175 



description, says, it is so much like that of a Buccinum, that " to 

 make of the Sigaretus a, Buccinum, it is only necessary that the 

 whorls of the shell should be less unequal, and should be elongated 

 into a more acute spire." The animal as delineated in his plate, 

 or that part which is visible from above, consisting entirely of the 

 expanse of the thick, fleshy mantle, is oval and convex. On the 

 anterior margin, a little on the left, is a deep emargination, which 

 is the extremity of an open canal beneath, originating above the 

 neck in the branchial cavity, to which it conveys the water, and 

 in which are two pectinated and vascular lamelliform branchia>. 

 The shell is entirely enclosed in the convexity of the mantle. The 

 head is formed as in Buccinum. The tentacula are conic, with 

 the eyes at their base. The vent is posterior to the canal and 

 before the middle of the body. The foot much smaller than the 

 mantle and also oval. The sexes are in separate individuals. 



Blainville has formed a new genus under the name of Grt/pios- 

 loma, for one or two East Indian species, the shells of which 

 though more depressed, are altogether generically similar to Sign- 

 retus, in which other naturalists place them ; but the animal, 

 agreeably to his description, differs in having a more elongated 

 form, appendiculated tentacula and but one large branchial pccten. 



SiGARETUS PERSPECTivus. — Specific character. Depressed ; 

 beneath, revolutions visible almost to the summit. 



Desc. Shell oval, very much depressed, but little convex, with 

 numerous, transverse, slightly undulated, sub-equidistant, impress- 

 ed lines and longitudinal wrinkles; transverse lines obsolete 

 beneath : spire not at all prominent, only a little convex : volutions 

 about three : sutui-e a simple impressed line : within, the slightly 

 elevated line is more or less obvious, not reaching the margin of 

 the labrum : revolution of the whorls visible almost to the summit. 



Ohs. This shell is abundant on the coast of New Jersey and 

 farther south ; but I have never had an opportunity to examine the 

 animal. 



I have carefully compared many specimens with a shell sent me 

 by Mr. Gr. B. Sowerby, under the name of haliotoideus, L., but 

 which seems more accurately to correspond with the leachii, Blain- 

 ville, as figured by Sowerby in his " Genera," and of which Blain- 

 ville has formed his genus Cryptostoma. So striking is the 

 resemblance that I have hesitated much to consider it a distinct 

 species. 



