520 BULLID^E. 



obtuse) than in its allied congeners. The length somewhat 

 exceeds the eighth of an inch ; the breadth is bare three- 

 fourths of a single line. 



This species ranges from low water-mark to great depths, 

 and is sparingly distributed around the British shores, 

 ranging from the British Channel to Zetland, and living on 

 both eastern and western coasts. 



To this genus belongs the Volvaria alba of Brown (111. Conch. G. B. p. 3, 

 pi. 19, f. 43, 44), said to have been found at Greenock, and usually supposed to 

 be (as British) a fossil species. The Cijlichna alba of Loven (" Index," p. 10, 

 figured in the " Thesaurus Conchy liorum," vol. ii. pi. 125, f. 137, from a specimen 

 sent by Loven to England) seems identical, and to be the same with the Sarsii of 

 Adams' monograph (Tlies. Conch, pi. 125, f. 135). The D. triticea of Couthouy 

 (Bost. Journ. vol. ii. p. 88, pi. 2, f. 8 ; Gould, Invert. Massach. p. 165, f. 98; 

 Thes. Conch, pi. 107, f. 139), stated by MoUer and Loven to be the corticata of 

 the former (Ind. Moll. Grcenl. p. G) is most closely allied to it, even if not a 

 synonym. 



AMPHISPHYRA. Loven. 



Shell thin, inflated, ovate or subglobose ; apex truncate ; 

 whorls of spire exposed, depressed, with a mammilated 

 nucleus; aperture expanded, not extending above the 

 body- whorl, outer lip sinuous, produced, inferiorly re- 

 tiring at its junction above ; pillar lip subumbilicated. No 

 operculum. 



Animal capable of being entirely retracted within the 

 shell ; its head broad and short, flanked by two distant 

 triangular tentacula, and bearing two immersed eyes some 

 way above their bases. Tongue broad, armed ; axile 

 denticle, broadly quadrate, with its upper edge inflected 

 and serrulate ; flanked on each side by a single hamate 

 lateral with a broad base. No gizzard. Foot broad, 

 truncate, and sub-bilobate in front, shorter than the shell, 

 and unequally bilobed behind. 



