IOO Bulletin American Museum of Natural History. [Vol. XIX. 



About one half of the series are fully adult, with the teeth 

 more or less worn; the others are 'young adults,' but none 

 are very young, nor are any very old. To this species are 

 referred four others collected at Guayaquil, on the mainland. 

 They present the same cranial characters as the Puna exam- 

 ples, but three of them are much darker above and more 

 grayish white below than the Puna* series. As, however, one 

 of the latter is indistinguishable from the three dark Guaya- 

 quil specimens, and one of the Guayaquil specimens is like 

 the more buffy examples of the Pun series, this color differ- 

 ence seems to indicate two color phases a gray and a slightly 

 rufescent phase rather than two geographical forms. 



