PLASTIC CUAKACTEUS. 



(relative length, for a forearm of 1000) of the whole of the third 

 linger (metacarpals and phalanges combined). This index is 

 between : — 



luOO-1000 : — In typical Eouscttus (i. e. li. amplexicaudatus and 

 allied forms), the shortest-winged Fruit-bats. 



lUOO-1700: — In the following genera of the Cjjno-plerns section, 

 viz. Cynopteras, Plenochirus, and FentJielor. 



1700-1800: — (In the following genera of the liousettus section:) 

 Eidolon (as a rule), Sttnonycteris, Bone'ui, and 

 Dobsonia ; {Epomophorus section :) Eponiophorus, 

 Micropteropus, iScotonycieris, and Casinycteris ; 

 (Cijnopterits section :) Myonycteris, Meycvrops, 

 Dyacopterus, Chiroiuuv, Thooptcrus, and Sphcerias ; 

 {Jlucroylossince :) Eonycteris. 



1800-1000 ■.—{liousettus section :) Lissonycteris, Pteralopex, and 

 JIarpyionycieris ; {EpomopJiurus section :) Flerotes, 

 Eponwps, llyps'ujnathus, and Nanonycteris ; (Cyno- 

 pterus section:) BaUonycteris ; (Alacroglossince :) 

 Megaloylossus and Macroylossus. 



1900-2000 :—(A'ot«e^<((S section:) Pteropns (as a xxAo), Acerodoa 

 (as a rule), and iStyloctenium ; {Cynopterns sec- 

 tion :) Nyctimene ; {Macroglossince :) Syconycteris. 



L'()00-2100 : — In the three Macroglossino genera, Melonycteris, 

 Nesonycteris, and JVotopteris. 



The table below shows the absolute minima and maxima of the 

 indices of all live lingers, and for comparison the actual indices 

 of one of the shortest-winged and one of the longest-winged 

 Fruit-bats. 



Archceopteropus, — Archceopteropus transiens, Meschinclli, from 

 the Upper Oligoceno of Italy, a bat which, judging from the length 

 of its forearm, was equal in size to an Eidolon or a female 

 JJypsiynathus, is the only Fruit-bat known only from a fossil state 

 (on " liousettus " yatUardi, from the Middle Miocene of France, 

 see footnote, p. 22), and as a tolerably complete impression of the 

 skeleton of its fore-limb has been preserved, it may be of some 

 interest to compare its wing-structure with that of living Mega- 

 chiroptera. It must be pointed out in advance, however, that 

 Meschinclli lias made a mistake in the identitication of two of its 



