208 RIEBECKIA. 



"This species varies considerably in stoutness, some ex- 

 amples being much more slender than others. The type is 

 25 millim. long and 8% broad. A narrowed specimen is 26 

 long and 7% broad, whereas the broadest example is 23% 

 long and 9 in diameter. Although the extreme forms have a 

 very dissimilar look, they appear to be connected by the 

 intermediate links occurring in the series of specimens ex- 

 amined. A comparison of a typical specimen of 8. sokotorana 

 kindly submitted by Professor von Martens, proves that that 

 species is identical with the present and not with 8. enodis, 

 as he originally supposed. The latter, the type of which was 

 a very young shell, is a very much more slender form alto- 

 gether, and of a pellucid white 'Color, the present species being 

 greenish yellow." (Smith). 



5. R. ENODIS (Godwin- Austen). PL 55, figs. 97, 98. 



"Shell dextral, elongately turreted, not rimate, very thin, 

 glassy, diaphanous; no sculpture; color milky white; spire 

 long, apex blunt and rounded, suture moderately deep ; whorls 

 9, sides convex, regularly increasing; aperture quadrate, sub- 

 vertical (not fully formed) ; peristome thin; columellar margin 

 straight, vertical. Length 13, diam. 4, alt. aperture 2.8 

 mm. (G.-A.). 



Sokotra : South side of the island, from limestone rocks, al- 

 titude 1000 feet. (Balfour) ; Jena-agahan, 1200-2500 ft. 

 (Bent) ; under stones on Gebel Fedehen (H. 0. Forbes). 



Stenogyra (Subulinaf) enodis G.-A., P. Z. S. 1881, p. 811, 

 pi. 69, f. 5 (young shell). 8. (Riebeckia) enodis SMITH, Nat. 

 Hist, Sokotra, p. 135, pi. 13, f. 16. 



"The unique type being a very young shell, gives only a 

 poor idea of this interesting species. The largest specimen 

 examined consists of 15 whorls, and is 37 mm. in length, 8 in 

 diameter. The aperture is inversely auriform, and the colu- 

 mella a little thickened and arcuate, and exhibits a slight 

 anterior truncation. The last whorl is rounded at the peri- 

 phery " (Smith). 



6. R. INSCULPTA (E. A. Smith). PL 54, fig. 84. 



"Shell subulate, imperforate, white; whorls 15, very gently 



