SPECIFIC DESCRIPTION. 



PLATE I. 



Explanatory of the parts of Univalve Shells. 



PLATE IL 

 Explanatory of the parts of Bivalves and Multi- 

 valves. 



PLATE IIL 



Fig. 1. Chiton squamosus. 



Shell 8-valved, semistriate ; marginal membrane 

 scaly. 



Born. Mus. Cas. p. 5. Tab. 1. Fig. 1, 2. 



Specimen ohve without, blue green within. 

 Middle valves divided on each side of the central 

 ridge into two parts, consisting of a triangular 

 compartment striated from the apex to the base, 

 and another very finely marked in the longitudinal 



