72 M0UB1NJE. 



Genus FlLTJRUS, Dekay. 



Tentacles two ; mouth terminal, composed of a loose fes- 

 tooned membrane, with two small labial appendages. Gills 

 in two series along the back ; caudal appendage long and 

 filiform. Vent terminal. 



Ex. F. dubius, Dekay. 



The abdomen, observes Mr. Dekay, appears to be com- 

 posed of numerous rings, the body is cylindrical, and the 

 branchial processes are furnished at their tips with five or 

 six spiculse, which are only seen when the animal is in 

 motion. The loose festooned membrane of the mouth alter- 

 nately dilates and contracts when the animal is alive. The 

 animal was taken swimming in the sea with its body 

 reversed. 



Sub-fam. ^EOLIDINiE. 



Gills in rows on each side. Foot developed. 



This section comprises elegant and beautifully-tinted 

 Nudibranchs, which chiefly inhabit the littoral and lamina- 

 rian zones, in shallow water and between tide-marks; a few 

 have been dredged on corallines from deeper water. Accord- 

 ing to Messrs. Alder aud Hancock, Flabellina punctata 

 devours other Nudibranchs, and feeds on its own spawn '> 

 Flabellina coronata has similar propensities; they feed 

 generally, however, on Lucernaria>, and other Zoophytes. 



Genus .2EOLIS, Cuvier. 



Body broad. Tentacles four, smooth, elongate, subulate ; 

 labial feelers elougate. Gills papillose, arranged in longi- 

 tudinal rows, numerous, depressed, and imbricated, 



