Bats from the Solomon Islands. 267 



extending on the inner side of the tooth ; inner main cusp not 

 essentially different from that of p* of a Pteropus, i. e. it has 

 preserved its character of a longitudinal ridge, is not much 

 shortened antero-posteriorly, and, as in Pteropus, it consti- 

 tutes the inner wall of the tooth (is not pressed inward, on 

 the crushing surface of the tooth). In Pt. atrata p'* is much 

 more conspicuously shortened, being only one-twelfth longer 

 than broad (actual measurements from four skulls, antero- 

 posterior diameter of crown 4'8-52 mm., transverse diameter 

 4*7-4'8) ; the anterior basal ledge is broad and extends, as a 

 well-marked ledge, on the inner side of the tooth round the base 

 of the inner main cusp, which is consequently cut off from the 

 inner side of the tooth and practically situated on the crushing 

 surface ; posterior basal ledge heavy, particularly postero- 

 internally, in some individuals showing a veiy pronounced 

 tendency to extend forward along the inner base of the tooth, 

 nearly meeting and uniting with the inner prolongation of the 

 anterior ledge ; inner main cusp of tooth much more shortened 

 antero-posteriorly, i. e. it has entirely lost its character of a 

 longitudinal ridge and is transformed into a conical cusp. 



p^ and m} . — Differential characters of m^ much the same as 

 those described above, under p^. p^ is in neither species so 

 much specialized as p*, the differential characters therefore 

 correspondingly less conspicuous. 



Pzt 7'45 "^"^ "'!• — '^^^Q bifurcation of the tip of the outer cusp 

 of p4 and nil (one of the most peculiar characters of the 

 genus) is much less pronounced in Pt. anceps; it is well 

 marked on the inner side (crushing surface) o£ the cusp, but 

 in the profile of the outer side of p* and m^ it shows only as a 

 slight depression in the upper margin of the cusp, whereas in 

 Pt. atrata it is a deep notch, ps, p4, and nii are conspicu- 

 ously less shortened, being about one-half (in Pt. atrata only 

 one-fourtli) longer than broad. As in the upper teeth, the 

 inner main cusp of p4 and m^ is more ridge-like, much less 

 cusp-like (conical), than in Pt. atrata. The posterior basal 

 ledge of p4 and nij, which in Pt. atrata is much more deve- 

 loped on the postero-internal than on the postero-external 

 corner of the teeth, thus rendering the posterior margin of the 

 teeth strongly oblique (particularly in nii), is in Pt. anceps 

 smaller and more equally developed postero-external ly and 

 postero-internally, rendering the hinder margin less oblique. 



Incisors and canines. — Upper incisors and canines, outer 

 lower incisors, and lower canines heavier than in Pt. atrata ; 

 upper incisors, combined breadth, 108 mm. (9*7-10 in four 

 skulls of Pt. atrata) ; upper canines, vertical extent from 



