1888.] OF THE SOLOMON ISLANDS. 473 



members of the genus, it agrees in the entire nakedness of the upper 

 surface of its legs. From that animal, however, it is readily distin- 

 guishable by having a bright-coloured collar, by its hairier and 

 less sharply pointed ears, and by its much more delicate teeth, the 

 canine especially being far slenderer and lighter. 



Pteralopex, Thos. 



Pteralopex, Thos. Ann. Mag. N. H. (6) i. p. 155 (1888). 



External characters as in Pteropus. Ears short, hairy. Wings 

 arising from the centre line of the back. 



Skull (Plate XXI. fig. 4) with a peculiarly short muzzle and flattened 

 frontal region ; planes of the orbits much more nearly parallel to 

 each other, and directed more upwards and less forwards, than in 

 Pteropus. Orbits completed behind by bone (as previously recorded 

 in Pteropus leucopterus alone of Chiroptera'). Sagittal crest more 

 developed than in any Pteropus. 



Teeth (Pkte XXI. figs. 5, 6) remarkable for their extraordinary 

 cuspidate character. Upper incisors with broad posterior ledges. 

 Upper canines (fig. 7) short vertically, enormously thick antero- 

 posteriorly, each with one stout secondary cusp halfway up its posterior 

 edge, and two smaller postero-internal basal cusps. Premolars and 

 molars short and broad, their anterior and posterior basal ledges so 

 developed and their main cusps so conical as to destroy all the appear- 

 ance of longitudinal grooving characteristic of the genus Pteropus. 

 Lower incisors extremely disproportionate in size, the outer not less 

 than about twenty times the bulk of the inner. Canines very short 

 vertically, with a simple posterior basal ledge. Cheek-teeth markedly 

 cuspidate, the general longitudinal grooving quite obliterated. 

 Posterior premolar and first molar each with three high anterior 

 cusps, and a low ])osterior basal ledge, a form of tooth strikingly 

 similar to that called " tuberculo-sectorial " by Prof. Cope, and 

 found in the primitive members of several of the orders of Mammalia, 

 and, notably, in the Insectivora. 



This remarkable genus is decidedly the most interesting of Mr. 

 "Woodford's Mammalian discoveries, both on account of its very 

 striking dental characters, and especially for the fact that it seems to 

 form an important hnk in the phylogeny of the Chiroptera. At 

 first sight it might appear to be merely a highly specialized offshoot 

 of Pteropus, but a careful comparison of the other members of the 

 family has convinced me that this is not the case, and that it is more 

 probably an isolated survivor from the time when the ancestors of 

 the modern Pteropodidse still possessed cuspidate teeth — such teeth, 

 which are still characteristic of nearly all the Microchiroptera, 

 having been inherited from the Insectivora by the Palaeochiroptera^, 

 or common ancestors of all the living Bats. 



^ Since the above was written, the British Museum has received, as a donation 

 from the Genoa Museum, a specimen of Pt. nicobaricus, from Pulo Nias, with 

 the orbits complete behind. Other specimens obtained at the same island, 

 however, have their orbits incomplete, as usual, and the comjjleted orbits of the 

 firat-named specimen are evidently due to its extreme age. 



^ Cf. Dobsoc, Mon. Asiatic Chiropt. pp. 7 to 10, and diagram (1876). 



