Annals of the Transvaal Museum. 
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type has been taken, and that the change which has come about has 
induced in Eucrangonyx robertsi a decided likeness to E. vejdovskyi. 
We must admit, in conclusion, that we cannot dogmatize in the 
matter of the origin of this detached cave-dweller. There seems to be 
insufficient evidence for us to assert definitely that it owed its origin to 
surface freshwater gammarids which may formerly have occupied the 
rivers of South Africa together, perhaps, with isopods and crayfishes. On 
the other hand, it is no easy matter to understand how, as a cave form, 
it has spread from Europe. The former theory, however, harmonizes 
pretty well with other facts concerning the dual nature of the South 
African fauna, and seems, on the whole, a likely explanation. 
