SPECIFIC DESCRIPTION. 



PLATE I. 



Explanatory of the parts of Univalve Shells. 



PLATE IL 



Explanatory of the parts of Bivalves and Mul- 

 tivalves. 



PLATE IIL 



Fig. L Chiton squamosus. 



Shell 8-valved, semistriate ; marginal membrane 

 scaly. 



B(jrn, Mus, Cess. p. 5. t. L fig. 1,2. 



Specimen olive without, blue green within. 

 Middle valves divided on each side of the centra] 

 ridge into two parts, consisting of a triangular 

 compartment striated from the apex to the base, 

 and another very finely marked in the longitudinal 

 direction of the shell ; terminal valves lunulate and 

 striate ; the scales on the marginal skin in alter- 

 nate black and white divisions. 

 k2 



