janthina. 277 



Family JANTHINID^E. 



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

 istral nucleus. 



Ocnus JA]\TIIIIVA, Lam. LSOL 



Shell sub-globose, thin, fragile, spire short ; a])crture 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, vcutricose, violaceous beneath, whiter on the spire. 



Helix janthina, Lin.; Gmelin, 83-51. 364.5, No. 103. — Listeu, Conch, t. 572, fip-. 24. — 

 RuMPHius, Mus. t. 20, fig. 2. — Gu.\lt. Te.st. t. 64, fig. O. — Sloaxe, Jamaica, 

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

 CuEMN. Conch. V. t. 166, figs. 1577, 1578. — Wood, Index^ pi. 34, t. 116. 



Janthina fra<i'dis, Desh Encyc. Mc'th. iii. 324, ])l. 456, fig. 1 ; Ann. dii Mus. xi. 123 (an- 

 im;i]). — Blainv. Malacol. pi. 37 bis. rig. la. — Sowerdy, 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 cd. vi. 206 ; 2d ed. ix. 4. 

 Listeu, 572, fig. 23. 



Shell globose-conic, thin, brittle, 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 

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

 darker at the suture ; surface shining, wrinkled hj the lines of 

 growth, and with short, oblique wrinkles above the angle of tlie 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 ; lireadth, 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 l)y storms. After a severe gale, in the autumn of 

 1839, great num1)ers of them were collected on the shores of Nan- 

 tucket, some specimens of which were furnished me by T. A. Greene, 

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



