PTKROPITS. 69 



Either towards complete or iiearlj- complete oliliteration of the 

 ledj;;es, as in the s[)ecics of the l^t. </ii/antei(x (five species), alecto 

 (four), cimspicillatus (three), neohiheniirux (two), and macrotis groups 

 (three), though in young teeth of some of these species a slight 

 remnant of the ledge is occasionally detectable. Or towards an 



A' 



B' 



C 



K' 



rig. 10. — p,, ]^^^. in,, m.^. profile and upper view of left r)w. All figures \. 

 A, a', typical Pteropine denti'ion ; posterior basal ledges moderate 

 {Pt. hiiiKiiiielanux lutcus, iminatiire, 78.9.14.2). B, B', posterior 

 basal Ifdges heavy, separated postero-externally by a deep notch 

 fmm base of outer main eusp ; note in tlie upper view tiie deep 

 transverse groove in the inner (in the figure right) longitudinal 

 ridge of p, and ni, in front of middle of ridge {I't. pselaphoii, adult, 

 92.2.4.1). (-", strong ])osteiior bnsal ledge of p^, nii, and in^ coii- 

 tiiiueil forward along ba.>ie of inner (right) side of tooth {Ft. aneti- 

 anu.-'. adult, 7.1.1.2.';r)). R, D', teeth short (ant«ro-posteriorly) and 

 brotid ; piisterior bisnl ledges practically obliterated (PL reo- 

 hiliernii-iis. immnture, 8().7.9.1. type of I'f. rvroiianis). E, E', de- 

 geuerat*.' ileutitioii (Pt. scapuUilus, adult, 7.8.9.4). 



unusual strengthening of the ledges, as in Pt. rodrirensis, nawai- 

 msis, sarnohms, anttliniu^, innuJdri.i, phceocephaJus, pselaphon, 

 pih.tus, and t'lhercnlntus ; in most of these species the ledges are 

 ■well-marked also in m' and nij. and not infrequently indicated in 

 m.. 



Inner hasal lodge in lower molarit'orm teeth (tig. 10 (V). — I't. 

 uiietianus is unique in the genus (but similar to Acerodon) in ha'^iug 



