440 



PULMONATA — STYLOMMATOPHORA 



CHAP. 



to this group), radula with usually few, large, sickle-shaped 

 teeth (p. 232), shell variable, rarely absent, usually external. 



Cretaceous . Principal genera: CJilamydeijliorns (shell a 



simple plate, internal), Apei^a^ 

 Testacella (slug-like, shell ter- 

 minal), Strehelia^ Streptostyla^ 

 Glandina, Salasiella^ Petenia^ 

 Pseudosuhulina^ Strei^tostele^ To- 

 mostele, Streptaxis (Fig. 203), 

 G-ihhus^ Ennea^ Daudehardia 

 (Fig. 193), Schizoglossa, Gueste- 

 ria^ Aerope, Paryphanta^ Rhytida 

 (subg. Diplomphalus, Elaea and 

 Rheiiea). 



Fam. 2. Selenitidae. — Shell 



A ' B 



Fig. 294.— a, Ennea (Glbbulina) pa- 

 langa Fer; A', young of same; B, 

 Gibbus lyonetianus Pall. 



internal, external, or absent ; jaw present, radula Testacellidan, 



central tooth present. Tertiary . Genera: tSelenites, Plu- 



tonia^ Trigonochlamys^ Pseudomilax (?), Rathouisia (?). 



Fam. 3. Limacidae. — Shell present or absent, internal or 

 external, spiral or not, tail often with a mucus pore, jaw (Fig. 

 107 A, p. 211) with projecting rostrum on cutting edge, radula 

 with central tooth tricuspid, laterals bi- or uni-cuspid, marginals 



aculeate. Eocene . Genera: Otoeoncha, Urocyclus^ Maria- 



ella (subg. Tennentia^, Parmario7i^ Helicarion^ Cystopelta^ Aspi- 

 delus^ Estria^ Vitrinopsis (subg. Vitrinoidea, Parmella')^ Damay- 

 antia, Nanina (= AriopJianta, including Pachystyla, Rhysota, 

 Hemiplecta, Troclionanina^ Eiiplecta^ Orpiella^ Xesta^ Macro- 

 chlamys^ Microcystis^ Sitala, Kaliella^ Duryella, Austenia, Girasia, 

 Parmacochlea^ Africarion, jSesara, Macroceras, and others), Vi- 

 triniconus^ Parmacella, Limax (subg. Amalia and many sections), 

 Vitrina (subg. Vitrinozonites^ Velifera)^ Zonites (subg. Stenopus^ 

 Moreletia^ Mesomphix^ Hyalinia., Gastrodonta, Pristiloma^ Poe- 

 cilozonites^ Thy rophor ella). 



Fam. 4. Pliilor)iycidae, — Shell absent, jaw limacidan, radula 

 helicidan, shield covering all the body. Single genus, Philo- 

 mycus (= TehennopJiorus), with subg. Pallifera. 



Fam. 5. Helicidae. — Shell present or absent, internal or ex- 

 ternal ; jaw of various types, radula with central tooth tricuspid, 

 equal in size to the first laterals, laterals bi- or tri-cuspid, margi- 

 nals smaller, cus]3ed. Eocene . Principal genera : Oopelta 



(no shell), Arion (shell absent or formed of calcareous granules), 



