106 GASTROPODA. 



within prominent \6hed sheaths ; gills branched, 

 tree-like. 



M. punctilucens. Fig. 146 j k. s. 



Thecacera (Fleming). Oblong, smooth ; ten- 

 tacles club-shaped ; retractile within sheaths ; head 

 with a simple veil ; gills feather-shaped, surrounded 

 by a ring of warts. 



T. pennigerum. Fig. 147 ; f. 

 virescens. 

 capitatum. 



Polycera (Cuv.) . Lengthened, smooth or warted ; 

 tentacles club-shaped, laminated, not retractile, not 

 sheathed ; veil edged with processes ; gills feather- 

 shaped, accompanied by club-shaped appendages. 



P. quadrilineata. 

 Lessonii. 

 ocellata. Fig. 148 ; n. s. 





St^^^^--~ 



147 HS 



Idalla (Leuckart). Oblong, broad, nearly smooth; 

 mantle small, margined with filaments ; tentacles 

 with filaments at their bases ; head slightly lobed. 



I. aspersa. Fig. 149 ; f . I. quadricomis. 



insequalis, elegans. 



Leachii. pulchella. 



