xn 



PHYLUM MOLLUSCA 



721 



Fra. 638. Shell-bearing Pteropoda. /. /. flns ; 1. liver ; o. ovary ; sh. shell. (From Cooke, 



after_Souleyet.) 



FIQ. 639. Atlanta peronii. a, cerebral ganglia; b, pedal ganglia; e. eye ; g, ctenidia; 

 h. heart ; Jc, kidney i. " liver " ; m. mouth ; o. ovary p. operculum ; t. testis. 



ctcn 



Fia. 640. Pterotrachea scutata. ali. alimentary canal; cten. gills; eye, eye ; fl. float"; 

 wo. mouth ; prob. proboscis ; repr. gonad ; sh. shield covering a portion of the dorsal 

 surface ; su. sucker. 



