HELIOID^. 31 



Thysanota, Albers, 1860. Narrowly' umbilicate, trochiform, 

 thin; whorls 7|^, scarcely convex, base carinated, with rigid 

 hairs ; aperture angularly lunar ; lip simple, acute ; columellar 

 margin slightly expanded. H. Guerini, Pfr. .5 sp. India. 



Kaliella^ Blanford, 1868. Uncharacterized. H. Barrak- 

 porensis, Pfr. 3 sp India. 



Videna^ H. and A. Adams, 1852. (Discus, Albers, 18.50.) 

 Shell widely iimbilicated, thin, discoidal, carinated at the 

 periphery, flat or somewhat elevated above, convex below ; aper- 

 ture subtriangular; peristome simple, sharp or slightly thickened. 

 75 sp. Mostly Polynesian and Australasian. H. acutimargo^ 

 Pfr. Philippines (xciii, 5). 



Sitala, A. Ad., 1856. (Conulema, Stoliczka.) Shell conoid, 

 thin, consisting of many whorls, usually spirally ribbed or 

 striated ; base convex, narrowly or indistinctly umbilicated ; 

 margin of aperture thin, not expanded, outer margin simple. 

 Animal narrow, long ; gland at the end of the foot, beneath a 

 distinct horn ; two shell-lobes and two dorsal lobes on the 

 mantle, all of them small and with no separately produced 

 appendages; jaw thin, smooth, indistinctl}'^ concentrically 

 striated in the middle. T sp. Southern Asia. H. attegia, 

 Benson. 



GLYPTOSTOMA, Bland and Binney, 1873. Shell widel}^ umbili- 

 cated, depressed, with wrinkle-like striae, solid ; whorls six, the 

 last depressed globose, not reflected at the aperture ; aperture 

 oblique, subcircular ; peristome simple, acute, thickened within, 

 its extremities approaching ; columellar lip scared}^ reflected. 

 Jaw imbricated; no mucous pore. The animal a true Helix, 

 although the shell has some resemblance to the Zonitidse. Z. 

 iVeto&e/'ryanits, Binney (xciv, 14). California. 



PHRiXGNATHTJS, Hutton, 1883. Shell conical or turbinated, of 

 five or six gradually increasing whorls; peristome thin, not 

 reflected. Animal heliciform ; mantle subcentral, reflected 

 anteriorly over the shell; foot without locomotive disk, rounded 

 posteriorly, without mucous gland. Jaw papillate, imbricately 

 folded ; teeth quadrate, the laterals bicuspid. H. marginata, 

 Hutton. N. Zealand. 



CARACOLUS, Montfort, 1810. (Discodoma, Swn,, 1840, Ser- 

 pentulus, Klein, Adams, 1855.) Shell solid, orbicularly de- 

 pressed, carinated, flattened at base, umbilicated or imperforate; 

 last whorl deflected at the aperture ; aperture oblong, subangular, 

 peristome thickened, reflected, widened below the columella, 

 which extends to or covers the umbilicus. H. caracolla, Fer. 

 (i, 16, scalariform). 16 sp. West Indies. 



Folydonfes, Moiat fort, 1810. Imperforate, globosely depressed, 

 or conoidally globose, solid, striate; spire hardly elevated, con- 

 oidal, apex obtuse ; whorls 5-5^, slightly convex ; the last large, 



