377 



PTEROPODA. 



In warmer seas than those which encircle our islands, 

 the surface of the water, when the weather is calm and the 

 sun is shining, glistens with glassy needles or shelly bub- 

 bles. These, upon closer examination, prove to belong to 

 curious mollusks, which, instead of creeping over submarine 

 rocks and weeds, or burying in the soft mud and sand of 

 the sea-bed, aspire to a gayer and more sportive life, and 

 play the part of Neptune's bees and butterflies. From our 

 less congenial waves they are almost altogether absent ; 

 only a few stragglers, and those, with one exception, of 

 microscopic dimensions, have met even the scrutinizing eyes 

 of practised naturalists. 



These animals are mollusks of the group to which 

 Cuvier gave the name of Pteropoda, so styling them on 

 account of the wing-like lobes which form their organs of 

 motion, and which appear really to be expansions of the 

 organs regarded as a foot among the true sea-snails. Their 

 organization is, however, so peculiar that zoologists have 

 differed materially respecting their true position in the 

 animal series, some, as Cuvier and Eang, placing them 

 high up among the mollusca, intermediate between the 

 sea-snails and the cuttle-fishes ; others, as Lamarck, con- 

 sidering them as intermediate between the sea-snails and 

 bivalves, and others placing them even below the acephala. 

 A few high-standing names have maintained that they 



VOL. II. 3 C 



