18 



CHITON. LEPAS. 



" Multivalves may be divided into two kinds, 

 the pedu7iculated, or those fixed to other bodies, 

 as rocks, stones, planks, &c. ; or free, as the 

 Chiton and Pholas. 



" Our first genus is Chiton. The shell is easily 

 known. The fixed character is, many valves 

 placed over each other along the back. I have 

 already noticed the membrane which connects 

 the valves, which is also a permanent character. 

 It is elastic : the sides are either scaly, as in C. 

 squamosus, (Plate 1,) and hairy, or spinous. 

 The species are determined by the margins. 

 Some of the Chiton genus are common upon our 

 own coasts ; they are frequently found among sea- 

 weed and stones, rolled up like a ball. C. fasci- 

 cularis and C. IcBvis are British ; there are some 

 other British species. The animal adheres to 

 rocks, like the Patelta, or limpet. The number 

 of species forty. 



•"' Second genus, Lepas. Shell multivalve, 

 fixed at the base ; valves erect, or upright. 



" Observe how much the situation of the valves 

 differs in Chiton and Lepas, It is scarcely pos- 

 sible to mistake the one for the other. The 

 feathery tentacula, or feelers, of Lepas anatifera 

 are worthy notice, and in a state of motion must 

 be yet more beautiful. (Plate 2.) The com- 

 mon acorn-shell, L. baldniis, is to be seen very 

 frequently upon the shells of muscles, oysters, 



