On the Native Rat of Pearson^ s Islands, 601 



LXIV. — The yative Rat of Pearson'' s Islands j S. Australia, 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



Prof. F. Wood Jones, of Adelaide, has now been able, 

 largely by the kind help o£ Sir George Murray, to make a 

 second vi.sit to the isolated Pearson's Isles, off tlie souihei'n 

 coast of South Australia, the place where he had previously 

 obtained the interesting Pock-Kangaroo {Pelror/ale 2:>earsoni) 

 which I described last year*. 



He has now sent half a dozen specimens of the local rat — 

 the only oilier land-mammal of the islands, — and this I find 

 to be a peculiar species, allied to the still existing Rattus 

 greyi of the mainland of South Australia, but so modified as 

 to demand local separation. 



On the suggestion of Prof. Wood Jones I have named this 

 animal in honour of Sir George Murray, the Lord Chief 

 Justice, and Chancellor of the University of Adelaide, by 

 whose generosity and assistance the former^s expedition to 

 the islands was rendered possible. Such exploratory work is 

 of the greatest value to science, and Sir George^s assistance 

 in this respect cannot be too warmly appreciated. 



Rattus murraiji, sp. n. 



Most nearly allied to R. greyi of the mainland. Size 

 about as in that animal. Fur fine and soft. General colour 

 pale greyish washed with bufFy brown, the grey showing 

 through the brown more than in greyi^ and the general tone 

 consequently paler. Under surtace drabby grey, the hairs 

 broadly slaty at base, their tips drabby whitish ; line of 

 demarcation scarcely marked. Hands and feet white, with a 

 certain darkening on the metapodials and digits which is not 

 present in R. greyi. Tail rather shorter than in R. greyi, but 

 imperfect or diseased in most of the specimens, this being, 

 perhaps, due to severe competition in a small island. 



Skull essentially similar to that of R, greyi, with similarly 

 reduced supraorbital ridges ; but the palatal foramina are 

 more widely open and the bullae are rather larger — the latter 

 a character one would not expect to find in an island animal. 



Molars conspicuously smaller than in R.greyi^ and, indeed, 

 far smaller in pro])ortion to the skull than in the great majority 

 of the species of Rattus. 



* Ann. & Mag. Nat. Hist. (9) ix. p. 681 (1922). 

 Ann. cO Mag. iY. Hist, Ser. 9. Vol. xi. 39 



