36 ON THE STUDY OF ZOOGEOGRAPHICAT REGIONS, 



A more typical Papuan contour is exhibited by the well-known 

 Ornithoptera-group of the Papilionidce. The species of this 

 group spread out from Papua as a centre, and a comparatively 

 small branch extends into Australia itself, one species reaching 

 as far south as the Richmond River in New South AVales. 



Another form of entogenic contour, not, so far, found amongst 

 the Odo7iata, appears to be shown by the distribution of the 

 Australian fresh-water Crayfish, in which zoocentres of low 

 numerical value occur in the North, South-East, and South- West 

 of the continent respectively. With sufficient records, it seems 

 that tliis contour would appear as the clear result of radial dis- 

 tribution in three separate directions from the large central lake 

 known to have existed in Australia in Cretaceous time. It 

 might, therefore, be suitably called a Radial Contour. 



The study of entogenic Australian groups occurring in Tas- 

 mania, and the careful contouring of their .separate distributions, 

 may be expected to throw some light on the question of Antarctic 

 connections. The evidence afforded by the Odonata, so far, is 

 not very strong, but the very close alliance between the species 

 of the isolated group Pefalini, found only in Chili and on the 

 Blue Mountains, will be regarded by some students as one link 

 in the chain of evidence for a former connection between Aus- 

 tralia and America via Antarctica. If the Blue Mountain 

 species exists also in Tasmania, the argument will be much 

 strengthened. The fact that it has not yet been recorded is of 

 little value, when we consider how many years it has taken to 

 secure only four specimens in a well collected locality close to 

 Sydney. 



C. PaJceogenic Contours. —Transparency 3 exhibits part of the 

 contour of the subfamily Petaluriiuf, a small group of Odonata 

 with no near allies. In the Australian region, it is represented 

 by the genus Petalura in Australia, and by Uropetala in New 

 Zealand. Petalura gigantea occurs in the Blue Mountains and 

 their southern spurs, and also on Stradbroke Island, South 

 Queensland. P. ingentissima is confined to Kuranda and Her- 

 berton, North Queensland, while P. pulcherrima extends from 

 Kuranda to Cooktown, Uropetala carovei is common in the 



