THE FAMILIES AND GENERA OF BATS. 
103 
KEY- TO THE GENERA OF MEGADERMIDiE. 
Upper premolars 2 - 2 ; interorbital region not conspicuously concave. 
Lachrymal width much less than distance from orbit to canine, 
Megaderma, p. 103. 
Lachrymal width greater than distance from orbit to canine, 
Lyroderma, p. 104. 
Upper premolars 1 — 1 ; interorbital region conspicuously concave. 
Rudimentary premaxillaries rather distinct, projecting beyond line of 
canines ; width of frontal expansion much less than distance be- 
tween outer sides of toothrows . Macroderma, p. 105. 
Rudimentary premaxillaries practically absent; width of frontal ex- 
pansion about equal to distance between outer sides of toothrows. 
Upper molars with W pattern distinct Lavia, p. 105. 
Upper molars with W pattern distorted by reduction of the rneso- 
styles Cardioderma, p. 106. 
Genus MEGADERMA Geoffroy. 
1810. Megaderma Geoffroy, Ann. Mus. Hist. Nat., Paris, XV, p. 197. 
1866. Spasma Gray, Proc. Zool. Soc. London, p. 83. 
1878. Megaderma Dobson, Catal. Chiropt. Brit. Mus., p. 154 (part, sub- 
genus). 
1907. Megaderma Andersen and Wroughton, Ann. Mag. Nat. Hist., 7th 
series, XIX, p. 130, February, 1907 (genus). 
Type-species. — V espertilio spasma Linnaeus. 
Geographic distribution. — From India, Ceylon, and the Malay 
Peninsula to Sumatra, Borneo, and the Philippine Islands. 
Number of forms. — Four forms are recognized by Andersen and 
Wroughton. 
Characters. — Dental formula: 
. 1 .- 2-4567 
1 2 -. 1 . - 2 - 4 5 6 V 
. 0-0 1-1 2-2 
* 2 ^ 2 ’ * 2 ^ 2 ’ m 
3 ~ Lao 
3-3 1 
Lower incisors large, indistinctly trifid, forming a continuous, 
slightly convex row between canines, the inner tooth smaller than 
outer. Canines large, with well-developed cingula, the lower with- 
out secondary cusps, the upper with a minute anterior cingulum 
cusp and a large posterior cusp at base of shaft. Anterior upper 
premolar minute, on inner side of toothrow in angle between canine 
and large premolar. First and second upper molars with three 
main cusps rather close together, particularly in m 1 , and mesostyle 
so reduced that the W pattern is considerably distorted by the partial 
obliteration of the median commissures. Postero-internal heel well 
developed but without trace of hypocone. Third upper molar with 
four cusps and two commissures. . Lower molars with cusps near 
together and those on inner side reduced in size, particularly the 
