INVERTEBRATE PALAEONTOLOGY. 377 



at the top of the aperture in thai figured by Dr. Stoliczka: which also differs 



in liming a low, broad ridge, or varex, at least on one of the Indian figured 



specimens. The latter two characters, particularly the varex, would seem to 



be generic differences; though it would be a little curious if two shells, so 



similar in most respects, should be so widely distinct as these characters 



would indicate. 



Locality and position. — Moreau River, Dakota; from the same horizon 



as the last. 



Genus CANTHARUS, Bolten. 



Synon.— Cantharus, Bolten (1798), Mns. Bolt. (ed. 2a, 98, 1819).— H. and A. Adams (185:?), Genera Recent 

 Moll., I, 84 (not Vogt, 1834, nor Phil., 1847). 

 Lagena, Bolten (1798), Mns. Bolt. (ed. 2a, 93, 1819) ; not Klein and others. 

 rollia, Gray (1839), Zool. Beech. Voy., Ill : and (1840) Wiegm. Arch., II, 212. 

 Tritonidea, Swainsou (1840), Moll., 302.— H. and A. Adams (1853), Genera Recent Moll., I, 85 (as 



a subgenus). — Stoliczka (18C8), Pala;ont. Indica, I, 117 (as a genus). 

 rolliana, M. E. Gray (1842), Figs. Moll. An., tab. 5. 



F.lym. — Cantharus, a kind of pot or jug, with bandies. 

 Examp. — Buccinum Tranqncbaricitm, Gmel. 



Shell bucciniform, or short-fusiform, with spire and aperture of nearly 

 equal length ; volutions with numerous equal vertical folds, or varices, and 

 revolving ridges ; last whorl more or less ventricose, and contracting abruptly 

 below into a very short, wide, or somewhat produced narrower canal ; colu- 

 mella arcuate in the middle, more prominent below, and generally provided 

 with more or less obtuse ridges ; inner lip usually thin or wanting, some- 

 times bearing a tooth-like ridge at the top of the aperture ; outer lip inter- 

 nally crenate or sulcate, and usually provided with a superior siphonal notch, 

 or canal. 



H. and A. Adams admit two subgeneric sections under this genus; 

 that is, they divide it into Cantharus proper, and Tritonidea, Swainson. Dr. 

 Stoliczka, in his East Indian Palaeontology, adopts these divisions, with differ- 

 ent limits and diagnoses, as two distinct genera, using Dr. Gray's name Pollia, 

 instead of Cantharus, for the first. This group he confines to species with a 

 very short, moderately-curved canal, and the inner lip transversely grooved 

 along its entire length, and toothed behind ; while Tritonidea he defines as 

 having its canal either moderately produced or short, and its "inner lip ante- 

 riorly thickened and smooth, and posterior thin, or cross-grooved, often 

 toothed at the end" It will be observed, however, that his diagnosis of 

 Tritonidea does not conform to Swainson's original description of the same, 

 48 H 



