ANATOMY OF THE CLAM. 



247 



gills, where the embryos in some species partially develop. 



Impregnation probably takes place within the branchial 



chamber, the spermatozoa being 

 swept in with the respiratory 

 current, and coming in contact 

 Avith the eggs as they are dis- 

 charged. 



An excellent general view of 

 the relation of parts to the 

 body -walls and shell may be 

 seen by hardening a clam, or 

 better a fresh -water mussel, 

 Unio (see Fig. 161, D) in alco- 

 hoi, and then making trans- 



vprsp q po fions A Sfotiori ran 

 veibC ^OUOIlb. A. bLCUOj 



be floated off in water and ex- 



amined with a lens - The P 61 " 



the pedal muscles. Drawn by w, K. feet bilateral symmetry of parts 



Brooks. J J 



will thus be seen. 

 The above description will answer for the majority of la- 



Fi 



and ot-> 



cysts (cars) of the clam, magnified 10 

 diameters d pedal ganglia- e, pedal 



1; 



Pig. 167. Lima Mans, flying through the water, its long numerous filaments ex- 

 tended. From Brehm's " Thierleben." 



mellibranchiate mollusks ; in the oyster (Ostrcea) or in A no- 



