Monograph of the Gasteropoda. 311 



covered, were merely the rows formed by tlie flexures of the trausverse 

 lamellse and not revolving lines at all. The beautiful cancellated 

 appearance of the Ci/rloUfes Di/eri is wholly wanting in this species. 



It has never been found in the range of CyrtoUtes Dyerl, which is 

 600 feet or more above low water-mark. Found on the hills within 

 and about the city of Cincinnati, from 400 to 475 feet above low 

 water-mark. It is rare. 



The specimen figured is from the collection of C. B. Dyer, Esq., 

 and is a good representation of it. 



Cyrtolites carinata — (S. A. Miller). 



Fig. 32.—Ci/rloUles carinita. Magainecl two diameters. 



Convolute; spire equally depressed on either side ; volutions two or 

 more, very rapidly enlarging toward the aperture ; shell sharply and 

 strongly carinated on the back and sides ; dorsal slopes plain between 

 the two carinated edges, with the exception of fine transverse lines 

 which take their rise on the dorsal keel, and arching slightly forward, 

 pass over the lateral carina and down the ventral sides in parallel lines. 

 These lines, even in good specimens, are nearly obliterated on the dorsal 

 sides, but preserve their character quite well on the ventral slopes. 

 Section quadrangular. 



This species may be readily distinguished from Cyrtolites ornatm, 

 which it most resembles, by the sharp carina on the sides and absence 

 of the " oblique transverse ridges," which characterize that species. The 

 fine curving lines, too, are wanting, so that it never presents a cancel- 

 lated appearance, at least not on any specimen observed. I think, too, 

 that it enlarges more rapidly toward the aperture. 



Its range is unknown, but the specimens collected, so far as I have 

 information upon the subject, have been found within two hundred 

 feet of low water-mark, at Bold Face Creek, opposite Fifth street, and 

 at the excavation for Columbia avenue. 



Genus Microceras — (Hall, 1845). 



{Microceras— in allusion to its small horn shape.] 



Shell small, smooth, convolute ; volutions few, horizontal, rapidly 



