CHITON. 227 



fleshcolour, more or less tinged with green, slightly shouldered: 

 notches deep, 16-20 on the head-plate, 15 on the tail-plate, 

 and 2 on each of the other plates, being altogether about 45. 

 L. 0-75. B. 0-4, 



Var. navicula. Smaller, narrower, and more arched. 



Habitat : On rocks, stones, and old shells, from Unst 

 to Sark, between low-water mark of spring tides and 

 70 f. j apparently not gregarious, nor so common as 

 some other species. The variety inhabits the west of 

 Scotland. C. Icevis has been noticed by foreign writers 

 as far north as Vadsoe, East Finmark, in 30-60 f. 

 (Danielssen), southward to the -^gean, in 31-80 f. 

 (Forbes), and Algeria (M^Andrew and Weinkauff), and 

 also in various intermediate places, at depths varying 

 from 8 to 50 f. 



According to Philippi, Sicilian specimens are much 

 smaller than the British. The largest in my collection 

 came from Oban, and are upwards of an inch and a 

 quarter long. The proportion of length to breadth is 

 variable. 



It is the C. corallinus of Risso, C. achatinus of Brown, 

 C. Cranchianus and Lepidopleurus punctulatus of Leach, 

 and C. Dorice of Capellini. Montagu described a seven- 

 plated specimen as C. septemvalvis, a name which Maton 

 and Rackett changed to C. discors. 



10. C. marmo'reus"^, Fabricius. 



C. marmoreus, Fabr. Faun. Groenl. p. 420 ; F. & H. ii. p. 414, pi. Iviii. 

 f. 2, and lix. f. 4. 



Body oval, inclining to oblong, yellowish or reddish-brown : 

 girdle rather broad, membranous and thin, apparently smooth, 

 but microscopically pustulated ; it is dusky-brown, sometimes 



* Marbled. 



