1902,] NATURAL SCIENCES OF PHILADELPHIA. 401 



Characters.— Similar to the Cuban Chilonyderis boothi Gunf]- 

 lach, but with smallei* ears. 



Color. — Upper parts rather dark brown, the exact shade inter- 

 mediate between the hair-brown and bistre of Ridgway. Under 

 parts broccoli-brown washed with ecru-drab, particularly on 

 throat. AVings and ears an indefinite blackish-brown. 



Skull and Teeth. — The skull and teeth resemble those of Chilo- 

 nycteris boothi in all respects. From that of the Jamaican C. par- 

 nellii the skull is, similarly indistinguishable, but the teeth differ 

 notably in the greater size of the second lower premolar. This 

 tooth, crowded quite out of the toothrow in C. pamellii, so that the 

 first and third premolars come fully in contact, is, in C. boothi and 

 C. portoricensis, so placed as to separate the first and third by a 

 distinct space readily noticeable when the toothrow is viewed from 

 the outer side. This character, though apparently trivial, is per- 

 fectly constant in a series of seven specimens from Porto Rico, four 

 from Cuba, and two from Jamaica. 



Measurements. — External measurements of type: Total length 

 (skin), 92; tail (skin), 22; tibia, 18.8; foot, 10 (9); forearm, 

 51.4; thumb, 8; second finger, 42 ; third finger, 85; fourth finger, 

 58 ; fifth finger, 58 ; ear from meatus, 20. 



Cranial measurements of type: Greatest length, 20; basal 

 length, 18.6; basilar length, 17; interorbital constriction, 4; lach- 

 rymal breadth, 7.4; zygomatic breadth, 11; mandible, 15; maxil- 

 lary toothrow (exclusive of incisors;, 8.8; mandibular toothrow 

 (exclusive of incisors), 9. 



Remarks. — The forms of the Chilonyderis pamellii group from 

 Cuba, Jamaica and Porto Rico may be distinguished by the follow- 

 ing key : 



First lower premolar in contact witli third, the second crowded out 



of toothrow on lingual side, C. pamellii. 



First lower i)remolar not in contact with third, the second in tooth- 

 row, though usually displaced toward lingual side : 



Ear from meatus 23-24 mm., C. boothi. 



Ear from meatus 19-21 mm., . . . . C. jyortoricensis. 



Chilonycteris mexicana sp. nov. 



Type.—Aduh male (skin and skull), No. 89,277, United States 

 National INIuseum (Biological Survey collection). Collected at 



