54 CORBT7LID.E. 



defines the snout-like process : pallial scar well marked, with 

 a semicircular sinus : muscular scars rather deep ; anterior 

 irregular, posterior triangularly oval. L. 0-55. B. 0-8. 



Yar. 1. curia. Rostral or snout-like process shorter. 

 Var. 2. cinerea. Shell ashcolour, and thinner. 



HABITAT : Land's End (M f Andrew) ; Northumberland 

 and Durham (Brown, Thomas, Alder, and Mennell) ; 

 Aberdeen (Macgillivray) ; Firth of Forth (Gerard and 

 Thomas) ; throughout the west of Scotland (Smith and 

 others) j Shetland (M f Andrew and others) ; off Cape 

 Clear (M f Andrew) ; Arran Isle, Galway (Barlee) ; in 

 muddy sand, at depths varying from 12 to 82 f. Var. 

 1 and 2. Hebrides (Barlee) . Searles Wood has recorded 

 this species as fossil in the Coralline Crag, Risso from 

 Nice, and Philippi from Sicily ; upper miocene bed near 

 Antibes (Mace). Its foreign distribution in a recent 

 state comprises Spitzbergen and South Greenland 

 (Torell) ; Scandinavia, 22-180 f. (Loven and others) ; 

 Carthagena and Gibraltar, 45 f. (M* Andrew) ; Provence, 

 in a gurnard's stomach (Martin) ; Italian coasts of the 

 Mediterranean (Maravigna and others) ; Adriatic (Olivi 

 and Chiereghini) ; Malta, 40 f. (M f Andrew) ; ^Egean, 

 12-185 f. (Forbes) ; Algeria (Deshayes and others) ; 

 Madeira, in 18-24 f., and Teneriffe, in 20-35 f. 

 (M f Andrew) . Mr. Hinds, after giving some European 

 localities, remarks, " Nor can I perceive any difference 

 in the valve of a shell obtained from 84 f. in the China 

 Sea ; the temperature below being 66, and at the sur- 

 face 83." 



It is much more globular and obliquely twisted than 

 N. rostrata, and it is more finely striated ; the snout in 

 all specimens is considerably shorter ; the front or ven- 

 tral margin is more curved; and the posterior dorsal 

 side is abruptly truncated, and not so rounded and pro- 



