18 Cincinnati Society of Natural History. 



the plane of separation of the valves. All lateral plications 

 on both valves become more or less indistinct or obsolete to- 

 ward the beak. Surface smooth^ with no distinct evidence of 

 concentric strise. Dental plates high near the beak, rapidly 

 thinning to their anterior extremity, about Smm. from the 

 most elevated part of the beak, divergent at an angle of about 

 twenty degrees. 



Kokomo limestone, at Kokomo, Indiana^ near the top of 

 the exposures at the George W. Defenbaugh and Traction 

 quarries. 



Compared with Spirifer vanuxcnii^ the beak is less ele- 

 vated, the shell is less angular laterally, and the lateral plica- 

 tions are much less distinct. Compared with Spirifer erien- 

 sis, Grabau, the absence of a subrhomboidal outline, of a high 

 area, and of a pronounced angular median sinus are sufficient 

 characteristics. Compared with Spirifer corallinensis, Gra- 

 bau, the wider median sinus, more rounded outline, and the 

 presence of lateral plications, though faint, are sufficient char- 

 acteristics. Compared with Spirifer hicostatus, the beak is less 

 elevated, the lateral plications are more narrow, and the con- 

 centric striae are practically obsolete. 



Spirifer corallinensis, Grabau, 



Several small and relatively wide Spirifers, with a narrow 

 fold and sinus, but without any indications of lateral folds, 

 were found at the Traction quarry in the southwestern part 

 of Kokomo, Indiana. These can not be distinguished from 

 the Spirifers represented by figures 9 a-h, on plate 74, volume 

 2, of the New York Paleontology. 



Trematospira camura-pauciplicata. 

 Plate II, Figs. 9 A, B. 



A pedicel valve, 6.5 mm.-'in width, and 4.5 mm. in length, 

 with two low and narrow central plications, and four strong 

 and angular lateral plications, resembling figure 24 on plate 

 49, volume VIII, of the Paleontology of New York, but of 



18 



