94 CONCHOLOGY. 



plates of this genus are never joined, the two may be easily 

 distinguished. 



Shell elongated, multivalve ; alternate pieces generally 

 longitudinal ; sides naked. 



Chitonellus striatus. Chitonellus larvaeformis. 



C. striatus. The striated Chitonellus. 

 Striae radiating from the apex of each valve ; margin ser- 

 rated ; base of the last valve obtuse. 



C. larvaeformis. The Caterpillar Chitonellus. 



More or less cylindrical, almost naked ; the valves of the 

 shell very small, and almost entirely concealed under the 

 skin ; tufts hairy or silky between the parts of the valves 

 near the margin. 



3. Chiton. Six species. 

 This genus was so called from the resemblance of its tes- 

 taceous covering to a coat of mail. The form of the Chiton 

 is very similar to a well-known insect called the woodlouse, 

 found in decayed timber ; it generally adheres to rocks, or 

 lies rolled up like a ball among seaweed and stones. In 

 length it seldom exceeds an inch, except in tropical climates, 

 where they are sometimes three or four inches long. In gen- 

 eral there are eight valves, the termination of which is sur- 

 rounded by a scaly or rough ligament, which enables the an- 

 imal to expand or contract its shell freely. It presents a 

 great variety of colour ; in general it is dark brown, overcast 

 with a shade of green, but some are beautifully variegated 

 with pink, yellow, blue, or red ; interior green or whitish. 



Shell more or less elongated, consisting of a longitudinal 

 series of eight very symmetrical calcareous pieces, more or 

 less curved, and round at both extremities ; summit more or 

 less marked, and when imbricated, always from front to rear. 



Chiton gigas. Chiton spinosus. 



C. squamosus. C. fascicularis. 



C. Peruvianus. C. marginatus. 



