346 VENERIM. 



cardinal tooth: inside dull chalky-white in the middle and 

 towards the beaks, with occasionally a slight stain of purple 

 inside the lips of the lunule ; margin crenulated on the ven- 

 tral and anterior sides, and more minutely on the inside edges 

 of the lunule : pallial scar broad and polished, with a narrow 

 and tongue-shaped indentation varying in depth, on the pos- 

 terior side : muscular scars distinct, triangularly oval. L. 1-15. 

 B. 1-3. 



Var. 1. laminosa. Shell more compressed, and produced on 

 the posterior side ; ribs fewer and regular ; longitudinal striae 

 more distinct. V. laminosa, Mont. Test. Brit. Suppl. p. 38. 



Var. 2. triangularis. Shell smaller, and larger in propor- 

 tion to its breadth. 



Var. 3. gibba. Shell more ventricose or tumid and rather 

 glossy ; ribs numerous, irregular, and at intervals confluent or 

 bifurcating on the posterior side. 



Habitat : Abundant everywhere on sandy ground 

 from low-water mark to 85 fathoms. Var. 1. Nearly 

 equally common; found in Balta Sound between 3 and 

 5 fathoms and off that coast in the deepest water. Var. 2. 

 Exmouth (Clark); Tenby and Fishguard (J. G. J.). 

 Var. 3. West coast of Scotland, and Shetland. This last 

 variety agrees with the Mediterranean form. Grainger 

 has noticed the present species in the Belfast deposit, 

 and Smith in the Scotch " glacial" beds. Steenstrup 

 has taken it in Iceland ; it has been recorded by all the 

 writers on Scandinavian conchology (under the name of 

 V. striatula), at depths varying from 3 to 70 fathoms, 

 and by writers on the conchology of other parts of the 

 European seas, from Normandy to both shores of the 

 Mediterranean and the Black Sea (under the name of 

 V. yallina), at rather less depths. Brocchi and Philippi 

 have enumerated it as fossil in the Italian tertiaries. 



This is not the least of the numerous discoveries for 

 which we are indebted to Lister. Macgillivray has 

 justly remarked that it is a very " instructive " species. 



