578 



MOLLUSCA 



PHYLUM VI 



Zonites Montf. Like the last, but with thinner shell, granulated above, and 

 smooth below. Tertiary and Recent. 



Fl(i. 1094. 



Archaeozonit.es s^Averticlllus 

 Sandb. Lower Miocene; 

 Eckingen, near Ulni. 



Fic. 1095. 



Hyalinia denudata 

 (Reuss). Miocene ; 

 Tuchoritz, Bohemia. 



1090. 



Lychnus matheroni Requien. 

 Upper Cretaceous (Garumnian) ; 

 Rognac, Provence. 



Hyalinia Fer. (Fig. 1095) ; Omphalosagda Sandb. ; Ariophanta Desm. ; Trocho- 

 morpha Albers. Tertiary and Eecent. 



Lychnus Montf. (Fig. 1096). Body whorl large, bent upward at first, and later 

 decurved, so that the margins of the aperture lie in the basal plane. Upper 

 Cretaceous of Provence and Spain. 



Family 2. Limacidae Lamarck. 



NaTced sliujft havin.fi a small vestigial shell, flat and non-sfiral^ concealed within the 

 mantle, which latter forms a small oval shield on the forepart of the body. Foot margin 

 narrow ; dentition and jaw as in the Zonitidae. Tertiary and Recent. 



The principal genera are Limax Linn., in whicli the intestine has four longi- 

 tudinal folds, and the back is keeled at the tail only ; and Amalia Moq.-Tand., with 

 spiral gut and strongly keeled back. Their small scale-like shells have been found 

 in the Tertiary and Pleistocene ; present distriliution nearly world-wide. 



, Family 3. Endodontidae Pilsbry. 



Shell spiral and external, varying from cylindric to helicoid and planorhoid, usually 

 rih-sculp>tured and with 02nique colouring ; lip thin, unexpanded. Jaw of sc^inrate or 

 united imbricating plates, or solid and striated ; margined teeth squarish ; genitalia 

 tvithout accessory organs. Carboniferous to Recent. 



Punctinae. Jaw of numerous separate plates ; shell minute. Includes the 

 Holarctic genera Punctum Morse and Sphyradium Charp., also the New Zealand 

 genus Laoma Gray. Recent. 



Endodontinae. Jaw-plates united more or less completely. Genera : Pyramidula 

 Fitz. Discoidal or low conical, with tubular ribbed whorls and ojien umbilicus. 

 Carboniferous to Recent. This is one of the most ancient land Mollusks known, and 

 is the oldest Helicoid form. Phasis, Amphidoxa, Flammulina and Endodonta Alb. 

 are similar austral forms, but are only known Recent. 



Family 4. Arionidae Gray. 



Slugs having the shell reduced, to a flat plate or a few granules, nearly or entirely 

 concealed, or absent. 'Mantle in the form of a shield on anterior piart of the body ; teeth 

 of the quadrate type. Recent. 



This family is probably derived from the Endodontidae by degeneration of the 

 shell. Arion Fer., and Anadenus Heyn. are leading genera of Europe and Asia ; 

 Ariolimax Miirch, and Prophysaon Bland occur abundantly in North America. 



