382 TRlTONIADiE. 



foot in length, and feeds on other mollusks and crustaceans. — 

 CuviER. 



Animal elliptical, depressed ; head covered by a broadly 

 expanded, fringed disk, with two conical tentacles, retractile into 

 foliaceous sheaths; gills slightly branched, a single row down 

 each side of the back ; reproductive orifices behind first gills, 

 vent on right side, behind second gill ; stomach simple. 



ScYLL^A, Linn. 



Etym. — Scyllsea, a sea-nymph. 



Distr. — 7 sp. Atlantic, South Britain, Mediterranean, Phil- 

 ippines, on floating sea-weed. S. pelagica (xc, 16). S. Grayi, 

 Ads. (xc, 17). 



Animal elongated, compressed ; foot long, narrow, and chan- 

 neled, adapted for clasping sea-weed ; back with two pairs of 

 wing-like lateral lobes, bearing small tufted branchiae on their 

 inner surfaces; tentacles dorsal, slender, with lamellated tips, 

 retractile into long sheaths ; lingual teeth 24-1-24, denticulated ; 

 gizzard armed with horny knife-plates ; orifices on the right side, 



NEREA, Lesson. 10 lines long, with ear-shaped tentacles, and 

 3 pairs of dorsal lobes. N. punctata, Lesson. 



Melibe, Rang. 



Syn. — Chiorhsea, Grould. 



Distr. — M. rosea.. Rang (xc, 18). M. (Chiorhsea) leonina, Gld. 

 (xci, 19). 



Head unusuall}^ large, upper tentacula or rhinophoria retrac- 

 tile, perfoliate ; pharynx with a strongly toothed jaw, but without 

 radula ; back with unequal leaf-, tree- and club-shaped papillaa ; 

 no distinct gills. 



Dendronotus, Alder and Hancock. 

 Etym. — Dendron, a tree, notos, the back. 



Distr. — Northern ; on sea-weed and corallines ; low-water to 

 corralline zone. D. arhorescens (xci, 20 ^ 



Animal elongated ; tentacles laminated ; front of the head with 

 branched appendages ; gills arborescent, in single series down 

 each side of the back ; foot narrow ; lingual teeth 10-M ; stomach 

 and liver ramified. 



LoMANOTUS, Verany. 



Syn. — Eumenis, A. and H. 



Distr 3 sp. Britain and Mediterranean, on corallines. L. 



Gened, Verany (xci, 21). 



Animal elongated, smooth; head covered with a veil; tentacles 

 elavate, laminated, retractile into sheaths ; gills filamentose, 

 arranged along the sides of the back, on the wavy margins of 

 the mantle ; foot narrow, with tentacular processes in front ; 

 stomach ramified. 



