LAMELLARIA. 201 



lobe greatly developed, entirely covering and concealing 

 the shell. 



Operculum none. 



Shell thin, spiral, covered by the hind lobe of the foot. 



The part of the animal which conceals the shell is 

 usually regarded as the mantle ; it appears, however, to 

 be more analogous to the operculigerous lobe of some of 

 the Naticidce, which more or less encroaches on the hind 

 portion of the shell, and in one genus, Caiinus, entirely 

 conceals it. 



Genus LAMELLARIA, Montagu. 



? Mantle convex, arcuated, thick, tubercular, anterior 

 fold median. 



Shell spiral, thin, pellucid; spire tumid, small; columella 

 greatly receding ; apei'ture very large, entire. 



Syn. Marsenia, Leach. Sigaretia, Rajin. Oxinoe, 

 CoutJi. 



Ex. L. tuberculosa, H. and A. Adams, pi. 21, fig. 3, 

 3, a. Shell, L. perspicua, Linudeus, fig. 3, h. 



The figure of the animal given is taken from a specimen 

 in spirits, in Mr. Cuming's collection, and appears to be 

 an undescribed species. 



Species of Lamellaria. 



antarctica, Couth. preetenuis, Couth. 



glacialis, Sars. tuberculosa, H. and A. Adams. 



perspicua, Linn. 



VOL. I. DO 



