iioior EXi'KornoN — summary. 1;)7 



(fi). A grailual iliying up of tJie interior, the physical harritT of the coaslal 

 ranges hcing pai'l.ly replaced, partly iutensitied, by a climatic Ijarriei' (le[)cn(lent 

 upon tile tiryness of the interior and the hiunidity of the coastal region. 



Tiie result of these series of events was the division of the continent into two 

 main areas : — 



(i). A northern, eastern and south-eastern coastal land coinciding in tliis 

 ])art witii the present rainfall limit of 25-50 inches per annum. 



(■J). A large central, western and southern area comprising the rest of 

 the continent. 



Owing, in the first instance;, to the nortlicru connection with Papua (and also 

 Polynesia) and to its southern connection witli an Antarctic land and, to a lesser 

 extent, to differences in temperature, the first of these areas contains two well- 

 marked faunas. 



(a) A nortli and north-eastorn. 

 (//) A south-eastern and .south. 



Tiie nortii-castcrn area niay l)e regarded as closely united with Papua and we 

 can thus at the present tinu; divide the Australian Region into three suli-rcgions 

 which may be distinguished as follows : — 



(1). The ToPPesian sub-region. This includes Papua and north and north- 

 eastern Australia as far south as tlie Clarence lliver. On its north-western side 

 it merges as might be expected to a certain extent into the western ai'ea. It is 

 characterised by such forms as Proechidna, Dorcopsis, Dendrolagus, Hypsipryni- 

 nodon, Phalanger and Dist:echurus ; Xeromys amongst llodents ; Casuarius, 

 Megapodius, Talegalla, and the Paradiseidie amongst birds ; Khynccedura, Oedura 

 and Physignathus amongst lizards ; Grocodilus amongst Keptilia ; liana amongst 

 Amj)hiljia ; Ceratodus and Osteoglossum amongst fisluis ; AcantJiodrilus and 

 true Pericluetes amongst earthworms ; Micropiiyura, Hadra, Chloritis, Janella, 

 Isidora, etc., amongst land and fresh-water mollusca. 



The name Papuan has already been suggested by Mr. Hedlcy for this sub- 

 region but the name Torresian is here suggested both as being less liable to lead 

 to confusion and as suggestive of the position of the old land connection which 

 gave rise to the faunal affinity of its now separated northern and southern parts. 



(2). The Bassian sub-region. This includes the eastern and south-eastern 

 coastal strip, lying between the coast line and the Dividing Range south of the 



