ITAKPYIONYCTERIS. 801 



relatively the same in both genera (about one-fourth of total length 

 of skull); front of orbit above middle of m' (as in Dobsonia). 

 Premaxillae solidly fused anteriorly, their ascending branches 

 similar in shape to those of Dobsonia (narrow, tapering to a 

 point above). Postdental palate as in Dobsonia, rather rapidly 

 narrowing behind tooth-rows. Postorbital processes moderate, as 

 in Dobsonia ; postorbital foramina present. A low sagittal crest. 

 General shape of mandible as in Dobsonia, except for greater 

 proclivity of sj'mphysial region and rather stronger development 

 of angular region ; condyle nearly at level with alveolar line. 



Dentition (figs. 78, 79).— !""P P P "^ "^ X 2 = 30. Dental 



i^cP. PsPi^i'^.ni. 

 formula as in Dobsonia, except for presence of p'. 



i'' * unusually proclivous,in front view obliquely bilobed (compare 

 Dobsonia), inner (medial) lobe hook-like and much longer than 

 outer ; posterior basal ledge strongly developed, making antero- 

 posterior at least equal to transverse diameter of crown, i^* rudi- 

 mentary, styliform, closely wedged in between canines (as in 

 Dobsonia), perhaps deciduous (in the single skull known only one 

 lower incisor is present, see tig. 78). Upper canines proclivous, 

 short and heavy as in Dobsonia, but with a strong secondary cusp 

 from posterior edge reaching to middle of crown ; cingulum well- 

 developed. Lower canines proclivous, situated at extremity of jaw, 

 nearly in contact with each other, both in position and general 

 shape recalling those of Dobsonia, but with a strong secondary 

 (cingulum) cusp at lower half of outer edge and a smaller one at 

 middle of inner edge. 



p^ small, slightly bicuspidate, the larger anterior cusp (e in 

 fig. 79) probably corresponding to outer cusp of p^, the smaller 

 posterior (pe) to postero-external cusp of p'. p^ remarkably 

 similar in structure to p' of Dobsonia ; outer (e) and inner cusp (i) 

 separated at tip, a small but quite distinct postero-external basal 

 cusp (p«), and a low and narrow antero-internal basal ledge (a), 

 the rim of which tends to develop one or two minute cusps. 

 Essentially the same elements reoccur in p\ but more highly dif- 

 ferentiated ; the outer cusp, which is sim])le in p', is in p* by a 

 sharp but not very deep notch split into two cusps (e\ e"), there is 

 a faint trace of a similar splitting of the inner cusp (i), the antero- 

 internal basal ledge (a) is some\\ hat heavier and its rim raised into 

 a distinct though small cusp, the postero-external basal cusp (jj(?) as 

 in p\ but the posterior (or rather postero-internal) corner of the 

 tooth has developed a conspicuous cusp (pi). m\ again, is essen- 

 tially similar to p\ but a little more complicated ; there are four 

 cusps along the external edge, the two anterior and largest (e', e') 

 being the bifid outer cusp, the fourth (j:)«') the postero-external 

 basal cusp, while the third (pe') is a small supplementary cusp 



* The houiologies of tlie single pair of upper and lower incisors of Har- 

 pyionycterU have been determined by comparison with its nearest relatire. 

 Dobsonia Csee n. 452, footnote). 



3f 



