790 MESSRS. O. THOMAS AND G. DOLLMAN ON [Nov. 3^ 



the ISTeAV South Wales " lutrilla " * is or is not distinct from 

 the Tasmanian " chrysog aster'' this Queensland Water-Rat is 

 separable by its darker colour, less suffused with yellowish or buffy. 

 Mr. Stalker's series is i-emarkably uniform in this respect. 



Geoffrey's Hydromys leucogaster was also from Tasmania, and 

 probably represents a partially albinistic phase of //. chr y so g aster. 



Gould's ff. fulvolavatus is more buffy throughout. Its name 

 may prove to be tenable for the South Australian representative 

 of the genus. 



Jourdan's H. fidvo-venter t, a name hitherto entirelj' over- 

 looked, was based on a specimen believed to be from Swan River, 

 but the description is wholly inapplicable to any W. Australian 

 specimen, and there can be little doubt that the type was an 

 example of H. chrysogaster, which, coming to M. Jourdan with 

 his specimen of Macropus irma, was erroneously supposed to have 

 come from the same place. 



10. MUS CULMORUM, sp. n. 



d . 296, 297, 298, 299, 300, 321, 324, 327, 329, 445, 481. 



§ . 278, 295, 301, 303, 304, 305, 306, 322, 323, 325, 326, 330, 

 361, 381, 434, 445, 447, 449, 450. 



One 2 ii^ spirit. 



Heath Island, Burdekin R. ; Beach Mount ; Mt. Abbot. 



A coarse or spiny-haired fulvous Rat with a whitish belly, 

 allied to M. tunneyi Size about as in Mus raitus, or rather 

 smaller. Fur sparse and coarse, moi'e or less mixed with flattened 

 spines. General colour above brownish fulvous, varying con- 

 siderably according to the degree of spinousness. Sides more 

 buffy. Under surface whitish, often with a tinge of yellow, the 

 hairs pale slaty basally on the belly, whitish throughout on the 

 throat and sometimes on the inguinal region. Ears rather short, 

 practically naked. Up]3er surface of hands and feet white. Tail 

 of medium length, longer than in J/, tuiriieyi, its rings (at base) 

 averaging about 10 to the centimetre, thinly haired, dull brownish, 

 little lighter below. Mammae, as usual in this group, 2 — 3=10. 



Skull of somewhat the peculiar short broad shape of that of 

 M. tunneyi, to which there is no doubt the species is most nearly 

 allied, but its chai-acters are not so extreme. Its bullae, although 

 much larger than those of M. assimilis, greyi, and terrce-regince, 

 are not so large as those of 21. tunneyi, and the molars not quite 

 so broad. The interorbital region is narrower, and not so heavily 

 ridged. 



Dimensions of the type (measured in the flesh) : — 



Head and body 150 mm. ; tail 135 ; hind foot 29 ; ear 17. 



Skull— greatest length 35"5 mm. ; basilar length 30 ; greatest 

 breadth 19; length of nasals 12-2; interorbital breadth 4-8; 

 palatilar length 16-7 ; diastema 9-7 ; palatal foramina 7*5 ; greatest 

 diameter of bullae 9 ; length of upper molar series 7-1. 



* '' Si/dromys lutrilla, Macleay " C4ould, Mamm. Anstr. i. lutrod. p. xxxvi, 1863. 

 t Ann. Sci. Nat. (2) viii. p. 372, 1837. 



