HORN EXPEDITION — SUMMARY. 145 



Cli(T.ropus cas/a)io/is, riiascologale caliira, Dasyuriis s^eoffroyi, Pliasco/oi^a/c ci'isti- 

 cai/da, Antecliiiinmys /n?iii;cr, Myrinccobius fascia/i/s. 



3. Those whicii as far as yet known aro peculiar to the central region. 

 Tlicse include Pernga/e iniiwr* Peraineles ereiiiia)ia^ Sinintlwpsis p'iainiiiol^Iiilus, 

 S. larapitita, Phascologak inaidonuellcnsis, Dnsyuroides byrnci, Notoryctcs tvphlops. 



The species included under the second head may again be divided into two 

 series : {a) those widely distributed over the interior from east to west (^/. rufits, 

 M. robusfus, P. lagotis (?), O. /iniafa, C. castarwtis, Phascologak cristicanda (?), P. 

 ca/iira, Avtcclii)winys laiiigcr (?), D. geojfroyi) ; (/') those restricted to the west 

 side {Pc/roi^a/c lateralis^ L. (onspicillalus, BfHoiigia Icsiiciiri). 



In addition to these positive features there are equally striking negative 

 features in the absence of many representative genera of other parts — an absence 

 often, but by no means always, associated with the lack of arboreal veget/ition. 

 Such genera are, for example, Dendrolagus, TEpyprymmus, Potorous, Dromicia, 

 Petaurus, Pseudochirus, Phascolarctos, Pliascolomys. Perhaps so far as specific 

 alHnity is concerned, in the case of the mai'supials just as in that of the rodents, 

 tiie most striking fact is the presence of only one species common to the Centre 

 and Tasmania and that is the ubiquitous Pcraiucles obesiila. 



Tlie most distinctive marsupial of the Central region is without doubt 

 Notoryctes typJilops and it must be confessed that the modification of tliis curious 

 creature to adapt it to a burrowing life in hot, sandy country — if this modification 

 be regarded as having taken place within the time during whicli the Centre has 

 undergone desiccation — is a most remarkable one, all the more so because it is a 

 modification without parallel in any other marsupial of the disti'ict. It seems 

 indeed preferable to suppose that Notoryctes is the modified sur\ivor of some 

 perhaps extinct liuri'owing marsupial similar in its habits to the true mole. On 

 the other hand it is quite likely that there may yet be found in some of the large, 

 incompletely explored parts of the continent one or more allied existing forms 

 whose burrowing habits have hitherto caused them to escape detection. 



Next to Notoryctes tlic most characteristic marsupials are the species of the 

 genus Peragale ; all three of these, viz., P. /agofi^, P. leiiciira, P. lu'nior, are found 

 in the Centre to which probably the latter two ai'e confined, while the first is also 

 a Western and South Australian form. 



* I'rohablv also /'c/w/o/c leiicimi. 



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