APLUSTRID^. 361 



truncate anteriorly ; outer lip produced behind. A. Cranchii, 

 Leach. 



ALiquLA, Ehrenberg, 1831. Shell subcylindrical, transversely 

 striate. 3 sp. Japan. A. translucens, A. Ad. Japan. 



LEUCONYX, H. and A. Ad., a supposed new genus of Bullidfe, 

 is the spatulate hinge process of Fholas costata. 



Family APLUSTRID^. 



Teeth, central none ; laterals numerous, uniform. Head with 

 the frontal disk produced into large ear-like tentacular lobes 

 folded over the back of the shell, and furnished with bifid labial 

 appendages ; eyes sessile at the inner bases of the tentacular 

 lobes. Mantle with the inner margin thin and membranous, the 

 outer forming a thick, fleshy lobe, curving round the spire of 

 the shell ; branchial plume long and single. Foot large and 

 membranous, auriculate in front, rounded behind. 



The shell has usually a short spire, the last whorl inflated, 

 aperture anteriorly distinctly eifuse, columella somewhat thick- 

 ened, rarely twisted, but alwaj^s anteriorly truncated. 



Aplustrum, Schumacher. 



Etym. — Aplustre, a ship's flag. 



Distr — 1 sp. Coral reefs. East Indies. A. aplustre, Linn. 

 (Ixxxvii, 43). 



Shell oval, ventricose, highly colored ; spire wide, depressed ; 

 aperture truncated in front ; outer lip sharp. 



DiflTers from Bullina by its smooth, somewhat thinner shell, 

 more depressed spire, the columella being very thick, slightly 

 twisted and truncated in front. 



Bullina, Fer. 



Distr. — B. lineata, Wood (Ixxxvii, 44). 



Shell oval, rather solid, subumbilicated ; spire distinct ; whorls 

 with revolving striae ; columella arcuated, obliquely truncated in 

 front ; outer lip crenelated. 



KLEiNELLA, A. Ad., 1860. Shell ovate, thin, umbilicated, can- 

 cellated, aperture produced anteriorly, inner lip not plicated. 

 Resembles Actseon, but without columellar fold. Japan. B. 

 cancellaris, A. Ad. 



Hydatina, Schum., 1817. 



Distr. — Recent, several sp. Fossil. Jurassic — . H. physis, 

 Linn. (Ixxxvii, 45). 



Shell ventricose, thin, smooth, not umbilicated, with a thin 

 epidermis ; usually banded ; spir.e involute ; columella arcuated, 

 reflected. 

 24 



