PTEROPODA. 



213 



Family S. — LIMACINACFA. 



The body of these animals is spiral, contained in a 

 shell, and having two fins without lobes between them. 

 The shell is spirally whorled ; thin, transparent, and per- 

 fectly smooth ; the aperture on the columella side is drawn 

 forward into an angle. An operculum is present. 



Limacina. Cuvier. (Spiratella Blain. ; Heterofusus 

 Flem. ; Helicophora Gray ; Spinalis Eydoux and Sou- 

 leyet; Atlanta D'Orb., part. ; Peracle Forbes ; 

 Scaea Ph. ; Campylonaus Benson ; Helicon- 

 oides D'Orb.) — Shell thin, fragile, papyra- 

 ceous, spiral ; the whorls discoid or elevated, umbilicated 

 on each side, and carinated on the back ; aperture large 

 and entire, or angulated below. Animal, elongated, spiral ; 

 head not distinct ; two fin-like expansions united at their 

 base by an intermediate lobe*, bearing an operculum ; 

 branchia in a cavity formed by the mantle ; operculum 

 vitreous, very thin and transparent, of few whorls. f — 12 

 species. 



This curious little mollusc can retire completely into 

 its shell. It inhabits the Mediterranean, the Northern, 

 and Indian Seas, and is said to be devoured in vast 

 quantities by whales; according to Mr. Scoresby it is 

 found in great profusion near Spitzbergen. These little 

 glassy shells are, some of them, like a minute Aryonauta, 

 and others are sinistral and turret formed. L. (Spinalis) 

 Fleminyii is found on our north coasts, but it is not larger 

 than an ordinary pin's head. L. Macandrei and Jeffreysii, 

 are also very minute. 



* This Philippi calls a rudimentary foot, 

 t Forbes's British Moll. 



p 3 



