HELIX. 107 



H. PETROBIA, Benson. PI. 20, fig. 81. 



Umbilicated, diaphanous, slightly shining, obliquely, unequally, 

 subdistantly plicate, the interstices slightly longitudinally striate,. 

 light corneous, suture lightly impressed ; whorls 41-5, a little con- 

 vex, slowly increasing, the last obtusely angulated above, more 

 cortvex below, and angularly compressed around the umbilicus. 



Diam. 6 mill. 



Cape of Good Hope* 

 H. RARIPLICATA, Benson. PI. 20, fig. 82. 



Narrowly umbilicated, thin, corneous, with curved subdistant 

 plications, suture deep ; whorls 4, the last narrow, not descending. 



Diam. 4'25. 



Cape of Good Hope* 

 H. SABULETORUM, Benson. PL 20, fig. 83. 



Rather widely umbilicated, somewhat solid, very closely striate, 

 with distant curved riblets, not shining, light corneous, suture deep; 

 whorls 41-5, slowly increasing, convex, the last rounded. 



Diam. 4'25 mill. 



Cape of Good Hope* 



H. VORTICIALIS, Benson. PI. 20, fig. 84. 



Widely umbilicated, thin, brownish corneous, spire a little 

 concave, closely radiately plicate, suture deep ; whorls 4, narrow, 

 convex, the penultimate prominent, last not descending, compressed 

 on the sides, convex below. Diam. 5'5 mill. 



Cape of Good Hope* 

 H. RIVULARIS, Krauss. PL 20, figs. 85-87. 



Rather widely umbilicated, thin, closely costulate, waxy, pellucid, 

 corneous brown ; whorls 4, slightly convex, slowly increasing ; the 

 last not descending, base convex. Diam. 8*5 mill. 



Natal, So. Africa* 

 H. AFRICA, Krauss. PL 20, fig. 88. 



Perforate, thin, with rough, close incremental striae, slightly 

 decussated by very close spiral lines, opaque, whitish, under a yel- 

 lowish corneous epidermis, apex papillary ; whorls 5, scarcely 

 convex, the last subangulated above, base convex ; lip thinly 

 labiate within. Diam. 9 mill. 



So. Africa. 



H. HARTVIGIANA, Pfr. PL 20, figs. 89-91. 



Subcovered umbilicated, rather thin, corded-costulate, with very 

 close intermediate striae, subpellucid, dark brown, shining; whorls 



