MIOCENE MOLLUSCA AND CRUSTACEA. 99 



numerous revolving ribs which exhibit a slight tendency to alternate in 

 size." (Gabb.) 



The specimen which I have figured on the plate is the type from which 

 Mr. Gabb drew his description. As he gives only a back view of the speci- 

 men it is difficult to tell whether it is in the same condition now as when he 

 used it. There is nothing of the outer lip showing at the present time, and 

 the columella is also ver}^ imperfect; the columellar fold shows imperfectly 

 and is quite oblique. The spiral or "revolving ribs" are very fine, and 

 would be as well designated as impressed striae as ribs ; they are very variable 

 in size, and on the lower side of the whorl are flattened on the surface with 

 a faint secondary line, giving the tendency to alternation mentioned. The 

 substance of the shell is quite thick and the shell generally of a heavy char- 

 acter. The transverse striae in crossing the spiral lines check them and give 

 a rugose surtace when seen under a glass. The species seems to have been 

 somewhat uncommon. Mr. F. B. Meek in his Check List cites this species 

 as from Texas. Under Mr. Gabb's description he gives the locality as "with 

 the above," which is Cantharus Cumherhmdiaini, stated to be from Shiloh, 

 N. J. 80 far as I can ascertain the species has not been recognized from 

 any other locality than New Jersey. 



Formation amJ JotaVdy : In the Miocene marls near Shiloh, N. J. From 

 the collection at the Academy of Natural Sciences at Philadelphia. 



Genus LYROSOMA Conrad, 1862. 

 Proc. Acad. Nat. Sci. Phila., 18G2, p. 286. 



" Subpyriform ; ribbed, beak narrow and produced, shghtly recurved; 

 one long, very oblique plait at the angle of the columella. FasrioJaria 

 (Fusiis) sulcosa Com-ad, Fossils Medial Tertiary." 



The above is Mr. Conrad's description and citation of type of this 

 genus. The species for which the genus was proposed is a pyriform shell 

 of small size, with a somewhat rounded spire and cancellated body, the 

 strong spiral lines being crossed by vertical lines of growth, which divide 

 the surface into quadrangular spaces, so as to present this checkered appear- 

 ance. The only point that I can see which would warrant a separation 

 from mail)- of the forms of Fasciolaria, is the existence of a single fold on 



