SEA-SNAILS AND SEA-SLUGS. 225 



of rock is placed in an aquarium, other creatures will make 

 their appearance, which were unobserved before, owing to 

 their colour, and the closeness with which they attach them- 

 selves. One of these is the Bristly Mail-shell (Chiton fasci- 

 cularis), distinguished from other British species by the posses- 

 sion of little bunches of short bristles, which are arranged 

 along the shell-border opposite each plate of mail. There is 

 considerable resemblance between these creatures and limpetr t 

 though there are also important differences. Instead of the 

 shell being in one piece, it is composed of eight transverse 

 plates, which overlap at their edges, and allow it to be rolled 

 up like a woodlouse. Each plate is 

 attached to the mantle by its front margin, 

 and the mantle forms a narrow border all 

 round the shell. The animal, like the lim- 

 pet, has a broad foot upon which it creeps, 

 mostly at night, so far as my observations 

 of C. fascicularis go. Its head chiefly con- 

 sists of its mouth and jaws, eyes and ten- 



-, , ,. . ... SMOOTH MAIL SHELL. 



tacles being dispensed with as unnecessary 

 to its manner of life. The breathing organs are similar to 

 those of the limpet, but are arranged round the posterior end 

 of the body only. The shell is very flexible in all directions, 

 so that the animal is not constrained, like the limpet, to return 

 to the same roosting spot each time it wishes to rest. 



There are a number of British species ; the one figured is 

 known as the Smooth Mail-shell (C. Icevis). It has a glossy 

 shell of a reddish hue, with a central ridge. The largest of the 

 native forms is the Marbled Mail-shell (C. marmoreus), whose 

 delicately sculptured shell is further ornamented with a mott- 

 ling of browns and yellows. It is about an inch and a quarter 

 in length. The British species is almost as long, but of much 

 more slender proportions. The most plentiful form is the 

 Grey Mail-shell (C. cinereus], which does not greatly exceed 

 half an inch in length. It is not entirely grey, though this is 



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