THE FAMILIES AND GENERA OF BATS. 
79 
KEY TO THE FAMILIES OF M ICROC H IROPTERA. 
Premaxillaries absent Megadermid.e, p. 101. 
Premaxillaries present. 
Premaxillaries usually free, always incomplete, their boundaries never 
obliterated. 
Premaxillaries represented by nasal branch only, or with a very 
incomplete palatal branch. 
Postorbital processes , absent ; second finger with two pha- 
langes Rhinopomhle, p. 80. 
Postorbital processes present ; second finger without pha- 
langes- Emballonuriile, p. 82. 
Premaxillaries represented by palatal branch only. 
Toes with two phalanges each ; pelvis with postacetabular 
foramen H ipposideriile, p. 109. 
Toes (except hallux) with three phalanges each; pelvis with- 
out postacetabular foramen. 
Premaxillaries bony throughout, in contact with each other 
and with maxillaries ; tragus present ; fibula absent, 
Nycterid^e, p. 99. 
Premaxillaries partly cartilaginous, free from each other 
and from maxillaries; tragus absent ; fibula present, 
Rhinolophid^e, p. 106. 
Premaxillaries always fused with surrounding parts, complete or incom- 
plete, their boundaries very early obliterated. 
Ischia fused together beneath posterior extremity of sacrum, 
Noctilioniile, p. 95. 
Ischia not fused together beneath sacrum. 
Fibula robust (its diameter usually about half that of tibia), 
contributing largely to strength of short, stout leg. 
Third phalanx of middle finger cartilaginous except at 
extreme base ; claws simple Molossid^e, p. 241. 
Third phalanx of middle finger bony; claws with basal 
talon Mystacophle, p. 239. 
Fibula very slender or rudimentary, not contributing essen- 
tially to strength of long, slender leg. 
Third phalanx of middle finger cartilaginous except at 
extreme base. 
Humerus with trochiter much longer than trocliin, 
projecting conspicuously beyond head, and forming 
a complete secondary articulation with scapula, 
VESPERTILIONimE, p. 195. 
Humerus with trochiter scarcely longer than trochin, 
not projecting conspicuously beyond head, its articu- 
lation with scapula frequently slight or none. 
Presternum not broadened anteriorly ; keel of 
mesosternum very high ; claw of thumb well 
developed : Natalhle, p. 180. 
Presternum greatly broadened anteriorly; keel of 
mesosternum a mere ridge ; claw of thumb rudi- 
mentary _ Furipterhle, p. 186. 
Third phalanx of middle finger bony. 
Canine teeth very large, shear like ; molars enormously 
reduced, without trace of crushing surface, 
Desmodonthle, p. 176. 
