182 TELHNA. BENT-WEDGE. CtAssVl. 



15. CRASSA. Venus crassa. Gm. Lin. Lin. Tr. viii. 55. 



fi aL 3288. Mont. Test. Br. 65- 



T. with very thick, broad, and depressed 

 shells, marked with numerous concentric stria. 

 Breadth, an inch and three quarters; length, 

 an inch and a quarter. 



Has the habit of the Venus borealis ; but the 

 sides of this are unequal, one being more ex- 

 tended than the other. Tab. li. Jig. I. 



16. LACTEA. Gm. Lin. 3240. Mont. Test. Br. 70. t. 2. 



Lin. Tr. viii. 56. f. 4. 



* T. with an orbicular, gibbous, white, pellu- 

 cid smooth shell; diameter three quarters of 

 an inch. This is distinguished at once by a 

 deep groove that runs from the beak by the 

 side of the teeth in each valve. 



Found on the coast of Llyn in Caernar- 

 vonshire, and in various parts, but not com- 

 mon. 



17- ROTDK- Lin. Tr. viii. 56. Mont. Test. Br. 71. t. 2. 



DATA. 



f.3. 



* T. with a shell rather convex, orbicular, hav- 

 ing two teeth in each valve, one of them forked, 



