13 



made by conchologists among the Lamellibranchiate Conchi/era. He 

 regards Anomia as being in some measure intermediate between this 

 order and the Brachiopoda ; and in illustration of this view describes 

 with some detail the structure of the auimal of that genus. 



Mr. Garner then adverts to the mode of growth of the shells and 

 to their structure, and considers them in the variations in form 

 which some of them undergo in their progress from the embryo to 

 the adult statė. He dwells also on the diversity of form assumed by 

 the Severai groups of Bivdlves, and shows in what manner these are 

 occasioned by the form of the animal that produces the shelly cover- 

 ings ; referring to the foot especiaUy as exercising in this respect a 

 very remarkable influence. 



The general review of the external form of the animal is succeeded 

 by an account of the several systems of which it is composed. These 

 are treated of in the follo\ving order : 1. Muscular system ; 2. Ner- 

 vous system; 3. Digestive system; 4. Circulating system; 5. Respi- 

 ratory system ; 6. Excretory system ; 7. Cilia (and into this part of 

 his subject the author enters with more than usual detail) ; and, 8. 

 Reproductive system. Under each of these heads a rapid review is 

 taken of the principai variations that occur in the order, and the 

 illustrative examples referred to are generally numerous. 



Finally, the author devotes a section of his paper to the diseases 

 and the parasites of the animals on ■vvhich he treats. 



In conclusion, Mr. Garner submits the subjoined tabular view 

 of an 



Anatomical Classification of the Lamellibranchiate Conchi- 

 FERous Animals. 



With but one adductor musele. Monomyaria, Lam. 



Tentacles very long, not distinct from the bran- 



chi(B ; an additional muscular system Anomia. 



Tentacles short, separate from the branchies. 



No foot Ostrea. 



A foot. 



Branchice disunited medianly. 



Foot long, cylindrical ; ocelli at the edge 



of the mantle Pecten. 



Foot short, thick, with a disk at the ex- 

 tremity, from the centre of vi^hich 

 depends a pedicellated oval body; 



ocelli Spondylus. 



Foot compressed ; no ocelli Lima. 



Branchie conjoined medianly Vulsella.* 



