414 



but smaller, antero-internal tubercle developed in p^ of most species, 

 and ill p^ of A. Jiumilis, jubatus, and lucifer. Posterior basal ledge 

 of p^, fflj, and m.^ unusually strong and extending along inner btiso 

 of teeth as a broad, sharply defined shelf, m" generally larger than 

 in Fteropus, its cusps always distinct : a higher outer, lower innei-, 

 and occasionally even a small antero-internal cusp. Upper incisors 

 slenderer, subterete, and more acutely pointed. 



Other characters. — Cingulum of upper incisors narrow, par- 

 ticularly in A. ceJebensis, mackloti, and gilvus. i^ in crown area 

 from twice and a half to three times the size of i^ (as in many 

 species of Picropus). Canines typical Pteropine, with well- 

 developed cingulum. p', if present, a minute spicule, scarcely 

 piercing gum, nearly always entirely lost in adults and young 

 adults, p^ about twice the bulk of i^. p^ p\ m', and Pj, m^, m,, 

 m, shorter and broader than in Ftero^ms, this character less con- 

 spicuoiis in the weak-toothed A. celebensis, more so in A. macJcloti, 

 ffdm(s, and Jmmilis, and strongly pronounced in the large and 

 heavy-toothed ^.Jw6a^MS and ^KCi/er. m^ subequal in length to p^ 

 (in Fteropus nearly always conspicuously longer than p^). m" larger 

 than, not infrequently twice the bulk of, p^. m, subequal to p^. 

 ■ Palate-ridges. — 5-t-8-f-3 (number of middle, divided ridges larger 

 than in any Fteropus, except Ft. papuanus and neoJiibernicus). 

 First ridge terminating laterally at frout of canine ; second at hack 

 of canine ; third at front of p^ ; fourth at front of p* ; fifth at back 

 of p''; sixth at back of m' ; seventh at back of m'^; eighth to 

 sixteenth postdental. The description is taken from a single 

 specimen oi A. jubatus. 



External characters. — Acerodon is externally indistinguishable 

 from Fteropus. Interfemoral narrow, but not quite obliterated in 

 centre. Distal phalanx of fifth digit nearly always shorter than 

 proximal ; this character is, however, more pronounced in the 

 southern {A. celehensis, macJcloti, gilvus; upper row in the subjoined 

 table of wing-indices) than in the northern species {A. Jiumilis, 

 jxibatus, lucifer; lower row), and, though rare, not perfectly unktiown 

 in Fteropus. 



Fur short, rather closely adpressed on back, somewhat spreading 

 round neck. A narrow line of short adpressed hair along upporside 

 of humerus, extending also more or less thinly on proximal third or 

 fourth of forearm, but generally leaving region round elbow naked. 

 Femur furred ; tibia naked above and below. Short thinly spread 

 woolly fur on underside of Ikteral membrane between humerus and 



