418 BULLID/E. 



Shell forming a short cylinder, or oblong, broader in the mid- 

 dle, and less solid than in the last species, semitransparent, and 

 decidedly glossy : sculpture, numerous and close-set but ex- 

 tremely fine and slight spiral stria?, which can only be de- 

 tected by the aid of a strong magnifier : epidermis, a pellucid 

 creamy film : colour white : mouth more open than in C. 

 cyUndracea, although having the same shape : outer lip gently 

 curved throughout ; it is higher at the top than in the last 

 species, and at the outer corner it recedes or slopes more 

 abruptly ; inner corner obliquely incurved : apex twisted 

 (not contracted); it is encircled by a strong and angulated 

 rim, and concave in the centre, with a minute perforation in 

 some specimens : inner lip forming at the upper end a thick 

 fold, which is reflected on the apex and usually covers the 

 perforation ; it is conspicuous, but thin, in other parts : pillar 

 short, broad, curved and twisted to the left, with an obscure 

 plait. L. 0-35. B. 0-175. 



Habitat : Fine sand, in 84-95 f., about 25 miles 

 N.N.W. of Unst, with Limopsis aurita and other rare 

 mollnsea. It is one of our post-glacial fossils, and has 

 been found at Greenock (Stewart Kerr, fide Brown), 

 Paisley and Lochgilphead (Crosskey),Dalmuir (Robert- 

 son), and Annochie in Aberdeenshire (Jamieson) j 

 Mammaliferous Crag near Norwich (Witham, fide S. 

 Wood as Bulla cyUndracea, var. monstrosa) ; Norway 

 2-40 feet (Sars). Its existing range is arctic and high 

 northern, and comprises Norway, Iceland, Spitsbergen, 

 Greenland, and North-east America; west coast of 

 North America (P. Carpenter) : depths 10-160 f. The 

 most southern limit appears to be Bergen. 



This lives with C. cyUndracea ; and its movements 

 are equally slow. In one Norwegian specimen the 

 colour of the epidermis is brownish-yellow, as in 

 the other species. I have figured the tongue, from a 

 drawing kindly made for me by my late friend Mr. Alder. 



It is the Bulla triticea of Couthouy, and B. corticata 



eck) of Moller. 



