GENUS DOLIUM. 5 



often widened, feebly convex, and separated by furrows hardly 

 apparent ; suture very distinct, slightly channeled towards the 

 last whirl. The aperture is large, subovate, marked by 

 transverse, slightly projecting bands, which correspond to the 

 furrows of the exterior. The interior of this cavity is of 

 a fawn color. The right lip is thin, everted, a little undu- 

 lated, and adorned with a white band the whole length of 

 its interior, with the exception of the edge, which is of a 

 deep brown. The left lip is spread out over the body of the 

 shell ; it is very thin, transparent, and terminated below by 

 a projecting plate which covers the umbilicus, and seems also 

 to form a part of it. The columella is smooth, polished, 

 and forms at the left of the umbilicus a thick rib, marked 

 by transverse striae, which terminates at the emargination of 

 the base. 



Length 5 inches. Width 3 inches. 



Inhabits the Channel, the Mediterranean, the equatorial 

 seas, the seas of India, of Africa, and of America. 



This shell is remarkable on account of its form, being gen- 

 erally more elongated than that of other species, and particularly 

 by its coloring, which makes the transverse ribs to appear as if 

 enameled with small white spots, for the most part curved in the 

 form of a crescent. 



The mollusk of this shell inhabits rapid waters, and appears 

 pretty quick in its movements. The ground of its color is a 

 bluish white, covered with irregular spots of a red brown, bor- 

 dering upon the violet. The foot is colored in the same man- 

 ner beneath, but above, it is furrowed with wide triangular 

 radiating bands. The tentacular are doubly ringed with brown. 



