OPEAS, CHINA. 163 



ably 0. clavulinum will be found to include some of the de- 

 scribed forms. 



44. 0. SCHENSIENSE Sturany. PI. 19, fig. 18. 



The turrited, yellowish-white shell with nipple-like apex 

 consists of iy 2 convex, delicately transversely striate whorls. 

 The umbilicus is crevice-like. Length 6.4, diam. 2.1, aper- 

 ture 1.8x1.2 mm. (Sturany). 



China: Southwestern Shen-si, in loess of the left bank of 

 the Tung-ho river (Obrutschew). 



Opeas schensiense STURANY, Denksch. Kais. Akad. Wis- 

 sensch., Wien., Ix, 1901, p. 37, pi. 3, f. 10. 



0. fauvelianum and 0. filare Hde. are related forms. 



45. 0. AMDOANUM Moellendorff. 



Shell minutely rimate, very slenderly turrited, thin, closely 

 striatulate, pale straw-colored. Spire much lengthened, very 

 slender, regularly tapering. "Whorls 12^, flattened, some- 

 what terraced, somewhat angulate at the margined, subcrenu- 

 late suture. Aperture narrowly oval, moderately excised; 

 peristome unexpanded, a-cute, the columellar margin shortly 

 reflexed, nearly closing the umbilical crevice. Length 11.5, 

 diam. 2.1 mm. (Mlldff.) 



China: province Gan-su, between Yu-linguan and Wen- 

 hsien; Dshie-dshou. 



Opeas amdoanum MLLDFF., Annuaire du Musee Zoologique 

 de 1'Acad. Imp. Sci. de St. Petersb., vi, 1901, p. 390. 



' ' No similar slender and acute species is known to me, and 

 there is none closely related among Heude's species." 



46. 0. TURGIDUM (-Greater) . PI. 20, figs. 29, 30, 31. 



Shell subperforate, turrited or conic-fusiform, thin, lightly 

 rugulose-striate, the striae arching forward, evanescent above, 

 glossy, waxen. Apex obtuse. Whorls T 1 /^, convex, the su- 

 ture rather deep, last whorl rounded 'below, one-third the 

 total length. Aperture subvertical, narrowly piriform; 

 columella subarcuate, vertical, scarcely truncate; columellar 

 margin dilated and reflexed above, adnate, gradually taper- 



