220 KELLIIM. 



middle, produced or wedge-like and rounded at the anterior 

 end : beaks broad, blunt, prominent, and contiguous ; they are 

 placed about two -fifths nearer to the posterior end : hinge-line 

 curved, occupying rather more than one-fourth of the circum- 

 ference : cartilage large, yellowish-horncolour, attached to the 

 shell below the hinge-plate and lodged on an oblique shelf : 

 Tiinge-plate very broad, thick, and strong : teeth, in the right 

 valve two triangular laterals with sharp points, the anterior of 

 which is a little more raised than the other ; in the left valve 

 similar laterals, besides a minute cardinal and erect tooth 

 directly below the beak ; the laterals in each valve lock into 

 corresponding grooves in the other : inside partially nacreous, 

 but otherwise of a dull hue ; margin plain : pallial scar scarcely 

 visible, but evidently existing on account of the adhesion of 

 the mantle inside the front margin : muscular scars oval and 

 distinct. L. 0-85. B. 0-1. 



Var. pallida. Shell yellowish-white and nearly trans- 

 parent, without any tinge of purple or red. 



HABITAT : Everywhere in crevices of rocks, inside the 

 empty cups of Balani and among the tufts of Lichina 

 pygmaa, near high-water mark, and at the roots or 

 footstalks of Corallina officinalis and other seaweeds, 

 and on mussel-beds, between tide-marks ; sometimes it 

 is found at depths varying from 3 to 20 fathoms. The 

 variety is not uncommon. This species is a Coralline 

 Crag shell. Steenstrup has found it in Iceland, and 

 Lilljeborg at Grip in Upper Norway ; but I am not 

 aware of any other northern locality. It is widely 

 diffused southwards from the north of France to the 

 Canary Isles, and throughout the Mediterranean. Spe- 

 cimens for which I am indebted to the kindness of 

 Mr. Cuming (so renowned for his unrivalled collection 

 of shells, as well as for the extent of his coiichological 

 experience), and taken by him on the south-western coast 

 of America, cannot be distinguished from the European 

 species ; and Dr. Philip Carpenter is of opinion that a 

 species from the Gulf of California is the same as ours. 



