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New American Paleozoic Ostracoda. 179

NEW AMERICAN PALEOZOIC OSTRACODA.

BY E. O. ULRICH.

No. 1. CTKNOBOLBINA AND KIRKBYA.

Since the publication of my paper on " New and IvittleKnown American Paleozoic Ostracoda," in Volume XIII ofthe Journal of the Cincinnati Society of Natural History(1890-91), much new material has been collected and pickedover, in part or wholly. The earlier washings, of whichsamples merely had been searched in 1890, have now beenalmost entirely worked out. The result is an astoundingnumber of new species, the number of the undescribed formsfalling little short of two hundred !

Perhaps the most interesting of all the localities furnishingostracoda is the Bryozoa bed, at the Falls of the Ohio, oppo-site the city of L,ouisville, Ky. In 1890, when my formerpaper describing species from this locality was written,the pickings from the small sample of washings thenexamined was believed to give a fair, if not a full, ideaof the species occurring there. How far from the truththis conception was, and how other localities when carefullyinvestigated may be expected to add, more or less largely, tothe number of known species, is shown by the fact that, whenthe last of the washings from the Falls in my possession hadbeen searched the number of species known from thatlocality was nearly doubled.

This continual accession to the number of known formsproves that we have not yet reached that point where anapproximately stable classification of the paleozoic represen-tatives of the class is possible. My aim, therefore, in this andsucceeding papers, in which I hope to publish illustrationsand brief descriptions of the new species and varieties, isprincipally to add to the facts and data pertaining to specificvariation, and to leave the restriction and characterization ofthe genera and families to such a future time when the dis-covery of more or less disturbing new forms will have becomecomparatively rare.

JOUR. CIN. SOC. N A T . H I S T . , VOL. XIX, No. 6.) 1 P R I N T E D J U N E 26, 1900.

180 Cincinnati Society of Natural History.

CTKNOBOLBINA SUBCRASSA, n. sp.

Plate VIII, Figs. 1-3.

Size: L,ength, 1.15 mm.; hight, 0.7 mm.; thickness,0.6 mm.

Carapace widest in the posterior half, obliquely subovate,the hinge line long and straight. Flange thick and welldeveloped along the posterior and ventral sides, weak or quiteobsolete in front, partly overhanging the ventral contact edgeof the valve and hiding a number of rather faintly markedtransverse depressions between them. Anterior sulcus obso-lete or distinguishable only in the dorsal region, the posteriorone strongly impressed, especially upon the posterior side,extending obliquely backward and downward more than two-thirds across the valve. A small tubercle occurs in theantero-dorsal corner of the posterior lobe, while a thin andprominent ridge runs along the lower side of the combinedmedian and anterior lobes. Between this ridge and the flangethe surface is sharply excavated. Surface without ornament.

This species finds its nearest relations in C. crassa and C.fulcrata, occurring in the shales of the Black River group inMinnesota. A comparison with the published figures ofthese species will not only show this relationship, but at thesame time reveal several obvious differences by which thespecies may be recognized.

Formation and Locality.—In a thin band of shale belongingto the Ridley limestone division of the Stones River group,near the bottom of the Kentucky gorge, at High Bridge, Ky.

CTENOBOLBINA OBLIQUA, n. sp.

Plate VIII, Fig. 4.

Size: Length, 1.1 mm.; hight, 0.7 mm. without flange,0.75 mm. with flange.

This is a moderately convex and very simple species of thegenus, there being a single sulcus, curved, but on the wholenearly vertical, and sharply defined on the posterior sideonly. The valves are shorter and more oblique than usual,and the flange a delicate projecting plate or fill; the surfaceis minutely reticulate or punctate. A small tubercle issituated near the middle of the autero-ventral fourth.


Only one other species of Ctenobolbina is known having apunctate surface; this is a Niagara species to which I gavethe name C. punctata. The present form is relatively shorter,less convex, and strikingly different in the outline of theanterior half. The sulcus also is much less developed.

Formation and Locality.—Rare on thin slabs of limestone,from the lower portion of the Clitambonites bed of the Tren-ton group at Kenyon, Minn.

CTKNOBOI/BINA SPICULOSA, n. sp.

Plate VIII, Fig. 5.

Size : L,ength, 1.65 mm.; hight, with flange, 1.0 mm., with-out flange, 0.8 mm.

This fine species, although given a very different expres-sion by its spinous surface, is nevertheless a close ally of C.antespinosa, Ulr., with which it is also associated at the Fallsof the Ohio. Comparing the two species, we find that thecentral tubercles and ridges of C. antespinosa are all repro-duced in C. spiculosa, but in a more subdued form. The ver-tical anterior ridge is represented by a couple of spinesmerely. The posterior lobe, on the other hand, is moreprominent and drawn out above into a strong spine. All thesurface elevations are granulose in C. spiculosa, and, except-ing one, spiniferous as well. Two bunches of spines occuralso near the post-ventral margin. The flange is wider in C.spiculosa and merely convex instead of bent angularly, andthe valve, excluding the flange, more nearly equal-ended.

Formation and Locality.—From the Devonian (Hamiltongroup) bryozoa bed at the Falls of the Ohio.

CTENOBOLBINA ARMATA, n. sp.

Plate VIII, Fig. 6.

Size: Length, 1.38 mm.; hight, 0.78 mm.

This also is related to C. antespinosa, but is readily distin-guished. The posterior sulcus passes completely through tothe flange, which, on the contrary, is a comparatively insig-nificant feature. The lower portion of the posterior lobe israised into a compressed spine, projecting outward and down-ward to the ventral margin. A similar but more prominent


and more curved spine is formed by the posterior extremity ofthe anterior lobe, which in this and other species of thissection of the genus is longitudinal rather than vertical.Excepting the two ventral spines, the elevated portions of thesurface are coarsely granulose. The middle lobe is rounded,situated about in the middle of the dorsal slope, and largerthan the rounded upper portion of the posterior lobe.

The large, compressed spines, arising in the post-ventralfourth of the valves, will distinguish this species from anyother previously described.

Formation and Locality.—Same as the preceding.

CTENOBOIVBINA CAVIMARGINATA, n. sp.


Size: Length, 1.35 mm.; hight, without flange, 0.72 mm.,with flange, 0.85 mm.; greatest thickness (from tip to tip ofventral spines), about 1.2 mm.

In a side view the valves of this species are so much likeC. armata that the two forms were at first confused. Interiorand ventral views, however, are so strikingly different thatthe separation of the specimens proved unusually easy.Even on the outside the two forms present some differences.Thus, the flange is thicker and more extensive, the middlelobe relatively smaller, and none of the surface granulose.The main distinction, however, lies in the flange. In C.armata this is a simple plate, and so little developed that itscarcely hides the contact edges. In C. cavimarginata, how-ever, it extends considerably beyond the edge and is sup-ported at regular intervals by cross-walls, so as to form fromten to twelve deep rounded cavities. The end view is trian-gular in both, but in C. cavimarginata the lower part of theprofile is much thicker than it is in C. armata.


CTENOBOIvBINA INSOLENS, n. Sp.

Plate VIII, Figs. 10 and IT.

Size: Length, with flange, 1.88 mm.; without flange, 1.70mm.; hight, without flange, 0.94 mm., with flange, 1.20 mm.


This also belongs to the C. antespinosa section of the genus,and stands in some respects intermediate between that speciesand C. cavimarginata. However, in views of the interior,the broad concave flange reminds even more strongly of C.spiculosa. The anterior ridge or tubercle of C. antespinosa ispresent; also a rounded knob in the post-cardinal angle,whose representative is more obscurely indicated in C. cavi-marginata. The lobatiou of the central and posterior portionsof the valves agrees better with the conditions prevailing inC. cavimarginata and C. armata than those marking C. ante-spinosa, but, instead of rising into curved spines, the lowerportions of the posterior and anterior lobes are lost in theconvex flange. The latter is peculiar in two respects, first,in the fact that its junction with the body of the valve is notdistinguishable externally, and, second, in its limited extentand abrupt termination just in front of the middle of the ver-tical edge. The contact edges around the ventral half arefinely toothed, a feature generally present in the typical sec-tion of the genus, but otherwise unknown in this section.The raised portions of the surface are more or less distinctlygranulose.


CTKNOBOIVBINA GRANOSA, n. sp.

Plate VIII, Fig. 12.

Size: length, without flange, 1.0 mm.; hight, with flange,0.68 mm., without flange, 0.58 mm.

A rather small, convex and granulose species, with a sub-central sulcus extending only about half across the valves, asmall longitudinal prominence just beneath it and a broadlyscalloped, delicate frill overhanging the post-ventral edge.The latter is generally broken. C. bispinosa, from the Uticagroup at Cincinnati, and C. punctata, from the Niagara group,at Iyockport, N. Y., are probably its nearest allies.

Formation and Locality.—Etched from limestone slabs con-taining an abundance of br} ozoa received from Mr. CharlesSchuchert, who collected them from the lower Helderbergformation, in Albany County, N. Y.


CTENOBOLBINA LOCULATA,n.sp.

Plate VIII, Figs. 13 and 14.

Size: length, 1.00 mm; hight, without flange, 0.54 mm.,with flange, 0.60 mm.

The lobation in this small species is singularly like that ofthe Ordovician C. crassa and C. stibcrassa, and the latter issimulated even to the possession of a small node in the upperand inner corner of the posterior lobe. The valves in C.loculata, however, are relatively longer and more equal-ended,while the construction of the flange is quite different. In-stead of the thick, yet simple type of flange, pertaining tothose species, we have here a strongly undulated plate sup-ported by walls or pillars which divide the space interveningbetween the flange and the ventral edge into four subequalcavities. The undulations and extent of the flange remindof the preceding species, C. granosa, but in that form thereare no cavities beneath, while the lobes are appreciably dif-ferent, and the surface granulose instead of smooth.

Formation and Locality.— Rather rare in Safford's Mauryshales of the L,ower Carboniferous system, at Mt. Pleasant,Tennessee.

KlRKBYA CYMBULA, n. Sp.


Size: L,eft valve: length, 0.97 mm.; hight, 0.50 mm.;thickness, 0.20 mm. Right valve: length, 1.10 mm.; hight,0.54 mm.

Carapace oblong subquadrate, the hinge line long, straightor slightly convex, the ventral edge straight or slightlysinuate in its central portion, the anterior margin obliquelytruncate and most prominent at the antero-cardinal angle;the posterior margin more rounded, though forming an anglewhere it joins the hinge line. Sides of valves enclosed by athin raised rim, within which the surface is almost flat andtraversed by more or less irregular longitudinal ribs, ten oreleven in number, separated by narrow furrows, of whicheach contains a row of small punctse. Situated a little behindand more above the middle of the valve is a well-definedoval pit.

6


Though falling readily enough within the limits of thegenus Kirkbya, as now understood, none of the species here-tofore described seem to be enough like K. cymbula to requirecomparisons. The next described species, K. germana, isnearer than any other known to me.

Formation and Locality.—From the Devonian bryozoa bed,Falls of the Ohio.

KlRKBYA GERMANA, 11. Sp.


Size: Right valve: length, 1.10 mm.; hight, 0.60 mm.;thickness, 0.23 mm. L,eft valve: length, 1.20 mm.; hight,0.60 mm.; thickness, 0.25 mm.

This species, evidently, is closely related to K. cymbula, withwhich it is also associated. On close comparison we find thatthe outline is not exactly the same, the anterior extremity ofthe hinge line being less prominent and angular. The mar-ginal rim is set a little further from the edge, and in theanterior part does not follow the outline of the valve, butbends downward from above, the junction with the lowerportion forming an obtuse angle a little above the midnight.The space included within the marginal rim also is convex,instead of flat, while the longitudinally arranged ribs andpits are much larger, and, therefore, fewer, there being butsix where K. cymbula has ten or eleven.



EXPLANATION OF PLATE VIII.

K1X, THE FIGURES ARE MAGNIFIED TWENTY DIAMETERS.

Figs, i to 3.— Ctenobolbina subcrassa, n. sp., p. 1801.—A right valve.2 and 3.— Lateral and ventral views of a left valve.

Stones River group, High Bridge, Ky.

Fig. 4.— Ctenobolbina obliqua, n. sp., p. 180A right valve retaining some of the flange.

Trenton group, Kenyon, Minn.

Fig. 5.— Ctenobolbina spiculosa, n. sp., p. 181Nearly perfect right valve.

Hamilton group, Falls of the Ohio.

Fig. 6.— Ctenobolbina armata, n. sp., . p. 181A right valve showing the usual characters of the species.


Figs. 7 to 9.— Ctenobolbina cavimarginata, n. sp., p. 1827 and 8.— Lateral and posterior views of a left valve.

9.— View of interior of another left valve.Hamilton group, Falls of the Ohio.

Figs. 10 and II.— Ctenobolbina insolens, n. sp., p. 18210.— Exterior of a left valve.11.— Interior of another left valve.


Fig. 12.— Ctenobolbina granosa, n. sp., . - p. 1S3A perfect left valve.

Lower Helderberg group, Albany County, N. Y.

Figs. 13 and 14.—Ctenobolbina loculata, n. sp., p. 18413.—Exterior of a right valve, apparently perfect.14.—Interior of a left valve.

Kinderhook group, Mt. Pleasant, Tenn.

Figs. 15 to 18.— Kirkbya cymbula, n. sp., p. 184'15.— A right valve.16,— A left valve, relatively shorter.

17 and 18.— End and ventral views of same.Hamilton group, Falls of the Ohio.

Figs. 19 to 22.— Kirkbya germana, n. sp., p. 18519.— A right valve.20.— End view of same.2i.— A left valve, relatively longer.22.— Vertical edge of same.


VOL. XIX. No. VI. PLATE VIII.

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