430 Mr. 0. Thomas— iV^o^es 



" Caught on tlie fore-sliore at night." — W. S. 



This species differs from the Key-Island species, //. heccarii, 

 by its much darker colour, especially below, that animal 

 having the under surface of a bufFy whitish. In fact, so far 

 as colour is concerned, it more nearly resembles the 

 N.-Australian species II. caurinus and the Melville-Island 

 form next to be described. 



Hydromys melicertes, sp. n. 



Apparently a small island representative of H. caurinus. 



Size and general appearance very much as in the geogra- 

 phically distant H. nauticus. Colour above rather greyer 

 than hair-brown, the crown and median dorsal area not 

 specially darker. Sides lighter grey. Under surface very- 

 pale grey, "pale olive-grey," the hairs pale grey for the 

 greater part of their length, their tips faintly buify. Hands 

 and feet dark brown. Tail with the proportions of black 

 and white as in U. nauticus. 



Skull as in //. nauticus, except that the muzzle is more 

 slender. Nasals narrow. Anteorbital foramina less high. 

 These differences, however, may in part be due to age. 



Incisors strongly orange in front. Molars small, about as 

 in nauticus^ much smaller than in caurinus. 



Dimensions of the type (measured in flesh) : — 



Head and body 232 mm.; tail 206; hind foot 54; 

 ear 20. 



Skull : basilar suture to gnathion 40 ; zygomatic breadth 

 25 ; nasals 16*8 x 5"5 ; breadth of muzzle on premaxillo- 

 maxillary suture 8'3 ; interoibital breadth 0*8 ; breadth of 

 brain-case 19 ; height of anteorbital foramen 5*8 ; palatilar 

 length 2o*5 ; palatal foramina 5'8 ; upper molars S'2 ; 

 breadth of m^ 2-9. 



Ilab. Melville Island. Type from Biro, Apsley Straits. 



Type. Young adult female, the teeth fully up, but little 

 worn. B.M. no. 13. 6. 28. 37. Original number 15*. 

 Collected 9th December, 1911, by J. P. llogers. 



" Trapped near tiie mangroves, among which the natives 

 say it lives."— J. F. E. 



Although geographically so close to the N.-Australian 

 U. caurinus, this animal is of the same small size as the more 

 distant Aru-Island form, from which it differs by its 

 unblackened head and fore back, its browner feet, and its 

 more slender muzzle. 



