riKuoPUs. 71 



as lo be ik^ui'Ij' si]u,iris!i in /'/. hucu/iU'nt.s ( [>;iil icuhirly in fJio U])pi'r 

 jaw). All the check-teeth are reduced, especially in width, in 

 PL suhnvjer. And the extreme of degeneiation is reached h}- 

 J't. pgrsonittus, sca/>nh(tHS (figs. 9 1), i)' , lU E, E'), and uwodfon/i, 

 in which the cheek teeth are excessively narrow ; a perfect parallel 

 to this peculiarity is seen in one species oIl Jiousetiux { li. lanosus) and 

 in the Macroglossi ; in the general shu])e of the teeth Pt. personatus, 

 aai/mhitus, and woodfordi bear in fact no small resemblance to 

 Eonyder'ts sjiehp.a. It should l)e noticed that a reduction of the 

 general size of the clieek-teeth (m length only, bieadth only, or both 

 in length and breadth) is a character developed independently 

 by species of entirely different groups of the genus {Pt. suhnhjer, 

 a member of the hifpomelaaus group ; Pt. moJossinus, of the loniboc- 

 eu-tis group; Pt. ]ierso)iatHS, of the teinniiucJii group; l^t. .sOTj)M?«<ici> 

 and woodfordi, geminate species fbrming a small natural group), 

 and therefore far from being indicative of natural relationship. 

 The moditication is ])robably in all cases due to adaptation to a 

 kind of food which rcijuircs less mastication than that taken by the 

 majority of species. 



Fig. 11. — Palale-ritlges, typical Pteropiiie number and arrangeiueMl, funiiiila 

 5-|-r)-l-3 (see text, infra) {Pt. hypomelanus tomesi, 94.7. 14.^). 1. 



Falate-riclf/es (fig. 11). — (1) The apparently commonest formula 

 is 5 + 5 + 3, i.e. five anterior, undivided, five middle, separated iu 

 the median line, and three posterior, approximately wedge-shaped, 

 situated near the hindei- border of the i)alate ; tliis formula has been 

 observed iu Pt. alecto, inii-tiittws, cJiri/.^ca'chen. da.fi/iimllus, tormosi(.s-, 

 (jirjaiittus, i/riseus, hi/jwiiieianus, k<'t/eiislx, melaiwpoijon , iiielanotits, 

 nttwaiciisig, inlo.sn.i, iisi laphon, rfii/neri, rudricensis, ruhianus, ton- 

 (janus, and v((>upi/ru,t. In some of these species there is a more or 

 less incomplete, sometimes nearly fully developed, additional ridge 

 between tiie normal ninth and tenth ridges (formula approaching 

 5 + 6 + 3: Pi. toni/cnnis. ;/i<ia)iteiis, vainiiip-us, but the same will no 

 doubt be found in many of the other species). ISuch species form 

 a natural transition to those in which the normal formula seems to 

 be 5 + + 3, viz. Pt. anratu.^, rtifus, limhocensis, i^olitarius. In some 

 individuals of various species the sixth ridge is only slightly, or not at 

 all, separated in tlie middle lino (rormulu nearly or quite (i + 4 + 3j. 



