222 ianthinidjE. 



CONSTANTIA, A. Ad. Acuminately oval, spire elate, whorls 

 rounded, the last ventrieose, decussated by thin longitudinal 

 plications and revolving elevated lirjB ; aperture oval, its con- 

 tinuous margin free, acute. S. elegans^ A. Ad. (Ixvi, 41). Korea. 



SCALIOLA, A. Ad. Animal with proboscidiform head ; rostrum 

 elongated, cjdindrical, anniilated ; tentacles filiform; eyes prom- 

 inent, black, at the external base of the tentacles; foot short, 

 oval, acuminated behind. Operculum corneous, oval, subspiral, 

 with subterminal nucleus. The shell agglutinates to its spire 

 particles of sand, etc. S. hella^ A. Ad. (Ixvi, 44). Japan. 



Family IANTHINIDJE. 



Shell globular-turbinate, thin . No operculum. Animal pelagic, 

 sustained by a vesicular natatory apparatus, called the float, 

 and to which the eggs are attached (xvii, 99). Dentition (xi, 35). 



Ianthina, Lam. 



Etym. — Ianthina^ violet-colored. 



Distr. — 10 sp. Atlantic and Pacific Oceans. /. communis, 

 Lam. (Ixvii, 49 ; xvii, 99 . 



Shell thin, translucent, trochiform ; nucleus minute, styliform ; 

 sinistral ; whorls few, rather ventrieose ; aperture four-sided ; 

 columella tortuous; lip thin, notched at the outer angle. Base 

 of the shell deep violet, spire nearly white. 



Animal. Head large, muzzle-shaped, with a tentacle and eye- 

 pedicel on each side, but no eyes ; foot small, secreting a float 

 composed of numerous cartilaginous air-vesicles, to the under 

 surface of which the ovarian capsules are attached. Lingual 

 ribbon, rachis unarmed- uncini numerous, simple (like Scalaria . 

 Branchial plumes two. Sexes separate. 



The lanthinse, or oceanic-snails, are gregarious in the open sea, 

 where they are found in myriads, and are said to feed on the 

 small blue acalephse i Yelella). When handled they exude a 

 violet fluid from beneath the margin of the mantle. In rough 

 weather they are driven about and their floats broken, or 

 detached, in which state they are often met with. The capsules 

 beneath the farther end of the raft have been observed to be 

 empty, at a time when those in the middle contained young with 

 fully formed shells, and those near the animal were filled with 

 eggs. The}^ have no power of sinking and rising in the water. 

 The raft, which is much too large to be withdrawn into the shell, 

 is generall^^ thought to be an extreme modification of the oper- 

 culum ; but M. Lucaze-Duthiers, who has seen the raft formed, 

 denies this. It is built up from glutinous matter secreted by 

 the foot. 



Recluzia, Petit. 



Etym. — Named in honor of Recluz, a French naturalist. 



