152 HELTCW^, 



and often of a whitish colour, in Steep Holm Island 

 in the Bristol Channel. 



The shells of this species, especially when imma- 

 ture, are often covered with mud or lichens, as is the 

 case with those of BiUimits obsctLinLS. 



Var. I. alba. — Shell white or coloudess. Lulworth, Dorset- 

 shire (J. G. J.), B.C. Pateley Bridge, Yorkshire (Lister Peace), 



Var. 2. Boileausiana. — " It is distinguished from the type by 

 its smaller size, the larger plication on penultimate whorl being 

 always double, and by the presence of a prominent additional 

 fold at the angle of the columella." Found by Mr. W. 

 Nelson at Dorridge near Knowle, Warwickshire (fide J. W. 

 Taylor).— J. C, January, 1879. 



Var. 3. cdentida. — " Shell smaller, thinner, smooth and 

 glossy ; striation regular and fine on the upper whorls, gradually 

 becoming fainter and more irregular on the lower ones ; aper- 

 tural phcations obsolete." Found "in 1877 at the foot of the 

 rocks near Ingleton, Yorkshire," by Mr. J. W. Taylor. — J.C, 

 January, 1879. 



B. Spire short ; mouth horseshoe-shaped, with one or 

 more teeth or folds ; outer lip considerably thick- 

 ened, more or less reflected. Im;nature shells 

 with transverse plates, and spirally twisted ridge- 

 like folds. 



2. B. rin'gens,* Jeffreys. Pl. IX. 



" Body yellowish-grey or slate colour, with several dark lines 

 or streaks along the sides, leaving a clear space in the middle, 

 underneath milk-white ; mantle thick, projecting a little beyond 

 the mouth of the shell ; tentacles short, of a lighter shade than 

 the upper part of the body, larger pair cylindrical and stumpy, 

 rather close together, the bulbs scarcely distinguishable, lower 



Grinning. 



