108 



GASTROPODA. 



Runcma (Forbes). Minute, slug-like; mantle 

 distinct ; eyes sessile ; no tentacles ; gills three 

 plumes beneath the mantle, on the right side of its 

 hinder edge ; shell wanting. 



R. Hancocki. Fig. 151 



• 3 

 ' 1* 



DiphyJUdia (Cuv.). Oblong, fleshy; mantle 

 ample ; gills placed beneath the hind edge of the 

 mantle, on both sides ; head mth a veil, and 

 minute tentacles ; shell wanting. 



D. lineata. Fig, 152 ; 'k n.s. 



152 



153 



PleiiToh^anchus (Cuv.). Oval or roundish, fleshy ; 

 mantle covering the back and sides, and over- 

 lapping the foot ; gill a single plume, beneath its 

 right edge ; tentacles two, grooved ; a broad lobed 

 veil ; shell flexible, convex. 



P. plumiila. Fig. 153 ; n.s. 

 membranaceus. 



