106 THE CHITONS. 



But the peculiar feature which distinguishes them 

 from the Limpets, is the fact that the shell of the 

 Chiton consists of eight parts, instead of a single 

 shield. These parts or valves run across the body 

 and overlap one another, like shingles on a roof. 

 They are highest in the center, and they end in a 

 leathern mantle which runs around the body, and 

 which is highly contractile. This being the case, the 

 Chiton shells can not be preserved with the same ease 

 as those of the Limpets, for the mantle must be dried 

 while the valves are in their natural position. 



Probably the best way to prepare fine specimens is 

 to bind the living animal, as it rests in a pan of sea- 

 water, upon a flat stone or a bit of shingle. It can 

 then be placed in warm fresh water, when, after the 

 lack of salt has destroyed life and the muscle has 

 lost its contractility, the animal may be unbound, 

 the viscera removed with a sharp knife, and the parts 

 to be preserved placed in a flat position to dry. 



We have a good many species of which the princi- 

 pal ones are the following. 



Tomcella lineata, Wood, Ton-i-sel'-la lin-e-a'-ta, 

 Fig. 92, Red-lined Chiton. 



This species is a beautiful represen- 

 tative of this singular group of mol- 

 lusks. The valves or parts of the shell 

 are smooth, moderately arched in the 

 center, and are of a yellowish brown 

 color. This back-ground of color is 

 crossed by wavy or zigzag lines of 

 orange, red or green, making the fresh 

 specimen an object of great beauty. 

 The mantle-border is smooth, thin, 

 delicate, and of a yellowish brown color. The com- 

 mon length of the animal is one inch. 



