432 



ASCOGLOSSA NUDIBRANCHIATA 



Fig. 288. — Radiila of one of 

 Ascoglossa (Elysia viridis 

 Mont. X 40). 



Claclohepatic Nudibranchs, while the Pleurobranchidae form a 

 somewhat similar link between the Holohepatic Nudibranchs and 

 the other Tectibranchiata. 



Fam. 1. Oxynoeidae} ■ — - Animal long, tentacles auriform, 

 epipodia large, simple, or wing-like, a ctenidivim and branchial 



chamber on right side, shell small, thin, 

 slightly spiral, not covering much of 

 the body. Genera : Oxynoe ( = Lopliocer- 

 cus), Lohiger. 



Fam. 2. Hermaeidae. — Body de- 

 pressed, cerata in several rows, no 

 branchiae, no shell. Genera : Hermaea, 

 Phyllohranchiis, Stiliger, Alderia. 



Fam. 3. Elysiidae. — Body depressed, 



head rather elevated, tentacles amiform, 



sides of body dilated into two large 



wings, which enclose branches of the liver and sometimes fold 



over the dorsal surface, no branchiae, no shell. Genera : Elysia, 



Thridachia, Placolranclms. 



Fam. 4. Limapontiidae. — Body slug-like, liver scarcely rami- 

 fied, no branchiae, shell, or appendages. Genera : Lima'poiitia, 

 Actaeonia, Cenia. 



Sub-order III. Nudibranchiata. — Shell absent in the adult, 

 no ctenidium proper, or osphradimn, cerata dorsal or dorso-lateral, 

 nervous system concentrated, kidney not compact, ramified, penis 

 retractile, jaws and radula usually present. 



Section I. Cladohepatica. — Cerata usually latero- dorsal, 

 elongated, or arborescent, buccal mass strong, jaws present, liver 

 generally ramified, rami generally entering the cerata. 



Fam. 1. Aeolidiidae. — Body slug-like, head with tentacles and 

 rhinophores, dorsal area with rows of cerata, which usually con- 

 tain sting - cells, radula variable. Genera : Aeolis, Cratena, 

 Tergipcs, Corypliella, Favorinus, Facelina, Flabellina, Fiona, 

 Glaucus, Janus, Hero, with many sub-genera. 



Fam. 2. Tethymelihidae. — Body slug-like, large, cerata very 

 large, no sting-cells, head large, cowl-shaped, no tentacles, rhino- 

 phores much foliated, no radula. Genera : Tethys, Melihe. The 

 cerata of Tctliys, which are capable of independent movement 



^ This family has also been classified witli the BuUoidea and with the 

 Aplysioidea. 



