180 HORN KXPRDITION SUMMAKV. 



received sucli portions of its fauna as Acantliodrilus, wliile the connection between 

 New Zealand and the nortli-east of Australia (or the Papuan land) nnist have 

 disappeared befoi'e the marsupial fauna had reached so far north on the continent. 

 This second connection must however ha\e taken place before Pli<icene times, as 

 then Australia had a well developed marsupial fauna, and may perhaps have taken 

 ]ilace just at the close of the Cretaceous pei'iod and before the deposition of the 

 Eocene l)eds which exist, as at TaV)le Cape, along the northern shore of Tasmania.* 

 Judging by the aljsence in the latt(M' of certain typical Diprotodduts, as well as of 

 the Dingo, there has been, at any rate, no land connection between Tasmania, 

 and the continent during or since the Pliocene period. 



If this be so, then at the close of the Cretaceous period, whilst the rich 

 Australian flora was located mainly in the western and south-westei'ii part of the 

 continent and was gradually extending o\er to the east, the main portion of the 

 at present typical Austi'alian fauna, at least so far as the Mammalia, Pisces, 

 Amphil)ia, and perhaps to a lesser extent the Aves and Reptilia aie concerned, 

 was located in the south-east and eastern parts of the continent and was gradually 

 spreading north and west. 



A slightly later union across the Torres Straits allowed of a passage further 

 north of certain types amongst the marsupials and a jias.sage .south into the 

 continent of other forms, such as the true Rana. 



The present fauna may therefore Ite regarded as consisting of some four 

 elements which may be very briefly outlined as follows: — 



(1). An older one derived from a land connection with Asia, the constituents 

 of which it is difficult to define and wliich existed partly in the western and partly 

 in the eastern division when these two were separated. We may perhaps regard 

 as representatives of this original fauna such forms as Xanthomelon amongst the 

 moUusca of the western area, Peripatus amongst the Arthropods and Ceratodus 

 amongst the lish of the eastern side. It is also quite pcssible that along with the 

 development of the Autochthonian flora were developed in the western area, such 

 characteristic Australian families of birds as the Meliphagida^ (honey eaters) and 

 TrichoglossidiC (brush-tongued parakeets), and amongst lizards the well maiked 

 Pygopodida? and pt^rhaps otluM's such as the members of the genus Amphibolurus 

 and the curious Moloch liorridus, which at the present day arc characteristic features 

 of the western fauna. 



» Or there m.iv cvoii have l)ec'M a itoulile coiincetioii, one in Lite Cret.arooiis mv\ one in Miocene times. 



