; wall thin to medium, composed of sand grains, well cemented; no apparent aperture. Measurements. — Figured specimen 34716 has length of 0.26 mm, nodes 0.13-0.14 mm, height 0.19 mm, wall thickness 0.015 mm. Specimen 34717 has length 0.30 mm, nodes of 0.15 mm, height of 0.22 mm, and wall thickness 0.01 mm. Occurrence. — Specimen 34716 from locality UWA 6018; 34717 from locality UWA 6010, both rare in occurrence, Discussion. — Summerson (1958 p, 555) characterized Webb- inelloidea nodosa by its two rows of nodes on the upper surface and its rectangular outline. He further described the species to be roughly hemispherical in section, and to have a slight peripheral lip where the basal surface joins the upper. The Nevada speci- mens are more nearly rectangular in section, the sides being verti- cal, however, they possess the nodes and similar outline. They also differ in the junction of the upper and lower surfaces, appearing as a rounded angle instead of a peripheral lip. Because of the sev- eral similar features, as well as the obvious differences also pres- ent, the material herein is deemed to have affinities for W. nodosa. Criteria for erecting a new species are considered insufficient, though perhaps these specimens, in view of the generic revision of Webbinelloidea by Conkin and Conkin (1970), should be con- sidered a species of Ateltkamara, n. gen. There is a similarity in development of incipient chambers and no apparent apertures. Webbinelloidea ventriquetra McClellan PIS35e fice 14: 1966. Webbinelloidea ventriquetra McClellan, Bull. Amer. Paleont., vol. 50, No. 230, p. 496, pls. 38, 42, figs. 6, 7a, b. Description. — Test attached, bilocular, high dorsal convexity, ventral surface formed by two planar surfaces separated by an acute angle which bisects the longitudinal axis of the test; cham- bers closely joined with a rectilinear boundary and deep dorsal suture; wall of medium thickness, finely arenaceous, moderate amount of cement; no aperture apparent. Measurements. — Specimen 34718 has an overall length of 0.56 mm, individual chambers are 0.30 mm and 0.26 mm, and height is 0.31 mm. 314 BULLETIN 274 Occurrence. — Rare, present only at locality UWA 6024 in the Roberts Mountains Formation. Discussion. — This species bears a much sharper angle at the junction of the dorsal and ventral walls than is characteristic for the genus. In this respect it is more like species of Hemisphaeram- mina, but that genus is restricted to unilocular forms, The only other species of Webbinelloidea which does not have a planar basal surface of attachment is W. globulosa McClellan (1966) which has a concave ventral wall. Such a configuration suggests a more ex- posed living position for the animal in contrast to W. ventriquetra, whose test is probably indicative of habitation in protected places, such as in a crack or small crevice. Family AMMODISCIDAE Reuss, 1862 Subfamily AMMODISCINAE Reuss, 1862 Genus GLOMOSPIRA Rzehak, 1885 1860. Trochammina [in part] Jones and Parker, Quart. Jour., Geol. Soc. London, vol. 16, p. 304. 1885. Glomospira Rzehak, Naturforsch. Vereins Briinn, Verhandl., vol. 23 (1884), p. 126. Type species.—Trochammina gordialis Jones and Parker, (1860, ibid., p. 304). Following is Cushman’s (1959, p. 96) redescription of the genus. Test free, with a proloculum and long, tubular, undivided, second chamber winding about its earlier coils in various coils in various planes; wall arenaceous with much cement; aperture at end of the tube, This genus frequently occurs in Lower Silurian rocks, but is poorly known from Middle Silurian through Devonian time. Glomospira siluriana Ireland Pl. 36, fig. 5 1939. Glomospira siluriana Ireland, Jour. Paleont., vol. 13, No. 2, p. 201, figs. B-27, 28. Description. — Test free, proloculus followed by tubular second chamber coiled in varying planes around it with four or five revolu- tions, tube inflated; wall thin, finely arenaceous, well cemented; aperture at end of tube which is slightly uncoiled. Measurements. — Specimen 34661 has minimum diameter of 0.37 mm and maximum diameter 0.53 mm, Wt StLtuRo-DEvontIAN MicroFauna: McCLeLLANn 3 Occurrence. — This species is rare; present only at locality UWA 6030 in the basal beds of the Roberts Mountains Formation. Discussion. —Glomospira siluriana is a common. species in Lower Silurian rocks from other regions. Its occurrence in the basal Roberts Mountains Formation of Nevada is the youngest yet recorded. In combination with Metamorphina gibbosa, it may be useful in correlating the lowest Roberts Mountains beds with Mid- dle Silurian rocks of Indiana. Further discussion of its stratigraphic implications is presented in the section on biostratigraphy. Subfamily TOLYPAMMININAE Cushman, 1928 Genus TOLYPAMMINA Rhumbler, 1895 1879. Hyperammina [in part] Brady, Quart. Jour. Micr. Sci., new ser., vol. 19. pe teeps 33: 1895. Tolypammina Rhumbler, Kong]. Gese!l. Wiss. Gottingen, Nachr, p. 83. Type species. —Hyperammina vagan Brady (1879, ibid., p. 33, pl. 24, figs. 1-5). The generic redescription of Cushman (1959, p. 98) is as follows: Test attached, with proloculus and long, tubular, undivided, second chamber, earliest portion sometimes coiled, later irregular; wall arenaceous with much cement; aperture at the end of the tube. Iituotuba Rhumbler (1895) has a similar habit of irregular growth in the second chamber. In comparing these two genera Loeblich and Tappan (1964, p. 213) considered that Tolypammina “differs from Litwotuba in lacking the early streptospiral coil.” Tolypammina tortuosa Dunn Pl. 36, fig. 4 1942. Tolypammina tortuosa Dunn, Jour. Paleont., vol. 16, No. 3, p. 341, p. 44, figs. 19-21, 32. Description. — Test attached, proloculus spherical, followed by long tubular second chamber which commonly coils around pro- loculus in early stages, later portion irregularly winding; wall thin, finely arenaceous, well cemented; aperture at end of tubular second chamber. Measurements. — Hypotype 34712 tube diameter is 0.18 mm. Occurrence. — This species is rare and present only at locality UWA 6018 in rocks of lower Helderbergian age. Discussion. — This is a well-known species in Lower Silurian rocks and has also been widely reported from the Lower Mississip- 316 BULLETIN 274 pian. While its occurrence in Nevada is Devonian and fills a gap in the record, it is rare and only present locally. Conkin (1961, p. 305) considered all species of Tolypammuna, including T. tortwosa, which occur in Lower Mississippian rocks, to be characteristic in shallow, warm, near shore, calcium rich sedi- — ments. He found that often the genus is common in environments which lack other organisms. T. tortuosa occurs here in the fine- grained basal beds of the McColley Canyon Limestone as part of a large microfauna. These limestone beds immediately overlie massive reef units of the Lone Mountain Dolomite. They indicate shallow, warm, alkaline conditions during deposition, which should have been quite favorable to species of Tolypammuna. Superfamily LITUOLACEA de Blainville, 1825 Family HORMOSINIDAE Haeckel, 1894 Subfamily ASCHEMONELLINAE Eimer and Fickert, 1899 Genus ASCHEMONELLA Brady, 1879 1879. Aschemonella Brady, Quart. Jour. Micr. Sci., new ser., vol. 19, pt. 1, p. 44. Type species. — Aschemonella scabra Brady (1879, ibid., p. 44, pl. 27, figs. 1, 2, 4-11). Loeblich and Tappan (1964, p. 214) redescribed the genus as given below: Test free, consisting of tubular or inflated chambers in single or com- monly branching series; wall thin, finely to coarsely agglutinated, firmly cemented; apertures several, rounded, at ends of tubular necks. Described species of this genus are known from the Cretaceous to Recent. Cushman (1959, p. 90) mentioned that somewhat similar, partially divided, tubular forms are known as far back as the Silurian, but he did not document his statement. The only Paleozoic occurrence, of which the writer is aware, is that listed by Hattin (1960, p. 2016) from the Middle Silurian Waldron Shale in south- eastern Indiana. Aschemonella bastillensis McClellan, n. sp. Pl 36; fis. 8 Description. — Test free, with tubular chambers inflated on apertural side, constricting ring divides chambers from tubes which connect them, tubes slightly expanding in direction of chamber addition; wall thin, finely arenaceous, well cemented; apertures S1LuRO-DEVONIAN MicroFAUNA: MCCLELLAN SL7 round and single for each chamber, at end of short neck on inflated side of chamber. Measurements. — Holotype 34656 has the following dimensions: maximum chamber diameter 0.11 mm, connecting tube minimum diameter 0.04 mm and maximum indeterminate (distorted), length of apertural neck 0.04 mm, and aperture diameter 0.055 mm. Occurrence. — Rare, present only at locality UWA 5982 in the Bastille Limestone of Wenlockian age. Discussion. — The presence of this genus in the Silurian is the first occurrence of the superfamily Lituolacea, indicating consider- able evolutionary development of Foraminifera early in their his- tory. The reported occurrence of the genus in the Waldron Shale (Hattin, 1960, p. 2016) appears correlative with that in the Bastille Limestone, and substantiates other biostratigraphic evidence of the probable age equivalence of these two units. The lower beds of the Bastille Limestone, from which Aschemo- nella bastillensis was recovered, are a thick-bedded, coarse-grained, biosparite. Residues obtained from samples treated with dilute hydrochloric acid contained abundant crinoidal fragments and com- mon well sorted and rounded, frosted, medium-sized quartz grains. These components suggest the sediment was deposited under con- ditions of relatively high energy. Family LITUOLIDAE de Blainville, 1825 Subfamily HAPLOPHRAGMOIDINAE Maync, 1952 Genus HAPLOPHRAGMOIDES Cushman, 1910 1910. Haplophragmoides Cushman, U.S. Nat. Mus., Bull. 71, pt. 1, p. 99. Type species. — Nomionina canariensis WOrbigny (1839, in Barker-Webb and Berthelot, Hist. Nat. Iles Canaries, vol. 2, pt. 2, ps AZSixpl. 2, figsn33.n34): Following is the redescription of Cushman (1959, p. 102): Test free, planispiral, of several coils, usually not completely involute; chambers simple; wall single, arenaceous or with sponge spicules, firmly cemented, amount of cement varying greatly in different species; aperture simple, at the base of apertural face of the chamber. This well-known and common genus is here reported for the first time from strata older than Carboniferous, in beds of lowest Devonian age. 318 BULLETIN 274 Haplophragmoides antiquus McClellan, n. sp. Rit ie tigsadle?, Description. — Test free, planispiral and involutely coiled, seven chambers in last whorl; chambers slightly inflated, narrowly arcuate in section; sutures radiate and partially indistinct; prom- inent, broad, umbilical plug present; wall finely arenaceous, grains aligned along trace of sutures, moderately cemented; aperture a thin interiomarginal slit, small accessory apertures near basal-lateral surface of chambers in last whorl. Measurements. — Maximum diameter of holotype 34792 is 0.31 mm and axial diameter is 0.11 mm. Occurrence. — Rare, only found at locality UWA 6010 in the Rabbit Hill Formation of lowest Helderbergian age. Discussion. — The two most distinctive features of Haplophrag- moides antiquus are the broad umbilical plug and pinpoint accessory apertures. The latter are only recognizable on electron micrographs. The presence of these apertures has not previously been noted on any known species of Haplophragmotides. There is the possibility that H. antiquus is generically distinct, but until the type species of Haplophragmoides is studied by electron microscopy for presence of similar apertures, such distinction cannot be made, Other char- acters of the species appear to be rather conservative when com- pared to the various complexities which have been added in many of the other species of the genus (1.e. the strongly lobate chambers of H. canariensis). This new species compares most nearly to H. pusilum Hoglund (1947) from the Recent. The latter species has similar sutures and manner of growth but lacks the umbilical plug and is more robust. Suborder FUSULININA Wedekind, 1937 Superfamily ENDOTHYRACEA Brady, 1884 Family ENDOTHYRIDAE Brady, 1884 Subfamily LOEBLICHIINAE Cummings, 1955 Genus NANICELLA Henbest, 1935 1935. Nanicella Henbest, Washington Acad. Sci., Jour., vol. 25, p. 34. Type species. — Endothyra gallowayi Thomas (1931, Jour. Paleont., vol. 5, No. 1, p. 40, pl. 7). Description. — Test free, planispirally coiled, mostly evolute, numerous low chambers; wall finely granular calcareous, two layers SILURO-DEVONIAN MicroFAuNA: MCCLELLAN 319 which may be similar or the outer one darker and thinner; aperture interiomarginal equatorial slit, Thomas (1931, p. 40) originally defined the type species as be- longing to the genus Endothyra Phillips (1846). Henbest (1935, p. 34) considered the species to be generically different from other Endothyra species. His considerations were based on the less inflated chambers, more regular coiling, and the distinct boundary between the spiral and septal walls possessed by the /. galloway1, which he then placed as the type species for Nanicella. This genus has been previously recorded from rocks no older than Devonian in Iowa and the USSR. Its presence in Nevada ex- tends its range to very earliest Devonian time (lower Helderberg). Nanicella dainae? Chernysheva Pl. 36, figs. 9, 10 1940. Nanicella dainae Chernysheva, Soc. Nat. Moscow Bull., new ser., tome 48 (Sect. geol. tome 18), No. 5-6, p. 127. Description. — Test free, discoid, planispirally coiled, evolute, laterally compressed; chambers slightly inflated, almost of equal height in each whorl, number 12-14 in last whorl; sutures irregularly radial, shallow; wall finely granular, two layers unrecognizable; aperture interiomarginal slit. Measurements. — Diameter of 34677 is 0.70 mm and thickness 0.18 mm. Specimen 34678 has a diameter of 0.52 mm and thickness 0.15 mm. Occurrence. — The figured specimens were found at locality UWA 6013 in the upper Roberts Mountains Formation of lowest Helderbergian age. Also present at locality UWA 5973 in the Rabbit Hill Formation, slightly younger in age. Discussion. — The specimens studied here possess all the fea- tures of Nanicella dainae, with the possible exception of the narrow, irregularly radial sutures. Preservation is inadequate to positively recognize the sutures, hence the questioned identification. Com- parisons with other Nanicella species shows N. dainae to be most closely related to the type NV. gallowayi. Chernysheva (1940, p. 127) considered N. dainae to have a somewhat more robust test with a rounded, rather than acute, periphery, and less distinct sutures. In addition, the chambers of N. gallowayt are more rapidly expanding in each whorl and have a much greater height. 320 BULLETIN 274 Namcella dainae has previously been recorded only from Lower Carboniferous (lower Visean) rocks in the southern Ural Moun- tains of the USSR. Subclass OSTRACODA Latreille, 1806 Order PALAEOCOPIDA, Henningsmoen, 1953 Suborder BEYRICHICOPINA Scott, 1961 Superfamily BEYRICHIACEA Matthew, 1886 Family BEYRICHIIDAE Matthew, 1886 Genus BOLBIPRIMITIA Kay, 1940 Type species. —Halliella fissurella Ulrich and Bassler, 1923. Bolbiprimitia teresaccula Swartz and Whitmore Pl. 41, figs. 1-3 1956. Bolbiprimitia teresaccula Swartz and Whitmore, Jour. Paleont., vol. 30, No. 5, p. 1082, pl. 104, fig. 18. Description. — Carapace subovate; straight hinge extending for nine-tenths of entire length; anterior cardinal angle obtuse, pos- terior a right, or slightly acute angle; valve strongly convex, anterior margin broadly rounded; flattened border extends along margins, with velate ridge in male valves; Ss forms a small rounded depres- sion slightly anterior of midpoint. Measurements. — Figured specimens, all male valves, have the following dimensions: PLOEX Spec. Number Length Height Fig. 1 34731 1.04mm 0.67mm Fig. 2 34732 0.64mm 0.44mm Fig. 3 34735 0.72mm 0.52mm Occurrence. — The hypotypes were all found at locality UWA 5974; also present at locality UWA 5975. Both occurrences are in the upper Roberts Mountains Formation. Discussion. — The original type for this species is a female valve, All the specimens found here are male valves, which com- pare elosely in all characters of the shell, and in addition have a velate ridge. The elongate dimorphic pouch occupies the position of the velgate ridge in female valves. The small rounded Ss on these specimens is distinctive from the elongate cleft of Bolbiprimitia limbata. Otherwise the species is similar. Stturo-DeEvonian MicroFAuNA: McCLeLLan 3 bo fomnk B. teresaccula has previously been known from the Manlius Limestone of uppermost Silurian age in New York. Its presence in the upper beds of the Roberts Mountains Formation in central Nevada, appears to represent approximately the same stratigraphic position. Genus KLOEDENIA Jones and Holl, 1886 Type species. — Beyrichia wilckensiana Jones, 1855. Kloedenia aparchoides Swartz and Whitmore IAL Gaby aay y/ 1956. Kloedenia aparchoides Swartz and Whitmore, Jour. Paleont., vol. 30, No. 5, p. 1067, pl. 103, figs. 11-14. Description. — Carapace subovate, dorsally truncated, anterior cardinal angle obtuse, posterior nearly a right angle; hinge line long, straight; convex anterior margin; valve moderately convex, slightly trilobate; S» slightly posterior to middle, S; halfway from S. to margin; flattened border along margin. Measurements. — Specimen 34744, not mature, has a length of 0.70 mm and height of 0.42 mm. Occurrence. — Present only at locality UWA 6024 in the Rob- erts Mountains Formation. Discussion. — This rarely occurring species is represented here by an immature individual which does not have the border as well developed as in the types of Swartz and Whitmore (1956). In addition, the lobation and sulci are barely recognizable, which is also probably due to the immaturity of the specimen. Genus MYOMPHALUS Swartz and Whitmore, 1956 Type species.— Myomphalus dorsinodus Swartz and Whit- more, 1956. Myomphalus ? sp. Pl. 41, fig. 13 Description. —Carapace nearly subrectangular, only slightly ovoid and dorsally truncated; hinge straight, three-quarters of length of shell, cardinal angles obtuse; shell moderately convex, S, and Ss shallow, elongate, poorly developed; exterior and pos- terior margins convex, marginal border distinct and narrow. Measurements. — The figured specimen has a length of 0.74 mm and height of 0.44 mm. Occurrence. — Specimen 34750 is from locality UWA 5981 BULLETIN 274 o>) bo bo in the lower Wenban Limestone. Also present in the McMonnigal Limestone at locality UWA 5994. Both formations are of Helder- bergian age. Discussion. — The genus Myomphalus is described as being subovoid, with a weak Sz and bordering rounded knobs. On the speci- mens found here, the median sulcus is bordered by two raised areas, but there is also an indication of an elongate S,. The shell outline varies from the characteristic subovoid form, being nearly rectangu- lar with convex anterior and posterior margins, The shell outline may appear subrectangular because of an elongate dimorphic pouch which is ill-defined. The material recovered here is insufficient and not adequately preserved to be specifically identified, or even defin- itely recognized as belonging to the genus Myomphalus. Genus PHLYCTISCAPHA Kesling, 1953 Type species. —Phlyctiscapha rockportensis Kesling, 1953. Phlyctiscapha keslingi Copeland Pl. 41, figs. 5, 6 1962. Phylctiscapha keslingi Copeland, Geol. Sur. Canada, Bull. 91, p. 36, pl. IX, figs. 20-24. Description. —Carapace subovaie, dorsally truncate; hinge straight, about two-thirds total length, dorsal corners rounded, cardinal angles obtuse; shell strongly convex, greatest width in female is median and in male is posteromedian; anterior and pos- terior margins convex, entire margin and narrow border separated from lateral shell surface by a furrow; left valve overlaps right valve, especially along ventral margin. Measurements. — The length of 34756 is 0.68 mm and height 0.38 mm. Specimen 34757 has length 0.56 mm and height 0.44 mm. Occurrence. — The figured hypotypes are from locality UWA 5985 in the Lower Devonian McMonnigal Limestone, where the species is abundant. It has been found widely distributed through- out the area in rocks no older than upper Ludlow in age. Discussion. — One of the most abundant ostracode species in central Nevada, Phlyctiscapha keslingi is restricted to rocks of latest Silurian and early Devonian age, In every case it occurs in fore-reef carbonates or calcareous shales. The figured specimens ap- pear to be representative adults in size but are less than one-half the size of Copeland’s types. Perhaps the Nevada specimens are dwarfed, though their abundance would suggest that they were a) S1turo-DEVONIAN MicroFauNnA: McCiLe__an Side quite satisfied in the environment represented here. If they are not dwarfs, then Copeland’s specimens may be abnormally large in- dividuals. Phlyctiscapha sp. Pl: 41, fig. 4 Description. — Carapace elongate subovoid, dorsally truncate; hinge straight, about two-thirds total length, dorsal corners rounded, cardinal angles obtuse; shell strongly convex, greatest width 1s median; anterior and posterior margins strongly convex, entire margin with narrow border separated from lateral surface of valve by shallow furrow. Measurements. — Figured specimen 34758, a female valve, has a length of 0.41 mm and height 0.27 mm. Occurrence. — Specimen 34758 is from locality UWA 5991 in the lower McColley Canyon Formation which is Helderbergian in age. Also present in the Roberts Mountains Formation at locality UWA 6024. Discussion. — This form is quite similar to P. keslingi in most of its characteristics. It differs in being more elongate in outline and has a more broadly convex posterior margin. A further con- sideration is the occurrence, Phlyctiscapha sp. was found in dolo- mite and argillaceous, cherty limestone samples, which represent much different environments than the fore-reef carbonates and cal- careous shales in which P. keslingt was found. Genus SACCARCHITES Swartz and Whitmore, 1956 Type species. —Saccarchites saccularis Swartz and Whitmore, 1956. Saccarchites saccularis Swartz and Whitmore Pl. 41, fig. 12 1956. Saccarchites saccularis Swartz and Whitmore, Jour. Paleont., vol. 30, No. 5, p. 1080, pl. 103, figs. 18, 19. Description. — Carapace subovate in outline, truncate dorsally; hinge straight, about four-fifths of length, cardinal angles obtuse and subequal; shell moderately convex, greatest width is median; an- terior margin more convex than posterior, narrow submarginal bor- der at both ends but Jacking on ventral margin. Measurements. — Length is 0.37 mm and height 0.26 mm on specimen 34772. Occurrence. — Rare; at locality UWA 6026 in the Roberts Mountains Formation. 324 BULLETIN 274 Discussion. — The specimen figured here appears to be an immature instar in which the lobation and sulcus are not recogniz- able. Adult specimens from the uppermost Silurian Manlius Lime- stone of New York are about five times larger (Swartz and Whit- more, 1956, p. 1080). The Manlius examples also are somewhat younger than those of central Nevada, which are still within the Upper Silurian. Genus VELIBEYRICHIA Henningsmoen, 1954 Type species. — Beyrichia moodeyi Ulrich and Bassler, 1908. Velibeyrichia? sp. Pl. 41, fig, 16 Description. —Carapace subovoid, elongate; hinge straight, nearly equal to shell length, cardinal angles both near right angles; margins of valve with well-developed, striated frill, which is at a sharp angle to the plane of contact between valves; greatest width is apparently slightly postero-median, median sulcus is a shallow groove extending to midpoint of height, poorly developed lobes border this sulcus. Measurements. — Figured specimen 34785 has a length of 0.93 mm and indeterminate height about % of length. Occurrence. — Present only at locality UWA 5985 in the Mc- Monnigal Limestone. Discussion. — All the specimens recovered here are poorly pre- served and none adequately exhibit all the features of the genus. The lobation is less distinct than normal for the genus, but the frill is usually mostly preserved and the general shape is that of Veli- beyrichia. The figured specimen appears to be a male left valve with only the anterior portion of the frill preserved, Genus WELLERIOPSIS Swartz and Whitmore, 1956 Type species. — Welleriopsis diplocystulis Swartz and Whit- more, 1956. Welleriopsis jerseyensis (Weller) Pl. 41, figs. 8, 9 1903. Beyrichia jerseyensis Weller, Geol. Sur. New Jersey, vol. 3, p. 255, pl. ey anes, 5. 1956. Welleriopsis jerseyensis (Weller), Swartz and Whitmore, Jour. Paleont., vol. 30, No. 5, p. 1075, pl. 105, figs. 14-16. Description.—Carapace subovate, dorsally truncated by straight hinge line for three-fourths of length; anterior cardinal angle bluntly obtuse, posterior angle more sharply obtuse; anterior SILURO-DEVONIAN MicroFAUNA: McCLELLAN 325 margin convex with greatest point anteroventral, posterior margin straight in upper part, curving gently into ventral margin, low marginal ridge is most prominently developed anteriorly; lateral surface moderately convex, median sulcus as narrow moderately deep furrow extending from hinge to two-thirds the distance to margin, L» well developed, broad, L slightly produced dorsally. Measurements. — Specimen 34786 length is 0.74 mm and height 0.48 mm; 34787 measures 0.67 mm and 0.41 mm. Occurrence. — Uncommon, found only in locality UWA 5973 in the Rabbit Hill Formation. Discussion. — The two specimens figured here appear to be immature and do not have the marginal ridge well developed ven- trally. The occurrence of this species in Nevada is in strata of Helderbergian age, younger than the uppermost Silurian occur- rence recorded to date in eastern North America. Beyrichiidae ? genus Pl. 41, fig. 16 Description. — Carapace broadly oval in outline, dorsally trun- cated; hinge gently concave dorsally, two-thirds of length; cardinal angles obtuse, anterior one more bluntly so; anterior margin mod- erately convex, posterior slightly convex, maximum height from mid-ventral point, narrow marginal border bounded by small fur- row; surface strongly convex, abundant small spines and few large spines, Ss a long, deep furrow slightly anterior of midpoint and reaching three-fourths of height toward ventral margin, S; shallow, curving around posterior of prominent median Ly», L; is broad, less prominent; dimorphic pouch enlarged anteroventrally, merging dor- sally with L,; extends ventrally to pceint directly below Ly». Measurements. — Length of 34789 is 0.30 mm and height 0.75 mm. Occurrence. — Rarely present at locality UWA 6024 in the middle Roberts Mountains Formation. Discussion. — The lobation and dimorphic pouch suggest that this form belongs in the Beyrichiidae. The figured specimen, to which the description refers, is believed to be a female right valve. Another specimen, which has been broken, apparently lacks the an- teroventral dimorphic pouch and is probably a male. The two speci- mens are not sufficiently well preserved to compare closely with any particular beyrichiid genera, and may represent a new genus. oS) bo ON BULLETIN 274 Superfamily DREPANELLACEA Ulrich and Bassler, 1923 Family AECHMINIDAE Boucek, 1936 Genus AECHMINA Jones and Holl, 1869 Type species. — Aechmina cuspidata Jones and Holl, 1869. Aechmina equilateralis Bassler Pl. 41, figs. 18, 19 1941. Aechmina equilateralis Bassler, Washington Acad. Sci., Jour., vol. 31, No. 1, p. 24, fig. 14. Description. —Carapace nearly equilateral, greatest height one-third of length from anterior; hinge straight, long; cardinal angles equally obtuse; anterior and posterior margins convex, an- terior slightly more so, ventral margin has maximum convexity in anteroventral area, entire margin denticulate; lateral surface great- est convexity anteroventral, stout mid-dorsal spine with broad base is directed slightly posteriorly. Measurements. — Specimen 34721 has a length of 0.69 mm and height 0.37 mm. Specimen 34722 length is 0.74 mm and height 0.44 mm. Occurrence. — This is a commonly occurring species at locality UWA 5973 in the Rabbit Hill Formation. Fragments found at locality UWA 6024 have questionably been referred to this species. Discussion. — No mention was made by Bassler (1941, p. 24) of dimorphism in this species. The figured hypotype 34772 appears slightly more enlarged in the anteroventral region of the valve, thereby distorting the equilateral outline. This enlargement may possibly be the representation of a dimorphic pouch. Aechmina longior Bassler Pl. 41, fig. 14 1941. Aechmina longior Bassler, Washington Acad. Sci., Jour., vol. 31, No. 1, p. 24, fig. 13. Description. — Carapace subequilateral, greatest height at mid- point; hinge straight, long, cardinal angles equally bluntly obtuse; anterior and posterior margins convex, entire margin denticulate; lateral surface has greatest convexity slightly anterior of midpoint, mid-dorsal spine is very long, slender, directed posteriorly. Measurements. — Dimensions of hypotype 34723 are length 0.59 mm and height 0.35 mm, Occurrence. — Present in the Rabbit Hill Formation only at locality UWA 5973. SttuRo-DEvoNnIAN MicroFAuNA: McCLeLLAN 327 Discussion. — This species is similar to Aechmina equilateralts except for the dorsal spine. A. Jongior is distinguished by the very long and slender dorsal spine, which is quite distinct from that of A, equilateralis. Both species are present at the same locality; the latter occurring in greater numbers. Aechmina aff. A. phantastica Kesling Pi ate fie a 1953. Aechmina phantastica Kesling, Mich. Univ., Mus. Paleont. Contr., vol. Wi joy So. fol, al ames, Joh, Description. —Carapace subrectangular, dorsally truncate; hinge straight, about three-fourths of length; cardinal angles obtuse, subequal, posterior margins moderately convex, ventral margin slightly convex; dorsally directed, slender curved spines at point of cardinal angles; lateral surface moderately convex, broad based, stout, mid-dorsal spine directed perpendicular to commissure plane and slightly posteriorly, and spine is bluntly terminated. Measurements. — Length of specimen 34724 is 0.71 mm and height is 0.50 mm. Occurrence. — Rare, present only at locality UWA 5973 in the Rabbit Hill Formation. Discussion. — The form and position of the prominent mid- dorsal spine on this specimen is identical to that of Aechmina phantastica. Overall dimensions are also quite similar. This form dif- fers in possessing long, slender, curved spines arising from the ends of the hinge line. It also has a less semicircular outline, greater width, and the major spine is not granuloreticulate as in A. phantastica. The extra dorsal spines (posterior one is broken at base) are the most significant characteristics of this form. Coupled with the other differences from A. phantastica, it probably repre- sents a separate, new species, but the single ?LV found here is believed to be insufficient for establishment of a species. Aechmina cortezensis McClellan, n. sp. Pl. 41> figss 1i15 Description. — Carapace ovoid to subellipsoidal, partially trun- cated dorsally; hinge straight, about two-thirds length, gradually merging with margin at ends; anterior and posterior cardinal angles subequal, broadly obtuse; anterior margin and posterior are equally stongly convex, ventral margin moderately convex; lateral surface moderately convex with greatest width median to slightly antero- median; dorsal median spine broad based, long, directed outward at 328 BULLETIN 274 angle of 40-60 degrees from commissure plane, distal half may curve slightly posteriorly. Measurements. — Holotype 34725 has length of 0.57 mm, height 0.30 mm, and length of spine 0.41 mm, Paratype 34726, a RV, has length 0.55 mm and height 0.29 mm. Occurrence. — The type specimens are present at locality UWA 5980 in the lower Wenban Limestone. Discussion. — Aechmina cortezensis is most similar to A. longior Bassler (1941) which is present in probable correlative beds of the Rabbit Hill Formation. The dorsal median spine and shell size of A. cortezensts are similar to A. longior. This species differs, however, in having more strongly convex anterior and posterior margins, broader cardinal angles, shorter hinge line, and lacks the denticles on the margin, There is some variability in the shape of the valves in this new species, the most typical being subellipsoidal, but they may also be nearly ovate. In addition there is an indication of Jateral swelling in the anteroventral area, as on figured specimen 34726, that may be distortion or possibly indicate a dimorphic pouch. Family BOLLIIDAE Boucek, 1936 Genus ULRICHIA Jones, 1890 Type species. — Ulrichia conradi Jones, 1890. Ulrichia obesita McClellan, n. sp. Pipa ehicshai-s Description. —Carapace subrectangular to ovoid; hinge long, straight; cardinal angles obtuse, subequal; anterior and _ posterior margins equally convex, marginal rim distinct, forming sharply defined, narrow shelf; lateral surface strongly convex, finely reticu- late in concentric pattern in adult, marginal rim more coarsely reticu- late; anterior dorsomedian node round, posterior node forms narrow, strongly developed ridge with dorsal end more posterior than ventral end, Ss forms a narrow short, deep groove between nodes. Measurements. — Dimensions of the figured specimens are as follows: Pl. 42 Spec. Number Length Height Fig. 1 34780 holotype 0.67mm 0.43mm Fig. 2 34782 paratype 0.44mm 0.30mm Fig. 3 34783 paratype 0.37mm 0.26mm SILURO-DEVONIAN MiIcrRoFAUNA: MCCLELLAN 329 Occurrence. — The type specimens were present at locality UWA 5985 in the McMonnigal Limestone. Also present at locality UWA 5986 in the same area and formation. Discussion. — This species differs from others within the genus in the shape of the dorsomedian nodes, the posterior one being a ridge rather than the characteristic subcircular form. It is also much more highly convex laterally, than is customary for species of Ulrichia. The reticulate surface pattern is recognizable only on adult forms, such as the holotype. The reticulation continues, more coarse- ly, on the narrow, marginal rim, which is not the usual pattern for the genus. Ulrichia sp. Pl. 42, figs. 4, 7 Description. —Carapace subrectangular, truncate dorsally; hinge long and straight; cardinal angles subequal; margin convex, narrow, well-defined rim; lateral surface moderately elongated, sharply defined, posterior node smaller, subcircular, Ss shallow, broad, extending down to midpoint. Measurements. — Specimen 34783 length is 0.92 mm and height 0.61 mm. Dimensions of 34784 are 0.78 mm and 0.48 mm, Occurrence. — Present only at locality UWA 5973 in the Rab- bit Hill Formation. Discussion. — This form differs from Ulrichia spinosa in the shape of the nodes but otherwise has many similarities. It also resembles U. acricula in the position and form of the nodes. How- ever, the marginal rim is narrower and the shell is more robust than the lowly convex shell of U. acricula. Bolliidae ? genus PIS 43 hiess 16h 7 Description.—Carapace subquadrate, dorsally truncated; hinge long, straight, nine-tenths of length; cardinal angles equal, obtuse, nearly right angles; anterior margin gently convex, pos- terior slightly convex, marginal rim very narrow and sharply de- fined; lateral surface strongly convex, greatest width at midpoint; anterior node slightly elongate, sharply elevated, positioned just anterior of midpoint; posterior node forms linear, prominent, knife- like ridge beginning at dorsal margin and merging posteroventral of midpoint into a lower, well-defined ridge that curves ventrally around anterior node and continues up and around until terminat- 330 BULLETIN 274 ing at dorsal margin directly above anterior node; S; forms shallow, arcuate depression between anterior median node and curving ridge, S2 is deep, linear groove slightly posterior of midpoint, Measurements. — The length of 34734 is 0.38 mm and height 0.29 mm. Specimen 34735 has been broken but dimensions are ap- proximately 0.45 mm and 0.35 mm. Occurrence. — The figured specimens are from locality UWA 5985. Also present at UWA 5994 and UWA 5975 in strata of latest Silurian to early Devonian age. Discussion. — This form has affinities for both Ulrichia Jones (1890) and Bollia Jones and Holl (1886). The separate anterior dorsomedian node is similar to that of Ulrichia. The posterior node and ventral ridge extending from it are suggestive of Bollia. The ridge in Bollia connects with an anterior lobe, whereas the ventral ridge on this form extends instead in an arcuate line around the anterior node to the dorsal margin. This last feature is distinctive from other bolliids, thus a generic placement cannot be made. There is neither sufficient, nor adequately preserved material to be de- scribed. Superfamily HOLLINACEA Swartz, 1936 Family HOLLINIDAE Swartz, 1936 Genus HOLLINELLA Coryell, 1928 Type species. — Hollinella dentata Coryell, 1928. Hollinella sp. Pl. 42, fig. 6 Description. — Carapace ovoid, truncated dorsally; hinge line long, straight; cardinal angles obtuse, anterior more broadly so; an- terior margin strongly convex, posterior tapers smoothly into ven- tral margin, well developed, broad striate frill extends along entire margin; lateral surface strongly convex, Ls well developed, round- ed node, Ls low, broad, and indistinct; median sulcus between lobes is shallow, short, extending only in curving pattern along posterior side of Le. Measurements. — Dimensions of 34743 are length 0.76 mm, height 0.51 mm and width of frill 0.15 mm. Occurrence. — Present only at locality UWA 6024 in the Rob- erts Mountains Formation. S1turRo-DEVoONIAN MicroFAuNA: McCLeELLAN 331 Discussion. — Well-preserved specimens of this form are rare, and, therefore, specific identification could not be made. The median sulcus is not as broad as normal for most species of the genus, and the L3 is poorly developed. Family SIGMOOPSIDAE Henningsmoen, 1953 Genus WINCHELLATIA Kay, 1940 Type species. — Winchellatia longispina Kay, 1940. Winchellatia fragilis McClellan, n. sp. Pl) 42: fig.5 Description. —Carapace ovate, dorsally truncate; hinge line long, straight; anterior cardinal angle barely obtuse, posterior is a right angle; anterior margin gently convex, ventral nearly straight, curving evenly into posterior margin which is straight; lateral sur- face has greatest width posteroventral of midpoint; S; very shallow, narrow groove, S» deep, beginning at midpoint and widening from a narrow groove upward to near dorsal margin where it bends slightly forward; Le forms rounded low node outlined by S; and Sz, L3 an indistinctly raised area with greatest height posteroventral; histial ridge fine and sharply defined extends from near anterior cardinal angle around ventral part of valve, ending posteroventrally where posterior margin begins; ventromedian based spine extends laterally from broad base, with thickened posterior margin, other- wise very thin and flat, appears winglike with backward directed tip. Measurements. — The holotype male, 34788, has length of 0.42 mm and height 0.34 mm, Occurrence. — Present only at locality UWA 6024, where it is rare in Roberts Mountains beds of Upper Silurian age. Discussion. — The fragile winglike spine on each valve is dis- tinctive from similarly placed nodes on other species in the genus. In other characters this new species resembles Winchellatia minne- sotensis Kay (1940) which has an acute posterior cardinal angle, while that of the former is a right angle. Previously the genus has been reported only from Middle Ordovician strata. >) Los) bo BULLETIN 274 Superfamily PRIMITIOPSACEA Swartz, 1936 Family PRIMITIOPSIDAE Swartz, 1936 Subfamily PRIMITIOPSINAE Swartz, 1936 Genus LIMBINARIA Swartz, 1956 Type species. — Limbinaria multipunctata Swartz, 1956. Limbinaria sp. Pl. 42, figs. 8, 9 Description. —Carapace subrectangular, dorsally truncate; hinge long and straight; cardinal angles obtuse, subequal; anterior and posterior margins lowly convex, ventral margin nearly straight; lateral surface has large, slightly elevated medial area with sub- rounded median pit; continuous narrow ridge parallels margins, separating them from medial area, is discontinuous dorsally; sur- face of valve coarsely punctate. Measurements. — Specimen 34746 length is 0.92 mm and height indeterminate. mm. Specimen 34746 length is 0.92 mm and height indeterminate. Occurrence. — Rare, only present at locality UWA 6024 in the Roberts Mountains Formation. Discussion. — The presently known specimens of this form are not well enough preserved to be specifically identified. They are similar to Limbinaria multipuncta Swartz (1956), except in having a subrectangular outline. The dorsal marginal area appears to vary somewhat also with a different configuration of the ridge that bor- ders the media] area. Suborder KLOEDENELLOCOPINA Scott, 1961 Superfamily KLOEDENELLACEA Ulrich and Bassler, 1908 Family KLOEDENELLIDAE Ulrich and Bassler, 1908 Genus EUKLOEDENELLA Ulrich and Bassler, 1923 Type species. — Eukloedenella umbilicata Ulrich and Bassler, 1923: Eukloedenella aff. E. dalhousiensis Copeland Pl. 42, figs. 10, 11 1962. Eukloecdenella dalhousiensis Copeland, Geol. Sur. Canada, Bull. 91, p. 42, p. X, figs. 1-6. Description. — Carapace elongate, ovate; hinge straight pos- teriorly, right valve hinge slightly angulated over left valve at mid- point; posterior margin convex, ventral nearly straight, anterior SiLturRo-DEVONIAN MicroFAUNA: MCCLELLAN 333 margin has greatest convexity anteroventrally; greatest width pos- teromedial, valves lanceolate in dorsal view; median sulcus faint to indistinguishable. Measurement. — Specimen 34740 measures 0.45 mm in length and 0.22 mm in height. Specimen 34741 is 0.37 mm in length and 0.19 mm in height. Occurrence. — Present only at locality UWA 5985 in the Lower Devonian McMonnigal Limestone. Discussion. — The specimens described here compare well to Eukloedenella dalhousiensis Copeland (1962) in most characters. A notable exception is the lack of the distinct median sulcus of that species. Since E. dalhousiensis adults are typically about twice the size of the specimens here, it is possible that this material either represents early instars in which the sulcus is not recognizable, or if such instars should exhibit the sulcus, the use of open nomen- clature is justified until more detailed information is available. E.. dalhousiensis has been recorded in the upper Dalhousie beds of New Brunswick, Canada, which have been called Helderbergian in age (Copeland, 1962, p. 23). The age of the McMonnigal Lime- stone, from which these specimens were taken, has also been con- sidered Helderbergian on the basis of its megafauna (Kay and Craw- ford, 1964, p. 440). Genus NEOKLOEDENELLA Croneis and Funkhouser, 1939 Type species.— Neokloedenella prima Croneis and Funk- houser, 1939. Neokloedenella ? sp. Pl. 42, fig. 12 Description. —Carapace subrectangular, lanceolate in dorsal view; hinge straight, overlap indeterminate; anterior cardinal angle very bluntly obtuse, posterior angle also obtuse; anterior margin strongly convex, posterior moderately so, ventral margin nearly straight; lateral surface highly convex, median sulcus unrecogniz- able, greatest width in posterior third of valve. Measurements. — Specimen 34751 has length of 0.56 mm and height 0.29 mm. Occurrence. — Present at locality UWA 5991 in the lower McColley Canyon Formation. Discussion. — The poorly preserved male RV figured here re- 334 BULLETIN 274 sembles the Neokloedenella sp. reported by Stover (1956, p. 1111) from the Middle Devonian Windom Shale of western New York. Family GEISINIDAE Sohn, 1961 Genus PSEUDOLEPERDITIA Schneyder, 1956 Type species. — Pseudoleperditia tuberculifera Schneyder, 1956. Pseudoleperditia ? sp. Pl. 42, ges Description. — Carapace subquadrate, dorsally truncated; hinge straight, long; anterior cardinal angle obtuse, posterior forms a right angle; anterior margin nearly straight, ventral margin curves into slightly convex posterior; lateral surface strongly convex, greatest width ventromedian, L» forms a small, rounded node with median sulcus directly adjacent, forming shallow, elongate depression; prominent, broad, short spines directed upward from lateral sur- face of valve at points of the cardinal angles; margin lacks border but has short denticles anteriorly and ventrally. Measurements. — Length of 34759 is 0.45 mm and height 0.30 mm. Occurrence. — Rarely present only at locality UWA 6024 in the middle Roberts Mountains Formation, Discussion. — This specimen has been questionably referred to Pseudoleperditia Schneyder (1956), which is monotypic, on the basis of the similarity in the lobation and cardinal spines. It seems to differ in lacking the marginal border of P. twberculifera, having den- ticles instead, in a straighter hinge line, less anterior convexity, and in having the greatest width ventromedianly. The last character may be caused by an elongate brood pouch in this position, The type of hingement is indeterminate which further hinders positive identification, as it is an important character of the genus. Superfamily LEPERDITELLACEA Ulrich and Bassler, 1906 Family LEPERDITELLIDAE Ulrich and Bassler, 1906 Genus PARAHEALDIA Coryell and Cuskley, 1934 Type species. — Parahealdia pecorella Coryell and Cuskley, 1934. Parahealdia aff. P. pecorella Coryell and Cuskley _ PI. 42, figs. 14, 16, 17 1934. Parahealdia pecorella Coryell and Cuskley, Amer. Mus. Nat. Hist., Nov. 748, text fig. 17. StturRo-DEvontAn MicroFAuNAa: McCLELLAN 335 Description. — Carapace elliptical, female shorter and more ro- bust, more sharply convex in posterior margin than in anterior; hinge long, straight; margins smooth, dorsally slightly convex; lat- eral surface strongly convex, greatest width in posterior third where two short spines are directed posteriorly, upper spine at a low angle posterodorsally, bases of spines separated by narrow, flattened area; median sulcus very shallow and broad, extending down from dorsal margin for about one-third of height. Measurements. — Specimen 34777, female RV, measures 0.46 mm by 0.33 mm. Occurrence. — Abundant at locality UWA 5980. Also, ques- tionable specimens present at locality UWA 5981; both in the lower Wenban Limestone. Discussion. — These specimens differ from Parahealdia pecorella in being slightly convex dorsally, the spines are somewhat closer together, and the sulcus is broader and less distinct. In addition, female specimens are shorter and more rounded in outline. Superfamily PARAPARCHITACEA Scott, 1959 Family PARAPARCHITIDAE Scott, 1959 Genus PARAPARCHITES Ulrich and Bassler, 1906 Type species. — Paraparchites humerosus Ulrich and Bassler, 1906. Paraparchites sp. P42 fis. 15 Description. — Carapace broadly ovate, strongly convex; hinge about two-thirds of length, cardinal teeth indistinct; small, narrow, marginal ridge extends posteroventrally to anteroventrally, dorsal margin nearly straight; surface smooth, nonlobate, nonsulcate. Measurements. — Length of 34754 is 0.64 mm and height 0.48 mm. Occurrence. — Figured specimen from locality UWA 6024. Al- so occurs at locality UWA 5974. Both localities are in the upper two-thirds of the Roberts Mountains Formation. Order PODOCOPIDA, Miiller, 1894 Suborder PODOCOPINA Sars, 1866 Superfamily BAIRDIACEA Sars, 1888 Family BAIRDIIDAE Sars, 1888 Genus BAIRDIA McCoy, 1844 Type species. — Batrdia curta McCoy, 1844. 336 BULLETIN 274 Bairdia sp. Pl 43y ficss sles Description. — Carapace lanceolate in outline, acuminate an- teriorly, maximum height one-fourth of length from posterior; LV with short, small spine at midpoint of posterior margin, RV with short, small spine forming anterior point, LV overlaps RV dorsally on margin between spines; lateral surfaces smooth, maximum width near midpoint, tapering gradually to acuminate anterior. Measurements. — Specimen 34727 length is 0.55 mm plus spines (0.04 mm each) and height 0.29 mm. Occurrence. — Present only at locality UWA 6024 in the mid- dle Roberts Mountains Formation, Discusston.— The genus Bairdia seems indicated by the man- ner in which the valves are joined as well as the form of the shell and presence of small spines. Positive identification and compari- sons to other, possibly related, species could not be made because of a lack of material. Genus BYTHOCYPRIS Brady, 1880 Type species. — Bairdia bosquetiana Brady, 1866. Bythocypris aff. B. alcocki Copeland Pl. 43, figs. 3-5 1962. Bythocypris alcocki Copeland, Geol. Sur. Canada, Bull. 91, p. 46, pl. X, figs. 16-20. Description. — Carapace elongate reniform, broadly ovate pos- teriorly; hinge straight, in anterior half; LV overlaps RV on entire margin; greatest height median to posterior, greatest width postero- median; margin nearly straight ventrally, anterior margin with maximum point of convexity median to ventral; lateral surface moderately convex, smooth. Measurements. — Specimen 34737 is 0.56 mm by 0.29 mm; 34736 measures 0.46 mm by 0.22 mm. Occurrence. — Specimen 34737 from locality UWA 5974, and 34736 from locality UWA 6026. This form is widely distributed throughout the area in strata from Ludlovian to Helderbergian in age. It occurs most frequently in rocks of the latter age. Discussion.— One of the more common constituents of the ostracode fauna in central Nevada, specimens referred to this species show a wide variation in shape. The shel] outline varies from S1LturRo-DEVONIAN MicroFAUNA: MCCLELLAN 337 reniform to elliptical and the point of greatest width from posterior to anteromedian in position. Bythocypris alcocki Copeland (1962 ) is reniform and has a maximum width posteriorly. The left valve overlaps the right along the entire margin, in the same manner as shown by whole specimens from Nevada. B. phaseolina Ulrich and Bassler (1923) is similar to B. alcocki but more ellipsoidal and elongate. The specimens studied herern show some resemblance to B. phaseolina as well as apparent gradation from that species to B. alcockhi. Bythocypris ? sp. Pl. 43, figs. 6 Description. — Carapace subreniform, arcuate dorsally, later- ally tumid; hinge straight, questionably anterior half; ventral mar- gin straight to slightly concave, forming acute angles where join- ing anterior and posterior margins, dorsal margin strongly convex; lateral surface highly convex, greatest width median to ventro- median, maximum height at midpoint; valves dorsally depressed on median marginal area, may be depressed to form flattened area along ventral margin. Measurements. — Dimensions of specimen 34739 are length 0.48 mm and height 0.29 mm. Occurrence. — Figured specimen from locality UWA 5974. This form is present at several localities in beds ranging from Lud- low to Helderberg in age. Discussion. — Species of Bythocypris are commonly reniform to ovate and not ventrally flattened as is this form, The dorsal de- pression of the valves along the hinge is suggestive of a similar structure present on Newsomites Morris and Hill (1952). How- ever, it is believed that these specimens are generally more compar- able in form to that of Bythocypris. Family BEECHERELLIDAE Ulrich, 1894 Genus ACANTHOSCAPHA Ulrich and Bassler, 1923 Type species. — Beecherella navicula Ulrich, 1891. Acanthoscapha aff. A. navicuia (Ulrich) Pl. 43, figs. 7, 8 1891. Beecherella navicula Ulrich, Amer. Geol., vol. 8, No. 4, p. 203, pl. 2, figs. 8, 9. Description. — Carapace elongate, spindle-shaped; hinge long, >) Loe) (oe) BULLETIN 274 adont; flattened flange of margins greatly reduced; LV with very short dorsoposterior spine, anterior spine in contact with margin, RV with anterior end produced into short broad spine, Measurements. — Specimen 34719, a RV, length is 0.74 mm and height 0.30 mm; 34720, a LV, length 0.57 mm and height 0.21 mm. Occurrence. — Present only at locality UWA 5981 in the lower Wenban Limestone of Lower Devonian age. Discussion. — These specimens differ from Acanthoscapha navi- cula, which occurs in Lower Devonian rocks of New York, in several respects. They are considerably smaller, the anterior and posterior spines are much shorter, the sheil is less acuminate anteriorly, and the anterior spines contact the margin. The original types of A. navicula have a narrow marginal surface between the spine and margin. Genus LONGISCAPHA McClellan, n. gen. Type species. — Longiscapha nevadensis McClellan, n. sp. Descriptwon. — Carapace elongate, scaphoid, middle third ven- traliy constricted, anterior spindle-shaped, posterior convex; hinge straight, long; lateral valve surfaces smooth, strongly convex with broad dorsum, compressed at ends, LV slightly overreaching RV; spines lacking, or reduced, on LV only. The general scaphoid form and adont hinge place this genus definitely in the family Beecherellidae. The constriction of the median portion of the valves is similar to that of Ulrichella Boucek (1936), but is only represented as a height reduction, as the great- est width of the shell is in the same area. This genus is less acum- inate than other genera within the family, and the spine is poorly developed. Longiscapha nevadensis McClellan, n. sp. Pl. 43, figs. 9-11 Description. — Carapace scaphoid, anterior spindle-shaped; dor- sal margin straight, anterior margin bluntly acuminate, ventral margin gently concave through medial third of shell, posterior strongly convex, anterior and posterior low marginal ridge defined by very shallow furrow; lateral surface of valve smooth, strongly convex, slightly convex dorsum, greatest height at end points of hinge; short, broad based, dorsal spine directed forward from antero- dorsal position on LY. SILURO-DEVONIAN MicroFAuNA: MCCLELLAN 339 Measurements. — Holotype 34747 length is 0.59 mm and height 0.22 mm. Paratype 34748 length is 0.53 mm and height 0.19 mm and paratype 34749 length is 0.64 mm and height 0.22 mm. Occurrence. — This species was found only at localities UWA 6024 (type material) and UWA 6026 in the upper Roberts Moun- tains Formation at Willow Creek, which is of probable Ludlow age. Discussion. — This species is characterized by the depressed anterior and posterior with the accompanying marginal border, and the greatest height being at the ends of the hinge line. At both localities, from which Longiscapha nevadensis was re- covered, the strata are cherty, argillaceous limestones. The bedding is very thin, with the shale and chert in laminae and stringers, sug- gestive of quiet bottom conditions and slow deposition. The micro- fauna is large and diversified here, but other invertebrate fossils are rare, Superfamily CYTHERACEA Baird, 1850 Family BEROUNELLIDAE Sohn and Berdan, 1960 Genus BEROUNELLA Boucek, 1936 Type species. — Berounella rostrata Boucek, 1936. Berounella sp. Pl. 43, fig. 13 Description. —Carapace subquadrate, with a long spine ex- tending from posterior dorsal margin; anterior cardinal angle pro- duced into long, thin spine directed dorsally and curving forward; lateral surface strongly convex, L; is anteromedian to ventral; deep, straight sulcus begins at dorsal margin above L; and extends to mid- point; ventral lobe leading from L, backward until merging with L;, has long, delicate lateral spine curving posteriorly from postero- ventral point; L; broad, rising from posterodorsal position to merge with ventral lobe; marginal flange developed only posteroventrally. Measurements.— Length of specimen, exclusive of spine is 0.58 mm and height 0.29 mm. Occurrence. — Only one specimen is known, from locality UWA 6024 in the Roberts Mountains Formation. Suborder METACOPINA Sylvester-Bradley, 1961 Superfamily HEALDIACEA Harlton, 1933 Family HEALDIIDAE Harlton, 1933 Genus HEALDIA Roundy, 1926 340 BuLLETIN 274 Type species. — Healdia stmplex Roundy, 1926. Healdia ? sp. PI. 43; fig.-12 Description. — Carapace ovate; dorsal and ventral margins moderately convex, anterior and posterior both rounded; lateral surface strongly convex, greatest width posterior, surface smooth with posterior shoulder bearing two very short and blunt spines. Measurements. — Specimen 34742 length is 0.63 mm and height 0.39 mm. Occurrence. — Found rarely, only at locality UWA 5981 in the lower Wenban Limestone. Discussion. — This form is poorly represented in the area and specimens cannot be positively identified as having healdiid hinge- ment and overlap of the valves. On the basis of shape and surface features it has been referred to the genus Healdia. The degree and direction of overlap could not be determined, so it is possible that the generic assignment is incorrect. Family CAVELLINIDAE Egorov, 1950 Genus BIRDSALLELLA Coryell and Booth, 1933 Type species. — Birdsallella simplex Coryell and Booth, 1933. Birdsallella sp. Pl. 43, fig. 14 Description. — Carapace elongate ellipsoidal, RV overreach of LV noticeable only on dorsal and ventral borders, dorsal view wedge- shaped; anterior margin convex, posterior nearly truncate, dorsal and ventral margins straight; lateral surface smooth, greatest width posterior; posterior swelling developed into strong ridge projecting backward to margin. Measurements. — The figured specimen has a length of 0.74 mm and height of 0.45 mm. Occurrence. — This genus occurs only at locality UWA 5980 in the lower Wenban Limestone. Family PACHYDOMELLIDAE Berdan and Sohn, 1961 Genus PHANASSYMETRIA Roth, 1929 Type species. — Phanassymetria triserrata Roth, 1929. Phanassymetria sp. Pl. 43, fig. 20 Description. —Carapace subovate, asymmetrical, angular in S1LtuRO-DEVONIAN MicroFAuNA: McCLeELLAN 341 cross-section; dorsum convex, forming longitudinal shoulders with straight hinge in groove between, ventral margin straight; LV over- laps RV strongly on venter and is the larger valve; maximum width slightly posteroventral of midpoint; lateral surface coarsely punctate. Measurements. — Length of figured specimen is 1.03 mm and height is 0.65 mm, Occurrence. — Present at locality UWA 5980 in the lower Wenban Limestone, from which only one specimen was recovered. Discussion. — This specimen differs from the known species of Phanassymetria, but it is not possible to establish a new species until additional material has been found. Genus TUBULIBAIRDIA Swartz, 1936 Type species. — Tubulibairdia tubulifera Swartz, 1936. Tubulibairdia cf. T. chaleurensis Copeland Pie43. figs, 15,19 1962. Tubulibairdia chaleurensis Copeland, Geol. Sur. Canada, Bull. 91, p. 47, pl. X, figs. 32-36. Description. — Carapace ovate, elongated; hinge straight, about half of total length; dorsal margin slightly convex, anterior and posterior strongly so, ventral margin straight; LV overlaps RV, most pronounced ventrally; lateral surface smooth, highly convex, greatest width posterior giving ovoid shape in dorsal view, maximum height slightly posterior of median. Measurements. — Specimen 34776 length is 0.55 mm and height 0.29 mm. Occurrence. — Specimen 34776 is from locality UWA 6024. This species is widely distributed in the area in strata ranging from Lud- lovian to Helderbergian age. Discussion. — Tubulibairdia chaleurensis has been previously recorded in the type area of New Brunswick, Canada, where it occurs in the Lower Devonian Dalhousie beds. The species described here occurs in strata of similar age. It differs from Copeland’s types in being more elongate with a straight venter, and the maximum width is closer to median. Tubulibairdia aff. T. chaleurensis Copeland Pl. 43, fig. 18 1962. Tubulibairdia chaleurensis Copeland, Geo}. Sur. Canada, Bull. 91, p. 47 pl. X, figs. 32-36. 342 BULLETIN 274 Description. — Carapace ovate; hinge straight, about half of total length; dorsal and ventral margins gently convex, anterior and posterior strongly convex; LV overlaps RV except dorsally; lateral surface smooth, robust with high convexity, greatest width at mid- point and tapering evenly to both ends, dorsum rises above hinge line. Measurements. — Specimen 34778 has a length of 0.63 mm and height of 0.43 mm. Occurrence. — This form was found only at locality UWA 5985 in the McMonnigal Limestone. Discussion. — In general outline, viewed laterally, this form re- sembles Tubulibairdia chaleurensis more so than the preceding species. Differences are seen, however, in the median maximum width, and the valve overlap, which is continuous on the anterior border in contrast to Copeland’s types. With these significant dif- ferences the present material has affinities for, but is distinct from, T. chaleurensis. Tubulibairdia sp. Pl... 43, figs2t Description. —Carapace ovate; entire margin convex; overlap of valves indeterminate; lateral surface smooth, strongly convex, maximum width posterior. Measurements. — Specimen 34779 length is 0.66 mm and height is 0.44 mm. Occurrence. — Several specimens of single valves were found at locality UWA 5973 in the Rabbit Hill Formation of Lower Devonian age. Discussion. — The single valves occurring at the above locality appear to belong to Tubulibairdia, although unrecognizable specifi- cally. Their characters are more generalized than the previously described species which compare to T. chaleurensts. Superfamily QUASILLITACEA Coryell and Malkin, 1936 Family QUASILLITIDAE Coryell and Malkin, 1936 Genus QUASILLITES Coryell and Malkin, 1936 Type species. — Quasillites obliquus Coryell and Malkin, 1936. Quasillites sp. Pl. 44, figs. 1-3 Description. — Carapace subquadrate, ends rounded; LV over- SttuRo-DEVvoNIAN MicroFAUNA: McCLELLAN 343 laps RV except on dorsal margin; lateral surface moderately convex, greatest width median, ornamented with fine ridges and grooves; both valves have flattened dorsum with shoulders forming narrow ridges for entire length, LV may also have ventral groove setting off part of valve which overlaps RV; LV has anterior and posterior, short, blunt spines placed near ventral margin; RV may have similar matching pair, only one, or no spines. Measurements. — The figured specimens have the following dimensions: specimen 34760 has length 0.48 mm and height 0.25 mm and specimen 34761 length is 0.44 mm, height 0.22 mm. Occurrence. — Present only at locality UWA 5985 in the Mc- Monnigal Limestone. Discussion. — None of the known species of Quasillites ade- quately fits the description of these specimens, which are more equilateral than described species as well as having a distinctive development of the lateral spines. Stover (1956, p. 1124) discussed the problem of variability encountered in Quasillites species. In the present material considerable variation is suggested, such that it is deemed advisable not to erect a new species until more speci- mens are available for study. Family ROPOLONELLIDAE Coryell and Malkin, 1936 Genus RUDDERINA Coryell and Malkin, 1936 Type species. — Rudderina extensa Coryell and Malkin, 1936. Rudderina mutaspina McClellan, n. sp. Pl. 44, figs. 48 Description.—Carapace elongated subtriangular, triangle hypotenuse formed by central margin; hinge straight, extending for over 0.8 of greatest length; dorsal margin straight, anterior slightly convex, venter straight to convex rearward, posterior margin strongly convex; well developed, flattened marginal ridge anteriorly separated from lateral surface by narrow furrow, similar posterior ridge mostly indistinct; LV with convex medial portion of dorsal margin, lateral surface smooth, greatest height anterior, great- test width posteroventral; single, long, tapering, finely pointed spine arises from point of greatest width; the spine is directed anterolaterally in early instars, progressively changing to a postero- lateral direction in adults. 344 BULLETIN 274 Measurements. — Dimensions of the several instars figured are listed below: Pl. 44 Spec. Number Length Height Fig. 4 34763 paratype 0.47 mm 0.23 mm Pig. e 34764 paratype 0.47 mm 0.23 mm Fig. 6 34765 paratype 0.65 mm 0.30 mm Fig. 7 34766 paratype 0.65 mm 0.30 mm Fig. 8 34767 holotype 0.76 mm 0.38 mm Occurrence. — The type specimens are from locality UWA 5985 in the McMonnigal Limestone. Also present at Jocality UWA 5984 and UWA 5975. These occurrences range in age from upper Lud- lovian to Helderbergian. Discussion. — The single spine is distinctive for this species. Previously known species have two spines, one directed anteriorly and one posteriorly near the valve margins. The spine of Rudderina mutaspina is more nearly median though still near the ventral border. This single spine appears to change direction with growth of the individual (see Pl. 44, figs. 4-8), suggesting considerable varia- tion within the species, Rudderina spp. Pl. 44, figs. 9-12 Description. — Carapace subtriangular, greatest height anterior; long, slender, curving spine directed posterolaterally from median area at point of greatest width; some specimens also with small, curving, dorsal spines at ends of straight hinge line. Occurrence. — Specimens figured here are from locality UWA 6024; also at UWA 6026. Both occurrences in the Roberts Moun- tains Formation. Discussion. — Several different forms have been included here which appear to belong under the genus Ruddeérina, because of the general outline and spine development. Superfamily THLIPSURACEA Ulrich, 1894 Family THLIPSURIDAE Ulrich, 1894 Genus THLIPSURA Jones and Holl, 1869 Type species. — Thlipsura corpulenta Jones and Holl, 1869. Stturo-DEvoNIAN MicroFAuNA: McCLeLLANn 345 Thlipsura bispinosa McClellan, n. sp. Pl. 44, figs. 13-15 Description. — Carapace subovate; dorsal margin convex, ven- tral straight, anterior and posterior strongly convex with maximum convexity of posterior below midline; lateral surface strongly con- vex, greatest width posterior, flat depressed area rises from posterior margin to form shoulder which leads from posteroventral margin to dorsal position at about one-third of distance to anterior of valve; two anteriorly directed furrows lead from shoulder, with small node representing maximum convexity point of valve and separating the furrows; marginal to the furrows are two short spines projecting from the shoulder, the ventral spine directed posteriorly and the dorsal one posterodorsally directed, Measurements. — Following are the dimensions of the figured type specimens. Pl. 44 Spec. Number Length Height Fig. 13 34773 holotype 0.90 mm 0.52 mm Fig, 14 34774 paratype 0.69 mm 0.41 mm Fig. 15 34775 paratype 0.92 mm 0.56 mm Occurrence. — Specimens 34773 and 34774 are from locality UWA 5980 in the lower Wenban Limestone. Specimen 34775 is from locality UWA 5973 in the Rabbit Hill Formation, Discussion. — The most closely related species to Thlipsura bispinosa is T. furca Roth (1929), which has a similar outline and two furrows. The latter differs in lacking the spines and having a better defined central node separating the furrows. This species is not widely distributed in the area and is known only from the Lower Devonian. Where it does occur, it is one of the more common constituents of the fauna. LOCALITY REGISTER Numbers in (_) refer to location numbers given for the sections on the index map, Fig. 1. Coal Canyon (15) — Long. 116°28’, Lat. 40°2’30”, Horse Creek Valley Quadrangle UWA 5973 Located at top of hill on east side of Coal Canyon at elev. 6905’, NE 1/4, SE 1/4, SE 1/4 Sec. 17, T25N, UWA 5974 UWA 5975 UWA 5976 BULLETIN 274 R49E, north end of Simpson Park Range. Rabbit Hill Fm. Located west and 830’ down section from UWA 5973 at elev. 6440’. Roberts Mountains Fm. Located south of UWA 5974, at elev. 6310’, on south line 1300’ west of E corner Sec. 17. Roberts Mountains Fm. Located on slope on west side of Coal Canyon, at elev. 6440’, southeast of UWA 5975. Roberts Mountains Fm. Copenhagen Canyon (7) — Long. 116°24’, Lat. 39°12’30”, Horse UWA 5977 UWA 5978 UWA 5979 Heaven Mountain Quadrangle Located at top of cliff on west side of road in Copen- hagen Canyon at elev. 7100’; NW 1/4, SW 1/4, SW 1/4 Sec. 36, TI6N, R49E. Roberts Mountains Fm. Located near base of cliff, east and down section 430’ from UWA 5977, at elev. 6970’. Roberts Mountains Fm. Located on west side of road, 350’ south and 180’ down section from UWA 5978, at elev. 6865’. Roberts Mountains Fm. Cortez Canyon (16) — Long. 116°38’ Lat. 40°11’, Cortez Quad- UWA 5980 UWA 5981 rangle Located on north side near top of hill which forms east side of Cortez Canyon, at elev. 6000’, by claim monu- ment located 13,025’ NI9W of SW corner Sec. 6, T26N, R48E. Wenban Limestone Located north and 55’ down section from UWA 5980, at elev. 5900’. Wenban Limestone Gatechff (2) — Long. 116°47’30”, Lat. 39°00’, Wildcat Peak UWA 5982 UWA 5983 Quadrangle Located 1/2 mile west of Caesar Canyon, on north side of Mill Canyon at elev. 7840’, 30’ above base of cliff where canyon is crossed by stock fence. Bastille Lime- stone Located on slope above and 220’ up section from UWA 5982, at elev. 7920’. Bastille Limestone StLtuRO-DEVONIAN MicrRoFAUNA: McCLELLAN 347 Ikes Canyon (5) — Long. 116°44’, Lat. 39°03’, Dianas Punch Bowl UWA 5984 UWA 5985 UWA 5986 UWA 5987 UWA 5988 Quadrangle Located on west side of Copper Mt., overlooking Ikes Cabin, on north side of canyon, at elev. 8360’ and 6700’ S87W from NW corner Sec. 17, T14N, R46E, in the Toquima Mountains. Masket Shale Located north and 10’ up section from UWA 5984, in small saddle at elev, 8320’. Base of McMonnigal Lime- stone Located northwest and 45’ up section from UWA 5985, on north side of saddle at elev. 8290’. McMon- nigal Limestone Located southwest of UWA 5986 on nose of hill 250’ above bottom of canyon, at elev. 8010’, 1/4 mile east of Ikes Cabin. Masket Shale Located south and 390’ down section from UWA 5987, at elev. 7790’. Masket Shale Kelley Creek (13) — Long, 116°20’30”, Lat. 39°56’, Roberts Creek UWA 5989 UWA 5990 Mountain Quadrangle Located 6600’ due south of BM 6109 which is in NW 1/4 Sec. 21, T24N, R50F, on slope of ridge on east side of Kelley Creek at elev. 6880’, near mouth of canyon on north flank of Roberts Meuntains. Roberts Mountains Fm. Located northwest and down section 135’ from UWA 5989, at elev. 6850’, Roberts Mountains Fm. Lone Mountain (10) — Long. 116°16’, Lat. 39°35’, Bartine Ranch UWA 5991 UWA 5992 Quadrangle Located 12,000’ north and 6200’ east of the NE cor- ner of Sec. 1, T19N, R50E, on southwest side and near top of Lone Mountain, at elev. 7200’. Lone Mountain Dolomite Located due south and 830’ down section from UWA 5991, at elev. 7040’. Lone Mountain Dolomite March Spring (4) — Long. 116°44’, Lat. 39°02’45”, Dianas Punch UWA 5993 Bowl Quadrangle Located 7550’ west of NW corner, Sec. 20, T14N, R47E on top of hill west of small spring and 4% mile UWA 5994 UWA 5995 UWA 5996 UWA 5997 BULLETIN 274 south of Ikes Canyon, at elev. 8200’. McMonnigal Limestone Located east and 70’ down section from UWA 5993, on hillside at elev. 8160’. McMonnigal Limestone Located east and 130’ down section from UWA 5994, at elev. 8090’. Masket Shale Located east and 100’ down section from UWA 5995, at elev. 8050’. Masket Shale Located east and 130’ down section from UWA 5996, at elev. 7980’. Masket Shale Mill Canyon (3) — Long. 116°48’, Lat. 39°01’, east side of To- UWA 5998 quima Mts., Wildcat Peak Quadrangle Located at base of ridge on the west side of the north fork of Mill Canyon, 3600’ north of junction with the main canyon, at elev. 8280’. Gatecliff Dolomite Northumberland Canyon (1) — Long. 116°50’, Lat. 38°54’, 7 miles UWA 5999 south of Mill Canyon in Toquima Mts., unsurveyed Located at base of hill on north side of Northumber- and Canyon, 100 yards west of the mouth of Perkins Canyon and approximately one mile west of national forest boundary, at elev. 7800’. Perkins Canyon Fm. (U. Ord? ) Pete Hanson Creek (12) — Long. 116°20’, Lat. 39°53’, Roberts UWA 6000 UWA 6001 UWA 6002 UWA 6003 UWA 6004 Creek Mountain Quadrangle Located in high saddle on ridge separating two forks of Pete Hanson Creek, 2300’ north and 2800’ west of Roberts Creek Mountain, at elev. 9150’. McColley Canyon Fm. Located due west on side of hill and 1850’ down sec- tion from UWA 6000, at elev. 8680’. Lone Mountain Dolomite Located west and 405’ down section from UWA 6001, at elev. 8570’ in low saddle. Roberts Mountains Fm. Located west and down section 125’ from UWA 6002, in low saddle, at elev. 8570’. Roberts Mountains Fm. Located west and 170’ down section from UWA 6003, at elev. 8600’ on small nob at end of saddle. Roberts Mountains Fm. Stturo-DEVONIAN MicroFAuNA: McCLELLAN 349 UWA 6006 UWA 6007 UWA 6008 Rabbit Hill UWA 6009 UWA 6010 UWA 6011 UWA 6012 UWA 6013 Located west and 170’ down section from UWA 6004, at elev. 8560’. Roberts Mountains Fm. Located west and 310’ down section from UWA 6006, at elev. 8500’. Roberts Mountains Fm. Located west and 740’ down section from UWA 6007, at elev. 8330’. Roberts Mountains Fm. (6) —Long. 116°25’, Lat. 39°12’, Horse Heaven Mountain Quadrangle Located in middle of flat top of Rabbit Hill %4 mile west of road on north side of Whiterock Canyon, at elev. 7200’, Rabbit Hill Fm. Located SSE and 400’ down section from UWA 6009, on edge of steep slope at elev. 7120’. Rabbit Hill Fm. Located east and 55’ down section from UWA 6010, at elev. 7070’. Roberts Mountains Fm. Located east and 25’ down section from UWA 6011, at elev. 7050’. Roberts Mountains Fm. Located east and 25’ down section from UWA 6012, base of the hill at elev. 7030’. Roberts Mountains Fm. Telegraph Canyon (21) — Long. 116°04’, Lat. 40°06’, Mineral Hill UWA 6014 UWA 6015 Quadrangle Located on low ridge 3900’ west of BM 6912 at top of pass above Telegraph Canyon; SW 1/4, SW 1/4, NE 1/4, Sec. 36, T26N, R52E, at elev. 6850’, Rob- erts Mountains Fm. Located east and 2080’ up section from UWA 6014, on nose of hill at elev. 7040’. Roberts Mountains Fm. Twin Springs Hills (9) — Long. 116°24’45”, Lat. 39°30’, Antelope UWA 6016 UWA 6017 Tyrone Gap Peak Quadrangle Located on low rise on east side of Twin Springs Hills in NW 1/4, NE 1/4, NW 1/4 Sec. 25, T19N, R49E, at elev. 6360’. Roberts Mountains Fm. Located southwest and 260’ up section from UWA 6016, at elev. 6380’. Roberts Mountains Fm. (19) — Long. 116°04’30”, Lat. 39°49’, Garden Valley Quadrangle 350 UWA 6034 BULLETIN 274 Located 250’ east of center of WL, Sec. 1, T22N, R52E at south end of hogback, at elev. 6000’. Lone Mountain Dolomite Willow Creek (14) —Long. 116°19’, Lat. 39°57’, Roberts Creek UWA 6018 UWA 6019 UWA 6020 UWA 6021 UWA 6022 UWA 6023 UWA 6024 UWA 6025 UWA 6026 UWA 6027 UWA 6028 UWA 6029 UWA 6030 Mountain Quadrangle Located 1150’ east and 3100’ south of SE corner Sec. 15, T24N, R50E, on point of ridge on east side of Willow Creek, at elev. 7100’. McColley Canyon Fm. Located northwest and 320’ down section from UWA 6018, at elev. 6950’. Lone Mountain Dolomite Located west and 1505’ down section from UWA 6019, at center EL Sec. 22, T24N, RSOE, at elev. 6590’. Roberts Mountains Fm. Located NNW and 110’ down section from UWA 6020 at elev. 6550’ Roberts Mountains Fm. Located west and 435’ down section from UWA 6021, at elev. 6320’, Roberts Mountains Fm. Located south and 70’ down section from UWA 6022, at elev. 6310’. Roberts Mountains Fm. Located west and 50’ down section from UWA 6023, beside trail behind ranch house, at elev. 6280’. Rob- erts Mountains Fm. Located west and 230’ down section from UWA 6024, on hill on west side of Willow Creek, at elev. 6500’. Roberts Mountains Fm. Located southwest and 310’ down section from UWA 6025, at elev. 6540’. Roberts Mountains Fm. Located west and 355’ down section from UWA 6026, at elev. 6500’. Roberts Mountains Fm. Located southwest and 130’ down section from UWA 6027, on north flank of mountains at elev. 6610’. Roberts Mountains Fm. Located west and 330’ down section from UWA 6028, at elev. 6580’. Roberts Mountains Fm. Located north and 155’ down section from UWA 6029, on small northward projecting nose of hill, S1LuRO-DEVONIAN MicroFAUNA: MCCLELLAN 351 midway between Willow and Birch creeks, at elev. 6500’. Roberts Mountains Fm. UWA 6031 Located NNW and 105’ down section from UWA 6030, at elev, 6455’ approximately 50’ above base of hill. Roberts Mountains Fm. Wood Cone (8) — Long. 116°09’, Lat. 39°23’, Bellevue Peak Quad- rangle UWA 6032 Located 2700’ west and 1100’ north of BM 7201 by road north of Wood Cone Peak, on slope of small nob of hill, at elev. 7160’. Roberts Mountains Fm. UWA 6033 Located southwest and 750’ down section from UWA 6032, at elev. 7080’. Roberts Mountains Fm. The following sections were studied, but no microfossils were recovered from the samples: Bailey Pass (20) — Long. 116°06’, Lat. 39°55’, Garden Valley Quadrangle, from top of pass down east side of Sul- phur Spring Range Cole Creek (23) — Long. 116°07’, Lat. 40°37’, Carlin Quadrangle, » 172 See 34, F32N; R52E Fourmile Canyon (18) — Long. 116°33’, Lat. 40°12’, Cortez Quad- rangle, at mouth of canyon Mill Canyon (17) — Long. 116°35’, Lat. 40°12’, Cortez Quadrangle, at boundary of Lander and Eureka counties Mitchell Creek (22) — Long. 115°35’, Lat. 40°09’, Sherman Moun- tain Quadrangle, west side of southern Ruby Moun- tains Sheep Corral Canyon (11) —Long. 116°34’, Lat. 39°56’, Walti Hot Springs Quadrangle, SW corner Sec. 14, T23N, R48E REFERENCES CITED Barker, R. W. 1960. Taxonomic notes on species figured by H. B. Brady in Foramini- fera of Challenger Expedition. Soc. Econ. Paleont. and Min., Spec. Publ. 9, 238 pp.. 115 pls. Barker-Webb, P. and Berthelot, S. 1839. Foraminiferes, in Hist. Nat. Iles Canaries. Vol. 2, pt. 2, Zool., pp. 119-146, pls. 1-3. gy BULLETIN 274 Bassler, R. S. 1941. Ostracoda from the Devonian (Onondaga) chert of west Ten- nessee. Washington Acad. Sci. Jour., vol. 31, No. 1, pp. 21-27, figs. 1-37. Brady, H. B. 1878. On reticularian and radiolarian Rhizopoda (Foraminifera and Polycystina) of North Polar Expedition of 1875-76. Ann. Mag. Nat. Hist., ser. 5, vol. 1, pp. 425-440, pls. 20, 21. 1879. Notes on some reticularian Rhizopoda of the Challenger Expedition. Quart. Jour. Micr. Sci., n. s., vol. 19, pp. 28-60, pl. 5 Browne, R. B., and Schott, V. J. 1963. Arenaceous Foraminifera from the Osgood Formation at Osgood, Indiana, Bull. Amer. Paleont., vol. 46, No. 209, pp. 191-242, pls. 48-52. Carlisle, D., Murphy, M. A., Nelson, C. A., and Winterer, E. L. 1957. Devonian stratigraphy of Sulphur Springs and Pinyon ranges, Nevada. Amer. Assoc. Petr. Geol., Bull., vol. 41, No. 10, pp. 2175- 2191, 3 text-figs. Carls, P., and Gandl, J. 1969. Stratigraphie und Conodonten des Unter-Devons der ostlichen Iberischen Ketten. Neues. Jahrb. Geol. Paleont., Bd. 132, No. 2, pp. 155-218, 3 text-figs. Chernysheva N. E. 1940. K. stratigrafii nizhnego Karbona Makarovskogo rayona yuzhnogo Urala po faune foraminifer. Soc. Nat. Moscow, Bull., n. s., tome , 48 (sect. geol. tome 18), No. 5-6, p. 127, pls. 1, 2. Clark, D. L., and Ethington, R. L. 1966. Gomadants and biostratigraphy of the Lower and Middle Devonian of Nevada and Utah. Jour. Paleont., vol. 40, No. 3, pp. 659-689, pls. 82-84, 10 text-figs. Conkin, J. E. 1954. Hyperammina kentuckyensis, n. sp. from the Mississippian of Kentucky. Cushman Found. Foram. Res., Contr., vol. 5, pt. 4, No. 119, pp. 165-169, pl. 31. 1961. Mississippian smaller Foraminifera of Kentucky, southern In- diana, northern Tennessee, and southcentral Ohio. Bull. Amer. Paleont., vol. 43, No. 196, pp. 131-368, pls. 17-27, figs. 1-43. , and Conkin, B. M. 1970. Middle Devonian arenaceous Foraminifera of central Ohio. Micro- paleont., vol. 16, No. 1, pp. 1-14, pls. 1-4. Copeland, M. L. 1962. Canadian fossil Ostracoda, Conchostraca, Eurypterida, and Phyllocarida. Geol. Sur. Canada, Bull. 91, pp. 18-51, pls. 5-10. Coryell, H. N. 1928. ie new Pennsylvanian Ostracoda. Jour. Paleont., vol. 2, No. 4, . 377-381, pls. 51. Coryell, H. N. and Cuskley, V. A. 1934. Some new Ostracodes from “White Mound” section of Haragan Shale, Murray Co., Oklahoma. Amer. Mus. Nat. Hist., Novitates, No. 748, 12 pp., 18 figs. Coryell, H. N., and Malkin, D. S. 1936. Some Hamilton Ostracodes from Arkona, Ontario. Amer. Mus. Nat. Hist., Novitates, No. 891, 20 pp., 38 figs. Croneis, C., Dunn, P. H., and Hunter, D. 1932. Pre-Carboniferous Foraminifera. Science, vol. 75, No. 1935, p. 138. Stturo-DeEvoNIAN MicrorAunA: McCLe.LLan 353 Cushman, J. A. 1910. Foraminifera of the North Pacific Ocean. U.S. Nat. Mus., Bull. 71, pt. 1, pp. 1-134. 1918. Foraminifera of the Atlantic Ocean. U.S. Nat. Mus., Bull. 104, pt. IS pp l-1ils spt) 2, ppel-11i- 1959. Foraminifera. Ed. 4, Cambridge, Mass., 605 pp. Dapples, E. C. 1959. Behavior of silica in diagenesis. in Silica in Sediments. Soc. Econ. Paleont. Min., Spec. Publ. No. 7, H. A. Ireland ed., pp. 36-54, figs. 1-0. 1967. Silica as an agent in diagenesis. in Diagenesis in Sediments. Devel. in Sed. 8, G. Larsen and G. V. Chilingar ed., Amsterdam, pp. 323-342, 1 text-fig. de Folin, L. 1887. Les Rhizopodes reticulaires. Naturtiste, Paris, vol. 9, No. 2, p. 127, text-fig. 12a. Dunn, P. H. 1942. Silurian Foraminifera of the Mississippian Basin. Jour. Paleont., vol. 16, No. 3, pp. 317-342, pls. 42-44. Ellis, B. F., and Messina, A. R. 1952 + suppl. Catalogue of Ostracoda. Amer. Mus. Nat. Hist., Spec. Publ. Gilluly, J., and Masursky, H. 1965. Geology of the Cortez Quadrangle, Nevada. U.S. Geol. Sur., Bull. 1175, pp. 1-97, pls. 1, 2, figs. 1-10. Glaessner, M. F. 1937. Studien iiber Foraminiferen aus der Kreide und dem Tertidr des Kaukasus; I-Die Foraminiferen der dltesten Tertiarschichten des Nordwestkaukasus. Moscow Univ., Lab. Paleont., Prob. Paleont., vols. 2, 3, p. 354. Grubbs, D. M. 1939. Fauna of the Niagaran nodules of the Chicago area. Jour. Paleont., vol. 13, No. 6, pp. 543-560, pl. 61, 62. Gutschick, R. C. 1959. Arenaceous Foraminifera from the Rockford Limestone of northern Indiana, Jour. Paleont., vol. 33, No. 2, pp. 229-250, pls. 33-37, 3 text-figs. _ Weiner, J. L., and Young, L. 1961. Lower Mississippian arenaceous Foraminifera from Oklahoma, Texas, and Montana. Jour. Paleont., vol. 35, No. 6, pp. 1193-1221, pls. 147-150, 5 text-figs. Hague, A. 1892. Geology of the Eureka district, Nevada. U.S. Geol. Sur., Mono- graphs, vol. 20, pp. 34-217. Hattin, D. E. 1960. Waldron Foraminifera in Indiana. Geol. Soc. Amer., Bull., vol. 71, No. 12, pt. 2, abstr., p. 2016. Henbest, L. G. 1935. Nanicella, a new genus of Devonian Foraminifera. Washington Acad. Sci., Jour., vol. 25, p. 34. Ireland, H. A. 1939. Devonian and Silurian Foraminifera from Oklahoma. Jour. Paleont., vol. 13, No. 2, pp. 190-202, 75 text-figs. 354 BULLETIN 274 Johnson, J. G. 1962. Lower Devonian—Middle Devonian boundary in central Nevada. Amer. Assoc. Petr. Geol., vol. 46, pp. 542-546, 3 text-figs. 1965. Lower Devonian stratigraphy and correlation, northern Simpson Park Range, Nevada. Bull. Canadian Petr. Geol., vol. 13, No. 3, pp. 365-381. , and Boucot, A. J. 1968. Llandovery to Givetian brachiopod zonal sequence in the Silurian and Devonian otf central Nevada. Geol. Soc. Amer., Cordilleran Sect., Program, Ann. Mtg., abstr., p. 69. Jones, T. R., and Parker, W. K. 1860. On the rhizopodal fauna of the Mediterranean, compared with that of Italian and some other Tertiary deposits. Quart. Jour. Geol. Soc. London, vol. 16, pp. 292-307. Kay, M. 1940. Ordovician Mohawkian Ostracoda; Lower Trenton Decorah fauna. Jour. Paleont., vol. 14, No. 4, pp. 234-269, pls. 29-34. 1960. Paleozoic continental margin in central Nevada, western United States. Internat. Geol. Congr. Rept., 21st sess., Copenhagen, Den- mark, pt. 12, pp. 93-103. , and Crawford, J. P. 1964. Paleozoic facies from miogcosynclinal belt in thrust slices, central Nevada. Geol. Soc. Amer., Bull., vol. 75, No. 5, pp. 425-454, pls. 1-6, 9 text-figs. Kesling, R. V. 1953. Ostracods of the family Aechminidae from the Arkona Shale of southern Ontario. Michigan Univ., Mus. Paleont. Contr., vol. 11, No: ey pp: 1-105 plas Klapper, G. 1969. Conodont succession in central Nevada. Geol. Soc. Amer., Cordil- leran Sect., Program, Ann. Megt., abstr., p. 72. Krauskopf, K. B. 1959. Geochemistry of silica in sedimentary environments, in Silica in Sediments. Soc. Econ. Paleont. Min., Spec. Publ. No. 7, H. A. Ireland ed., pp. 4-19, figs. 1-6. Loeblich, A. R., and Tappan, H. 1957. Eleven new genera of Foraminifera. U.S. Nat. Mus., Bull. 215, pp. 223-232, pl. 72. 200 ——————— 1964. Treatise on Invertebrate Paleontology. R. C. Moore ed., Pt. C Protista 2, vols. 1, 2, 900 pp. Martinsson, A. 1962. Ostracodes of the family Beyrichiidae from the Silurian of Got- land. Uppsala Univ., Paleont. Inst., Publ. No. 41, 369 pp., 203 text-figs. McClellan, W. A. 1966. Arenaceous Foraminifera from the Waldron Shale (Niagaran) of southeast Indiana. Bull. Amer. Paleont., vol. 50, No. 230, pp. 447-518, pls. 36-42. Merriam, C. W. 1940. Devonian stratigraphy and paleontology of the Roberts Mountains region, Nevada. Geol. Soc. Amer., Spec. Paper 25, pp. 1-114. 1963. Paleozoic rocks of Antelope Valley, Eureka and Nye counties, Nevada. U.S. Geol. Sur., Prof. Paper 423, pp. 1-55, pl. 1, 2, 8 text- figs. On SILURO-DEVONIAN MIcRoFAUNA: McCLELLAN 35 , and Anderson, C. A. 1942. Reconnaissance survey of Roberts Mountains, Nevada. Geol. Soc. Amer., Bull., vol. 53, No. 12, pt. 1, pp. 1675-1728, pls. 1-4, figs. 1, 2. Moore, R. C., ed. 1961. Treatise on Invertebrate Paleontology, Pt. Q Arthropoda 3, 442 pp. 1962. Treatise on Invertebrate Paleontology Pt. W Miscellanea, 259 pp. Moreman, W. L. 1930. Arenaceous Foraminifera from Ordovician and Silurian lime- stones of Oklahoma. Jour. Paleont., vol. 4, No. 1, pp. 42-59, pls. 5-7. 1933. Arenaceous Foraminifera from the lower Paleozoic rocks of Oklahoma. Jour. Paleont., vol. 7, No. 4, pp. 393-397, pl. 47. Mound, M. C. 1961. Arenaceous Foraminifera from the Brassfield Limestone of south- eastern Indiana. Indiana Dept. Conserv., Geol. Sur. Bull. No. 23, 38 pp., 3 pls. Murphy, M. A. 1968. Stratigraphy of the Roberts Mountains Formation in the type region, Geol. Soc. Amer., Cordilleran Sect., Program, Ann. Mtg., abstr., p. 86. Nolan, T. B., Merriam, C. W., and Williams, J. S. 1956. Stratigraphic section in the vicinity of Eureka, Nevada. U.S. Geol. Sur., Prof. Paper 276, pp. 28-52, pl. 2. Norman, A. M. 1878. On the genus Haliphysema. Ann. Mag. Nat. Hist., ser. 5, vol. 1, pa 28ihepls 6s digs Rhumbler, L. 1895. Entwurf eines natiirlichen systems der Thalamophoren. Gesell. Wiss. Gottingen, math-physik. Kongl., Nachr., No. 1, pp. 51-98. 1904. Systematische zusammenstellung der recenten Reticulosa. Archiv. Protistenkunde, vol. 3, pp. 181-294, text-figs. 1-142. Roberts, R. J., Hotz, P. E., Gilluly, J., and Ferguson, H. G. 1958. Paleozoic rocks of north-central Nevada. Amer. Assoc. Petr. Geol., Bull., vol. 42, No. 12, pp. 2813-2858, 11 text-figs. Roth, R. 1929. Some Ostracodes from the Haragan Marl, Devonian of Oklahoma. Jour. Paleont., vol. 3, No 4, pp. 327-372, pls. 35-38. Rzehak, A. 1885. Bemerkungen iiber einige Foraminiferen der Oligocaén Formation. Naturforsch. vereins Briinn, Verhandl., vol. 23 (1884), pp. 123- 129" Sars, M. 1869. In Carpenter, W. B., On the rhizopodal fauna of the deep sea. Roy. Soc. London, Proc., vol. 18, No. 114, pp. 59-62. 1872. In Sars, G. O., Underspgelser over Hardangerfjordens fauna. Vidensk.-Selsk. Christiania, Forhandl., vol. 1871, pp. 246-255. Schulze, F. E. 1875. Zoologische ergebnisse der Nord-seefahrt, 1872, I. Rhizopoden. II: Komm. Untersuch. deutsch. Meere in Kiel, Jahresber., vol. 1872- 73, pp. 99-114, pl. 2. Sharp, R. P. 1942. Stratigraphy and structure of the southern Ruby Mountains, Nevada. Geol. Soc. Amer., Bull., vol. 53, No. 5, pp. 647-690. 356 BULLETIN 274 Shchedrina, Z. G. 1939. Nowvyg rod peschanistykh Foraminifera iz Arkticheskikh Morey. Akad. Nauk SSSR, Doklady, n. s., vol. 24, No. 1, p. 94-96. Smith, D. L. 1966. Tippecanoe sequence in western North America. Unpubl. Ph.D. thesis, Univ. Washington, Seattle, 83 pp., 6 figs. Stewart, G. A. 1936. Ostracodes of the Silica Shale, Middle Devonian of Ohio. Jour. Paleont., vol. 10, No. 8, pp. 739-763, pls. 100-102. , and Priddy, R. R. 1941. Arenaceous Foraminifera from Niagaran rocks of Ohio and In- diana. Jour. Paleont., vol. 15, No. 4, pp. 366-375, pl. 54. , and Lampe, L. 1947. Foraminifera from the Middle Devonian Bone Beds of Ohio. Jour. Paleont., vol. 21, No. 6, pp. 529-536, pls. 78, 79. Stover, L. E. 1956. Ostracoda from the Windom Shale (Hamilton) of western New York. Jour. Paleont., vol. 30, No. 5, pp. 1092-1142, pls. 111-119, 8 text-figs. Summerson, C. H. 1958. Arenaceous Foraminifera from the Middle Devonian limestones of Ohio. Jour. Paleont., vol. 32, No. 3, pp. 544-558, pls. 81, 82, 7 text-figs. Swartz, F. M. 1936. Revision of the Primitiidae and Beyrichiidae, with new Ostracoda from the Lower Devonian of Pennsylvania. Jour. Paleont., vol. 10, No. 7, pp. 541-586, pls. 78-89. , and Oriel, S. S. 1948. Ostracoda from Middle Devonian Windom beds in western New York. Jour. Paleont., vol. 22, No. 5, pp. 541-566, pls. 79-81, 4 text- figs. , and Whitmore, F. C. 1956. Ostracoda of the Silurian Decker and Manlius limestones in New Jersey and eastern New York. Jour. Paleont., vol. 30, No. 5, pp. 1029-1091, pls. 103-110, 4 text-figs. Thomas, A. O. 1931. Late Devonian Foraminifera from Iowa. Jour. Paleont., vol. 5, No. 1, pp. 40, 41, pl. 7. Ulrich, E. O. 1891. Beecherella, a new genus of lower Helderberg Ostracoda. Amer. Geol., vol. 8, No. 4, pp. 197-204, pl. 2. Weller, S. 1903. The Paleozoic faunas. New Jersey Geol. Sur., Paleont., vol. 3, 462 pp., 53 pls. Wheeler, H. E. 1963. Post-Sauk and Pre-Absaroka Paleozoic stratigraphic patterns in North America, Amer. Assoc. Petr. Geol., Bull., vol. 47, No. 8, pp. 1497-1526. White, M. P. 1928. Some index Foraminifera of Tampico embayment area of Mexico. Jour. Paleont., vol. 2, No. 3, pp. 177-215, pls. 27-29. Winterer, E. L., and Murphy, M. A 1960. Silurian reef complex and associated facies, central Nevada. Jour. Geol., vol. 68, No. 2, pp. 117-139. PLATES The University of Nevada provided the funds for the illustrations of this paper. 358 BULLETIN 274 EXPLANATION OF PLATE 33 All figures «60 Page Rhabdammina major de Folin. ...0...0.......00.00cccccoceccceecceceee 277 #34686 (X30) Hyperammina: casteri-Conkan 6... 5.:<...0.5<-scec0cesececcste couse eee 279 2. Microspheric form, #34670. 6. Megalospheric form, # 34669. Marsipeilan'Sps foe cea seen a ee ee 279 # 34674. Hyperammina constricta Gutschick and Treckman ......... 280 Megalospheric form, #34671. Hyperammina curva (Moreman) .....0000.....0oocccccocccccceeeecceeee 281 Megalospheric form, #34672. Marsipella torta Stewart and Priddy ..................... eS # 34673. Rhabdammina bifurcata Browne and Schott .................. 276 8. £34682. 9. #34683. Rhabdammina cylindrica Glaessner 0... 276 10. #34684. 11. #34685. Raibosammina aspera Moreman .......... figs ie fla ae, eed ee 286 # 34681. BuLL. AMER. PALEONT., VOL. 62 PLATE 33 BULL. AMER. PALEONT., VOL. 62 PLATE 34 Figure 1-5. 6-10. 11, 12. 13, 14. 15, 16. 17. 18. 19. 20. 21. 22. 23, 27. 25. S1tuRo-Devontan MicroFauna: McCLetian 359 EXPLANATION OF PLATE 34 All figures «60 Page Anictosphaera progressa McClellan, n. sp. . 284 1. Paratype, showing interior, #34651. 2: Paratype, #34652. 3. Paratype, #34653. 4. Holotype, # 34654. 5. Paratype, # 34655. Storthosphaera malloryi McClellan, n. sp. 296 6. Holotype, #34703. 7. Paratype, #34704. 8. Paratype, # 34705. 9. Paratype, #34706. 10. Paratype, #34707. Sorosphaera inflata McClellan, n. sp. 0... . 290 11. Paratype, #34689. 12. Holotype, #34690. Showing wall dividing two chambers. Sorosphaera compacta McClellan, n. sp. ......000000.. 290 13. Holotype, #34691, broken wall shows divisions between three chambers. 14a, b. Paratype, #34692, shows slight constriction of test and walls dividing three chambers on broken side. Sorosphaera osgoodensis Stewart and Priddy .................. 288 15. T'wo-chambered form with part of third, #34790. 16. Four-chambered specimen, #34688. Stegnammina moremani (Dunn) ............c ei ccecceeeeeeeeeeee, 294 # 34699 Stegnammina cylindrica Moreman. .......0.............cccccceeeeeeeeeee. 292 # 34697 Stegnammina hebesta? Moreman |..........000...0ccccccecceeeeeeeee 293 # 34692 Sorosphaeraws ptm se cc ssoe estes caste ete Soe ae 291 # 34693 : Psammosphaera cava MoOreman ooo.........ccccccccccccccccccccceeceeceeeeees 282 # 34679 Stegnammina contorta McClellan .oooo.2.0o.o oo oococccceeeeeeeeee 292 With damaged test wall, #34696. Stegnammina quadrangularis (Dunn) ......0000.0...00...... ee. 295 23. Top view, #34700. 27. Top view of broken specimen, # 34701. Sorosphaera’ confusa/ brady =. eee. 287 # 34687 Ceratammina cf. C. cornucopia Ireland ................................ 285 With partially broken wall, #34660. Psammosphaera laevigata White 2000s. 283 # 34680 Figure 12. 13. 14. 16. fie 18. 19) 20. BuLLeETIN 274 EXPLANATION OF PLATE 35 All figures 60 Hemisphaerammina brady Loeblich and Tappan .............. 302 Side view, #34663. Hemisphaerammina cf. H. bradyi Loeblich and Tappan .. 302 Side view, #34664. Hemisphaerammina discoidea? (Summerson) ................... 303 Side view, #34666. Hemisphaerammina coronata (Ireland) ...................... oe 303 4a. Top view, 4b. Side view. #34665. Hemisphaerammina bipatella McClellan, n. sp. ................. 304 5. Paratype, top view, #34667. 6a. Holotype, top view, 6b, end view, #34668. . Sorostomasphaera waldronensis McClellan ...............0........ 297 7. £34694. 8. With part of second chamber remaining, # 34695. Webbinelloidea hemispherica Stewart and Lampe ............ 312 9. Top view, #34715. 10. Side view, #34714. Webbinelloidea aff. W. nodosa Summerson ........................ 312 lla. Side view, #34717. 11b. Top view. 15. Top view, # 34716. Webbinelloidea hattini McClellan 00.0000... 311 Side view, #34713. Metamorphina tholus (Moreman) .............. Sees ee eae 308 13a. Top view. 13b. Ventral view; #34676 Webbinelloidea ventriquetra McClellan ..............000000000000.... 313 Ventral view, #34718. Metamorphina gibbosa (Ireland) .......000000.......cecceccceccccccee 309 16a. Top view. 16b. Ventral view. 16c. Side view; #34675. Thurammina trituba Dunn 0... .c..ce:6.-..scssusadecssteactesssspsseoes ecco 300 #34710 Thurammina arcuata Moreman. ..........................0..000.cceee 299 # 34708. Thurammina tubulata Moreman. ....0.00......0.....00000.ccccceeeceeeee 301 # 34711. Thurammina quadritubulata? Dunn |... 300 # 34709. BuLL. AMER. PALEONT., VOL. 62 PLATE 35 BULL. AMER. PALEONT., VOL. 62 PLATE 36 Figure 9, 10. Stturo-Devonian MicroFAuNA: McCLELLAN 361 EXPLANATION OF PLATE 36 All figures 60 Page Atelikamara incomposita McClellan, n. sp. .....00000000.......... 306 la. Holotype, top view, #34658. 1b. Ventral view. 2. Para- type, top view, #34793. 3. Paratype, top view, #34657. Tolypammina tortuosa Dunn .......... eA ee ee ee . 815 #34712 Glomospira siluriama Ireland ......000.0........0cccccccccccececcceeeeeteeeeee 314 + 34661 Atelikamara incomposita McClellan, n. sp... 306 # 34659. Top view with attached, #34662. Stomasphaera brassfieldensis Mound ..........0..0.0....00.00000000005. 298 # 34702 Aschemonella bastillensis McClellan, n. sp. ......00..0000.0..00.... 316 Nanicella dainae? Chernysheva. .................0.0...c:cccccceeceeee . 319 9. #34678. 10. #34677. 362 BULLETIN 274 EXPLANATION OF PLATE 37 Figure Page 1. Haplophragmoides antiquus McClellan, n. sp. ............. 23 318 Scanning electron micrograph 300, #34792. Needle-like fragment on surface of specimen is foreign material. ion Scanning electron micrograph 200, #34792. Main aper- ture at point A, aligned grains indicate suture at S. BULL. AMER. PALEONT., VOL. 62 PLATE 37 PLATE 38 BULL. AMER. PALEONT., VOL. 62 SttuRo-DeEvonian MicroFAuNA: McCLELLAN 363 EXPLANATION OF PLATE 38 Figure Page 1. Webbinelloidea hemispherica Stewart and Lampe .......... 312 # 34715, top view 160. 2. Webbinelloidea aff. W. nodosa Summerson ..... .......... eer 312 # 34717, top view 120. 3. Hemisphaerammina bipatella McClellan, n. sp. .................. 304 3. Holotype, end view 160; #34668. 3b. Top view 160. 4. Hemisphaerammina coronata (Ireland) ..........0.00..0........... O05: Top view showing ordered arrangement of grains, 320; #34665. 364 BULLETIN 274 EXPLANATION OF PLATE 39 Figure Page 1. Psammosphaera laevigata White 2.000.000.0000 283 # 34680, «240. 2. Stegnammina moremani (Dunn) ......... ...................c.ccc0eeeeeeees 294 Partially broken specimen 240; #34699. 3. Raibosammina aspera Moreman ..........0.0.........:cccccccccceeeeeeeee 286 # 34681, X80. 4. Rhabdammina bifurcata Browne and Schott .........000000...... 276 Showing interior and wall structure, X120; #34683. 5. Metamorphina tholus (Moreman) .....................00..ccccseeceeeeeeecees 308 Ventral view and interior, X160; #34676. 6. Sorosphaera osgoodensis Stewart and Priddy .................... . 288 # 34688, 120. PLATE 39 nN © 4 ° > a Z fe) a 4 < a oe a = < = | 5) Q N ve) =| S > a a 2) Q 4 < Ay 8 fa 5 < S =) a) Figure Situro-DeEvoniaAn MicroFauna: McCLeLLAn 365 EXPLANATION OF PLATE 40 Page Sorosphaera inflata McClellan, n. sp. o.......0..0cccccceceeeeeeeeeeees 290 Holotype shows wall dividing two chambers of partially broken test, X160; #34690. Sorosphaera compacta McClellan, n. sp. oo......cccccccccece 290 Holotype, broken wall shows divisions between three cham- bers and lack of definite sutures, X160; #34691. Storthosphaera malloryi McClellan, n. sp. .........0...000.00000.... 296 Holotype, 160; #34703. Rhabdammina cylindrica Glaessner ......0....0.0..00cccccccccccseeeeeeee. 276 X80; #34685. Atelikamara incomposita McClellan, n. sp. ..................0000008.. 306 5a. Holotype, top view, X80; 334658. 5b. Ventral view, X80; #34658. 366 eT: 12. 13. 14. 16. We LG SAS: BULLETIN 274 EXPLANATION OF PLATE 41 All figures «45 Page Bolbiprimitia teresaccula Swartz and Whitmore ................ 320 1. #34731 RV. 2. #34732 RV. 3. #34733 LV. Phlyctiscaphia:Sp:, 223..A0¢42.. ene eee eee eee 323 # 34758, RV. Phiyctiscapha keslingi Copeland ..............0.0...0..0ccccececeee 322 5. Male, #34756 LV. 6. Female, #34757 RV. Kloedenia aparchoides Swartz and Whitmore .................... 321 H# 34744. Welleriopsis jerseyensis (Weller) ......0.00000...ccccccccceeceeeeeeeeeeees 324 8. #34786 RV. 9. #34787 RV. Velibeyrichia? “Sp. 25:2 2iw....c.0.c. eee 324 # 34785. Aechmina cortezensis McClellan, n. sp. .............00.0.0cee. 327 11. Paratype RV, #34726. 15. Holotype, oblique view of LV showing spine of RV, #34725. Saccarchites saccularis Swartz and Whitmore .................. , BES #34772 LV. Myomphalus?* Sp... ..:....22:c.e%ts.. sc tcieh cd ee ee ee 321 # 34750, RV. Aechminajlongionsbasslererr ee 326 # 34723. Beyrichiidae ? genus. ............255 oe eee 325 #34789 (X23). Aechmina aff. A. phantastica Kesling ..........0.......000000..... BAN #34724. Aechmina equilateralis Bassler ...........0.......ccccccceeeeee 326 18. #34721 LV. 19. #34722 LV. BULL. AMER. PALEONT., VOL. 62 PLATE 41 BULL. AMER. PALEONT., VOL. 62 PLATE 42 Figure 13. i416, 17. 15. S1turo-DEvonIAN MicroFauna: McCLeELLAN 367 EXPLANATION OF PLATE 42 All figures «45 Page Uirichia obesita) McClellan: me Spe is... ccce.-ceiccecedeceecvnceseeosss 328 1. Holotype RV, #34780. 2. Paratype LV, #34781. 3. Para- type RV, #34782. UW ichiiams pameette k enc hc in enc a ee Renee coe Seene, Oey 4. #34783. 7. #34784. Winchellatia fragilis McClellan, n. sp. ...............000000... 331 5a. Holotype LV, #34788. 5b. Ventral view showing pos- teriorly directed lateral spines. EON nell ages Deemer 5 se eee eee tec ee care tee eee ats 330 #34743. Limbinaria sp. .................... goa a a eane Oe, Seana aero a son BYE 8. #34746. 9. #34745. Eukloedenella aff. E. dalhousiensis Copeland ............ nee 332 10. Dorsal view, #34740. 11. #34741 RV. Neokloedenella? sp. oo... Peer eh 333 # 34751 RV. PSeucOlemerciiid: SD... ilsiycc2. ee oer teoet oteh oo eee ea. eee 334 # 34759. Parahealdia aff. P. pecorella Coryell and Cuskley .... .. 834 14. #34777 RV. 16. #34753 RV. 17. #34752 LV. ParapanchitesmS} ges. cote cea erences ae Meet eaee te 335 # 34754, RV?. Figure 15, 19. 16517. 18. 20. 21. BULLETIN 274 EXPLANATION OF PLATE 43 All figures «45 Page Bairdia (Sp). <....0...08...0:. dee. ae eee 336 12384727 RVE2. 3534728 Ve Bythocypris aff. B. alcocki Copeland |.....232...) ee 336 3. 334736 LV. 4. #34737 RV. 5. #34738 LV. Bythocypris? Sp; ci. natn eee 35i// # 34739. Acanthoscapha aff. A. navicula (Ulrich) ...............0............ 337 7. #34719 RV. 8. #34720 LV. Longiscapha nevadensis McClellan, n. sp. ................0..00000.. 338 9. Holotype RV, #34747. 10. Paratype, dorsal view, #34748. 11. Paratype LV, #34749. Fealdia (SDs. .c...7..68. eee Ree Err re eee Py ec cubbnccoce:. 340 # 34742. Berounelia: ‘Spi tei). c0d. neces eee ee eee 339 # 34729, RV. Birdsallella sp. 2.0.5.5. tin. eee eee 340 # 34730. Tubulibairdia cf. T. chaleurensis Copeland .......................... 341 15. #34776 RV. 19. Ventral view, #34776. ‘ Bolliidae .? . 317, 318 Carlini os ee 351 casteri, Hyperammina .... 33 255, 279-281, 303, 305 cava, Pasmmosphaera 34 253, 256, 261, 282, 283, 287 ‘Ceratammina ............ 255, 261, 285, 286 chaleurensis, Tubuli- bairdia aff. ... 43 341, 342 chaleurensis, Tubuli- bairdia cf. .. ......43 251, 341 chitellata, Fairliella.. 302 370 INDEX GoalaCanyonwe-.-ce es 242, 245, 247, 345, 346 GolewCreek tks eee 351 Columbus Limestone .. 304 compacta, Sorosphaera . 34, 40 253, 254, 290, 291 confusa, Sorosphaera ....... 34 262, 287, 288, 291, 292 conradi, Ulrichia ...... 328 constricta, Hyperammina ... 33 254, 280 contorta, Stegnammina ... 34 250, 256, 292 Copenhagen Canyon... 243, 346 Copper Mountain ...... 347 cornucopia, Ceratammina ........... 261, 285, 286 cornucopia, Ceratammina cf. 34 255, 261, 285 coronata, Hemisphaeram- mina ............ 35, 38 249, 303, 305 Webbinella .............. 303 corpulenta, Thlipsura 344 Cortez 1S eens 346, 351 Cortez Canyon .......... 250, 346 cortezensis, Aechmina ............ 41 PAIL, BPAL CUrta Balrdia <0.) 335 curva, Hyperammina ... 33 281, 282 curvatus, Icriodus .... 252 curvus, Bathysiphon.. 281 cuspidata, Aechmina.. 326 cylindrica brevis, Stegnammina .......... 292-294 cylindrica, Rhab- dammina ....33,40 256, 275-277 cylindrica, Stegnammina ..... 34 292-294 Cytheraeea t..).h........... 339 D dainae, Nanicella ...... 319, 320 dainae?, Nanicellame.. 36 249, 256 Dalhousie beds .......... 251, 333, 341 dalhousiensis, Euklo- edenella aff. ..42 251, 332, 333 dentata, Hollinella .... 330 Diana Limestone ........ 241, 242 Diana’s Punch Bowl. 347 dicantha, Rainwellae 2. 302 diplocystulis, Welleriopsis 324 discoidea, Fairliella 303 discoidea, Hemisphaerammina 261, 303-305 discoidea ?, Hemis- phaerammina ..... 35 256 Distacodus? sp. .......... 252 dorsinodus, Myomphalus ............ 321 E elongata, Hyperammina ........ 279 Marsipella .............. 277, 278 Stegnammina ........... 293 RnGothynay pe eee 318, 319 equilateralis, Aechmina ............ 41 251, 326, 327 Eukloedenella ............ ADIL, BBVA, ate: exiguus, Bathysiphon eee 276 expansus, Icriodus .... 252 extensa, Rudderina .... 343 F EFairliella’ ~2-2............ abana), 302 fissurella, Halliella .. 320 Fourmile Canyon ...... 351 fragilis, Winchellatia ...... 42 251, 262, 331 fundamentatus, Spathognathus ...... 252 furca, Thlipsura ........ 345 fusca, Psammosphaera 282 USUI ae eee 318 G gallowayi, Endothyra 318, 319 Nanicellay =. 319 Garden Valley ............. 349, 351 Gateehii, oo focccon. 346 Gatecliff Dolomite .... 244, 247, 301, 348 gibbosa, Metamorphina ... 35 309, 310, 315 Webbinella i 309 glabra, Hyperammina 280 globulosa, Webbinelloidea ...... 314 Glomospira’......... 249, 262, 314, 315 Sf INDEX gordialia, Trochammina ........ 314 H rane ee ae 320 Hanson Cree Formation o6..--...5- 241, 243-245, 293 hattini, Webbinelloidea ..35 250, 311, 312 Haplophragmoides .... 249, 256, HAs Haragan Shale ............ 250, 261 Healdia.!¢ a 339, 340 Healdtaz sp. >...::..---3 43 340 hebesta, Stegnammina .......... 293 hebesta?, Stegnammina ...... 34 250, 254 Hemisphaerammina .. 249, 255, 256, 261, 301-305, 308, 310, 311, 314 hemispherica, Web- binelloidea ....35, 38 262, 302, ae Hindeodella sp. .......... 252 Hollinellageee--- 330 Hollinella sp. .......... 42 330 Horse Creek Valley .. 345 Horse Heaven Mountainee.)= 346, 349 humerosus, Paraparchites ........ 335 Hyperammina ............ 249, 254, 255, 279, 282, 315 I leniodus =. 252 Icriodus spp. .............. 252 Tkes Canyon: .....:..:-:-.:- 243, 246, 347, 348 incomposita, Atelikamara ..36, 40 255, 305, oe inconstans, Trichonodella ........ 252 inconstans, Trichonodella cf. .. 252 inflata, Sorosphaera .34, 40 290 imbricata, Metamorphina ........ 305, 309 irregularis, Sorosphaera ............ 289 J jerseyensis, IB CyIC hice eee 324 Welleriopsis ...... 41, 251, 324 K Kelly Greek ......0::4.... 241, 242, 347 keslingi, Phlyctiscapha_ ....41 251, 262, 322, 323 Kloedenellocopina 332 Filoedenia: «....6:.0..2:6 321 L laevigata, Psam- mosphaera ....34, 39 255, 262, 283 Lagenammina ............ 249 Laketown Dolomite .. 241 latericresens, Teriodus... 252 limbata, Bolbiprimitia .......: 320 IMBMaAria —. ois: .ca 263, 332 Limbinaria sp. ...... 42 250, 332 linearis, Rhabdammina ........ 275 eibuOtubas &..meneeoe 249, 257, 315 Lodgepole Limestone 309 Lone Mountain .......... 245, 347 Lone Mountain Dolomites 228. oe 238, 241-245, 247, 254, 291, 295, 316, 347, 348, 350 Lone Mountain Limestone ................ 238 longior, Aechmina 41 326-328 Longiscapha ................ 251, 338, 339 longispina, Winchellatia ............ 331 M major, Rhabdammina _....33 250, 255, 277, 278 malloryi, Stortho- sphaera .......... 34, 40 254, 296 Manlius Limestone .. 321, 324 Mareh Spring «.....222" 244, 347 Marsipella’ de. .es2ca.: 249, 256, 275, 277-279 Marsipella sp. ........ 33 256, 279 Masket Shale .............. 241-244, 246, 247, 256, 347, 348 maxwelli, Psammonyx 261 McColley Canyon HOLM Aabionmnes eee 244, 254, 299, 316, 323, 333, 348, 350 372 INDEX McMonnigal Mimestone. 22.0... 243, 244, 292, 294, 299, 322, 324, 329, 333, 342-344, 347, 348 media, Ozarkodina aff. ...... 252 Metacopina .................. 339 Metamorphina ............ 249, 255, 261, 305, 308, 311, 315 mica, Raibosammina ........ 286 Stegnammina .......... 286 Mille Canyon) -2.-........ 346, 348, 357 Mineral Hill. 349 minnesotensis, Winchellatia ............ 331 Mitchell Creek .......... 244, 351 moodeyi, Beyrichia .... 324 mormani, Stegnammina 34, 39 250, 254, ote 95 Thekammina .......... 294 multicella, Sorosphaera ............ 288 multipunctata, imbinariae 0. 332 mutaspina, Rudderina ........ 44 251, 343, 344 Myomphalus ............... ByYA yy) Myomphalus? sp. .41 251, 321, 322 N INanICeliaweeet.. ee 249, 256, 318, 319, 320 navicula, Acantho- scaphayratf. ...0.2 43 337, 338 Beecherella ............ sbi Neokloedenella .......... 333, 334 Neokloedenella PSUS sci ne ee 42 333 Newsomites ................ SBM/ Nevada Limestone .... 238, 244 nevadensis, Longiscapha ....... 43 251, 338, 339 New Brunswick ......... 333, 341 nodosa, Webbinelloidea ...... 312, 313 nodosa, Webbinel- loidea aff. ... 35, 38 312 Nonioninaiae.22........... 317 Northumberland Canyon 246, 348 fe) obesita, Ulrichia ...42 251, 328 obliquus, Quasillites.. 342 Osgood Formation .... 253, 257, 276, 278, 301 osgoodensis, Sorosphaera .34, 39 261, 288, 289 Ozarkodina -7..0.-.02-- 252 P Palaeocopida .............. 320 Banderodus) ~..0.........- 252 papillata, Thurammina .......... 299, 301 Parahealdiay 250, 334, 335 Paraparchites .............. 335 Paraparchites sp. ..42 335 pecorella, Para- healdia aff. ....... 42 334, 335 perforata, Arenosphaera ........ 290 Perkins Canyon ....... : 348 Perkins Canyon Mormatione 348 Pete Hanson Creek .. 348 Phanassymetria .......... 340, 341 Phanassymetria sp. 43 340 phantastica, Aechmina aff. ....41 327 phaseolina, Bythocypris ............ 337 Phlyctiscapha ............ PASSA Va BY -ed 323 Phlyctiscapha sp. 41 323 Podocopinaw.......-..- 335 Prionodina’ sp. =: 252 prima, Neokloedenella ...... 333 Primitiopsinae ............ 332 progressa, Anictosphaera 34 254, 261, 283- 285 PSammonyxe eee 261 Psammosphaera ........ 249, 253, 255, 256, 261, 282, 283, 287 Pseudoleperditia ....... 334 Pseudoleperditia? Dit eee 42 334 pusillum, Haplophragmoides 318 Q quadrangularis, Stegnammina .... 34 250, 253, 295 Thekammina .... 373 INDEX quadritubulata, Thurammina _.......... 300 quadritubulata?, Thurammina ..... 35 300 @uasiliteS” °28\....-..---: 342, 343 Quasillites sp. ........ 44 251, 342 R TPyslojods JeGUUL 55.5 sce sesooes 349 Rabbit Hill mormatione 1 242-244, 262, 281, 284. 318, 319, 325-329, 342, 345, 346, 349 Radiolariae. .p.csseee-e-e- 252 Raibosammina ............ 249, 256, rot Rhabdammina ............ 249, 250, 253, 255, 256, 275- 277, 279 Rhizammina <...........-..: 278 Roberts Mountains .... 245, 280, 347 Roberts Mountains Kormation 2... 241-248, 281, 283, 284, 291, 293, 297, 298, 300, 303, 305, 307, 309, 310, 314, 315, 319- SPALL BPBY ayA3). 330-332, 346, 347-350 Roberts Creek. Mountain =... 3 347, 348, 350 rockfordensis, Hyperammina ........ 281 rockportensis, Phlyctiscapha ........ 322 rostrata, Berounella. 339 Ruby Mountains ........ 351 Rud derinaee 1: 251, 343, 344 Rudderina spp. ...... 44 344 S Saccamminay ss... 249, 298 Saccamminoides ........ 297 Sacearchites! =...) ee. 251, 323 saccularis, Saccarchites ........ 41 2514320 scabra, Aschemonella ......... 316 Sheep Corral Canyon 351 Sherman Mountain .... 351 siluriana, Glomospira ........ 36 262, 314, 315 similis, Webbinelloidea ...... 310-312 simplex, Birdsallelia —o5-. 340 JECCRIIGIIE, ~. Jgeeesanansternoe 340 simplex, Panderodus cf. ...... 252 Simpson Park Range.. 242, 247, 346 Spathognathus 252 Spathognathus spp. .. 252 Sorosphaera’ -.....2.-.- 249, 253, 254, 257, 261, 262: 287-292, 296, 297 Sorosphaera sp. ... 34 291 Sorosphaeroidea ........ 310 Sorostomasphaera .... 249, 250, 255, 297, 298 spinosa, Ulrichia ...... 328, 329 Stegnammina ............ 249, 250, 253, 254, 256, 261, 262, 286, 292- 295 Stomasphaera ............ 249, 250, 298 Storthosphaera .......... 254, 284, 296, 297, 306 subconfusa, Sorosphaera .......... 289 Sulphur Spring Range 256, 351 symmetricus, KeriOdUSi ee ee 252 Synprioniodina sp. .... 252 T Telegraph Canyon .... 242, 256, 349 Tentaculitids .............. 252, 291 teresaccula, Bolbiprimitia ..... 41 250, 320,321 hentulariinay 3. 275 Thekamminay ee 294, 295 LED SULANe eee 251, 344, 345 tholus, Meta- morphina ...... 35, 39 255, 308, 309 Webbinella .............. 308 Thurammina 25s... 249, 250, 254, 299-301 Tippecanoe SEQUENCE 5.0. .catesscccse 238 Tolypammina ............ 2A9, 250, 254, 315, 316 Toquima Range ........ 246, 347, 348 torta, Marsipella .......... 33 249, 278, 279 tortuosa, Tolypammina ... 36 250, 254, cae tuberculifera, Pseudoleperditia .... 334 374 INDEX tubulata, Thurammina ..... 35 254, 301 Tubulibairdia ......... 251, 341 Tubulibairdia sp. . 43 342 tubulifera, Tubulibairdia 341 Turitellellay 4. 249, 257 triangularis, Belodella 252 tricella, Sorosphaera ....... 288 Trichonodella 252 triserrata, Phanassymetria ..... 340 trituba, Thurammina 35 300 Trochammina 314 Twin Springs Hills 349 Tyrone Gap 349 U Wilrichellap eee 338 Wirichiae ee 251, 328-330 Ulrichia sp. 42 329 umbilicata, Eukloedenella 332 unicostatus, Panderodus 252 Ural Mountains ... 320 Vv vagan, Hyperammina ...... 315 Velibeyrichia 324 Velibeyrichia? sp. 41 251, 324 ventriquetra, Webbinelloidea . 35 250, 255, 313, 314 WwW Wallbridge Discontinuity .......... 238, 244 Waldron Shale ......... 248, 257, 261, 262, 279, 280, 287, 300, 302, 304, 310, 316. 317 waldronensis, Soro- stomasphaera ... 35 250, 255, 297 298 Walti Hot SPHNES 351 Webbinella 301, 302, 308, 309 Webbinellodea 249, 250, 255, 261, 262, 303. 310, 314 Welleriopsis 251, 324 Wenban Limestone 248, 244, 247, 250, 322, 328, 335, 338, 340, 341, 345, 346 Whiterock Canyon 349 wilckensiana, Beyrichia 321 Wildcat Peak ... 346, 348 Willow Creek 242, 245, 263, 297, 339, 350. 351 Winchellatia 251, 262, 331 Windmill Formation 242 Windom Shale 334 Wood Cone 351 \ 7 i a] P aa! ; SAC | Te) ea i 7 4 ; wilde: ont ee aa a4 eh) Midas ay 1s Wits : . . a! - ‘i He Bis Alla é ge Ni Ades ‘ ae a1 ae a Ws Seed 4 (= OTE VE = se ri te" 7 a4 ate i ‘ Phe eae we Ate ; at > | ce - ; : 4 n er Pere tee gD Ri be Sligie, Wipes +d i deh ; a ; ij ‘ . LAN Py BF { Ley iP Py ff a ae: aft @ ; xyes haa4 r a gy tel fy r i Ady nt es ee ee, ‘of Sol Le he te aie es | itt ink yiwat aE.) rT 7 Pay AEDT beh Te 1*% i. ' one : ' eS at yy ye Ae, y yc 74 iy nde) ane ; ingth te ‘3 TA dow = } y's y) fi ry ee i , : ; er f. bode ie ee Hollad it? i athe iiey ‘, 4 amet) Ushi ; r y pe ride ie Lt ba is 2 Mids ah al dee hy ay fa 1s a ui ¢ ' : te @ F } i iT? all ; : eae ker amie Pa i" ‘ mie > i Le Ee vu 7 | J j (7s i ; : 7 vy Lie Li; s Terie i , i ain Pe he ra 71 ; : rm Ke 7 , ? ; 1h ar a iba , R a? - a a! yi) 4 ra i. , vy 7 PGT 7 1 eau MOAN: LII. LIII. LIV. LV. LVI. LVII. (ONS 225-230) eno Sin Ps 4-2 DIS py crecrce ce eat earn areeccnccnetecnnceenecreeness Venezuela and Florida cirripeds, Antarctic forams, Lin- naean Olives, Camerina, Ordovician conodonts, Niagaran forams. (Nos: 23-232). 420 pp.,’-10., plas: = Antarctic bivalves, Bivalvia catalogue. (Noa:-233,;230).. 9387. pp. 43 ple. New Zealand forams, Stromatoporoidea, Indo-Pacific, Mio- cene-Pliocene California forams. (Maas 237ec08) 0 S88, DD, 5 Se a aeons Venezuela Bryozoa, Kinderhookian Brachiopods. (Nos. 239-245). EHO!) pisyee 5 gp) Sem tecce ccectracectesee ee eeeeeee ev cncteoare rence Dominican ostracodes, Texan pelecypods, Wisconsin mol- lusks, Siphocypraea, Lepidocyclina, Devonian gastropods, Miocene Pectens Guadaloupe. (Nos. 246-247). GH TPAD oO Ut LS greene tae en eee een ee Cenozoic corals, Trinidad Neogene mollusks. (Nos. 248-254). Sy PHN 0 8 epee OS as 0) Pp ena sea cause Ao ete eee ee ee American Foraminifera, North Carolina fossils, coral types, Belanski types, Venezuelan Cenozoic Echinoids, Cretaceous Radiolaria, Cymatiid gastropods. (Nos. 255-256). S2 TU D DSA OSD Smee ene een) eee Jurassic ammonites. LVIII. (Nos. 257-262). S05 pps ws 9 spl ster nee yee oles recone ee ee Cretaceous Radiolaria, Cretaceous Foraminifera, Pacific Silicoflagellates, North American Cystoidea, Cincinnatian Cyclonema, new species Vasum. LIX. (No. 263). SHAE DD eee a Re ee ee See eee LX. ( Bibliography of Cenozoic Echinoidea. Nos. 264-267). SSDP ie OS DISa ae eee eee ee neers Jurassic-Cretaceous Radiolaria, cirripeds, Bryozoa, paly- nology. LXI. (Nos. 268-270). 3 GSA DD rs UD Seece ta eae ee eee ee Mollusks, Murex catalogue, Cretaceous Radiolaria. WSEN (CIN 20 EAST A sy a ee sec cieeeeee cere ace Volumel. II. Til. EV. VI: VII. Trace fossils, ammonoids, Silicoflagellates, microfauna. PALAEONTOGRAPHICA AMERICANA 18.00 18.00 18.00 18.00 18.00 18.00 18.00 18.00 18.00 18.00 18.00 18.00 See Johnson Reprint Corporation, 111 Fifth Ave., New York, N. Y. 10003 Monographs of Arcas, Lutetia, rudistids and venerids. (Nos. 6-12). CI a) wee Alta oy (Che reece seer cee eee ee rece ataete et ae Heliophyllum halli, Tertiary turrids, Neocene Spondyli, Paleozic cephalopods, Tertiary Fasciolarias and Pale- ozoic and Recent Hexactinellida. (Nos. 13-25). BY SEND Dye 6 lea Dl Seow ere ee ee eee ee ra Paleozoic cephalopod structure and phylogeny, Paleozoic siphonophores, Busycon, Devonian fish studies, gastropod studies, Carboniferous crinoids, Cretaceous jellyfish, Platystrophia and Venericardia. (Nos. 26-33). CRU AI 0) = ARP Am 0) (Fas peer see eee er an ee Rudist studies Busycon, Dalmanellidae Byssonychia, De- vonian lycopods, Ordovican eurypterids, Pliocene mol- lusks. (Nos. 34-47). CU FoFo ee oi AOI hyo) Lite eee ae ae ee cee ee eee Tertiary Arcacea, Mississippian pelecypods, Ambonychiidae, Cretaceous Gulf Coastal forams. (Nos. 38-41). AAR Tt S Sik DISA erect note cence ee ee Lycopsids and sphenopsids of Freeport Coal, Venericardia, Carboniferous crinoids, Trace fossils. (Nos. 42-45). DANTE S01 8h estab) a) LN me en eR Reesor ai eee aes Torreites Sanchezi, Cancellariid Radula, Ontogeny, sexual dimorphism trilobites, Jamaician Rudists. 23.00 28.00 28.00 32.00 35.00 BULLETINS OF AMERICAN PALEONTOLOGY Vols. I-X XIII. See Kraus Reprint Corp., 16 East 46th St.. New York, XXIV. XXV. XXVI. XXVII. XXVIII. XXIX. XXX. XXXI. XXXII. XXXIII. XXXIV. XXXV. XXXVI. XXXVII. XXXVIII. XXXIX. XL. N. Ye, 10017,.US:A2 (Nos. 80-87))5).334. ppi7 27) pls es ee Mainly Paleozoic faunas and Tertiary Mollusca. (Nos588-945)23064pps 3 0mplss ee eee Paleozoic, Mesozoic, and Miocene fossils. (Nos: 955100)! 420 appt SSipisy\ eo) eee Florida Recent, Texas and South America Cretaceous, Cenozoic fossils. (Nos. <1Q1-708).) 376 hppe S36. opis. Ae ee ee Tertiary mollusks, Paleozoic Venezuela, Devonian fish. (Nose l09S114) 412) ppans4 ips.) cst -8 ee ee ee Paleozoic cephalopods, Cretaceous Eocene, forams. (Nos: DIS=116).. 73S pp S520 pls: 4. eee Bowden forams and Ordovician cephalopods. (No: a) eo S63 pp 65> plaints ne ee Jackson Eocene mollusks. (INos sl S3128) 745 Sm ppiea 7. aps. re Mollusks, crinoids, corals, forams, Cuban localities. CNos31295133)'-294 “pps. 39) piss. kel Silurian cephalopods, crinoids, Tertiary forams, Mytilarca. (INos:2134-139)s “448 pps 516 plss, 2. Devonian annelids, Tertiary mollusks, Ecuadoran strati- graphy paleontology. (Noe; 140-145).:-4000 pp, 19) pls. ..2.3..2 8) eee Forams, cephalopods, ostracods, conularid bibliography. (INos:7146-2154).2386