116 POPULAR BRITISH CONCHOLOGY. 



On releasing the Chiton from its hold, and looking at the 

 under side, we find the greater part of the oval occupied by 

 the foot ; at one end the head is represented by a kind of 

 proboscis, with a dentated mouth, covered by a sort of hood ; 

 at the other end we see, between the border and the foot, on 

 each side, a pair of leaflets, which constitute the breathing 

 apparatus of the animal. 



Among the foreign species of this genus there are some 

 very large, very beautifully and variously sculptured ; some 

 which have the border armed with strong spines ; some 

 which have the valves beautifully beaded, or elegantly 

 marbled; some which have the shells nearly, and others 

 entirely, covered by the membrane; and others (called 

 Chitonellus) which resemble a long banded slug, with small 

 shelly pieces along the back. The British species are — 

 C. fascicularis : with bunches of bristles on the border, and 



coarse granules on the valves; dark- coloured. 

 C. discrepans or cnnitus : the same as G. fascicularis^ but 



with the valves more angular, and the granules finer 



and more numerous ; mottled. 

 C. Ranleyi : with spines on the border ; middle of the valves 



beaded, side areas of the valves with few granules ; 



brownish. 



