OF MOLLUSCA. 227 



Mantle indistinct. Tentacles two, sublateral, linear ; oral pair flat- 

 tened into two lateral lobes. Gills subcylindrical, simple, in a single 

 or double, in part alternating series down each side of the back. Lin- 

 gual membrane with a single series of plates bearing a central spine 

 and lateral denticles. Orifices on the right side. 



1. E. pulchra, Alder fy Hane. Monog. t. 38. Pterochilus pulcher, 



Ann. fy Mag. Nat. Hist. xiv. 329. 



2. E. minuta, Forbes $■ Hanley, B.M. t. B.B.B. f. 5. 



13. Calliop^ea. 



Gills in lateral series. Tentacles none. Labial feelers elongate, 

 subulate. Front of foot angular. 



1. C. bellula, t. 194. f. 5. 



b. Reproductive organs with two external orifices. Body with two 

 posterior latero-gastro-hepatic vessels (p. 221). 



Fam. XVIII. FIONIDiE. 



Tentacles four, simple. Branchiae papillose, numerous. Vent 

 latero-dorsal. Mouth with jaws. Lingual membrane with a single 

 series of plates. 



1. Fiona. 



Body elongate. Tentacles four, linear ; sheaths none, subdorsal ; 

 anterior pair similar to oral tentacles of Eolis, but behind the lips. 

 Lingual membrane with a single series of plates, with a short central 



spine and marginal denticles. Jaws horny. Stomach ? Gills: 



papillae irregularly scattered on a subpallial expansion on the sides of 

 the back and meeting behind ; a produced membranous margin or 

 fringe on the inner side of each papilla. Vent on right side of the 

 back ; orifice of reproduction separate, below the right tentacles. 



1. F. nobilis, Alder $■ Banc, in Brit. Moll. 589. 



Fam. XIX. HERMiEID.E. 



Tentacles two, dorsal. Branchiae papillose. Vent dorsal. Jaws 

 none. Lingual membrane with a single longitudinal series of teeth 

 or plates. 



1. Heumjja. 

 Body elongated, lanceolate. Mantle indistinct. Tentacles two, 

 dorsal, ear-like, involute, grooved externally. Gills fusiform or linear 

 elongate, papillose, on each side of the back. Vent in middle of the 



Q2 



