460 calyptr^idtE. 



The FooVs-cap Limvet, as it is familiarly called, was, 

 from its peculiarity of form, one of the earliest species 

 recognised by the British collector. Modifying its shape 

 according to the peculiarities of its habitat, it is by no 

 means symmetrical ; its general outline, however, is sub- 

 conical, or if viewed laterally, semicordate, reminding us 

 forcibly of one of the valves of an Isocardia. It is 

 tolerably strong, but not solid, rather transparent for its 

 thickness, and under its drab or ashy brown pilose epi- 

 dermis, which is sometimes dull and shaggy, sometimes as 

 smooth and glossy as satin, is either pale flesh-coloured or 

 white ; in the latter case usually more or less tinged with 

 yellow, in the former frequently stained internally with 

 various intensities of crimson. The surface, which is often 

 disfigured by irregular indentations, besides distant wrinkles 

 of increase, is everywhere marked with simple rounded 

 coarse raised strite or narrow costellee, whose interstices are 

 of about the same breadth with them, and are unsculp- 

 tured, except by such still narrower complementary costellse 

 as the gradual widening of the interstices demand. The 

 vertex is spiral, a little inclined to one side, but only at its 

 termination, where the rapidly attenuated whorls, if not 

 loosely coiled, are only visible on one side ; the penult 

 whorl is always disunited from the shelving pillar-lip, and 

 rarely, if ever, descends to its level. The inside is smooth, 

 shining, more or less circular in marginal outline, and 

 either white or stained with rose or a pinkish flesh-colour ; 

 the rim is not crenated. 



The bases of some of our larger specimens measure only 

 an inch and a half, and their height is one-third less, yet 

 occasionally, and especially in foreign examples, these 

 dimensions are greatly exceeded. ^lontagu mentions one 

 from Salcomb Bay in Devonshire of two inches in diameter, 



