24 Cincinnati Society of Natural History. 



vex, especially anteriorly. Nevertheless, the general appear- 

 ance and structure of our specimens appear to correspond 

 more nearly to that of Schuchcrtella subplanus than to that 

 of any other genus. The strong dental lamellae exclude it 

 from Strophcodonta; moreover, there is no evidence of crenu- 

 lations along the hinge line. The strong crural ridges are un- 

 known in Raiinesquina ; moreover, the dental lamellae are too 

 long, and the faint indications of the muscular areas in both 

 valves are not in favor of such a relationship. 



Our specimens apparently agree w^ith the species originally 

 described as Leptcuna ohscura, by Hall, in the slight convex- 

 ity of the pedicel valve, and in the general outline. More- 

 over, figure 6a on plate 21 of volume 2 of the Paleontology 

 of New York apparently agrees also in the coarseness of the 

 radiating striations. Unfortunately this type has been lost, 

 and the associated figure on the same plate, figure 6b, indi- 

 cates a form with much shorter and less conspicuous dental 

 lamellae, and the reference of this form to Rafincsqitina sug- 

 gests entirely different generic affinities. 



Chonetes vetustus, Focrste. 

 Plate I, Fig. 16. 



This species attains a width of 9 mm. and a length of 

 6 mm. There are about 60 to 70 radiating striae. Compared 

 with Chonetes corniitus, our specimens are wider, have more 

 numerous striae, and the hinge spines are more inclined and 

 relatively shorter. 



Near the top of the Alger clay at numerous localities in 

 Lewis county, Kentucky. The types were fomid between 

 Valley and the W. H. Lawrence store. 



Chonetes colliculus^ sp. nov. 

 Plate T. Figs. 10 A, B, C. 



Shell small. The largest-^ specimen found so far has a 

 width of (S mm. and a length of 6.5 mm. Pedicel valve strongly 

 convex. In shells 7 mm. in width this convexity usually does 

 not exceed 2 mm., but in the more mature shells it may equal 



24 



