336 VENERIS. 



teeth ; margin very finely toothed or crenulated in every part 

 except on the dorsal or ligamental side : pallial scar broad and 

 polished, with a narrow and not deep sinus : muscular scars 

 distinct, semioval and polished, marked by a few symmetrical 

 lines, which denote the successive shiftings of the muscles. 

 L. 0-8. B. 0-9. 



Var. 1. radiata. Shell beautifully marked with many red- 

 dish-brown rays, which sometimes are alternately large and 

 small, or double. 



Var. 2. raricostata. Shell smaller and having propor- 

 tionally fewer ribs. 



Habitat : In every part of the British seas, among 

 nullipores and in gravelly and sandy ground, from the 

 shore to the deepest water. The first variety occurs at 

 Exmouth and Falmouth, in Bantry Bay, off Arran Isle 

 (co. Galway), and in Shetland. The other variety is 

 from the west of Scotland. This common but pretty 

 species is a member of our newer tertiaries, having been 

 recorded by Smith from a postglacial deposit at Ayr, 

 and by Searles Wood from the Mammalian and Red 

 Crag. Havosund, near the North Cape, appears to be 

 in the highest, and the iEgean in the lowest latitude 

 where it has been noticed. It is extensively diffused over 

 the intermediate area. M' Andrew found it living be- 

 tween tide-marks at Gibraltar. According to Brocchi 

 and Philippi, it is a fossil of the Italian tertiaries. 



The animal is inactive, and does not seem to be fond 

 of exhibiting itself to curious malacologists. In the 

 ' Cornish Fauna * by Mr. Jonathan Couch it is stated 

 that this species, as well as V. gallina, frequently creep 

 into crab-pots in search of the bait. I should scarcely 

 have imagined that any bivalve possessed such an extra- 

 ordinary habit. Some specimens are more convex than 

 others, and the shell is now and then distorted. The 

 crenulations which border the inside margin resemble 



