Family IANTHINIDJE. 



Shell thin, fragile, tuvbinatod ; whitish or purplish; aperture 

 oval or subtetragonal, the columella a little twisted, lip simple, 

 curved. No operculum. 



Animal pelagic, sustained by a vesicular body called the float, 

 and to which the eggs are attached. The float is composed of 

 a mass of vesicles filled with air, the walls resisting, sul)cartila- 

 ginous, supported by a narrow peduncle, formed by and adhering 

 to the foot. Sexes separate, no copulatory organ. Rostrum 

 proboscidiform ; no jaws ; radula com[)osed of a gfeat number 

 of elongated teeth, no central tooth. Carnivorous. Secretes a 

 purple fluid, which is ejected from the branchial cavity, when 

 irritated. 



Genus lANTHINA, Lam., 1799. 



Head large, muzzle-shaped, e3-es not visible or sessile, tentacles 

 forked so that each appears like a pair, foot rather short, the 

 epipodial lobe somewhat elongated and ciliated, branchial 

 plumes two, unequal. 



The float is found in both sexes, and whilst in the female the 

 eggs are usuall}' attached to the lower surface thereof, the 

 animal in some species is viviparous ; embryos taken from 

 the uterus are operculated, the head has a ciliated velum, the 

 eyes are large and well pigmented. 



Siiell imperforate, without epidermis, fragile, trochiform or 

 turbiniform, nucleus small, styliform, oblique, spire light pur- 

 plish white, base deeper purple ; whorls few, convex, with striae 

 of growth, angular or gathered at the peripliery ; outer lip with 

 a sinus in the middle, columella thin, twisted. 



About 30 nominal species have been described, from the 

 Atlantic and Pacific Oceans ; I reduce them to three species, 

 with a few varieties. 



A species is found in the Pliocene of Italy. 



Reeve monographed lanthina in 1858, including 25 species, a 

 portion of which he first described, and Miirch, in the Journal 

 3 (33) 



