(2) o 4- 4-)- 2 (or 3) pnlafe-ridges have been found in six species : 

 A"/, molossinu.-i, ingul.nri!:. phcfocejjhtihis, epidarius, scapidat.us, wood- 

 fordi ; in at least two of these (Pt. insidaris anA pJuvocephahis) the 

 formula appronches 6 + 3 + 2, owing to the sixth ridge being only 

 very alightl}' inteiTupted in the middle. (3) In two species, Pf. pa- 

 pwinns and 7uohd)ernicvs, the number of middle divided ridges is 

 noticeably larger than usual, formula 5 + 8 + 3. — The palate-ridges 

 have been examined by the present writer only in tho tJnrty-one 

 species referred to above, but inasmuch as these rei)resent practically 

 all groups of the genus, it appears unlikely that any formula essen- 

 tially difieront from those given above will be found. 



E:trx. — In most species moderate in length (not reaching eye, 

 when laid forward), subtriangular, exposed ; inner margin convex 

 from base to tip, outer margin convex in lower two thirds, straight 

 or very flatly concave in upper third ; tip obtusely pointed or 

 .somewhat narrowly rounded off. The deviations from this general 

 type go chiefly in two opposite directions: — (1) Ears considerably 

 reduced, half exposed, or so much reduced as to be nearly concealed 

 in the fur ; this modiflcation is predominant in two Polj'^uesian 

 groups, the Pt. samuensis and ps^elaphon groups, and occurs also in 

 a few members of other groups, e. g. Pt. snhnir/er, w<iei\ rodricensis, 

 molossinus, and woodfordi; but the line between normal-eared and 

 small-eared species is in some cases difficult to draw, the difference 

 being one of degree only. (2) Ears long (reaching, or extending 

 beyond, eye), outer margin more distinctly concave in upper third, 

 ear therefore conspicuously attenuated above, tip acutely or sub- 

 acutely pointed ; this modification is characteristic of the Pt. rvfus 

 group (except the single Mascarene species), the Pt. vitmpyrufy group, 

 the Pt. maootis group, and Ft. caniceps, arf/entatus, and scapuJatys. — 

 Pt. livim/stonei is unique in the genus (but compare Pteralopex) 

 in having the ears nearly semicircularly rounded oft' above ; it is 

 alhcd to species {Pi. melanojtor/on, kn/ensls, ai'uensis) which have 

 the ears rather more broadly rounded off than usual. 



Wintjs. — Chief characters : second digit clawed, membranes from 

 sides of dorsum and back of second toe. — The line of origin of the 

 membranes from tho back varies somewhat in position ; generally 

 it is rather nearer the s])ine than the flanks ; in a few species 

 (Pt. ivelanopoi/on, papxrinus, ncohihernicus) the membranes arise 

 very close together, nearly from the sides of the spine. 



The wing-structure of Pteropus differs from that of the subgenus 

 Rousettus (the subgenera Stenonycteris and Lissonjfctens are more 

 specialized in this respect ) chiefly in the following four points : — 

 (1) pollex relatively longer, index about 440, in Bov,settns about 

 340-390 ; (2) second digit with claw (index 740) decidedly longer 

 than third metacarpal (index 690), in Ronsettus subequal to third 

 metacarpal ; (3) third metacarpal a trifle longer than fourth, fifth 

 slightly the longest, while Kov.seitng sliows the more primitive 

 cot;dition of having tiie fifth metacarpal tlie shortest ; (4) second 

 j)halanx of third digit longer than, rarely subequal to, metacarpal 

 of same digit, in llnnnrUnx decidedly shorter than metacarpal. 



