434 



NUDIBRANCHIATA 



CHAP. 



Hexahranclius, 



Fig. 289. —Z)om {Archidoris) 

 tuherculata L., Britain: a, 

 anus ; 6;% branchiae sur 



Archidoris (Fig. 289), Discodoris^ Diaulula, 

 Cadlina^ Centrodoris^ Platydoris^ Chro- 

 modoris^ Miamira^ with many sub- 

 genera. 



Fam. 2. Doriopsidae. — Branchia and 

 rhinophores as in Dorididae, oral aper- 

 ture pore-shaped, suctorial, no radula. 

 Single genus, Doriopsis. 



Fam. 3. Phyllidiidae. — Body oval, 

 depressed, leathery, a ring of branchial 

 lamellae, only interrupted by the head 

 and genital papilla, under the pallial 

 edge, oral aperture pore-shaped, suc- 

 torial, no radula. Genera : Phyllidia^ 

 Fryeria. Bergh unites this and the 

 rounding the anus ; ?n,maie preceding family in the group Porosto- 



organ;rA,rA, rhinophores. ,^^^^^^ ^^^^-^j^^ ^.^|^ ^^^ ^^ f^^.^^ ^^^^ 



group Dorididae eryptohranchiatae. 



Fam. 4. Polyceridae. — Body slug-like, branchiae not retrac- 

 tile, usually surrounding the anus, rhinophores foliate, tentacles 

 simple, radula variable, central tooth generally wanting. Genera : 

 Notodoris^ Triopella^ Aegires^ Triopa^Issa^ Triopha^ Qrimora^ Theca- 

 cera, Polycerella, PaUo, Polycera^ Ohola^ Trevelyana^ Nemhrotha^ 

 Euplocamus^ Plocamoplieriis., Kalinga. 



Fam. 5. G-oniodoridae. — Body oval, depressed, branchia mul- 

 tifoliate, usually disposed in shape of a horse-shoe, rhinophores 

 foliate, retractile or not, mouth with a large suctorial proboscis, 

 radula variable. Genera : Akiodoris^ Doridunculus., Acanthodoris, 

 Adalaria, Lamellidoris, Calycidoris^ Goniodoris^ Idalia^ Ancula^ 

 Drepania. ^ 



Fam. 6. Corambidae. — Body otherwise D<97'zs-like, but with 

 two posterior branchiae under the mantle edge, jaws present, no 

 central tooth, about five laterals. Single genus, Coramhe ( = 

 Hypohranchiaeci). Bergh unites this and the two preceding 

 families in the group Dorididae phanerohranchiatae. 



Sub-order IV. Pteropoda. — The Pteropoda are pelagic 

 animals in which the lateral portions of the foot are modified 

 into fins, which are innervated by the pedal ganglia. Their 

 systematic position has undergone recent revision. It has been 

 the custom to regard them as an Order of equivalent value to the 



