664 



inOOPTEEUS. 



their alveoli. Inner cusp of p^ absent (or fused with outer), that 

 of p, completely fused with outer (see fig. 57). Inner ridges of p* 

 and m' verj' low, those of p^ and m^ perfectly obsolete, the inner 

 edge of these teeth being even on a lower level than the crushing 

 surface (fig. 57). p^ and m, with a large, central, freely projecting 

 surface tubercle (or rather longitudinal ridge), m' and m^ nearly 

 as large as, respectively, p' and Pj. m^ similar in size to p,. 



Palate-ridijes. — Unknown (probably not differing essentially from 

 those of Penihefor). 



External cliaracters. — Tail reduced to a rudiment more easily 

 discovered by the touch than by the eye. Calcar unmodified. 

 Wings from first phalanx of second toe. Pollex slightly shorter 

 than in C'l/noptenis ; all other digits conspicuously longer, owing 

 to an increase in the length of all metacarpals, of both phalanges 

 of third digit and proximal phalanx of fourth, whereas the proximal 

 phalanx of the fifth is unmodified in length, the distal phalanx of 

 same digit even a little shorter than in Cynopterus (see table below, 

 showing in upper row the wing-indices of Tlwoptervs based on one 

 specimen, in lower row those of Cjinoptenis). Fur of single species 

 known longer than usual in Cynopterine bats and extending 

 thickly on upperside of tibia and metatarsus. 



Affinitus. — The absence of postorbital foramina, the grooved 

 upper canines without cingulum cusps, the peculiar structure of 

 the cheek-teeth, the greatly increased breadth of p, and m,, the 

 reduction of the tail to a mere spicule, and the different insertion 

 of the membranes on the hind feet are the principal characters 

 distinguishing this genus from Cynopterus. In Indo-Malaya it is 

 represented by the genus Penthetor, and phylogenetically both 

 genera are probably more closely connected with Balionycteris and 

 Chironax (no postorbital foramina) than they are with Cynopterus 

 (large postorbital foramina). 



History in literature. — As originally described by Matschie (1899), 

 Thoopterus formed a subgenus under Cynopter^is, numbering three 

 species, nigrescens (type), [C'/a'raiw.r j melanocephalus, and [Sphcerias] 

 hlanfordi. Miller (1907) removed melanocephalus and blanfordi 

 from Thoopterus (placing the former in Cynopterus, the latter in a 

 distinct genus, Sphvrias), but included " Cynopterus " spadiceus. 

 As pointed out elsewhere (p. 653), spadice^is must be generically 

 separated from Thoopterus, leaving niyrescens as the only known 

 species of this genus. 



