156 PULMONATA. 



5. Pfeifferiana. Mantle edge dilated, produced and re- 



flexed over, covering more or less of the polished surface of 

 the shell. 



6. Helicina, Mantle edge enclosed within the edge of the 



shell. 



b. Body of animal and mouth of the shell compressed, longer 

 than broad from back to front than from side to side, that 

 is to say, in the direction of the longitudinal axis of the 

 shell. 



7. Succiniana. Animal vesicular, very large for the shell. 



Shell expanded, imperforate. Spire short. Aperture very 

 large. Peristome thin, simple, pillar rounded in front. 



8. AcHATiNiNA. Animal moderate, enclosed. Shell ovate, 



imperforate. Whorls many. Aperture elongate. Peri- 

 stome thin, not reflected. Front of the pillar truncated. 

 Pillar rarely plaited. 



9. BuLiMiNA. Animal moderate, enclosed. Shell ovate, per- 



forate or imperforate. Whorls many. Apertm-e elongate. 

 Peristome thin or reflected, rounded in front. 



10. Clausiliana. Animal small, enclosed. Shell subcylin- 

 drical, perforated. Mouth roundish or elongate, entire or 

 plicate, with a distinct groove in front forming a rido-e 

 round the axis. Peristome reflexed. Whorls at first slowly 

 enlarging, then nearly of the same size, then contracting in 

 size near the perfect mouth. 



Scutifera. Body elongate, attached its whole length to the 

 upper surface of the foot, and entirely or partially covered 

 with a dorsal mantle. 



Tribe 1. PHILOMYCINA. 



Mantle thin, as large as the foot, entirely covering the back. 

 Tentacles four. Respiratory aperture on the side near the 

 head. 



Philomycina, Gray, P. Z. S. 1847, p. 170. 



