VENERUPIS. 159 



On the whole it may be considered as a southern species 

 so far as the coasts of Britain are concerned. Indeed it 

 does not appear to range further north, and is most 

 abundant in the southern part of the Celtic province 

 (Atlantic coast of France) and in the Lusitanian and 

 Mediterranean regions of the European seas. Geologically 

 it dates as far back as the epoch of the Red Crag, but 

 retired for a time from our seas during the unfavourable 

 conditions of the pleistocene period. It is an inhabitant of 

 the littoral and laminarian zones, and rarely occurs even 

 dead in the dredge, unless in very shallow water and close 

 to shore. 



SPURIOUS. 



Venus suhslriuta, Mont. Test. Brit, suppl. p. 48, pi. 29, f. 6. — Turt. Conch. 



Diction, p. 245. — Turt. Dithyra Brit. p. 152. — Flem. 



Brit. Anim. p. 448. — Brit. Marine Conch, p. 91. 



Vemrupis decussaia, Philippi, Moll. Sicil. vol. i. p. 22, pi. 3, f. 5, and vol. ii. p. 



20.— Exped. Scien. Algerie, Moll. p. 06. f. 10 to 13 (shell 



and animal). 



Kouncled, subquadraiigular, solid, opaque, more or less ventri- 

 cose, rather dull, of an uniform white both within and without, 

 most crowdedly set with radiating elevated strisc, which assume 

 a subgranular appearance, especially in front, by being decus- 

 sated with irregular concentric wrinkles, which are more mani- 

 fest anteriorly. Ventral margin but little convex, ascending in 

 front, not crenated within: hinder dorsal edge straightish, and 

 not declining ; front dorsal edge straightish, and considerably 

 sloping. Anterior side much attenuated, very small, tolerably 

 rounded at the extremity : posterior termination broadly subbi- 

 angulated, the angles being rounded off, and the extreme edge 

 somewhat convex. Ligament almost concealed ; umbones pro- 

 minent ; beaks incurved and distinct ; no lunule. Two diver- 

 gent compressed primary teeth in the right valve ; three, of 

 which the bifid central is the largest, in the other. Length f, 

 breadth ^ of an inch. A Mediterranean shell, introduced hy 

 Montagu, as dredged hy Mr. Laskey, off the Isle of May, in the 

 Frith of Forth. Prohahly brought in ballast. 



