182 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
emargination ; teeth normal; tragus present, variously distorted and 
thickened; muzzle without nose leaf in adult, though a structure 
resembling a rudimentary leaf has been described as occurring in the 
fetus of Natalus ; chin occasionally with ridge-like outgrowths. 
History. — As shown by the synonymy, this family has been asso- 
ciated by different authors with the Vespertilionidse, Phyllostomidse, 
and Noctilionidse as a group of varying importance. In 1899 I 
regarded it as a distinct family, containing also the genera Thyrop- 
tera , Furipterus , and Amorphochilus. Further study of more ex- 
tensive material convinces me that the family, as then understood, 
should be divided into three, the Natalidse containing the genera 
Natalus , Chilonatalus, Phodotes, and Nyctiellus, the Furipteridse con- 
taining Furipterus and Amorphocilus , and the Thyropteridse 
Thyroptera alone. 
Remarks. — The members of the family Nataliclie are small, deli- 
cately formed animals, in all but one genus (. Nyctiellus ) with dis- 
tinctly funnel-shaped ears and noticeably elongated legs. The 
thumb is well developed and furnished with a normal claw, and there 
are no adhesive disks on thumb or sole. By these superficial char- 
acters alone they may generally be recognized among American bats. 
The position of the family is evidently near to the Pliyllostomidse, 
as shown by the structure of the premaxillaries ; but the shoulder 
j oint is of a distinctly higher type, clearly foreshadowing the com- 
plete double articulation of the Vespertilionidse, Molossidse, and 
Mystacopidse. The fused lumbar vertebrae indicate a strong degree 
of specialization, but the same peculiarity is found in the high Keri- 
voula and in some genera of the relatively low Hipposideridae. It 
therefore is of no assistance in determining the position of the group. 
Principal subdivisions. — The family Natalidae as now restricted 
contains four genera. 
KEY TO THE GENERA OF NATALIDiE. 
Breadth of braincase about equal to that of palate, including third molars ; 
canines reduced, scarcely higher than corresponding large premolar ; 
legs and tail not specially elongated, the tail shorter than head and 
body Nyctiellus, p. 185. 
Breadth of braincase much greater than that of palate including third 
molars ; canines normal, much higher than corresponding large pre- 
molar ; legs and tail noticeably elongated, the tail longer than head and 
body. 
Sides of rostrum from orbits to nares so inflated that molars are not 
visible when skull is viewed from directly above Phodotes, p. 184. 
Sides of rostrum not inflated ; molars distinctly visible when skull is 
viewed from above. 
Muzzle and chin simple ; no glandular swelling on forehead in 
either sex Natalus, p. 183. 
Muzzle and chin with ridge-like dermal outgrowths ; a large glan- 
dular swelling on forehead of males Chilonatalus, p. 185. 
