CASSIS. 



TESTA ventricosa, seu iuflata, spira brevi. 

 ^pertura longitudinal is, angusta, in canalem 

 brevem, subito reflexum desinens. Columella 

 transversa plicata vel rugosa. Labium externum 

 incrassatum, reflexum, saepissime intern^ den- 

 tatum. 



Almost every person who knows what a shell is^ has seen 

 and is acquainted with the Helmets, which ai'e rendered in 

 general remarkable on account of their size; and, as 

 being common and handsome, are used as ornaments. 

 They formed a part of the Linnean Genus Buccinum, but 

 taking the Common Whelk, Buccinum undatum, as the 

 type of that Genus, they certainly differ very materially, 

 particularly in the form of the aperture, which is narrow 

 and dentated on both sides, in the thickened and reflected 

 outer lip ; in the inner lip being expanded over the last 

 volution and in the reflected canal. Some of the La- 

 marckian Dolia approach nearer to the Cassides than the 

 Buccina, but their want of the reflected canal will also 

 distinguish them; his Cassidarice have the same general 

 form, but are characterized by a canal not reflected, 

 though in a slight degree ascending : it is to JVassa, which 

 Lamarck formerly separated from Buccinum, but which 

 he has recently reunited to it, that Cassis appears to us 

 to be most nearly related^ both as respects the form and 

 general characters of the shell and some of the habits of 

 the animal : for they both appear to belong to that family 

 of predaceous Trachelipodes that bury themselves in the 

 sand in search of their prey; for Lamarck tells us of the 

 Cassides " that the shells live in the sea at a distance from 

 the shores and upon sandy bottoms, where they bury 

 themselves in the sand;" and we know of the common 

 Buccinum reticulatum, jLwz??. and jLa???.,* from the actual 



* In conformity with Lamarck's definition thiss^liell ought to be placed with 

 the Nassa. 



