90 THE WANDERINGS OF ANIMALS [CH. 



PERIPATUS. 



Peripatus is the sole surviving genus of the 

 Protracheata. The group, ancestral to spiders and 

 insects, must be of enormous age, but this genus need 

 not date further back than into the Cretaceous to 

 allow us to account for the scattered distribution of 

 its species as follows : the occurrence of the same 

 species in Australia, including Tasmania, suggests this 

 region as the original centre, whence other species 

 spread into New Britain and Indo-Malaya. Then ex- 

 tension across Antarctica by Patagonia to Chile, 

 whence into the rest of South America (Guiana) as 

 this became consolidated in Tertiary times. For 

 getting to the West Indies and into Mexico they 

 would have had to wait until the Miocene, but long 

 before that time they could arrive in Africa, there 

 surviving as a Congolese and a Cape species ; but 

 they never reached Madagascar. 



INSECTS. 



The genus Carabus, flightless beetles, lives to the 

 north of about the 30th parallel in both hemispheres 

 and reappears in Chile : by no means a solitary in- 

 stance of such a discontinuity in America, e.g. bears. 



