rXERALOPEX. 



435 



than in Pteroims, m^ slightly smaller than p^ (in rteropus the 

 largest of the lower cheek-teeth), p^ t}'pical Pterojnne in struc- 

 ture ; posterior basal ledge short, separated postero-externally by a 

 distinct notch from base of outer main cusp. Inner main cusp of 

 p, and m, nearly Pteropine (ridge-like) in Pt. anceps, shortened 

 antero-posteriorly and more cusp-like in Pt. ntrata ; cutting-edge 

 of outer main cusp of same teeth slightly bifid in Pt. anceps, more 

 deeply so in Pt. atrata (fig. 22, C, C, p. -iUS); postfirior basal 

 ledge heavy, particularly postero-internally, and separated by a 

 rather deep notch from base of outer main cusp (as in Pteropi with 

 large basal ledges), m^ subsquarish, structure essentially as in p^ 

 and m^, but all characters much less pronounced, m^ subcircular 

 ■with concave crushing surface ; a shallow notch, generally present 

 in external margin, is homologous with postero-external notch in 

 anterior molars. 



Palate-r'ulges. — 5 + 6 -|- 3; number quite, arrangement very nearly 

 Pteropine. First ridge immediately behind upper incisors ; second 

 between canines ; median point of third at level of back of canines, 

 extremities at front of p^ ; fourth between p^-p', with extremities 

 at back of p^ ; median point of fifth at level of back of p^, with 

 extremities at front of p\ Of the six middle ridges, the five 

 anterior are interrupted in the median line, the sixth undivided ; 

 median point of this latter at level of back of last molar. Three 

 posterior ridges situated near palation border. 



Ears.^^\\ort, quite {Pt. anceps) or partly {Pt. airata) concealed 

 b}' surrounding fur. Upper margin semicircularly rounded off 

 {Pt. atrata), or with only a slight indication of a blunt tip {Pt. 

 anceps). No antitragal lobe. 



Wings. — Lateral membraues arising from spinal line (or so close 

 together that the interspace is scarcely appreciable) and inserted 

 posteriorly at base of first and second toes. Wing-structure 

 Pteropine, but second phalanx of fourth digit conspicuously (one- 

 fifth to one-fourth) longer than first phalanx ; in Pteropiis the 

 former phalanx is generally slightly shorter than or equal to 

 the latter {cf. wing-indices, p. 73), but even if longer {cf. e. g. Pt. 

 .^olomonis, nalamis, riihianas, grandis, tuheradattis, leticopterus, 

 ariel, gniddi), the discrepancy is apparently never so jtrononnced as 

 in Ptrralojie.v. The subjoined wing-indices are calculated from 

 measurements of only three adult individuals: — 



Affinities. — Among known bats Pteralopex has no closer relatives 

 than the species of the Pteropus pselaplion group. Highly peculiar 



2r2" 



