30 



Christmas Island, 



To the above account it need only be added that some specimens 

 are of a much warmer brown than others, a difference that occurs 

 irrespective of sex. In some individuals there is a small irregular 

 patch of white fur on the bell5\ In very young specimens the fur 

 is a bluish black. The mammary formula is — a = 6. 



This rat, though very numerous in places, especially on the hills, 

 e.g. Phosphate Hill, is very much less common than M. macleari. 

 I never saw one in Flying Eish Cove, though they certainly have 

 been killed there. They seem to live in small colonies in burrows, 

 often among the roots of a tree, and occasionallj' several may be 

 found living in the long, hollow trunk of a fallen and half -decayed 

 sago-palm {Arenga listeri). The food consists of wild fruits, 

 young shoots, and, I believe, the bark of some trees. M. nativitatis 

 is a much more sluggish animal than M. macleari, and, unlike it, 

 never climbs trees ; and it is difficult to avoid the belief that the 

 former species is being supplanted by the latter in spite of the 

 abundance of food. Both animals are strictly nocturnal, and 

 M. nativitatis, when exposed to bright daylight, seems to be in 

 a half-dazed condition. The Ross familj^ in Christmas Island have 

 given this species the name "Bull-dog Eat," and this has been 

 adopted by the Malays. 



Measurements of the specimens in the present collection are given 

 "below : — 







Head and Body. 



Tail. 



Ear. 



Hind-foot 



$ 



(figured) 



275 mm. .. 



. 182 



mm. . 



. 24 



mm. . 



50 mm. 



$ 







. 273 ,, 



. 159 





. 23 





. 52 „ 



$ 







. 265 ,, 



. 170 





. 23 





. 53 „ 



$ 







. 260 „ 



. 170 





. 25 





. 54 „ 



? 







. 253 ,, 



. 170 





. 22 





. 53 „ 



? 







. 250 ,, 



. 168 





. 25 





. 52 „ 



$ 







. 235 ,, 



. 160 





. 23 





. 55 „ 



? 







. 228 „ 



. 183 





. 21 





. 55 „ 



? 







. 202 „ 



. 140 





. 21 





. 50 „ 



5. Mus macleari, Thomas. 



P.Z.S., 1887, p. 513. 



Mr. Thomas's description of this species is as follows : — 



"Eur very long, thick, and coarse, but not or very slightly 

 spinous, thickly intermixed on the back with enonnously long 

 piles from 2 to 2^ inches in length. General colour grizzled 

 rufous-brown, belly but little lighter pale-rufous. Shorter hairs 

 everywhere, pale slaty- grey at base, shining red at tip ; longer 

 piles unifoiToly black ; the general tint of the dorsal surface not 

 unlike that of Arvicola amphihius, except that the median line 

 is a good deal darker owing to the great number of the longer 

 black piles there present. "Whiskers very long, manj'- of them 

 more than three inches in length, mostly black. Ears naked, 

 black, broad, short, and rounded, their breadth about equal to 

 their length; laid forward they fall short of the eye by about 



