HELIX. 107 



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



Urnbilicated, diaphanous, slightly shining, obliquely, unequally,, 

 subdistantly plicate, the interstices slightly longitudinally striate, 

 light corneous, suture lightly impressed ; whorls 4J-5, a little con- 

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

 convex 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. PI. 20, fig. 83. 



Rather widely umbilicated, somewhat solid, very closely striate, 

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

 whorls 43-5, slowly increasing, convex, the last rounded. 



Diam. 4'25 mill. 



Cape of Good Hope. 

 H. VORTICIALIS, Benson. PL 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. PI. 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. PI. 20, fig. 88. 



Perforate, thin, with rough, close incremental strise, 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. PI. 20, figs. 89-91. 



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

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



