GASTEROPODA. 



Cyclophorus (see p. 308). 



Sub-genera: — Jerdonia, Blanford, 18G1. 



Type, J. trochlea, Benson sp. Nilgiri Hills, India. 



Shell minute, umbilicated, pyramidal, horny, tricarinated ; 

 operculum concentric, arctispiral, with a marginal sulcus all 

 round ; membranous internally, shelly externally ; inner edge 

 of each whorl resting on the outer edge of the next= 



CyatJwpoma, Blanford, 1864. 



Type, C. filocinctum, Benson sp. 



Shell minute, umbilicated, turbinated, or somewhat depressed ; 

 epidermis thick, sometimes hispid, smooth, spirally striated, 

 or lirated ; operculum truncate, conoid, concentric, multispiral ; 

 internally membranous, externally shelly; external margins 

 of the whorls raised in the form of shelly plates, incurved; 

 sometimes sculptured. 



Animal white, with a short oval foot, undivided beneath; 

 tentacles small, black, with eyes at the base. 



Distribution, 5 species. India. 



Spibaculum, Pearson. 



Distinguished by the possession of a retroverted sutural tube 

 open at both ends, and by a modification of the form of the 

 mantle corresponding to the same. 



Opisthoporus forms a sub-genus to Spiraculum. 



Clostophis, Benson, 1860. 



Etymology, clostos, coiled, and ophis, a serpent. 



Type, C. Sankeyi, Benson. Moulmein, Burmah. 



Shell subconic; penultimate whorl the largest, last whorl 

 separate and descending, subaxial small ; aperture subcircular, 

 entire, toothed ; margin expanded. 



Ehiostoma, Benson, 1860. 



Etymology, rhion, a promontory. 



Type, E. Haughtoni, Benson. 



Shell subdiscoidal, broadly umbilicated ; last whorl separate, 

 laterally descending ; aperture free, with an incision at the top, 

 and a subtubular prominence crownings the slit ; operculum 

 tDultispiral. 



Distribution, 6 species. Burmah, Siam, Cochin China. 



47 



