Affinities of " Desmalopex " and Pteralopex. 219 



is shown by the form and relative size of the incisors, the 

 well-developed small upper premolar ["upper" a slip for 

 lower?], the squarish outline of the molars, and the extra 

 cusps of mj and ra^." 



In the foreg'oing pages I have endeavoured to show that 

 " Desmalopex," i. e. Pt. leucopterus, cannot be separated from 

 Pteropus. But I perfectly agree with Miller that Pt. leu- 

 copterus in certain respects distinctly foreshadows Pteralopex, 

 only I must add that this is the case also with the other typical 

 members of the Pt.pselaphon group, viz. Pt.pselaphon,pilosus, 

 and tuber culatus, and that this group is again closely con- 

 nected with the Pt. samo'msis group {Pt. nawaiensis, samo- 

 ensis, anetianus). The following review of all the essential 

 characters of Pteralopex will, I think, place these suggestions 

 as to a rather close relationship between Pteralopex and the 

 Pteropus pseluph on group on a firmer basis : — 



(1) General shape of skull Pteropine, on the whole nearest 

 that of the short, broad-faced, heavily- built, strongly-crested 

 skulls of Pt.pselaphon, pilosus, and tuberculatus. 



(2) Rostrum short and very broad. In both characters 

 rather closely approached by all species of the Pt. pselaphon 

 and samoensis groups, but the rostrum of Pteralopex is 

 relatively broader anteriorly, no doubt owing to the ex- 

 cessively heavy upper canines. 



(3) Premaxillae lieavy, as in all species of the Pt.pselaphon 

 group. 



(4) Postorbital processes of frontals strong at base, very 

 long, quite or nearly reaching zygoma; postorbital pro- 

 cesses of zygoma small. In all species of the Pt. pselaphon 

 group the upper postorbital processes are heavy at base and 

 very long, the lower processes small or practically unde- 

 veloped ; if, as is the case generally in Pt. leucopterus and 

 occasionally in Pt. pselaphon, the orbital ring is complete 

 behind, it is therefore formed almost entirely by the upper 

 processes, as in Pteralopex. 



(5) Coronoid process of mandible high, very broad, steeply 

 ascending (front margin almost at right angles with alveolar 

 border), angular process unusually prominent, rami deep, 

 gonys low (vertical extent), broad, and more steeply ascend- 

 ing than usual. Precisely all the same characters are found 

 in the vi\'A\u\'\h\e% oi Pt. pselapjhon, pilosus, axxd tuberculatus ; 

 the mandible of Pt. leucopterus is weaker, coronoid more 

 sloping, angular process less developed, gonys more typical 

 Pteropine. 



(6) Upper. incisors very large. The nearest approximation 

 to this in the genus Pteropus is found in the species of the 

 Pt. pselaphon. group. 



1,0* 



