426 Mr. O. Thomas— Z\'(?/es 



not to mention tlie larger forms related to R. lu/reola. Bufc 

 examination shows that no S.-Australian S[)eciinens are 

 really referable to fuscipes, which seems quite peculiar to 

 Western Australia. 



Tiie S.-Australian series, however, is none the less divisible 

 into two, one, the true R. greyi, of which I now designate 

 no. 41. 1266, one of the co-types, skin and imperfect skull, 

 as the lectofcype, being the form sent home by Prof. Wood 

 Jones, so that t!iis native rat at least is still existent. 



It is the smaller of the two species, the molars are deci- 

 dedly smaller, the supraorbital edges are not ridged, even 

 posteriorly, and, externally, the fur, though long, is not so 

 excessively long as it is in the other species. 



At least eight of the Museum specimens are referable to 

 greyi, all received in 1841-1845, Prof. Wood Jones's example 

 being the first additional specimen that has come home. 



The other South-Australian species belongs to a type of 

 rat widely distributed in the interior from Adelaide to North 

 Queensland, in which latter region it has received the name 

 of cuhnorum. Tt would appear to be divisible geographically 

 into three forms, from Queensland, Interior New South 

 Wales, and South Australia respectively. The three are 

 alike in most essential characters, but there is a progressive 

 increase southward in the softness and length of the hair, and 

 a decrease in the size of the bullae ; the more southern forms 

 also have greyer bellies and shorter feet. 



Ratius cuhnorum vallesius, subsp. n. 



General characters of true cuhnorum, but the fur thicker 

 and softer; hairs of back about 15 mm. in length. Colour 

 above very much the same, but below the belly is much 

 greyer, the hairs ?laty for most of their length, while in 

 cuhnorum they are either wholly whitish or else merely have 

 their extreme base greyish. Feet rather shorter than in 

 culmorum. 



Skull essentially similar 

 tooth-row is shorter and the bulhe rather smaller. 



Dimensions of the type : — 



Head and body (on skin) 160 mm. ; tail (as recorded by 

 Sir T. L. Mitchell) 140 ; hind foot 28 ; ear 19. 



Skull : greatest length 36*5 ; condylo-incisive length 35"2 ; 

 zygomatic breadth 20; nasals 13*5; interorbital breadth 5; 

 palatal foramina 7"5 ; bulla 8"3 ; upper molar series Q'Q. 



Hah. Interior of New South Wales. Type from Duck 

 Creek, Macquarie Eiver, Upper Darling ; 31° 10' S., 

 147° 40' E. A skull in the Gould collection from the 

 Darlinf£ Downs. 



