386 LAND AND FRESH-WATER SHELLS OF N. A. [pART IV. 



green; spire short, pointed; sutures linear; whorls four, somewhat 

 convex ; aperture ovate, large, within, purple or white. 



Habitat. — Vicinity of Cincinnati, Ohio. 



Diameter, -30; length, -37 of an inch. 



Observations. — This is a fine species about the size of Melania s^ib- 

 globosa, Say (Ancidosa) , and it has been confounded with it. I have 

 specimens of subglobosa which were brought by Prof. Vanuxem from 

 the Holston, at the time he gave them to Mr. Say for description. 

 They certainly do not appear to me to be the same, although in many 

 characters they agree. The animal of occidentalis I have not seen ; 

 the operculum is spiral ; at present I prefer to place it among the 

 Melania. Some of the varieties before me are very beautifully fur- 

 nished with raised revolving striae. When there is a single one, it 

 gives the shade the appearance of being carinate, as it appears near 

 the centre of the whorl. In some specimens these stria3 are more 

 numerous ; in a single one I have counted fifteen. There appear to be 

 no bands on the outside, but sometimes purple lines on the inside 

 mark the places of the exterior striae. There is generally more or 

 less color in the intei'ior and about the columella the base of which 

 is disposed to be angular. The aperture is nearly three-fourths the 

 length of the shell.* — Lea. 



The nomenclature of this species is singularly confused. 

 Mr. Lea described the quite young shell of A. pntirosa, which 

 is then carinate, as Melania Cincinyiatiensis, and he has consid- 

 ered costatus to be the mature form and a synonyme, and dis- 

 tributed shells so labelled. Prof. Haldeman, in his monograph 

 of Leptoxis, declares costatus, Anthony, and occidentalis, Lea, 

 to be synonymes of trilineatus, Say ; and succeeding authors 

 have acquiesced in these views. Costatus is, however, a 3'oung 

 shell of which occidentalis is the mature form. That it is per- 

 fectly mature is shown by the deposit of enamel upon the col- 

 umella of some of the specimens before me. The strife still 

 appear on the old shell, when the surface is not too much worn. 

 A. trilineatus is never costate and has three broad, brown 

 bands, and Mr. Anthony informs me that it has never been 

 found in the upper Ohio River, while costatus is plentiful at 

 Cincinnati. The figures of costatus are from specimens fur- 



* since tlie above was written I liave seen In tlie" Boston Journal of Science" tlie de- 

 scription andfijrure by Mr. Anthony of Anculo/iis costatus vihich In some respects answers 

 to this shell. Mr. A. says that his shell has " about five costa) rcvolviag around It." 



