NEW BATS FROM PANAMA — HANDLEY 467 



"helmet" at their juncture in the interparietal region; rostrum long 

 and shallow; inner cutting edge of outer upper incisor (I 2 ) usually not 

 crenulated; middle upper premolar (P 3 ) about two-thirds the size of 

 P 1 ; M 1 and M 2 with protoconule, hypocone, metaloph, and cingulum 

 fairly well developed. 



Measurements: Holotype and a female paratype (USNM 310256) 

 from the t} r pe locality, together with measurements, in parentheses, 

 of two female topotypes of simus (AMNH 76244 and 76246) : Total 

 length 89, 86 (-, -) ; tail vertebrae 40, 36 (-, -) ; hind foot 8, 8 (9, 10) ; 

 ear from notch 14, 13 (-, -); forearm 39.1, 35.7 (-, -); tibia 14.3, 13.5 

 (-, -); calcar 12.8, 13.2 (-, -). Greatest length of skull 13.9, 13.8 

 (14.0, 13.7); zygomatic breadth 8.8, 8.9 (9.4, -); intcrorbital breadth 

 3.5, 3.5 (3.9, 3.7) ; braincase breadth 6.4, 6.3 (7.0, 6.7) ; braincase depth 

 5.0, 5.0 (5.1, 4.9); maxillary tooth row length 5.3, 5.4 (5.1, 5.1); post- 

 palatal length 4.5, 4.7 (4.7, 4.6) ; palatal breadth outside of M 3 5.5, 5.7 

 (5.7, 5.2); rostral breadth behind canines 3.7, 3.6 (4.0, 3.8). 



Comparisons: Compared with Amazonian simus, the Panamanian 

 specimens have the rostrum longer, shallower, and narrower at the 

 tip; the braincase narrower, less inflated; the tooth row is longer and 

 less crowded; the middle upper premolar (P 3 ) is larger (two-thirds 

 the size of P 1 as opposed to one-fourth to one-third the size of P 1 ); 

 the protoconule, hypocone, metaloph, and cingulum are better devel- 

 oped in M 1 and M 2 ; the inner cutting edge of the outer upper incisor 

 (I 2 ) is entire in four of six specimens, rather than consistently crenu- 

 lated ; the sagittal crest is lower and expanded at the juncture with 

 the lambdoidal crests in the interparietal region to form a triangular 

 helmet not seen in the Amazonian specimens; the fur of the dorsum 

 is slightly longer and more burnished (thus brighter). 



Remarks: Coloration and length of fur are seasonally variable in 

 simus. In a series of sixteen specimens from Boca de Rio Curaray, 

 Ecuador, those collected in February and March have short (2-3 mm. 

 on rump), orange-brown fur, with the individual hairs monocolored 

 on all parts of the body. The remainder of the series, collected in 

 October and December, are quite different in appearance. The fur 

 is longer (3-4 mm. on rump), chocolate brown, with slightly burnished 

 tips, and the individual hairs of the underparts are sharply bicolored. 

 Several Brazilian and Peruvian specimens (e.g. AMNH 74378, 74380, 

 74105, 91889, 92702) show molt from short, orange, monocolored fur 

 to the longer, brown, bicolored pelage. 



Several characters ascribed to simus by Thomas (1901, p. 541) and 

 subsequent authors cannot be substantiated in the specimens of 

 simus that I have examined. Most important is the supposed inser- 

 tion of the wing at the ankle. Possibly this feature had been distorted 

 in Thomas' specimen by labels tied to the ankles, as in the two USNM 



544232—60 2 



