ON MAMMALS FROM NEW GUINEA. 73 1 



practically naked, dark grey. Hands dark on wrists, whitish terminally. Feet slender, pale 

 brown with light digits. Tail rather shorter than head and body, slender, faintly scaled, the 

 rings about 14 to the cm.; dark brown, not or little lighter below. 



Skull lightly built, smooth, with 'scarcely any ridges or crests, the supraorbital edges 

 smooth, square, but not beaded ; muzzle long; upper profile straight or even slightly concave. 



Dimensions of the type, measured on the skin: 



Head and body 132 mm.; tail 130; hindfoot 29. 



Skull, greatest length 34.2; condylo-incisive length 31 ; zygomatic breadth 17; nasals 

 13.5; interorbital breadth 5.8; breadth of braincase 14; palatilar length 15.5; palatal fora- 

 mina 5 ; upper molar séries 6.4. 



Hab. as above." 



Type. Adult maie. B. M. N°. 22. 2. 2. 44. Original number 90. Collected 16 October 

 1920 by W. C. van Heurn. 



While this species appears to hâve been extremely common around the Doormanpad 

 bivouac no other spécimens are contained in the collection, nor am I able to identify it in 

 any other of the species described from New Guinea. Its small size, smooth slender skull, 

 and rufous colour readily distinguish it from the other species obtained. 



The three small species collected by Mr. VAN HEURN may be distinguished from each 

 other by the colour of their lower surfaces, M. stalkeri with a certain amount of hairs white 

 to their roots, M. platyops with its clear grey belly, and M. rubex with a more or less 

 rufous washed one. 



24. y Hydromys esox illuteus, Thos. 



cf 45. Prauwenbivak, Idenburg River, iS September 1920, W. C. van Heurn. Type B. M. 



N°. 22. 2. 2. 61. 

 [2 çf in al. Kloof-bivak, N"oord River. Dr. Versteeg.] 



A greyer and less fulvous-suffused form of H. esox. 



Size and essential characters as in esox. General colour above lined blackish-grey, 

 without the fulvous or drabby suffusion so marked in esox. Lower colour not rising so high 

 on the flanks. Undersurface greyish, with slaty bases to the hairs; longer hairs pale buffy, 

 but the whole has nothing like the strong fulvous or buffy colour so marked in the type of 

 esox. Wool hairs of back mostly dark slaty for three fourths their length, with black ends, 

 but on the rump they are darker, brownish slaty. In esox their basai three fourths is light 

 grey — „light gull grey". Hands with whitish fingers, but the metapodals are more or less 

 brown, the corresponding colour in esox not going beyond the waist. Hind foot mostly white, 

 but blackish on the proximal part of the metatarsus, and along its outer side (inner in the 

 prepared skin) to the minimus. Tail with its short haired portion about half white and half black. 



Skull about as in esox. 



Dimensions of the type, measured in flesh: 



Head and body 260 mm.; tail 215; hindfoot 50.5; ear 17. 



Skull, condylo-basal length 48.5; condylo-incisive length 47; zygomatic breadth 23.7; 

 intertemporal breadth 7; breadth of braincase 19; palatilar length 22.5; palatal foramina 

 5.5 X 3-6; upper molar séries 8.2. 



