Wil.hiu the- genus Plcro/'U.^- the wing-structure is rather uniform, 

 the variations chietlj' confined to the greater or lesser relative 

 length of the terminal phalanges, and even in this respect the 

 variations are rather inconspicuous. .Subjoined the wing-indices 

 of Ft. hiJj>omeJanus, calculated from measurements of 56 adult 

 specimens representing the eleven known races of the species: — 



Inter femorfd. — In most species scarcely developed, or only a few 

 millimetres deep, in centre ; in the species of the Pi. rufus and 

 )iiel(niotus groups generally distinct (8-lt) mm.), in the Pi. vampijrm 

 group unusually deep (sometimes 25 mm.) in centre. 



Fur. — Typical Pteropino pelage : Pur of back short, distinctly 

 adpressed, e.xtcnding on upper.side of lateral membranes somewhat 

 beyond their origin from back, breadth of furred area of back 

 therefore greater than space between linos of origin of membranes ; 

 fur of mantle and underparts generally slightly longer, but difter- 

 ence in length often more apparent than real, owing to fur of 

 mantle being less adpressed, more spreading than that of back ; 

 femur fuired above ; upperside of humerus clothed with short 

 adpressed hair; fleshy part of forearm with thinly spread adpressed 

 hairs ; tibia naked. Underside of antebrachial membrane, and of 

 lateral membrane along outer side of forearm and near body 

 between humerus and femur, clothed with short woolh' fur. — There 

 is every intergradation from this typical style of pelage (charac- 

 teristic of a majority of species), in one direction to species with 

 the fur of the back excessively short and restricted to the narrow 

 spinal tract between the origin of the lateral membranes {Ft. mda- 

 nopoijon, papiuiims, ntohihc micas : aged individuals sometimes 

 nearly naked on back), and in the opposite direction through species 

 with rather longer fur, extending more or less thickly on the 

 upperside of the tibia (most si)ecies of the Pi. rnifncri, Io7nliocensis, 

 samoeiisis; pselaphon, and toumincJri groups, and a few aberrant 

 species of other groups, viz. Pt. solonionis, hrunneHX, oruatu.i, uuraius, 

 niger, and jyoIiocqthah(.^), to species with very long and spreading 

 fur {Pt. das)/>nallus, formosus, subniijer) *. 



* It lias been stated in literature that species " provided with long woolly 

 liairs extending t>iirkly >ipnn the extremities appear to be coufined to the 

 small wind-swept oceanic- islands situuted toward.'* t)ie extreme northern or 

 s.mthern limit of the distribution of the family " (Dobson, Cat. Chir. B. M. p. 18 ; 

 nee al.M) 'IVmminck, F.^q. Zool. ]i. 6+). In so far a.s tins <t-it.'mc'iit niiffht convey 

 the idea that long-furred and haii-y-leej;ed .species arc contiiiMl to the extreme 

 iiorllKMn and southern isl.-uuls inhal>iled hy the genus.it is n.« well to point out 

 that this is I'ar from beiiii: corn-ct. It is true thai on,- of the two species 



