308 Transactions of the South African Philosophical Society. 



specialised. The third line of descent was probably started by a 

 large form with narrow skull and no temporal bulla, a form to which 

 the small C. sclateri and C. duthiece are near allies. The loss of the 

 last small molar would give rise to C. hottentota and its allies. The 

 afi&nities of C. ohtiisirostris are not very apparent. 



Key to the Species. 



A. Vesicular bulla for head of malleus, 

 (a). Teeth 40. 



(a). Zygomatic arch greatly developed posteriorly. 



(a'). Dental series 17 mm trcvelyani. 



{jS'). Dental series 13 mm villosa. 



(/3). Zygomatic arch feeble. 



{a'). Interorbital region very broad ; large pad on inside 



of manus lointoni. 



{j3'). Interorbital region not expanded ; breadth of 



skull 18-19 asiatica. 



(y'). Interorbital region narrow ; breadth of skull 15-16 namaquensis. 

 (b). Teeth 36. 



Skull narrow tenuis. 



B. No vesicular bulla for head of malleus, 

 (a). Teeth 40. 



(a). Lower molariform teeth without posterior talon ; skull 



broad granti. 



(/3). Lower molariform teeth with posterior talon ; skull 



narrow. 



(a'). Skull breadth to length 66: 100; fur reddish .. sclateri. 



(/3'). Skull breadth to length 62 : 100 ; fur blackish . . dutliiece. 

 [h). Teeth 36. 



(«). With 5 molariform teeth ; skull broad -' " .„ 



^ ' [0. chrysilla. 



{8). With 4 molariform teeth : skull narrow -i , 



' { and varieties. 



The examination of probably many times more moles than have 

 been studied by any other zoologist, while it has enabled me to clear 

 up a number of points, leaves very much still to be done before 

 the genus can be regarded as thoroughly well known. The high 

 mountain ranges which are so numerous in South Africa largely cut 

 up the country into divisions, which to animals like the mole living 

 in low ground are practically isolated. And probably for many ages 

 a species has had no chance of migrating from a very local area. 

 Thus Chrysochloris sclateri is only known to occur at Beaufort West. 

 To the north are the high Nieuweveld Mountains, and to the south 

 the very dry and barren Little Karroo. Further south lies the very 

 high Zwartberg Kange. Between this and the Langeberg Eange is 

 a large fertile tract of country, but so far no moles have been dis- 



