1 84 Shell Life 



yellow. The narrow girdle is fringed with short 

 spines, and the surface coated with polished yellowish 

 granules. It is less than a quarter of an inch long ; 

 and it may be found on stones and about the smaller 

 seaweeds just beyond low-water mark. The Grey 

 Mail-shell {C. cinereiis) is similar to the last species, 

 but larger and more compressed ; shell with slight 

 but distinct keel, the sculpturing not producing the 

 latticed appearance. The girdle is broader, and more 

 thickly covered with granules. The colour of the 

 shell varies from pale yellow to brown, streaked with 

 dark lines, but the general effect is an ashy grey. It 

 is one of the most frequent of all our Chitons, and 

 may be found on rocks, stones, old shells, etc., on all 

 our shores from low water downwards. 



The White Mail-shell (C. alhus), which is less than 

 half an inch in length, is a local northern form. Its 

 white has a yellow bias, but it is unmarked by lines 

 or mottling of another tint. It is similar in general 

 appearance to the Grey Mail-shell, but is more slender 

 and convex, has a more prominent keel, the granula- 

 tions finer, more radiating than chain - like. The 

 margins are slightly notched ; the head-plate having 

 13 notches, the tail -plate 11, and the intervening 

 ones 2 each. The brownish girdle is broader and 

 more regularly beaded, whilst its margin is fringed 

 with short spines. It occurs in the Isle of Man, and 

 at various places on the coasts of Scotland, Shetland, 

 and the Orkneys. Tlie Bordered Mail-shell (C. mar- 

 ginatus) is similar to G. cinereus, but larger, 

 narrower, and more convex ; the plates broader, with 

 a surface like shagreen, mottled or variegated with 

 yellow, red, and green, and their edges deeply notched. 



