BY R. J. TILLYARD. 



37 



North Island of New Zealand. In Chili, the group is repre- 

 sented by Phenes raptor, and in North America by Tachopteryx 

 thoreyi in the State of New York, and by T. hageni in Nebraska. 



This contour, therefore, is seen to be discontinuous over three 

 separate regions, the Australian, Neotropical, and Nearctic. 

 Such a contour, as is well known, can only be exhibited by 

 archaic groups, and is only explicable on the supposition that it 

 represents the remains of a once much more complete and wide- 

 spread contour over several regions. One of the best known 

 examples is that of the Dipnoi. 



In Odonata, a further example of a palseogenic contour is 

 exhibited by the group Petalini of the jEschnince, mentioned 

 above, with one species on the Blue Mountains, and six in Chili. 



Contours exhibiting the passage from the entogenic type to 

 the disconti'iuous palseogenic type are not infrequent. Such, for 

 instance, amongst the Odonata, are probably those of the genera 

 Rannophya and Nannophlehia; while the Monotremata furnish 

 an excellent example that will be more clearly appreciated. 



We may now exhibit the various types of contour for the 

 Australian region as follows, bracketing those that are not fully 

 established. 



