Notes on South African Mollusca. 169 



DORCASIA ALEXANDEI, Gray, var. MINOR, O. Boettger. 



(PI. Ill, f. 6.) 



1886 Helix (Dorcasid) alexandri, Gray, var. minor, Bttg., Ber. 

 Senckenb. Naturf. Ges. Frankfurt, p. 22. PI. II, f. 1. 



Shell differing from typical D. alexandri in being smaller, and in 

 having a comparatively higher spire, very slightly more pronounced 

 sculpture above, and a deeper, less eccentric umbilicus. 



Animal unknown. 



Hab. BECHUANALAND. Ghous. 



GREAT NAMALAND. .Geitsi Gubib. 



Type in Senckenberg Museum, Frankfurt am Main. 



The example figured, S.A.M. No. A 2818, from Geitsi Gubib, 

 measures: Diam. maj. 22-6, min. 18'8 ; alt. max. 13 - 5 ; apert. 

 11-0 x 9-9 mm. 



Bottger founded the variety on five specimens from Ghous, north 

 of Smalviseh Kop, Gordonia, and gives the measurements as : 

 Diam. 21-24 ; alt. 10-111 ; apert. 10-10 X 11-12 mm. 



Almost every intermediate size between the typical form and the 

 smaller variety can be found, the sculpture, height of spire, and 

 consequent form of the umbilicus being by no means constant. 



DORCASIA ALEXANDRI, Gray, var. ROTUNDATA, Mousson. 

 (PL III, f. 7. PL IV, f. 6, 16, 24. PL V, f. 8, 11.) 



1887 Helix alexandri, Gray, var. rotundata, Mouss., J. de C. xxxv. 



p. 292. PL XII, f. 1. D.F. 

 1914 Dorcasia alexandri, Gray, var. sier/manni, Honigmann, Nach- 



richtsbl. d. D. Mai. Ges. Ixiv. p. 29. D.F. 



Shell depressed-globose, umbilicate, thin, semitransparent, pale 

 corneous, peristome white and glossy. Spire depressed, each whorl, 

 in profile, just projecting above the next ; apex obtuse. Whorls 4^, 

 narrowly rounded, rapidly increasing, all but the apical sculptured 

 with close, regular, transverse costae, which become closer and finer, 

 but show very clearly, on the base and extend into the umbilicus ; 

 last whorl descending very abruptly in front. Suture deep, simple. 

 Aperture rounded-ovate ; peristome quite free, continuous, widely 

 reflexed, but in no way overhanging the umbilicus, which is deep, 

 but strangulate and very narrow. 



Dimensions of a specimen from Eehoboth : Diam. maj. 2T1, 

 min. 16'8 ; alt. max. 12~3 ; apert. 1O8 x 9'2 mm. 



