410 ACERODOX. 



Interrelations of species. — The six species of Acerodon fall into 

 two well-marked natural sections, the one confined to the Celebes 

 and Timor groups, the other and more specialized to the Talaut 

 Islands and Philippines. In the former section the antero-internal 

 tubercle of p* and m' is rather smaller; a similar tubercle is often 

 developed in ]f, but not in p^ ; the ears are longer and moi-o sharply 

 })ointod ; the general colour of the fur unusually pale, and showing 

 no essential modification according to the species. Externally (ears, 

 distribution of fur, colour, size) the species of this section bear mucli 

 resemblance to the pale-coloured phase of Pteropus caniceps. Of 

 the three species, A. celebcnsis is apparently the most primitive ; the 

 dentit;ion is relatively weak, and the premolars show but little of the 

 peculiar shortening and broadening of the crowns so pronounced 

 in all other species of the genus ; an antero-internal cusp in p" 

 (generally present, or at least indicated, in A. macMoti and </iluus) 

 seems to be constantly wanting in this species. A. maehloti (Timor, 

 Flores, Alor) and A. gilrnis (Sumba) are closely related, differing 

 from each other chiefly in size. In the second section of the genus, 

 the antero-internal tubercle of p^ and m' is larger ; a similar, though 

 smaller, tubercle is always present in p^ and p^ ; the ears are 

 shorter and less pointed ; the general colour of the body, mantle, 

 and face much darker. The small A. humilis (Talaut Islands) is 

 externally very similar to certain races of Pteropus hypomelaaus. 

 The large A. jiibatus and luclfer (Philippines) show the extreme 

 phase of the broadening and shortening of the large premolai's and 

 molars ; externally they are at once distinguished from any species 

 of Acerodon and Pteropus by the peculiar, sharply defined huffy 

 nuchal patch contrasting with the general dark colour of the head, 

 mantle, and body. 



Synopsis of the Species. 



I. No antero-internal cusp in pj. Ears longer than 

 muzzle (front of eye to tip of nose), subacutely 

 pointed. Colour pale : back and imderparts 

 approximately mars-brown or vandyck-browu 

 lightened with golden bufiy, head and mantle 

 essentially bufiy. (Celebes and Timor groups) 

 <(. Dentition weaker: m', length (antero- posterior 



extent of crown) 4'7-5umi. Skull, total length [p. 417. 



62-63. Forearm 130-140. (Celebes group) . . 1. A. celehetisis, 

 b. Dentition much heavier : m', length 5"6-6 mm. 

 Skull, total length 66-72. (Timor group) 

 a. Larger : skull, total length 69-72 mm. ; fore- [p. 418. 



arm 139-156. (Timor, Flores, Alor) '2. A. mackloti, 



b\ Smaller: skull, total length 66 mm.; fore- 

 arm 135. (Sumba) 3. ^4. gilinis, 



il. A distinct antei-o-interual cusp in pg. Ears shorter [p. 423. 



than muzzle, narrowly rounded off above. Colour 

 dark : back and underparts seal-brown or burnt- 

 umber, more or less sprinkled with pale hairs ; 

 mantle chestnut or dark cinnamon-rufous. 

 (Talaut Is. ; Philippines) 



