INDK. 107 



en vi-iT.i: in. c****d. 



ProoeM of evolutions singular, . . r*uB M 



Natural prej of the teeth tribe, ... ib. 



Plate XI. described, .... il.. 



II M'TKK III. BIVALVE SHELLS, ..... 57 



Fonn mod habit* of the bivalve not to eauily ascertained, . ib. 



The Sytttma Natura imperfect, . . . . M 



SbelU an ingredient of traffic, .... ib. 



Organic distinctions probable among the bivalve*, . . ib. 



Genera of both univalve* and bivalve* numerous, . . ' 



Many of the univalve* terrestrial, . . . . ib. 



Some at the bivalve tribe the largest of the Testacea, . ib. 



Their progression slow and laboured, . . . ib. 



Faculty of forming threads by which to anchor, . . 6<> 



Glutinous matter lubricates the body, . . . . ib. 



Substance of the bytnu various, .... ib. 

 All the animal secretions extraordinary, . . .61 



Calcareous secretion originates with the embryonic stale, . ib. 



Some of the shells very fragile, ..... ib. 



Structure of shells illustrated by Or Carpenter, . . 6'.' 



Shell undergoes progresiire modification, . . . ib. 



The sue and quality of shell fish dependent on the site, ib. 



Instincts of the bivalves imperfectly displayed, . ib. 

 Enjoy fresh supplies of water, and exhibit a sense of security in the 



... ... 63 



I. MTTILUS The Muuft, ... ib. 



The mussel perhaps the most valuable of the bivalve*, . ib. 



MYTILUI EDOUS, ..... 64 



Used as food, . . . ib. 



Some of them deleterious, .... ib. 



Test of boiling them with a silver coin, . ib. 

 Edible raiusel very profusely dispersed, 



Mussel beds sometimes remote from each other, . 65 



Seed pearl* food in the mussel, ib. 



MTTILCS PCLLCCIUCI, ... ib. 



Shell described, .... ib. 

 Considered a yorager stage of t** MgiAu e***, . ib. 



It U comparatively rare, ..... ib. 



