GLAUCUS. 111 
into tentacular processes, at others margined with a 
fringe. Tethys, another beautiful genus inhabiting 
the Mediterranean, has this veil enormously de- 
veloped, and profusely fringed. The animal is 
said to use this organ to aid it in swimming, but 
this is hardly probable. 
So little has been recorded concerning the 
habits and economy of the marine, and especially 
the oceanic Mollusca, that I with pleasure quote the 
observations of Mr. George Bennett, on a species of 
Glaucus taken in the tropical part of the Atlantic 
ocean. The accompanying figure will convey an 
GLAUCUS. 
idea of the form of the animal, the colour of which 
is a vivid blue or purple on the upper surface, and 
silvery white beneath :— 
“These little animals were very delicate and 
