456 BOBSUXIA, 



are conspicuous. The bouy palate oi Dobsania, both in its interdental 

 and postdental portions, is decidedly Pteropine, not Itousettiiie, in 

 outline ; the occiput slightly lengthened (^tuhular), though not 

 quite as much as in Pleropus ; the angular and coronoid processes 

 perfectly Pteropiue ; the outline of all premolars and molars, tooth 

 tor tooth, Pteropine ; the degree of reduction of p,, m^, and m^ pre- 

 tiselv as in Pteropus ; the crowns of the single pair of upper incisors 

 (i') modified Pteropine, not Kousettine : the palate-ridges differing 

 from those of Pterojnis only in the disappearance of the first ridge. 

 But the tympauic ring is a trifle broader and the ectopterygoid 

 processes distinctly smaller than in Pteropus. 



The peculiar modifications of the dentition and skull are these : — 

 The upper canines are slanted obliquely forward, the lower canines 

 moved forward to the anterior extremity of the mandible. The 

 shifted position of the caniues has put the lower incisors quite, the 

 upper incisors partly out of function ; ij has disappeared, i^ is 

 rudimentary, wedged in between tlie closely approximated canines, 

 aud in some species deciduous, i' has disappeared, and i^ is smaller 

 than in Pteropus aud somewhat modified in shape, because acting 

 not against i^ but against the tip of the lower canine ; as a conse- 

 (juence, the premaxilla3 are greatly reduced in breadth and directed 

 ;not obliquely forward but) nearly vertically downward between 

 the canines, the nasals are shortened proportionately, the symphysis 

 of the mandible, which iu Pteropus and Rousettus is sloping, is very 

 short and almost vertically ascending. The disappearance of p' 

 and narrowing of the diastemas c-p' and c p, contribute to the 

 shortening of the rostrum. The detailed structure of the premolars 

 and molars is iu the most primitive species (D. minor) essentially 

 llousettiue or primitive Pteropiue; in all other species modified by 

 the development of more or less sharply differentiated pos^terior and 

 autero-internal basal ledges and of median surface-ridges, in some 

 species also by a distinct tendency to a splitting of the longitudinal 

 ridges iuto separate cusps. But even when most completely dif- 

 ferentiated the structure of the premolars and molars of Dohsonia 

 is only the extreme phase of characters developed or tendencies 

 traceable in other offshoots of the Kousettine section ; posterior 

 basal ledges are present in most species of Pteropus (see anttd, 

 p. HO), antero-internal ledges are slightly indicated in certain 

 species of Pteropus (p, 70) and well-developed in Aeerodon and 

 FteraIope:c, tendency to a splitting of the longitudinal ridges is seen 

 in a few species of Pteropus (p. 70), and much more pronounced 

 in Pleralopex ; median surface-ridges are not developed in other 

 genera of the Rousetto- Pteropine section, but they are common in the 

 Cynopterine group, which is derived from a Rousettine type of bat. 

 ' The tail is similar in length to that of Rousettus (absent in 

 Pteropus), the proportionate length of the metacarpals and phalanges 

 nearer the Rousettino than the Pteropine type, the style of colour 

 of tho fur Rousettine not Pteropine. But Dobsonia is highly 

 peculiar in having the furred back completely covered by the naked 

 dorsal wing-membranes, and in the loss of the claw of the index. 



