64 SKENEID.E. 



Family XI. SKENE'ID^, (Skeneadce) Clark. 



Body coiled in a circle : head large and snout-shaped : ten- 

 tacles cylindrical in one genus, and wanting in another : eyes 

 proportionally large, either almost sessile and placed at the 

 outer bases of the tentacles, or quite sessile and placed behind 

 the head : foot short : opercular lobe not furnished with any 

 process or filament. 



Shell minute, circular, with a wide umbilicus : spire much 

 depressed, or even involute : mouth round, having united edges 

 that form a complete peristome : operculum horny, circular, 

 and spiral. 



There is a seeming incongruity in the above descrip- 

 tion, with regard to the characters founded on the soft 

 parts ; but certain genera of Bullidce are provided with 

 tentacles, while others have none. The form of the 

 shell in the present family exhibits a greater concord- 

 ance than that of the animal. At all events some kind 

 of classification is indispensable : as with heraldry, so 

 with our science, 



" Order is Nature's beauty, and the way 

 To order is by rules that Art hath framed." 



The Skeneidae are at present not much known, owing 

 to their minute size. All the species hitherto described 

 (three in number) inhabit the North Atlantic and Me- 

 diterranean ; two are post-tertiary. In a recent or living 

 state they are gregarious, and are sublittoral or fre- 

 quent the higher part of the laminarian zone. 



Genus I. SKE'NEA* Fleming. PL I. f. 4. 



Body depressed : tentacles cylindrical : eyes almost sessile, 

 and placed at the outer bases of the tentacles. 



Shell having the spire very little raised : whorls cylindrical : 

 * Named after Dr. David Skene, a friend and correspondent of Solander. 



