CLASSIFICATION, 
LINNAUS has made three principal or grand divisions 
of Testacea, viz. Multivalves, Bivalves, and Univalves; of 
which he has given the following generic description. 
I. MULTIVALVES. 
i. Curron: Valves placed in transverse plaits down the back. 
2. Lepas: Valves unequal; body sessile. 
3. Puoxas: Shell bivalve, with accessory valves at the hinge. 
Il. BIVALVES. 
4. Mya: Hinge with generally a broad thick tooth, not let 
into the opposite valve. 
5. Soren: Shell open at each end; hinge witha single or 
double subulate reflected tooth, not let into the opposite 
valve. 
6. Texitina: Hinge with the lateral teeth of one valve not 
let into the other. 
7. Carpium: Hinge with remote penetrating lateral teeth. 
8. Macrra: Hinge with a complicated triangular middle 
tooth, and an adjoining hollow. 
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