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POPULAR CONCHOLOGY. 



middle of the back, allows a Bulla-shaped shell to appear ; 

 the tail is much lengthened and compressed. — 1 species. 

 L. Sieboldii is the only known species. 



Lobiger. Krohn. — Separated from Lophocercus, by 

 the body having four processes on each side resembling 

 butterflies' wings; the shell has only a slight trace of 

 volutions. — 1 species. 



L. Philippii is the only species. 



These animals and shells form a connection with the 

 following family. 



Family 3. — BULL ACE A. 



The gills of the animal are situated on the back, and 

 are covered by the mantle ; sometimes there are no feelers ; 

 some have no shell, others have an internal one, and others 

 again have an external shell sufficiently large to contain 

 the whole body. — Marine. 



Aplustrum. Schum. (Hydatina Schum. ; Bullina 

 Fer.) — Shell oval, globular, thin, with a few 

 quickly increasing whorls, which are visible at 

 the apex ; the aperture wide, entire beneath, or 

 lengthened into a short canal. Animal, having 

 a head with four large ear-shaped tentacula; 



° " 1 7 Aplustrum. 



behind the hinder pair there are two eyes, from 

 behind these proceed two broad lancet-shaped lobes, which 

 turn back over the shell; the foot is far broader and 

 longer than the shell, truncated in front, and running out 

 on each side into a sickle-shaped point ; the tongue in the 

 A. physis has not a middle row of teeth, but on each side 

 there are thirteen rows of strong hooks, with four notches 

 on the inner side. — Few species. 



