1 IXTERREfATIOXS OF GENERA. 



tl>o coronoid process of the mandible broader and more steeply 

 ascending, i^ is always distinctly smaller than i^ (and in some 

 species, chieHy of the Fterojms lomhocensis group, nearly rudi- 

 mentary), p^ usually deciduous, m' and ni^ somewhat reduced ; the 

 occipital (sublambdoid) jiortion of tlie skull is more elongaie, vub- 

 tubular. The tail has entirely disapjiearcd, the colour's of the fur 

 are mucli more varied (that of the nnpe of the neck, the " mantle," 

 generally conspicuously brighter than the back), and the size of the 

 animnls often greatly increased, tlio sjiecies varying in size from 

 that of a .Fieldfare (or a medium-sized Jlousettus) to that of a Haven. 

 Pteropus is distributed over nearly the whole area inhabited bj^ 

 Megachiroptera, with the important exception of the African 

 continent, a fact all the more remarkable inasmuch as the genus is 

 relatively richly represented in the wliole of the Malagas}' region 

 and occurring also in tiio island of Pemba, south of Zanzibar. 



The only claim of Acerodon (six species, nine forms: western 

 Austro-Mitlaya and Philippine Islands) to stand as a genus distinct 

 from Pteropus is the rather liigher specialization of its dentition : 

 p'' and m' (sometimes also p^ and p.,) have develo])ed a well-defined 

 antero-internal tubercle, and the lower molariform teeth (p^, m,, 

 and m^) a sharply defined inner basal ledge; more or less distinct 

 approximations to similar modifications are, however, seen in some 

 specialized forms of Pteropus (see p. 415). 



The principal characters of Pteralopex (two species : Solomon 

 Island^) are the excessively heavy dentition, the shortened, snb- 

 sipiarish form of the upjier molariform teeth, the prominent anterior 

 and posterior basal ledges of the same teeth, the bicnspidato outer 

 lidge of the lower molariform teeth, the thick upper canines with 

 a heavy external secondary cusp and small inner basal cusps, and 

 the very large outer and small inner lower incisor. As pointed 

 out in detail elsewhere (p. 436) all these peculiarities represent, in 

 fact, onl}^ the last phase of modifications exhibited, more or less 

 in an initial stage, by certain species of the Pteropus ^^sflaphon 

 group (2'>sel'jpJwn, pilosus, tuhercuJatu?, and leucopterus). That 

 Pternlope.v lias developed from a bat closely related to the living 

 species of that group, or is, in other words, the peculiarly modified 

 Solomon Islands representative of that group, is scarcely open to 

 doubt. 



From another branch of Pteropus has developed the genus 

 Styloctenium (one species: Celebes): i, and m^ have disappeared, 

 and the colour of the fur is pale with dark bases to the hairs and 

 sharply defined head markings,- — all characters so distinctly fore- 

 shadowed in, or closely apy)roached by, the living species of the 

 Pteropus iemmincki and lomhocensis groups as to indicate, almost 

 with certainty, tlie origin of Sti/locienium from a form closely 

 allied to the living species of those groups of Pteropus (for a dis- 

 cussion of details, see p. 444). 



At some, probably not very remote, period of the growth of the 

 Eousetto-Pteropine main branch of Megachiroptera a bat must 



