2OO Bulletin American Museum of Natural History. [Vol. XXII, 



total length, 895 (812-970); tail, 30 (25-37); hind foot measure- 

 ments not available; ear, 93 (89-110): 5 adult females (teeth only 

 slightly worn, the wear except in one specimen limited to m 1 ), total 

 length, 913 (889-939). The females average slightly larger than the 

 males, in both external and cranial measurements, as shown by the 

 subjoined table of measurements of the skulls. 



There is much variation in respect to coloration. Taking the 

 series as a whole, two color phases are fairly recognizable, a yellowish 

 phase and a gray phase, the latter predominating in the ratio of about 

 6 gray specimens to i yellow. In the yellow phase the yellowish tint 

 is most pronounced on the ' collar, ' or oblique shoulder stripes, and 

 on the sides of the head and neck. In several specimens these parts, 

 but especially the 'collar,' are strong yellowish buff, as in T. a. 

 humerale, and the sides of the body are also strongly suffused with 

 buff. In the gray phase, in extreme specimens, the collar is white, 

 as is the ground color of the sides, but generally there is a more or less 

 decided suffusion of pale buff. The shoulder stripes are a pronounced 

 feature in only about half the specimens; in some they are entirely 

 obsolete; in a few they are strongly developed, but in most of the speci- 

 mens they are not conspicuously prominent. The amount of black 

 in the dorsal area is also variable, depending upon the amount of black 

 tipping the bristles. 



There are several noteworthy cases of individual variation in 

 cranial characters, especially in the length of the upper molariform 

 series, the breadth of the skull as compared to its length, breadth 

 of the posterior nares, relative size of the bullae, etc. In one adult 

 male skull with a basal length of 192 mm. the zygomatic breadth is 

 104 mm.; in another adult male skull of exactly corresponding age, 

 but having a basal length of only 183 mm., the zygomatic breadth is 

 120 mm. This skull is not exceptionally broad in other measure- 

 ments, and only in this respect forms a striking variant from the 

 rest of the series. A female skull, the largest and slightly the oldest 

 of the series of females, also departs widely from the normal in the 

 great length of the palatal region and of the upper molariform beries, 

 which each have a length of 6 mm. above the average, combined with 

 a zygomatic breadth 2 mm. below the average. There is great 

 individual variation in both the form and size of the audital bullse, 

 the breadth sometimes nearly equalling the length (24 X 26 mm.) 

 or being much less (20 X 25 mm. or 18 X 22 mm. etc.). 



The length of the upper molariform series (pm 1 m 3 ) varies 

 in the males from 61 to 67 mm., and in the females from 54 to 69 



