Od a Collection of Mammals from Central and Northern Queensland. §41 



6. Ilydromys chrysogaster Geofpk. 1805. 



Hydromys chrysogaster Geoffk. in : Ann. Mus. d'Hist. Nat. Vol. VI, 



p. 90 (1805). 

 Hydromys /eucogas/er Geoffe. in: Ann. Mus, d'Hist. Nat. Vol. VI, p. 90 



(1805). 



A. Herbert Vale, 19. Dec. 1882 (skin with skull). 



The specimen was taken by a tarne dingo in a rocky district, 

 3 English miles south of Herbert Vale, in the neighbourhood of a 

 swamp, but in quite a dry place. No other individuals were seen. 



Some measurements taken from the mounted specimen : 



Length of body (head included) about 260 mm 



Length of tail 220 „ 



Height of ear (along the outer margin) 17 „ 



Sole of bind foot (to the tip of the claw) 52 „ 



In the colouring this individual is intermediate between the 

 varieties H. chrysogaster and leucogaster, as these are described and 

 figured by Gould in Mamm. Austr. Pt. V (1853). The back is black 

 with a slight mixture of reddish yellow hairs, the sides gradually 

 lighter, the belly light reddish grey, the throat more whitish. The 

 dark patch on the outer side of the fore limbs is present. Only the 

 extreme tip of the tail (45 mm) is white. 



The skull. The size of the skull: length 51 mm, breadth 

 25 mm. 



Breadth behind the zygomatic arches 25 mm 



The interorbital space 6 „ 



Height (above the auditory bulla) 15 „ 



The bullae osseae are small and rather compressed from the 

 sides. No trace of orbital or sagittal crest is to be found on the 

 skull. 



The dentition is normal: i{m^ (12), The teeth are worn, 

 with deep concave surfaces, which form cavities, surrounded by a 

 raised margin of enamel. In the upper jaw, m ^ has three such ca- 

 vities, of which the central one is nearly square and largest, the 

 posterior the least ; m ^ has two cavities , of which the anterior, 

 which is situated on the inner side, is quite small. 



In the lower jaw, each tooth has two cavities, but those in w ^ 

 are somewhat larger than in m *, 



