TASMANIAN LAND SHELLS. 



Sub-Kingdom II — MOLLUSCA. 



Class II— GASTEROPODA. 

 Order II.— PULMONIFERA. 



This order embraces all the land snails and other Mollusca which breathe 

 air. They are normal gasteroj^ods, having a broad foot, and usually a 

 large spiral shell ; theii* breathing organ is the simplest form of lung, 

 and is like the br/nchial chamber of the sea snails, but lined with a net- 

 work of respii'atory vessels. One large division of the land snails is 

 furnished with an operculated shell ; the rest are inoperculate, and some- 

 times shell-less. — WoodvmrcVs Manual. 



Section A.— INOPERCULATA. Section B.— OPERCULATA. 



Section A.— INOPERCULATA. 



Family— HELICID^. 



Shell external, usually well developed, and containing the entu-e 

 animal ; aperture closed by an epiphra,gm during hybernation. 



Animal with a short retractile head, with four cylindrical retractile 

 tentacles, the upper pair longest, and bearing eye-sj)ecks at their sum- 

 mits. Body spiral, distinct from the foot ; respiratory orifice on the 

 right side, beneath the margin of the shell ; reproductive orifice near the 

 base of the right ocular tentacle ; mouth armed with a horny, dentated, 

 crescent-shaped upper mandible ', lingual membrane oblong; central teeth 

 inconspicuous j laterals numerous, similar. 



