64 MELIBEINiE. 



Genus TETHYS, Linneeus. 



Head with a very large frontal veil, the circumference 

 fringed with cirrhi. Gills in tufts along the sides of the 

 back, alternately unequal. 



Syn. Fimbria, Bohadsch, not Mithlf. 



Ex. T. leporina, Cuvier, pi. 65, fig. 1. 



The very large, semicircular, frontal veil, ciliated at the 

 circumference, gives this genus a remarkable appearance ; 

 the tentacular sheaths are very wide ; in the fleshy gizzard 

 of a Tethys, which is both toothless and without a tongue, 

 Cuvier found fragments of shells, and the legs and other 

 fragments of little crabs. 



Sub-fam. MELIBEIN^. 



Stomach branched. 



In this division the stomach is curiously extended, and 

 sends ramifications into the branchial appendages of the 

 back, which arrangement led M. Quatrefages to found an 

 order termed by him Phlebenterica for this tribe of Nudi- 

 branchs. 



Genus MELIBE, Eang. 



Body elongated, ending in a slender tail. Head with a 

 large, membranous, funnel-shaped veil, with internal ra- 

 diating cirrhi ; tentacles linear, retractile within long trumpet- 

 like sheaths. 



Syn. Melibeea, Forbes. Melibcea, Herrmannsen. 



Ex. M. rosea, Rang, pi. 64, fig. 6. 



The sheaths of the tentacles in this genus are slender and 

 infundibuliform, but the principal feature is the large frontal 



