152 Annals of the South African Museum. 



(axis 6'", diarn. 8'") with a white mouth is not uncommon at Bredas- 

 dorp, while a large white form (axis 1", diam. 1" 3'") exists at 

 Mossel Bay." 



Chemnitz's figure (1786) is almost unrecognisable, while Lamarck 

 (1822) described globulus for lucana, and Kossmassler (1837) figured 

 globuhis as the last-mentioned species. Krauss (1848) included 

 lucana, Lam., in the synonymy of globulus, Mull., but unaccountably 

 omitted lucana, Miill., altogether from his catalogue. 



286. DORCASIA PONSONBYI, Fulton . 



1910 Dorcasia ponsonbyi, Fulton, A.M.N.H. vi. p. 212. D. 

 Type in British Museum. 

 Hab. CAPE OF GOOD HOPE (fide Fulton). Mossel Bay (Gibbons). 



SUB-GENUS TULBAGHINIA, Melv. & Pons., 1898. 

 (A.M.N.H. i. p. 28.) 



Type of Sub-Genus, D. isomerioides, M. & P. 



287. DORCASIA ISOMERIOIDES, Melv. & Pons. [S.A.M.] 



1898 Dorcasia (Tulbaghinia) isomerioides, M. & P., A.M.N.H. i. p. 28. 

 pi. 8, f. 10. D.F. 



Type in British Museum. 



Hab. CAPE OF GOOD HOPE. Winterhoek Mt., Tulbagh (Marloth). 



Owing to its considerable divergence from the type, I append the 

 description of a fine specimen in the South African Museum. 



Shell depressed-globose, deeply and openly umbilicate, thin, trans- 

 lucent, thickly covered above with rough, curved striae, which are 

 continued more smoothly beneath. The upper portion moderately 

 glossy, of dark olive-brown horn colour, beautifully marked on the 

 earlier whorls with pale yellow dots and blotches, merging later into 

 irregular, interrupted concentric streaks ; the earlier whorls similarly 

 marked on the underside, but the last is paler, of a greener tint, 

 glossy and unmottled. The interior shows plainly the colour and 

 markings of the epidermis. Spire but little produced, apex flattened. 

 Whorls 4|, rapidly increasing, rounded, with no trace of carination. 

 Aperture ovate, peristome white and glossy, a little thickened and 

 reflexed. The columellar margin, half-way up between the base of 

 the aperture and the umbilicus, shows trace of two small pro- 

 tuberances on its inner side ; above these it becomes more widely 

 reflexed, and forms a sharp angle of about 95 degrees, projecting 



