1887.] COLLECTION FROM CHRISTMAS ISLAND. 511 



I. MAMMALIA. 

 By Oldfield Thomas. 



The Mammals collected at Christmas Island consist of foui 

 specimens, of which three belong to a species of Flying-Fox 

 {Pteropus) and the fourth is a large Rat. Remarkable to say, both 

 tiie species are new, but whether it will be found in the future that 

 both are peculiar to the island it is at present impossible to say. On 

 the whole the probability is that the Pteropus really is peculiar, since 

 members of this genus are often extraordinarily confined in the extent 

 of their range, while, on the other hand, it is by no means unlikely 

 that the Rat will turn out to be also a native of Java. 



As to the affinities of the Christmas-Island fauna to that of other 

 places, no definite conclusions can be drawn from so small a collection ; 

 it must therefore suffice to remark that the closest ally of the Pteropus 

 is a native of Lombock, while the Rat has its nearest relatives in the 

 Philippine Islands and Celebes. 



Pteropus natalis, sp. n. (Plate XLI.) 



a, h, c. Two adult females and a new-born male. 



Colour ( 5 ) uniformly deep shining black all over, the only 

 variation in tone being that while the head is absolutely black, there 

 is a faint brownish tinge in the fur of the body. Fur thick, soft, and 

 woolly, more so of course upon the head and neck than on the back, 

 but nowhere really straight ; on the fore limbs above it extends along 

 the humerus, and thinly along the proximal half of the forearm ; on 

 the back its least breadth is about 2| inches ; on the hind limbs it 

 extends thinly to about halfway down the tibia. Below, the humerus, 

 proximal half of forearms, hind limbs to just below the knee, and 

 wing-membranes between the body and a line drawn from the centre 

 of the forearm to the knee are all thinly clothed with scattered 

 woolly black hairs. Muzzle broad and obtuse. Ears rather short, 

 laid forward they barely reach to the posterior canthus of the eye ; 

 their anterior edges evenly but slightly convex, their tips pointed or 

 narrowly rounded off, their outer margins straight or faintly concave 

 for their upper half, markedly convex for their lower ; their basal 

 half thinly hairy internally; their distal half quite naked, black. 

 Wings arising on the back about an inch apart. Interfemoral 

 membrane narrow, quite hidden in the fur. 



Teeth, especially the canines, small and short. Upper incisors 

 forming an evenly curved series, touching one another, their total 

 breadth 5 miUim. Canines short, .5 millim. from cingulum to tip 

 behind, thin, and acutely pointed ; their postero-internal basal ledge 

 proportionally rather broad. Anterior premolars minute or absent. 

 Posterior premolars and first molar short, evenly oval in section ; the 

 surface of the molars and last premolar singularly smooth and rounded; 

 the cusps but little developed, and merely consisting of low rounded 

 ridges ; last molar circular in section, rather larger than one of the 

 outer incisors, about 1'5 millim. in diameter. 



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