152 Bulletin American Museum of Natural History. [Vol. XVI, 



gray above and below the eye, forming an imperfect eyering; but this 

 seems exceptional, and is probably a remnant of the summer coat, the 

 majority of the specimens having the eye region dark like the adjoining 

 parts of the face. 



Female and Young-oj -ike-year. The female does not appear to differ 

 materially from the male. The young-of-the-year, however, is much 

 lighter than the adult, having the whole ventral area white, and the 

 whole neck and the sides much lighter; the dark color of the upper 

 parts is lighter and restricted in area to the middle of the back from 

 the shoulders posteriorly; the tail is all white except at the base above. 



Measurements. The following are the collector's measurements 

 taken from the freshly killed specimens before skinning: 



EXTERNAL MEASUREMENTS. 



Skull. In addition to its large size, the skull of R. montanus is pe- 

 culiar in the unusual elongation of its facial portion. The antlers are 

 similar in length and proportions to those of the Barren Ground Car- 

 ibou, but more massive, with the palmated portions much broader 

 and heavier. (For measurements see p. 153.) 



Of the six specimens collected by Mr. Stone in the Cassiar 

 Mountains, four are adult males, one is an adult female, and 

 the other a young-fo-the-year female. The female and three 

 of the males agree very closely in coloration; the other male, 

 apparently the oldest of the series, is much paler-colored 

 throughout. 



1 Collector's numbers. No. 6 = Mus. No. 15714; No. 8 = Mus. No. 15715; No. 9 = 

 Mus. No. 15716. The original measurements, given in inches, are here reduced to 

 millimetres. 



2 Measurements from dry skins, exclusive of hair. 



