NATURAL SCIENCES OF PHILADELPHIA. 331 



by him ; and it seems to be equally distinct from all of those de- 

 scribed in this country and Canada. 



The specific name is given in honor of Prof. Edward Orton, of 

 the Ohio Geological Survey. 



Locality and position. — Cincinnati group, at Cincinnati, Ohio. 

 Mr. Dyer's collection. 



ARTICULATA. 

 CRUSTACEA, 



CYTHERE CINCINNATIENSIS, Meek. 



Carapace-valves varying from transversely suboval to subcir- 

 cular ; moderately and rather evenly convex, the gx'eatest convex- 

 ity being in the central and anterior regions ; without any visible 

 tubercle or nodes ; ventral margins rounded or semioval, and 

 but slightly unequal or thickened ; anterior and posterior margins 

 more or less rounded, the former being more broadly rounded 

 generally than the latter ; hinge margin very short, very slightly 

 sinuous just behind the umbones, and rounding into the posterior 

 margin so as scarcely to produce any visible angularity ; umbones, 

 near the anterior, a little tumid, rising very slightly above the 

 hinge, and rounding off regularly into the anterior margin. Sur- 

 face nearly smooth. 



Length of one of the larger nearly circular specimens, 0.21 

 inch; height, 0.17 inch; convexity, 0.11 inch. Length of a smaller 

 more oval specimen, 0.14 inch; height, 0.08 inch; convexity, 0.07 

 inch. 



This species seems to vary a good deal in form, some specimens 

 being, as the above measurements indicate, proportionally higher, 

 and thus presenting a more rounded outline. It is possible that 

 these forms may belong to two distinct species ; but, with the spe- 

 cimens yet accessible for study, I have not felt warranted in sepa- 

 rating them. 



Locality and position. — Cincinnati group, at Cincinnati, Ohio. 

 Mr. Dyer's collection. 



The following interesting Crustacea were discovered by Prof. 

 Frank H. Bradley, of Knoxville, Tennessee, at the base of the 

 Waverley group, at Danville, Kentucky. As the same species 

 will doubtless yet be found at this horizon in Ohio, they are here 



1872.] 



