214 FERUSSACID.E. 



The Ferussacida are characteristic snails of the European 

 fauna. The leading genera Cochlicopa, Azeca, Coilostele 

 had already been differentiated in Eocene time, and appar- 

 ently have undergone only minor changes since then. 

 Ferussacia and Cacilioides appear in typical forms in the 

 Miocene, but doubtless are much older. The family Ferus- 

 s&cida is therefore to be classed with the Clausiliidce, Mega- 

 spiridce, Oleacinida, and various Cyclostomacea, groups al- 

 ready well developed in Europe in the Mesozoic, and continu- 

 ing on into Tertiary time, in the same area. References to 

 the fossil species may be found under the several generic 

 heads. 



Synopsis of genera. 



1. Genera with pedal grooves and a caudal pore, teeth 

 tricuspid. 



FERUSSACIA Risso. Shell cylindrie-oblong to acutely ovate, 

 rather solid, aperture more than half the shell's length, outer 

 lip sinuous or arched forward, columella usually not truncate 

 at base. Mediterranean region, etc. 



CRYPTAZECA Folin. Shell ovoid, thin, the aperture half its 

 length; outer lip thin, arched forward; columella short, 

 abruptly truncate at base. Pyrenees. 



CALAXIS Bgt. Shell lanceolate, thin, glassy ; aperture very 

 narrow above, usually with a parietal lamella and a palatal 

 plica; base of the columella lamellar, projecting, strongly 

 truncate. Soft anatomy unknown. Syria to Egypt. 



DIGONIAXIS Jouss. Shell turrite, of 10-11 whorls; aperture 

 small, semiovate ; outer lip simple, columella strongly bilamel- 

 la,te. Internal axis spirally lamellate. Aden, Ceylon. 



2. Grenera without pedal grooves or a caudal pore, and hav- 

 ing an appendix on the penis and a direct ureter, so far as 

 known. 



AZECA Leach. Elliptical-ovate or oblong, rather solid, with 

 the aperture more or less obstructed with teeth, outer edge 

 of the parietal callus thickened, cord-like; columella usually 

 strongly truncate at base. Eur- Africa. 



COCHLICOPA Fer. Cylindric-oblong, with rather convex 



