44 Mr. A. Adams on Cavolina, Diacria, and Pleuropus. 



VI. — On the Synonyms and Habitats of Cavolina, Diacria, and 

 Pleuropus. By Arthur Adams, F.L.S., Surgeon of H.M.S. 

 Actseon. 



To the Editors of the Annals of Natural History. 



Gentlemen, 



Having captured in the towing-net almost all the known 

 species of the genera Cavolina, Diacria, and Pleuropus, while 

 traversing the Atlantic and Indian Oceans and the China Sea, 

 the results of my experience with regard to the species of these 

 Pteropods may prove acceptable to your readers. 



Gen. Cavolina, Gioeni. 



1. C. Telemus, Linn. 



Monoculus Telemus, Linn. 

 Anemia tridentata, Forsk. 

 Cavolina natans, Abildg. 

 Hyalaea cornea. Lam. 



papilionacea, Bory. 



teniobranchia, Per. ^ Les. 



Chemnitziana, Lesueur. 



■ Forskalii, Blainv. 



Peronii, Blainv. 



affinis, B'Orb. 



Caulina natans, Poli. 



Hah. Atlantic and Indian Oceans. Common. Varies from 

 amber- and pale-yellow to transparent ; varies also in size. 



2. C. gibbosa, Rang. 

 Hyalsea flava, D'Orh. 



Hah. Atlantic and Indian Oceans. Common. Varies in 

 colour like the last. 



3. C. uncinata, Rang. 

 Hyalsea Rangii, Desh. 



Hah. Atlantic and Indian Oceans. Rather scarce. 



4. C. globulosa, Rang. 

 Hah. China Sea. Rare; one specimen. 



5. C. quadridentata, Lesueur. 

 Hyalsea quadrispinosa, D'Orb. 

 Hah, Atlantic and Indian Oceans. Common. 



