the Bats of the Family Mega'lermatiJ«. 1-43 



first phalanx, except in MucroJerma, in wliicli it has remained 

 ratluT slioit. 



The total resnlt of these modifications is b^st realize! hv a 

 comparison of the total index of tlic third, fonrth, and fifth 

 diirits: in Me^adermatidiB 1824, 1303, and 1-404, as aj^ainst 

 1372, 1106, nnd 1081 in If. diadema and allied species. 

 The fTieatest increase (452) falls on the third diijjit, the next 

 (323) on the fitth, the smallest (197) on the fourth; i. e. the 

 area of the win;:; in the family I\Iegadermatid;c is enormously 

 increased in size, the wing beino; at the same time much 

 more pointed (lengthening of third digit in proportion to 

 fourth) and much broader (lengthening of fifth digit in 

 proportion to fourth). 



General Remui-ka. 



The five genera of Megadermatida3 are referable to two 

 fundamental types. In the one, represented by Megaderma, 

 Eucheira^ and Jlacroderma, the frontal shield of the skull is 

 but moderately developed, the median external cusp (cusp 2) 

 of the n|)per m^ is more or less on the point of disa])pearance, 

 and, with the exception of the somewhat aberrant Macro- 

 derma, they have preserved the small anterior upper premolar 

 (p^). h\ the other group, represented by Laviu and Cardio- 

 derma, the frontal shield is largely developed, giving the 

 skull a quite peculiar aspect, the median external cusp of the 

 upj)er 7«' is of normal (or almost normal) size and p^ has 

 completely disappeared. Tiie former group is Oriental, 

 Malayan, and Australian, the latter Ethiopian. 



Megaderma and Eucheira, from the Malay Archipelago and 

 S. Asia, are very closely related, differing in no other 

 important respects than the t/e^z-eeof modification of the cusps 

 of the upper molars, the size of th6 prenasal notch, and the 

 size and shape of the tragus. In having cusp 2 of w/' still 

 more reduced in size, cusp 3 still more posterior in position, 

 and the prenasal notch still deeper, the strictly continental 

 Eucheira is clearly on a higher level of development than the 

 Malayan and continental Mtgaderma. 



The Australian Macroderma is undoubtedly an offshoot of 

 the Megaderrna-Eucheira branch ; broadly speaking, it 

 accords with these latter genera in the general sliape of the 

 frontal shield, the strong reduction of cusp 2 of m', and the 

 posterior jiosition of cusp 3 of //t', but it has completely lost 

 p', and the prenasal notch is unusually deep and (iiff>irent in 

 shape. 



Tlie two Ethiopian genera Lavi'a and Cardioderma, forming 

 the second section of the family, are closely related inter se. 



