East and West Africa and the Transvaal. 181 



triangularly expanded, the expansion bearing a depression in 

 the middle ; parietal wall somewliat excavated in the region 

 of the columella : peristome slightly thickened, reflexed ; 

 aperture subquadrate. 



Alt. 22, diani. maj. 12 mm. 



Aperture : alt. 9, diam. 5*5 mm. 



Hah. (type specimen) . Bitze, near the River Ja, Gameroons ; 

 several broken specimens also from Akok, 30—35 miles from 

 the coast at Kribi. 



Distinguished from O. liberiana, Lea *, from Liberia, by 

 its smaller size, thinner texture, and much finer transverse 

 sculpture ; moreover, the exceedingly fine punctate sculpture 

 easily separates it from G. liberiana. 



Helicariun bifceensi's, sp. n. (Figs. 2, 3.) 



Shell corneous, semitransparent, dark yellowish green ; 

 spire much depressed ; whorls 3, here and there showing 

 traces of slight malleation, puckered into irregular arcuate 

 riblets or creases, on and between which appear fine lines of 

 growth, the last whorl subcarinate, somewhat widely ex- 

 panded towards the aperture ; sutures well impressed; aper- 

 ture subovate, dilated above, rather lateral!}- constricted. 



Alt. 11, diam. maj. 25'5 mm. 



Aperture: alt. 12, diam. 14 5 ram. 



Bab. Bitze, near the River Ja, Gameroons (type) ; also a 

 single specimen taken at Akok, 30-35 miles from the coast 

 at Kribi. 



Helicarion undtrosolabiata, sp. n. (Figs. 4, 5.) 



Shell corneous, thin, light olive-green, somewhat inflated ; 

 whorls 3, marked with giowth-lines and occasionally creased 

 into broad riblets, the last whorl scored with very fine irre- 

 gular spiral scratches ; sutures impressed ; peristome folded 

 inwards so as to form a narrow thickening, dark brownish 

 green ; aperture obliquely ovate. 



Alt. 15, diam. maj. '26'5 mm. 



Aperture : alt. 13, diam. 14 5 mm. 



IJab. Bitze, near the River Ja, Gameroons. 



Thapsia rosenhergi, sp. n. (Fig. 6.) 



Shell depressed, perforate, discoidal, thin, polished, horny, 

 light reddish brown ; whorls b\, sculptured with very fine, 

 wavy, spiral striae and transverse lines of growth ; base lighter 

 * Philad. Trans, vii. p. 4rj7, pi. ii. 



