112 COLIMACEA. 



the genus Achatina, Auct. not including those with undulated 



outer lips. 

 COCHLODINA. Fer. A sub-genus of Helix, including the genus 



Clausilia, Auct. 

 COCHLODONTA. Fer. A sub-genus of Helix, containing Pupa 



Uva, Auct. &c. 

 COCHLOGENA. Fer. A sub-genus of Helix, containing pupi- 



form shells, such as Azeca tridens, fig. 290. 

 COCHLOHYDRA. Fer. A sub-genus of Helix, composed of the 



genus Succinea, Auct. 

 COCHLOSTYLA. Fer. A sub-genus of Helix, composed of the 



genus Bulinus, Auct. 

 COLIMACEA. Lam. This Family, of the order Trachelipoda, 



Lam. includes all land shells, which might with propriety be 



divided into three sections, the first of which contain the follow- 

 ing well-known genera : — 



1 . Succinea. Oval, transparent, oblique ; animal amphi- 

 bious. Fig. 265, 266. 



2. Helix. The type of which is the common snail shell. 

 The separation of Carocolla, on account of the angulated 

 whorls, or that of Geotrochus, on account of the turbinated 

 shape, cannot be well maintained. Fig. 264, 267, 268, 

 273 to 276, 278 to 281, 294. 



3. Anostoma. The aperture turned up towards the spire. 

 Fig. 271, 272. 



4. Streptaxis. Whorls excentric. Fig. 269, 270. 



5. Bulinus. Oval; aperture entire, including Bulimulus, 

 Balea, Cionella, Azeca. Fig. 282 to 285, 289, 290, 296. 



6. Achatina. A notch terminating the columella. Fig. 286 

 to 288. 



7. Pupa. Cylindrical ; including Vertigo, Alcea, &c. Fig. 

 291 to 293. 



8. Clausilia. Cylindrical, with a clausium. Fig. 295. 

 Obs. The above are united in the system of De Ferrusac under 



the generic name Helix, and divided into sub-genera as 

 explained under that word. 



