JANTIIINA. 277 



Family JANTHINIDJ3. 



Shell thin, translucent, spiral, more or less turbinate, with a sin- 

 istral nucleus. 



Genus JANTHIXA, Lam. 180L 



Shell suh-globosc, thin, fragile, spire short ; aperture angular at 

 the anterior junction of the inner and outer lips ; pillar twisted ; lip 

 thin, with a sinus at the middle. 



Janthina fragilis. 



Shell thin, brittle, conical, ventricose, violaceous beneath, whiter on the spire. 



Helix janthina, Lin.; G.melin, Syst. 3645, No. 103. — Lister, Conch, t. 572, fig. 24.— 

 IvUMiMiius, ISLis. t. 20, fig. 2. — Gu.vLT. Test. t. 64, fig. O. — Sloaxk, Jamaica, 

 t. 1, fig. 4. — Brown, Jamaica, t. 39, fig. 2. — D'Argenv. Conch, ph 6, fig. .5. — 

 Chemx. Conch, v. t 166, figs. 1577, 1578. — Wood, Lidex, pi. 34, t. 116. 



Janthina fnujiUs, Desii Encvc. Mcth. iii. 324, pi. 456, fig. 1 ; Ann. du Mus. xi. 123 (an- 

 nual). — Blainv. Malacol. pi. 37 his. fig. la. — Soweuby, Conch. Man. fig. 333. — 

 De Kay, N. Y. Moll. 125, pi. 36, fig. 360. — Stimpson, Check Lists, 4. 



Janthina communis, Lam. An. sans Vert. 1st ed. vi. 206 ; 2d cd. ix. 4. 

 Lister, 572, fig. 23. 



Shell globose-conic, thin, l)rittle, transparent ; whorls three or 

 four, forming a short spire, the last one very large and angular at 

 the middle ; beneath the angle the color is deep violet, lighter about 

 the axis, and above it the color is merely tinted with violet, a little 

 darker at the suture ; surface shining, Avrinkled by the lines of 

 growth, and with short, oblique wrinkles above the angle of the last 

 whorl, and marked with revolving lines beneath that angle ; aper- 

 ture large, semi-oval, outer lip very thin, retiring as it passes the 

 angle of the whorl, so as to produce a shallow recess ; inner lip 

 cylindrical, straight, corresponding with the axis of the shell. 

 Length, eight tenths of an inch ; breadth, one inch. 



The Janthina floats, by means of a mass of vesicles, at the sur- 

 face, throughout the wide ocean, and is not unfrequently driven upon 

 the ocean shores Ity storms. After a severe gale, in the autumn of 

 1839, great numbers of them were collected on the shores of Nan- 

 tucket, some s|)ecimens of which were furnislied me by T. A. Greene, 

 Esq., of New Bedford. Sable Island, fragment {Willis^. 



