442 Evolution and Distribution of Fishes 



The distribution also of the tree frogs (Hyla) parallels, 

 in suggestive manner, that of the polyprotodont marsupials. 

 No connection is known to exist for any of these with East 

 Indian lands. 



Amongst reptiles equally confirmatory results are got. 

 Thus in the division Chelonia, the family Chelididae in- 

 cludes Chelys of S. America, and the allied genus Chelodina 

 of S. and E. Australia; while one species of Chelodina 

 survives that had reached up into New Guinea. But during 

 the short-lived connection that permitted this, the Malayan 

 Crocodile (Crocodilus porosiis) was able to pass across 

 into, and now inhabits N. Australia. But this species only, 

 and none of the northern or Arctogaea tortoises, reached 

 Australia. 



The lizards, and not least the snake-like Pygopodidae 

 are most instructive, but their history is too extended for 

 study here. Amongst snakes the poisonous group Elapinae, 

 so far as known at present, suggests any one of three distri- 

 butional possibilities, (i) Either the group may have 

 evolved as a northern or Arctogaean series that spread 

 into Australia, and later across the Antarctic continent to 

 S. America, where species of Flaps are now widely scatter- 

 ed; or (2) the reverse journey may have been made; or (3) 

 a double invasion of Australia may have been effected, one 

 from S. America by way of Tasmania, and another from 

 the north by the Cape York peninsula. The first of these 

 seems most likely. But the question can probably be correct- 

 ly decided only after exhaustive comparisons have been 

 made of all species of the existing genera. 



The migrational powers, and adaptive capacity of 

 flying birds are so great that very limited deduction can be 

 drawn from the group. As to freshwater or land inverte- 

 brates, the many striking facts already gathered almost 

 wholly favor Forbes' contentions. Enough therefore has 

 been advanced to "show the fallacy" of Lydekker's views. 



But we may now present further some definite evidence 

 in favor of Forbes' views, and which parallels the record 

 from the side of plant life. Amongst primitive cyclostome 

 fishes Geotria chilensis occurs in Valdivia, is expected by 

 Eigenmann in Patagonia, and appears also in N. Zealand 



