OF DENISON UNIVERSITY. 55 



lateral margins uniformly rounded. Right (?) valve moderately con- 

 vex, hinge four-fifths the greatest length; beak nearly central; ante- 

 rior wing small, ill-defined ; posterior wing larger, separated from the 

 body by an oblique plane surface, rather flat ; no indications of a bys- 

 sal sinus. Surface finely cancellated by uniform, high, regular radi- 

 ating and concentric ridges, the latter sub-imbricating. There is little 

 to determine which valve our single specimen represents, it may quite 

 possibly prove to be a left valve. There is some resemblance to small 

 specimens of L. orbiculatus. The most that can be said is that our 

 shell possesses a decidedly Devonian aspect. -Nodule layer at Moot's 

 run. 



Linatulina {?) ohioensis, sp. n. 

 (Plate II, Fig. 20: Plate III. Fig. 10.) 



Shell of moderate size, obliquely and rather narrowly oval ; height 

 over one- fifth greater than length; hinge line very short ; surface with 

 distant, irregular furrows. Left valve moderately convex near the 

 beak, elsewhere quite flat, with hinge line equal to about one-half the 

 greatest length ; valve not very oblique, umbonal ridges meeting at the 

 beak at less than a right angle, beak somewhat acute; anterior ear 

 well-defined, but small, rounded and separated from the body of the 

 valve by an abrupt descent, its margin concavely sinuated below ; j)os- 

 terior ear very small and obtuse. The posterior margin makes a broad 

 curve which is straightened above, but curves more rai)idly in passing 

 into th? very convex front outline. The valve is marked by about 20 

 distant and very irregular narrow and deep radiating striit and folds. 

 Right valve very oblique and short, hinge line relatively longer, [X)s- 

 terior margin straight, making an angle with the hinge of about 130**; 

 posterior angle produced; anterior ear small, convex, projecting, sep- 

 arated from the valve by a profound acute byssal sinus; marked by 

 about four or five distinct costae ; markings of the body as in th" ''-«*' 

 valve. Evidently the shell was quite inequivalve. 



Height of perfect left valve 20 (23) mm; lenght 15 (iS) mm . 

 hinge 9 (8) mm; height of right valve 1 .- mm ; IriiL-ht 10 innif?); 

 hinge 8 mm. 



A number of specimens have been secured unly une d winch, 

 unfortunately, was a right valve. The shell is so thin as to make il 



