74 AUSTRALIAN FIIRUDINEA, VI., 



which, as will be pointed out later, is very closely allied to> 

 Phikemon and might very well, on many scores, be regarded as a 

 subgenus, is confined to the northern half of New South Wales, 

 Queensland and New Guinea. In considering, then, the distri- 

 bution of these two genera, we are forced to conclude that both 

 have been evolved from a common stock, and that Geobdella has 

 adapted itself to tropical and subtropical conditions, and Philcenion 

 to more temperate conditions. 



I think that I may now reasonably suggest, if not conclude, 

 that both forms are distinctly archaic. In concluding these 

 remarks in their special reference to the question of distribution, 

 it may be stated that one might reasonably have expected to 

 meet with representative species of one of our Australian terres- 

 trial genera in some of the Island groups to the east of 

 Northern Australia which, many men of science, in consideration 

 of the continental nature of the group, have suggested were 

 connected as an extension in an easterly or south-easterly 

 direction with the Austro-Malaysian Peninsula. When engaged 

 in a collecting tour in Fiji some years ago, although I spent 

 some months in active collecting in the thick bush of that region, 

 I met with no member of the group, nor did I ever hear any^ 

 reference made by natives, a vast number of whom rendered me 

 every assistance possible iii my work, and most enthusiastically 

 proferred any information they had. Further, I know of no 

 records from the New Hebrides. This leads one, at the least, to 

 suggest that neither of the Australian forms found its way beyond 

 New Guinea, either in an easterly direction or in a westerly 

 direction. I have mentioned these details witli a view to- 

 suggesting that our two Australian genera have arisen from, 

 a common Australian ancestor which was evidently not far 

 removed from either of them in nature; and further, that 

 this evolution has taken place since the splitting up and separa- 

 tion of the outer portion of the supposed peninsular continental 

 mass but prior to the separation of New Guinea from Australia. 

 Again, if New Zealand were ever connected in a northerly or 

 north-easterly direction with any of the continental masses above- 

 mentioned, the absence of these forms in New Zealand is explained 



