38 Proceedings of the Biological Society of Washington. 



Skull of type: condylobasal length, 17.1; greatest length, 18.2; breadth 

 of braincase, 8.5; interorbital constriction, 4.4; length of maxillary tooth 

 row (including canine), 7; length of mandibular tooth row (exclusive of 

 incisors), 7.8. 



Remarks. — The Porto Rican brown bat needs critical comparison only 

 with Eptesicus cubensis from which it can be separated by the diagnosis 

 above given. A male topotype (skin and skull. No. 179,230, U. S. 

 National Museum, Biological Survey Collection) is immature, but as far 

 as is determinable bears all the characters of the type. 



