exftmined Ij}' the present writer is there any appreciuble sexual 

 ditl'erence in the cvposed colour of the mantle. 



Vi"*/))*/^.— Malagasy region generally, but not extending to the 

 continent of Africa : Oriental region ; Austro-Malaya ; North and 

 East Australia (not known with certainty from Tasmania) ; western 

 Polynesia, north-west to Volcano, Bonin, 8. Liu-kiu Islands (not 

 Japanese main islands), and Formosa, east and south-east to 

 Caroline, Sta Cruz, Fiji, Tonga, and Samoa Islands. See geo- 

 graphical review of species, infrci pp. 79-86. 



Affinities. — Pteropus has originated from a Itousettus-\i\e type. 

 It comes nearest the living species of Itouseftus in the general 

 shape of the skull, and the dental formula is the same in both 

 genera. In at least one point Pteropus appears to be slightly more 

 jirimitive than Jiousettus ; the t\mpanic is rather nearer in form 

 (narrow, annular) to the generalized insectivorous type than to that 

 of IloHsettns (broader, annular ; compare F/idolon : tympanic still 

 broader, with short bony auditory meatus). Already in llousettus 

 the occipital region shows a slight tendency to lengthening (com- 

 pare HovskUus with Oynoptenis and allied genera) ; in Pteropus 

 it is more distinctly lengthened into a short " tube"; the rostrum 

 is relatively somewhat longer, the palate narrower, especially in its 

 postdental portion, the skull on the whole (in all typical forms) 

 more heavily built, with stronger crests, and broader and more 

 steeply ascending coronoid process of the mandible. The dentition 

 of Pteropus is conspicuously heavier, i.^ enlarged (a slight enlarge- 

 ment of ij, as compared with i,, is already seen in certain species 

 of Nonsett^is ; compare also lioneia), p' still more reduced and 

 generally deciduous (comj)are liovsettus hrachyotis), the cingulum of 

 the canines and incisors stronger,' and the posterior portion of the 

 molariform teeth generally differentiated into a more or less con- 

 spicuous basal "ledge" (in certain specialized forms of the genus 

 this ledge is again obliterated, but even then a trace of the ledge 

 is often detectalile in the young unworn teeth). Also externally, 

 Pteropus is decidedly on a higher level than llousett.us : the tail 

 has disappeared, its wing-structure is slightly less primitive (see 

 p. 72), the mnntle generally conspicuously different in colour from 

 the back, and the size of the animals generally much larger. Both 

 genera are distributed over continental S. Asia, Indo-Malaya, 

 and Austro-Malaya ; but whereas Roiisettus extends to Palestine, 

 Cyprus, and the Ethiopinn region, exclusive of Madagascar and its 

 adjacencies, Pteropus finds its western limit in the Indian Penin- 

 sula, including Ceylon and the Maldives, is rather richly represented 

 in the whole of the Malagasy region, but perfectly unknown in the 

 African continent ; and eastward, liousettus does not extend beyond 

 the Solomon Islands, and is unrepresented in Australia, whereas 

 Ptero^ms has spread over the whole western portion of Polynesia, 

 northward over Micronesia, and southward to Australia. 



Suhdivisions. — The 82 species (1*9 distinguisliable forms) are 

 arranged in seventeen groups according to their probable natural 

 affinities, viz. :— the Pt. hi/pojiielanvs {Hi species, 26 forms j, )nnri- 



