229 IANTHINIDA. 
CONSTANTIA, A. Ad. Acuminately oval, spire elate, whorls 
rounded, the last ventricose, decussated by thin longitudinal 
plications and revolving elevated lire; aperture oval. its con- 
tinuous margin free, acute. 8S. elegans, A. Ad. (Ixvi, 41). Korea. 
SCALIOLA, A. Ad. Animal with proboscidiform head ; rostrum 
elongated, cylindrical, annulated ; 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. bella, A. Ad. (Ixvi, 44). Japan. 
Famity IANTHINIDA. 
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). 
JANTHINA, Lam. 
Htym.—TIanthina, violet-colored. 
Distr.—l0 sp. Atlantic and Pacific Oceans. J. communis, 
Lam. (xvii, 49; xvii, 99 . 
Shell thin, translucent, trochiform ; nucleus minute, styliform ; 
sinistral; whorls few, rather ventricose; 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 Ianthinee, or oceanic-snails, are gregarious in the open sea, 
where they are found in myriads, and are said to feed on the 
small blue acalephee ‘ Velella). 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. They have no power of sinking and rising in the water. 
The raft, which is much too large to be withdrawn into the shell, 
is generally thought to be an extreme modification of the oper- 
eculum; but M. Lucaze-Duthiers, who has seen the raft formed, 
denies this. It is built up from glutinous matter secreted by 
the foot. 
Reciuzia, Petit. 
Etym.—Named in honor of Recluz, a French naturalist. 
