SPECIFIC DESCRIPTION. 
PLATE I. 
Explanatory of the parts of Univalve Shells. 
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PLATE II. 
Explanatory of the parts of Bivalves and Multi- 
valves. 
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PLATE III. 
Fig. 1. Chiton squamosus. 
Shell 8-valved, semistriate ; marginal membrane 
scaly. 
Born, Mus, Cas. p. 5. Tab. 1. Fig. 1, 2. 
Specimen olive 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 
