400 PROCEEDINGS OF THE ACADEMY OF [May, 



Ijrowu. lu the former (represented by the type) the fur is every- 

 where ochraceous, that of the under parts imifonn from base to tip 

 of haii-s, that of the back slightly washed with clay color. In 

 the brown phase the fur is broccoli -brown, somewhat paler beneath 

 tlie surface and on the under parts. All shades of iutergradation 

 between the two phases may be found in any series of specimens. 



Skull and Teeth. — In general form the skull is like that of 

 X. straviineus, but the brainca^e is smaller and the anterior part of 

 tiie rostrum is more tapering, differences readily appreciable on 

 comparison. 



Measurements. — External measurements of type: Total lengtii, 

 95; tail, 53; tibia, 19; foot, 7.6 (7); forearm, 35.4; thumb, 

 5; second finger, 37; third finger, 77; fourth finger, 56; fifth 

 finger, 57; ear from meatus, 14; ear from crown, 12. 



Cranial measurements of t}'pe: Greatest length, 16 (17);^'* 

 basal length, 14 (15.6); basilar length, 13 (14); zygomatic 

 breadth, 8 (9); interorbital constriction, 3 (3.2); greatest breadth 

 of braincase above roots of zygomata, 7.6 (7.8); mandible, 12 

 (13); maxillary toothrow (exclusive of incisors), 7 (7.8); man- 

 dibular toothrow (exclusive of incisors), 7 (7.8). 



Specimens Examined. — One hundred and seven, from the follow- 

 ing localities in Mexico: Campeche — Apazote, 1 (skin); Durango 

 — Chacala, 25; Jalisco — Ameca, 17; Itzatlan, 1 (skin); Lower 

 California — San Jose del Cabo, 3 ; Santa Anita, 2 ; Sinaloa — near 

 Mazatlan, 1; Plomasas, 9; Rosario, 42 (7 skins); Tuxtla— San 

 Andres, 4 (1 skin); Vera Cruz — Mirador, 2. 



Remarks. — Natalus mexicanus differs from its South American 

 representative in the same characters and to about the same extent 

 as Dermonotus fulvus and Chilonyderis mexicanus. In all three 

 cases iutergradation probably takes place betvreen the large southern 

 form and the smaller northern one. 



Chilonycteris portoricensis sp. nov. 



%?e— Adult female (skin and skull), No. 102,358, United 



States National ^Museum Collected in cave near Pueblo Viejo, 



Porto Rico, W. I., March 19, 1900, by L. Stejneger and C. AV. 



Richmond. 



'" Measurements in parentheses are those of an adult male Natalas 

 stramineus from the island of Dominica (No. 113, 60o). 



