MAMMALS OF THE MEXICAN BOUNDARY. 417 



[Pcromyscus rouityi] pinalis, Elliot, Field Col. Mus., Zool. Scr., II, 1901, p. 135 



(Synop. Mam. N. Am.). 

 Peromyscus hoylii pinaZis, Miller and Rehn.Pi'oc. Bost. Soc Nat. Hist., XXX, No. 1, 



Dec. 27, 1901, p. 70 (Syst. Re,sult.s Study N. Am. Mam. to close of 1900). 

 [Peromyscus] rowleyi pinalis, Elliot, Field Col. Mus., Zool. Ser., IV, 1904, p. 189 (Mam. 



Mid. Am.). 



Type-locality. — Granite Gap, Grant County, New Mexico. (Type, 

 skin and skull, in the collection of Gerrit S. Miller, jr.) 



Geographical range. — Upper Sonoran and Transition zones of the 

 Elevated Central Tract, in southern Ai'izona and New Mexico, and 

 in the adjacent parts of Mexico. 



Description. — Above pale grayish drab (sometimes buffy), darker 

 and l)rowner in the vertebral region; sides varying in different speci- 

 mens from buffy drab to cinnamon; orbital area dusky; ears short- 

 coated and colored like the surrounding parts; tail bicolor, hair 

 brown above, white below, with a conspicuous terminal pencil. 

 Young, slate-gray above, with the faintest possible tinge of fawn 

 color on cheeks. The adult pelage is sometimes acquired on the 

 under parts before the animal is more than one-half grown. Young 

 are born throughout the year. Mamma\ 3 pairs. 



Seasonal variation. — Examination of a series of more than 115 

 specimens, from the Elevated Central Tract of the boundary strip, in 

 which every month from I\Iay to December is represented, shows the 

 seasonal changes in coloration to be slight in comparison with those of 

 some species of the genus Peromyscus. There is, however, a cinna- 

 mon-colored coat, acquired late in the summer, which appears quite dif- 

 ferent from the winter coat. This, however, is extremely evanescent, 

 for it is scarcely acquired before it begins to be replaced by the winter 

 pelage, which comes in from before backward on the upper surface. 

 The winter coat of adults is always complete in November and Decem- 

 ber, and there is no change more than the wearing away of the tips of 

 the hair and a general fading before June. A good series taken hi 

 May shows no indications of a spring moult; but in July or, sometimes, 

 late in June, moulting begins, and the coat grows shabby and ragged. 

 In August, which is still another month of change and shedding, the 

 pelage receives a reddish cast as the transient summer coating comes 

 to predominate late in the month, by which time some individuals are 

 already receiving the drab winter coathig. It is exceptional for one to 

 appear with the completed summer coat, probably because the 

 winter coat begins to replace that of summer before the latter has 

 been perfected. By the end of September the drab winter coloring 

 predominates, October specimens showing but slight traces of the more 

 reddish summer pelage, and those taken in November none at all. It 

 is, perhaps, unnecessary to add that the winter coat is longer, denser, 

 and less rigid than that of summer, besides being more grayish. 

 30G39— No. 56—07 m 27 



