172 Annals of the South African Museum. 



Animal unknown. 



Hab. Damaraland. Khoma's Plateau. 

 Type in Senckenberg Museum. 



Boettger founded this variety on 13 specimens, and gives the 

 measurements as : Diam. 24-30; alt. 14-15 mm. 



DoRCASiA ALEXANDRi, Gray, var. perspectiva, nov., 1915. 

 (Pi. Ill, f. 8.) 



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

 pale buff, peristome white and glossy. Spire flattened, each whorl, 

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

 very rounded, fairly rapidly and regularly increasing, the apical 

 smooth, remainder beautifully sculptured with curved transverse 

 costae, at first close, fine and regular, gradually becoming coarser 

 and, towards the aperture, irregularly waved or broken and wider 

 apart. The last whorl descends abruptly in front, but not so as to 

 conceal the aperture entirely. Aperture roundly ovate ; peristome 

 continuous, broadly reflexed, quite free and clearly projecting from 

 the last whorl, but in no part overhanging the umbilicus, which is 

 broad and very deep, so that the apex is fully disclosed and quite 

 transparent. 



Diam. maj. 29-0, min. 22-0 : alt. max. 12-8; apert. 13-8 x 11-5 mm. 



Animal unknown. 



Hah. Damaraland. Omaruru Eiver (A. Wohlfahrt). 



Type in Kimberley Museum. 



This is the most northerly form of alexandri yet known. The 

 Type set, being almost subfossil, are nearly colourless, but would 

 doubtless be pale corneous were they in live condition. 



The shell differs from that of var. trivia, Boettger, in having even 

 coarser sculpture, and in its umbilicus being very broad and deep 

 instead of more or less shallow and narrow, as in other described 

 forms of alexandri. The dimensions vary considerably. I have 

 selected the largest example as Type ; others measure respectively : — 



Diam. maj. 260, min. 19'8 



230, „ 18-5 



22-6, „ 18-2 



22-0, „ 17-4 



alt. max. 110 mm. 

 10-5 „ 

 10-7 „ 

 10-1 „ 



A glance at D. alexandri and its varieties will show that, if they 

 all belong to the same widely distributed species, it is an extremely 



