162 MOLLUSC A. 



Glaus divides this order into two sections Dermatobranchia 

 [or Gyrnnobranchia] and Pleurobranchia. The last contains tha 

 Tectibranchiata and Inferobranchiata ; the first the remainder of 

 the following suborders: 



No shell in the adult. 

 Without branchiae ........................... ABRANCIIIATA. 



With branchia3. 



Branchiae on the back ..................... NCDIBRANCIIIATA. 



Branchiae on both sides ........ ......... INFEROBRANCHIATA. 



A shell in most ; branchiae on one side ...... TECTIBRANCHIATA. 



ABRANCHIATE (=Apneusta=Dermatopnoa). No branching ; 

 upper surface of the body ciliated. A shell only in the larval 

 state. 



A subclass for Schmarda ; but not differentiated from the Nu- 

 dibranchiata by Glaus. 



Limapontiidce. PhyllirJioida. 



Limapontia = Pontolimax. Phyllirhoe. 



Cenia. Acura. 



. 

 Ehodope. .* 



Elysia^Actseon. 



.NUDIBRANCHIATA ( = NotobranchiaV Branchiae placed on the 

 back, often retractile. Shell only in the larval state. 



Branchiae either cylindrical, fusiform, or club-shaped (Cera- 

 tobranchia) ; leaf -shaped, feathered, or branched (Cladobranchia) ; 

 or placed behind and arborescent (Pygobranchia). 



Pavorinus. TetTiyididcB. 



Proctonotus. Embletonia. Scyllsea. 



Antiopa. -5Colis. Tritonia. 



Fiona. Tergipes. Tethys. 



lderia - Dendronotida. Voridida. 



Hermaea. ^ T 



JEolididcB. Melibo 2 a. Onchidoris. 



Glaucus. Hero. Polycera. 



Cratena. Dendronotus. Doris (Sea-lemon). 



INFEROBRANCHIATA (=Hypobranchia; Dipleurobranchia). 

 Branchiae leaf-shaped, situated in a fold on each side. No shell. 

 A family of Pleurobranchia for Schmarda, the true Pleuro- 



