84 SYSTEMATIC ARRANGEMENT 



creasing, with the nucleus very excentric. Shell oblong-turrited, 

 often truncated, sometimes globose-turbinated ; aperture ovate. 

 Peristome simple or more or less distinctly doubled, nearly straight, 

 expanded or broadly reflexed. 

 1. C. pictum, 



c. Pomatianina. Operculum thick, of two horny coats, conca- 



merated within. 



27. POMATIAS. 



Operculum cartilaginous, few-whorled, composed of two plates, 

 concamerated within. Shell somewhat imperforate, conico-turrited 

 or turrited, longitudinally striated or ribbed. Peristome nearly sim- 

 ple or double, the internal edge continuous, the external expanded or 

 reflexed, often auriculated. 

 1. P. maculata, t. 311. f. 19. 



d. Realiana. Operculum thin, horny ; front of last whorl with a 



keel round the axis, and sometimes a notch in the front of 

 the Up, like Pupiniana, but the operculum is ovate, few-whorled. 



28. LlAREA. 



Operculum thin, few-whorled, horny. Shell turrited, rather 

 smooth ; aperture ovate. Peristome continuous, double. 



1. L. Egea. 



29. Realia. 



Operculum thin, few-whorled, horny. Shell perforate or narrowly 

 umbilicate, turrited, or globose-turbinate, keeled round the perfora- 

 tion ; aperture ovate. Peristome straight or expanded, with distant 

 margins. 



1. R. rubens, t. 311. f. 11. 



2. R. erosa, t. 311. L 12. 



30. BoTJRCIERA. 



Operculum ovate, rather solid, horny, of a few rapidly-increasing 

 whorls. Shell Helicina-shaped ; columella toothed beneath ; aper- 

 ture ovate. Peristome spreading. 



1. B. helicinseformis. 



Fam. VII. OLIGYRAD.E. 



Eyes on outer side of the base of the tentacles. Gills vascular, 

 free. Shell conical or subglobose ; aperture half-ovate. Operculum 

 annular, not spiral, shelly, thick, or horny and thin, semi-ovate or 

 rather triangular ; nucleus subcentral, lateral. 



Terrestrial. 



The animal absorbs the septa between the upper whorls, as in 

 Auriculidce, Helicinidee, Proserpina, Neritina, &c. 



