574 



MOLLUSCA 



PHYLUM VI 



Auricula Lam. 

 rounded anteriorly, 

 times denticulated. 



Cassidula Fer. ; 



(Fig. 1078). Elongate-oval, witli ei^idei-mis. Aperture narrow, 

 Inner lip bearing two or tliree folds ; outer lip thickened, some- 

 Jura to Recent. 

 Plecotrema Adams; Alexia Leach (Fig. 1079); Pythiopsis Sandb. 



(Fig. 1080) ; Melampus Montf. 



Carychium Miiller (Fig. 1081). Shell small, smooth and glossy. Inner lip 



Fic. 1078. 



Auricula dutemjilei 

 Deshaye.s. Lower 

 Eocene ; Sainceux 

 (after Deshayes). 



Fio. 1079. 



Alexia pisoUna Desh. 

 Miocene ; Pontlevoy, 

 Touiaine. -/i. 



Fig. 1080. 



I'ythiopsis la- 

 marcki (Desh.). 

 Eocene ; Houdan 

 (aftei- Deshayes). 



Fi(i. lOSl. 



Canjchiuin antiquum 

 A. Biaun. Miocene; 

 Hocliheini, near May- 

 ence. EnlarLred. 



bearing one or two folds ; outer margin thickened, sometimes with a tooth. Jura to 

 Recent. Terrestrial. 



Scarabus Montf. (Polyodonta Fischer von Waldh.) ; Leuconia Gray ; Blamieria 

 Shuttleworth, etc. Tertiary and Recent. 



Family 2. Chilinidae Dall. 



Shell ovdl, auriculate, with large aperture, the colitmellar margin 

 provided ivifh spiral folds ; surface coloured in various patterns. 

 Tertiary and Recent. 



Ghilina Gray. This is said to be Streptoneurous. The 

 dentition resembles that of Physa. Miocene and Recent ; South 

 America. 



Family 3. Physidae Dall. 



Shell sinistral, oval, glossy, unicoloured. Aperture large; colu- 

 mella twisted or simple. Jura to Recent. 



Physa Drap. (Fig. 1082). Shell brilliantly polished, thin, 

 sinistral. Upper Jura to Recent. 



Pio. 10S2. 



Physa giganteti 

 Michaud. Lower 

 Eoci^ne ; Hilly, near 

 Rheims. 



Fi(!. 1083. 



Lymnaca 'pai'hyfiastcr 

 Thorn. Fresli - water 

 Miocene ; Morsingen, 

 near Ulm. 



Family 4. Lymnaeidae 

 Keferstein. 



Shell thin, turreted, or dis- 

 coidal. Fresh-water inhabitants. 

 Lias to Recent ; especially abun- 

 dant in the Tertiary. 



Lymnaca Lam. {Limnaeus 

 auct.) (Fig. 1083). Shell very 

 thin and corneous. Body whorl 

 very large ; spire acute, and 



moderately high. A])erture wide, oval ; outer margin sharp, 

 to Recent ; maximum in Tertiary. 



Planorbis Guettard (Figs. 1084, 1085). Discoidal (exceptionally turreted), with 



!Flo. 1084. 



Planorbis cornu Brongt. var. mantclli 

 Dimker. Upper Miocene ; Mundingen, 



Wnrtcinberg. 



Upper Jura (Purbeck) 



