'o2i Mr. 0. Thomas on new 



XLII. — Xeio }[ammals from the Australian Ixegion. 

 By Oldfield Tiiojias. 



Ilydromys esox, sp. n. 



Size vatlier less tlian in the Australian forms of tlie genus. 

 Cii-neral colour of body above mummy-brown, this colour 

 being produced by an even intermixture of bh\ck and buffy- 

 lijiped hairs. Sidts more buffy, passing on the lower surface 

 into a dull whitish, strongly suffused with a peculiar brownish- 

 salmon tone (between Ridgway's *' vinaceous cinnamon" and 

 " vinaceous buff") ; tiiis suffusion is strongest on tlie chest, 

 weakest in the inguinal region. Top of head, above a lino 

 from halfway between the nose and mouth running back 

 below the eye and ear, blackish, markedly darker than the 

 body on the crown, and quite black laterally on the sides of 

 the muzzle and on a large patch round each ear. Ears small, 

 ])ractically naked. Fore limb wholly like belly, except for a 

 dark mark running down the outer side of the wrist. Back 

 of legs broAvn, front of legs and top of feet buffy whitish. 

 Tail with about three fiftlis of its short-haired part black, 

 two fifths white. 



Skull decidedly smaller than that of the Australian 

 II. chrysogaster^ but similar in general characters. The nasals 

 do not so far surpass posteriorly tlie frontal premaxillary 

 ])rocesses, which are themselves more slender, only 1 mm. 

 broad at their narrowest point above the anteorbital foramina. 

 Front of nasals above hinder edge of incisors, more usually 

 above their anterior surface. I'alatal foramina penetrating 

 well into maxillae. 



Dimensions of the type (measured in skin) : — 



Head and body 295 mm.; tail 225; hind foot (wet) 50; 

 ear (wet) 15. 



Skull: basal length (c.) 46; zygomatic breadth 24*7; 

 nasals 15"5x5*4; intertemporal breadth 6*7; breadth of 

 brain-case above meatus 18*8 ; height of muzzle behind 

 incisors 8"5 ; palatilar length 23*7; diastema 14*2; palatal 

 foramina 5'3 ; length of upper molar series 8'1, of rii' 5"9. 



Ilah. Port Moresby, British New Guinea. 



Type. Adult male. B.M. no. 6. 1. 26. 1. 



The only species with which this water-rat need be com- 

 pared is U. Beccarii, Peters *, described originally from the 



* Ann. Mus. Geiiov. vi. p. 30-3 (1874); Peters and Doria, op. cit. xvi. 

 p. 700, pi. xviii. (1881). 



