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Family V. Limacinea. 



I would counsel thee, 

 If young in science, to note well the page 

 "Wliicli thus unfolds the structure of strange forms: 

 Despised it may be, yet most fitly made 

 For destined purpose. 



With the family Limacinea terminates the great series 

 of air-breathing mollusks^ of which the most part are found 

 buried in damp earthy where they subsist on small worms 

 and various vegetable matter. Their leading characteristics 

 are intermediate between those of the AjdysiiS and the He- 

 lices; resembling the former in the nature and purpose 

 of their shells — namely, that of affording protection to the 

 respiratory cavity, — and the latter as respects their general 

 habits and organization. The breathing apparatus varies 

 considerably in its position : — in some it is situated on the 

 anterior portion of the body, in others at the back, in 

 others, again, it occupies a middle place, whilst the shell, 

 being internal or external, is either simple or spiral. 



The Limacinea are divided into four genera — Parnia- 

 cella, LimaXf TestaceUus, Vitrina. 



The genus Parmacella was instituted by Cuvier, for the 



