5 78 MOLLUSCA phylüm vi 



Zonites Montf. Like the last, biit with thinner shell, graniilatecl above, and 

 smooth below. Tertiary and Recent. 



Fig. 1095. Fig. 1096. 



Archaeozonites subverticillui! HyaUnia denudata Lychnus matheroni Requien. 



Sandb, Lower Miocene; (Reuss). Miocene ; Upper Cretaceous (Gariimnian) ; 



Bckingen, near Ulm. Tuchoritz, Bohemia. Rognac, Provence. 



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

 morpha Albers. Tertiary and Recent. 



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

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

 Cretaceous of Provence and Spain. 



Family 2. Limacidae Lamarck. 



NaJced slugs having a small vestigial shell, ßat and non-spiral, concealed within the 

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

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



The principal genera are Limax Linn., in which 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 distribution nearly world-wide. 



Family 3. Endodontidae Pilsbry. 



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

 rih-sculptured and with opaque colouring ; lip thin, unex2)anded. Jaiv of separate or 

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

 without 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 : Fyramidula 

 Fitz. Discoidal or low conical, with tubulär ribbed whorls and open umbilicus. 

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

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

 are similar austral forms, but are only known Recent. 



Family 4. Arionidae Gray. 



Slugs having the shell rediiced to a ßat plate or a few granules, nearly or entirely 

 concealed, or ahsent. Mantle in the form of a shield on anterior part of the hody ; teeth 

 of the quadrate type. Recent. 



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

 shell. Ärion Fer., and Änadenus Heyn, are leading genera of Europe and Asia ; 

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



