nORN EXPEDITION — SUMMARY. 189 



Oldfiold Thomas lias suggrstcd tliat tlio Pcraniflida* do in rospoot of llicir 

 Syndact.ylous feoli and are to bo logardfd as a group coniinod to AiiuMica and not 

 genetically allied to the Australian Diprotodonts. 



The remaining groups may lie dealt with briefly as follows. 



Rodotfin. — The rodents, which are doubtless comparatively late immigrants 

 which entered by way of the north, are represented by six genera, of wliicli 

 Hydromys with two species, Mus with twenty-seven species are widely seattered ; 

 Xeromys with one species is confined to the north-east, Conilurus with thiiteen 

 species is characteristic of the interif>r region, scarcely being represented in the 

 cast and south-east coast ; Uroniys with two species is confined to the north-east 

 and east coast, and Mastacomys is represented by one species living in Tasmania 

 and fossil in the intei-ior of New South Wales and also by an undi'termined species 

 in Central Australia. Its distribution points to its being an early introduced foiin 

 which has largely become extinct. 



C/ic/otu'a. — This group is represented l)y two genera, Emydura (Chelymys) 

 and Ciielodina. The foi-mer contains three species, of which one, E. )/iocijua>-ia\ is 

 limited to the rivers of the interior and does not occur in the east or south-east 

 coastal rivers, wliile two othei's, E. krcfftii and E. la/is/cnii/in, occur in the noith- 

 east only. The second genus is also represented by three species, of which 

 Ciielodina longicollis occurs on both sides of the Dividing Itange, while C. c.xpctina 

 is a Queensland and C. ohlonga a western and northern form. 



Crocodilia. — This group is represented l)y two species, Crocodiliis porosin and 

 C. jfl/insfonii. The former is a widely distributed species, tlie latter is confined to 

 Australia and both arc chai-acteristic of the noitli and north-east, to which tliey 

 are now confined, whilst the extinct form Pa/iin/ian/tiis pidlois is found fnssil in 

 the Lake Eyre district. 



Aves. — -The most important points in the distribution oi birds in Australia so 

 far as the subdivision of th(^ continent into faunal areas is concerned aie the 

 following: The Megapodiida^ or mound l)irds are represented by three genera, Taie- 

 galla, Megapcxlius and Leipoa. Of these the first two are distinctly north-eastern 

 forms, not spreading into the interior or to the south, whilst the single species of 

 the third (Z. occllata) is as distinctively a central form spreading right across from 

 the internal parts of New South Wales, Victoria and South Australia to West 



