174 Annals of the South African Museum. 



TULBAGHINIA ISOMEKIOIDES (Melv. ct PonS.). 



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

 p. 28. PL VIII, f. 30. D.F. 



Shell rather large, depressed-globose, umbilicate, fairly thin, trans- 

 lucent, bright corneous, slightly paler beneath ; peristome white and 

 glossy ; interior showing the colour of the exterior. Spire depressed, 

 apex very obtuse. Whorls 5A-, rounded, rather gradually increasing, 

 all but the apical covered with close, curved, well-defined transverse 

 striae, the earlier whorls showing considerable faint malleation, 

 and the last, clear microscopic granulation. Suture simple, rather 

 shallow. Aperture truncate- ovate ; peristome narrowly reflexed, 

 ends joined by a thin callus. Columella furnished with three small 

 protuberances on the inner edge ; outer columellar margin forming 

 a distinct angle of 130° 3-8 mm. from its junction with the paries. 



Dimensions of Type: Diam. maj. 30-0, min. 24-6; alt. max. 15-8; 

 apert. 16"2xl2-4 mm.; ends of peristome 4'1 mm. apart. 



Animal unknown. 



Hah. Cape Province. Tulbagh. 



Type in British Museum. 



Only three specimens are known, and in these the peculiar 

 columellar dentition is variable, there being three processes in 

 the Type and only two in another example. The last mentioned, 

 which I described in Vol. XI. p. 152 of these Annals, also differs 

 widely from the Type in coloration, being dark olive-brown, 

 beautifully mottled with yellow on the upper whorls. Whether this, 

 or the uniform brown of the Type, is the normal colour scheme of 

 the species, will be proved when further examples come to hand. 



Although the little protuberances on the columella may prove to 

 be of specific value in the case of T. isomerioides, something of a 

 similar nature is of irregular, though infrequent occurrence in other 

 Dorcasiinae. Possibly owing to its slime attracting minute par- 

 ticles of sand, the parietal region of Trigonejihrus globulus is some- 

 times quite rough with brown, horny points, while even in the 

 shell figured (PI. II, f. 1) a somewhat similar excrescence is notice- 

 able on the exterior of the outer lip. I have also seen an example of 

 T. gypsinus, which showed a minute, perfectly formed denticle just 

 inside the basal margin of the aperture. 



Tulbaghinia schaerfiae (Pfeiffer). 

 1861 Helix schaerfiae, Pfr., Mal.Blatt., viii. p. 73. PI. II, f. 1-3. D.F. 

 Shell depressed orbicular, umbilicate, thin, glossy, semitrans- 

 parent, bright corneous, with several narrow, regular, spiral rufous 



