DISCONTINUOUS DISTRIBUTION. 65 
in more or less separated areas. Thus is produced the 
phenomenon known as “ discontinuous distribution.” 
From the causes producing discontinuous distribution 
it is evident that such a distribution will prevail amongst 
primitive or vestigial types. The mudfishes were at one 
time a widely scattered marine order of fishes, but at the 
present day the only survivors are the vestiges of the race 
which are found in various rivers. Amongst terrestrial 
forms, one of the best instances is the archaic Peripatus, 
which is found at the Cape, in New Zealand and Guiana, 
but not in intermediate districts. 
