444 BULLION. 



creamcolour ; young and half-grown specimens are often 

 adorned with narrow reddish-brown zones, parallel and alter- 

 nating with the white spiral striae and their walls : spire 

 loosely coiled, not exposed in the adult, being coated over by 

 successive deposits from the hinder lobe of the mantle : crown 

 obliquely indented, and encircled by an angular rim; it is 

 perforated in the young and fry, so as to show the outer part 

 of the spire : mouth narrow above, and dilated below, with a 

 rounded base ; its length exceeds that of the spire : outer lip 

 not much curved in the middle ; it projects beyond the crown, 

 forming in that part an obtuse angle : inner lip broad and 

 flexuous, consisting of a rather thick glaze: pillar arched, 

 visible throughout by holding the shell upside down. L. 2-33. 

 B. 1-5. 



Var. 1. alba. White, with a creamcolour epidermis. 



Var. 2. curta. Smaller and shorter, but not having the 

 compactly convoluted spire and comparatively small mouth of 

 S. librarius. 



HABITAT : All our coasts : it usually frequents the 

 coralline zone, ranging as deep as 90 f. ; but. Dr. Lands- 

 borough says that " at Whiting Bay, in Arran, it may 

 be taken by digging in the sand at ebb tide." The 

 1st variety is generally diffused, but rare. Var 2. 

 Shetland. This species occurs in the quaternary and 

 upper tertiary beds at Belfast (Grainger) ; Greenock 

 (Robertson) ; and the Red and Coralline Crag (Wood) ; 

 as well as throughout Belgium, France, Italy, Germany, 

 and the southern parts of Europe. Its distribution, in 

 a living state, extends from Finmark (Danielssen and 

 Sars) to Gibraltar (M* Andrew), and through the Medi- 

 terranean, Adriatic, and ^Egean ; depths 8-60 f. 



This voracious mollusk does not despise any kind of 

 animal food, from minute Foraminifera to the sea-mouse 

 or Aphrodita, the spines of which I found in the gizzard 

 of one individual. Corbula gibba is evidently a favour- 

 ite morsel ; and I have observed Dentalium entails, 

 Odostomia rufcij andDitrupa arietina in other specimens. 



