174 



POPULAR CONCHOLOGY. 



Family 3. — HE LICE A. 



The body of these Mollusca is more or less spirally 

 formed, separated from the foot, and covered by a spiral- 

 formed unoperculated shell ; the tentacula are four, on 

 two of which the eyes are placed at the extremity. — 

 Terrestrial. 



This extensive family has been divided by several 

 writers into various genera. Ferussac mentions five : — 

 Helixarion, Helicolimax, Helix, Vertigo, and Partula. 

 Lamarck has eight: — Helix, Carocolla, Anastoma, Pupa, 

 Clausilia, Bulimus, Achatina, Succinea. Beck has thir- 

 teen : — Vitrina, Helicarion, Helicopsis, Nanina, Steno- 

 pus, Daudebardia, Helix, Artemon, Bulimus, Achatina, 

 Pupa, Clausilia, Succinea. Pfeiffer arranges them in 

 seventeen genera, which is the plan adopted by Philippi, 

 as follows : — Daudebardia, Vitrina, Succinea, Helix, 

 Anastoma, Tomigerus, Streptaxis, Odontostoma, Bulimus, 

 Achatinella, Achatina, Pupa, Cylindrella, Megaspira, 

 Balea, Tornatellina, and Clausilia. 



Daudebardia. Hartmann. (Helicophanta 

 Eer.) — Shell dextral, very thin, roundish, al- 

 most ear-shaped; spire scarcely projecting; the 

 aperture very large, half-moon shaped. Animal, 

 too large to enter the shell, and exactly similar 

 to Limax. — Few species. 



Found in Europe. 



Vitrina. Draparnaud. (Cobresia, Helixarion, Heli- 

 colimax, Hyalina, Limacina.) — Shell small, very thin, 

 flattened, terminated by a short spire ; the last whorl 

 large; mouth large, and rather oval; columella not per- 

 forated. Animal, body long, the shell only covering part ; 



