XXXU PLASTIC CHAR.VCTERS. 



Alisence of teeth that are normalli/ present in the species. — The moat frequent 

 anomaly is the absence of the last lowei* molar (m, or ra^) or the last upper 

 molar (ra'^}; more rarely p', pi, or i^ are undeveloped: — 



inj. — Absent on one side of the jaw, in four cases, viz. one Ptcropus vampi/r/f.i 

 vampi/rus (British Museum, no. 9.1.,5.8(.)7), two Eonycteris spelaa 

 (B.M. 0.8.2.1, 8.2.2.5.4), one Macroc/lossus minimus minimics (10.4.G.1.'»). 



Absent on both sides, in five cases, viz. one Pteropus qiqantcus (79.3.31.3), 

 four Pteropus soapwlatm (.')7. 10.24.1, 62.5.2.3, 8.8;8.'4, 8.8.8.0). 



m,, is always greatly reduced in size in Pteropus and Eonycteris spelma ; 

 in a gouus closely related to Pteropus, viz. Stylocteniam, the tooth 

 has perniauently disappeared, and the same seems to be the case 

 in one species of Eonycteris {E. rosenhcrgi). In Pteropus scapulatus 

 and Eonycteris the cheek-teeth are tending to degenerate in size 

 (breadtli), and in Macroglossus the degeneration is even more pro- 

 nounced. 

 m'. — Absent on one side, in one Pteropus scapulatus (8.8.8.4). 



Absent on both sides, in one Macroglossus minimus minimus (10.4.6.15). 



As noted above (under m^ both are forms with degenerated dentition, 

 ni.,. — Absent on one side, in two cases, viz. one Cynopterus hrachyotis angulatus 

 (8.2.5.13), and one Cynopterus hrachyotis minutus (U.S. National 

 Museum, 141243). In Cynop)terus and related genera the number of 



cheek-teeth is reduced to r, tliat is, nij and m^ are lost ; ui^ is therefore 



flie last lower molar, and it is always considerably reduced in size. 



p\ — Absent on both sides, in one Eonycteris spelaa (0.8.2.1). In Eonycteris, 

 as in many other Mogaehiroptera, p'^ is rudimentary ; in certain genera 

 it is deciduous or lost. 



p,.— Absent on one side, in one Acerodon celehensis (94.7.4.2). p^ is always 

 small, but in no Fruit-bat deciduous, and only in one genus {Noiopteris, 

 entirely unrelated to Acerodon) lost. 



ij. — Absent on one side, in three cases, viz. one Cynopterus hrachyotis angulatus 

 (60.3.19.1400), one Cynopterus h. hrachyotis (97.1.2.9), and one Cyno- 

 pterus h.javanicus (79.11.21.68). This anomaly, it will be noticed, has 

 only been observed in Cynopterus, and ia several genera related to 

 Cynopterus i^ is permanently lost. 



Occurrence of teeth that are normally absent in the species, hut present in re- 

 lated Jorms : — 



lUj. — Present on one side, in one Cynopterus hrachyotis javanicus (9.1.5.73). 

 The tooth is normally lost in Cynopterus, but present in all Fruit-bats 

 with unmodified dental formula. 



Occurrence of teeth that are normally lost in all living Mcgachiroptera, but no 



doubt have been present in some extinct form : — 



jn3_ — Present on one side, in five cases, viz. one Eidolon helvum (B. M., un- 

 registered, specimen c', p. 15), one Rousettus lea/;hi (.37.4.28.67), one 

 Bousettus seminudus (unregistered, specimen a, p. 39), and two Macro- 

 glossus lagochilus lagochilus (10.3.3.23, 10.3.3.24). 

 Present on both sides, in four cases, viz. one Eousettus agyptiacus (4.4.9.2), 

 one Pteropus gigantcus (45.5.15.4), one Macroglossus minimus minimus 

 (10.4.7.2), and one Macroglossus lagochilus lagochilus (U.S. National 

 Museum, 125316). 



\. n]3 is normally lost in all Megaohiroptera, but present in some Micro- 

 cliir<)ptera. Of the nine cases recorded above of the occurrence 

 of what seems to be an " m' " it is perhaps safest to eliminate the 

 four observed in Macroglossus, owing to the nigh degree of degeneration 

 of the dentition of that genus and the unusually frequent occurrence 

 of supernumerary molars (compare the Marsupial genus Myrmecobius'.). 

 There remain five cases in Eidolon, L'ousiitus, and Pteropus, and in ' 

 view of the fact that all three genera occupy a low position in the 

 suborder it is at least not unlikely that the anomaly is a reversion to a 

 more primitive condition. 



