PART II. 



AMPULLARIN-E. 



339 



THALLICERA. 



THALLICERA Quoy. Shell globose; spire depressed; 

 outer lip thin, with a sinus above ; inner lip thick- 

 ened, with a prominent plait near the base. 

 T. avellana. (fig. 34. p. 196.) Chem. 188. 1919-2O. 



SUB-FAM. AMPULLARINJE. 



Animal with a respiratory siphon; shell globular or 

 turbinate. 



VALVATA Drap* Shell turbinate, sometimes nearly dis- 

 coid; spire very short; the whorls convex; aperture 

 circular ; operculum spiral ; umbilicus pervious. 

 V. piscinalis. Sow. Man. f. 322. 



AMPULLARIA Lam. Shell glo- 

 bose, rarely discoid, turbinate ; 

 spire very short ; aperture ob- 

 long, pointed above, rounded 

 below. 



Ampullaria Lam. Outer lip thin ; 

 operculum horny. 



fasciata Lam. (fig. 101. a.) 



Pachylabra.^ Outer lip thick- 

 ened ; operculum shelly, 

 globosa&o. Zool. 111. i. pi. 119. 



Lanites Montf. Shell reversed ; 



the body-whorl ventricose only in the middle 

 lip generally thin. 



L. Guinaica. Sow. Man. f. 319. 



Ceratodes Guild. Shell discoid ; body- whorl higher 

 than the spiral whorls ; outer lip thin ; operculum 

 horny. 



C. Cornu-Arietis. Sow. Man. f. 320. 



PALUDINA. Spiral; spire equal, or longer than the 

 aperture ; lips thin. 



* Affinities uncertain. 



t Pachystoma Guild., already used in Ichthyology. 



z 2 



outer 



