CHITON. 219 



zones ; occasionally between tide -marks at high springs ; 

 off Mull of Galloway, 145 f. (Beechey). Macgillivray 

 savs he found it at Aberdeen on a starfish ! The 

 variety is from the west of Scotland in deep water. 

 "Glacial" bed at Fort William (J. G. J.); Coralline 

 Crag, Sutton (S. Wood). Greenland (Fabricius and 

 Eschricht) ; Iceland (Steenstrup and Torell) ; Scandi- 

 navia, 1-130 f. (Miiller and others) ; north of France 

 (De Gerville) ; Vigo Bay (M f Andrew) ; and along the 

 coasts of the Mediterranean to the iEgean, 5-10 f. 

 (Forbes, as C. Rissoi). 



Chemnitz called the specimens in Spengler's cabinet 

 " the negress/' owing to their swarthy complexion. 

 When this Chiton opens its mouth and shows its teeth, 

 a double row of black glistening points, separated by a 

 central column, is suddenly unfolded, and as rapidly 

 withdrawn ; this operation is repeated several times in 

 the course of a minute. Is it caused by the blind 

 cravings of hunger, or is it a process like that of rumi- 

 nation, or merely for the purpose of keeping the teeth 

 clean ? Mr. Dennis says that all the specimens which 

 he dredged in 17 f., seven or eight miles off Blatching- 

 ton, on the Sussex coast, are small and light-coloured in 

 comparison with those procured by him at low water. 

 The largest specimen I have came from Oban, and 

 measures T 8 oths of an inch in length by \ an inch in 

 breadth ; the smallest is not much more than ^oth of an 

 inch long. The fry are broader than the adult, and their 

 granules are tubercular, few in number, and apparently 

 analogous to the external bulbs of the tubular perfora- 

 tions in shells of Brachiopoda. C. cinereus may be dis- 

 tinguished from C. cancellatus by its larger size, ex- 

 panded and compressed shape, finer sculpture, the lateral 

 compartments being inconspicuous, and by its central 



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