MOLLUSCA PROPEE. 



207 



are probably carnivorous, feeding upon small Crustaceans and other 

 diminutive creatures. Though all the living forms are small, Geo- 



Fig. 147. — Pteropoda. A, Spirialis rontralis. B, Pneumodermon violaceum. C, Hetero- 

 fusus iulirainoides. All enlarged, e Epipodia or fins ; t Tentacles. D, Larva of 

 Cleodora lanceolata, greatly enlarged (after Fol) : y Ciliated lobes ; o Mouth ; 

 ce Gullet ; g Stomach ; i Intestine ; s Shell ; u Yolk-.sac. 



logy leads us to believe that formerly there existed comparatively 

 gigantic forms, which appear to be truly referable to this class. 



