1906.] MAMMALS FROM WESTERN AUSTRALIA. 775 



45. Lagorchestes hirsutus berxieri, subsp. n. 



Ten males ; seven females. 



General characters as in the typical subspecies ; but the fur is 

 not nearly so long (hairs of back in Avinter specimens about 

 18 mm., wool-hairs 12 mm., instead of 32 and 24 mm. resjDec- 

 tively) ; the ears are slightly shorter ; the long hairs on the feet 

 are of a more glossy sandy colovir, instead of brownish ; and the 

 tail, instead of being well-haired throughout and blackish on 

 the upper side of the terminal half, is practically naked above, the 

 few minute scattered hairs being sandy. 



The skulls are remai'kably uniform in chairacter ; but, no equally 

 good material existing of the true L. hirsutus, it can now be 

 stated only that the bullae, in correlation with the shorter external 

 ear, are very decidedly smaller than in the ty23e. Tlie interorbital 

 is broad and parallel-sided. 



Dimensions of the type, measured in the flesh : — 



Head and body 370 mm.; tail 270; hind foot s.u. 112, 

 c.u. 125; ear 48. 



Skull — greatest length 76 mm. ; basal length 66 ; greatest 

 breadth 41*5 ; nasals 30 X 11"8 ; interorbital breadth 12-9 ; palatal 

 length 42 ; length of secator 4"7 ; combined length of three 

 anterior molariform teeth 15'2. 



Hah. Bernier Island, Shark's Bay. 



Type. Adult male. B.M. No. 6.10.5.18. Original number 571. 

 Collected 16 June, 1906, by G. 0. Shortridge and presented by 

 Mr. W. E. Balston. 



This animal, which differs from its mainland relations in veiy 

 much the same way as do the other two Rat Kangaroos of the 

 island from theii'S, is fortunately able to take its proper position 

 in nomenclature as an insular subspecies of L. hirsibtus, the 

 mainland foi'm having in this case been first described. No 

 record exists as to how far north the true L. hirsiUus occurs, the 

 only specimen with an exact locality that I am aware of being 

 the type, which was obtained by Mr. Gilbert at York, in the 

 Avon district inland of Perth. 



But further, a careful compaiison of two specimens obtained by 

 Mr. J. T. Tunney on Dorre Island, just to the south, with the 

 series from Bernier Island shows that a slight difference has already 

 been developed between the two ; and one that I think should be 

 recognised by name. The Dorre Island foi-m may therefore 

 be called Lagorchestes hirsutus dorreai. 



Externally the differences are not essential, though it may be 

 noted that the fur of dorreai is slightly softer, and in one example 

 longer (specimens obtained in the southern summer, and compared 

 with winter specimens of hernieri), though not so long as in true 

 hirsutus, and that the ground-colour is more rufous, the ordinaiy 

 and wool hairs, and not only the long piles of tlie rumj), having a 

 tinge of sandy rufous. 



The skull may be at once distinguished from that of hernieri 

 Proc. Zool. Soc— 1906, No. LII. 52 



