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 Natalns; chin occasionally with ridge-like outgrowths. 



History. — As shown by the synonymy, this family has been asso- 

 ciated by different authors with the Vespertilionidse, Phyllostomidae. 

 and Noctilionida? as a group of varying importance. In 1899 I 

 regarded it as 'a distinct family, containing also the genera Thyrop- 

 iera, Furipterus, and Amorphochilus. Further study of more ex- 

 tensive material convinces me that the family, as then understood, 

 should be divided into three, the Natalida? containing the genera 

 Natalus, Chilonutahis, Phodotes, and NyctieUus, the Furipteridsc con- 

 taining Fvripterus and Amorphocilus, and the Thyropteridse 

 Thyroptera alone. 



Remarks. — The members of the family Natalidse 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 Phyllostomidae, 

 as shown by the structure of the premaxillaries ; but the shoulder 

 joint is of a distinctly higher type, clearly foreshadowing the com- 

 plete double articulation of the Vespertilionidae, Molossidse, and 

 Mystacopidse. The fused lumbar vertebras 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 Hipposideridse. It 

 therefore is of no assistance in determining the position of the group. 



Principal subdivisions. — The family Natalidse as now restricted 

 contains four genera. 



KEY TO THE GENEBA OF NATALIDSE. 



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 yiicticUus. 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 mires 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 Xatahix, p. 183. 



Muzzle and chin with ridge-like dermal outgrowths ; a large glan- 

 dular swelling on forehead of males Chilonatalus, p. 185. 



