Osgood — Thirty Neiv Mice of the Genus Peromyscus. 61 



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Peromyscus polius .sp. iiov. 



Tt/pc from Colonia Garcia, Chiluiahiia, Mexico. OKI female, No. 

 i»S,22G, U. S. National Museum, Biological Survey Collection, June 2(5, 

 1S99, K. W. Nelson and E. A. (loldman. 



Characlers. — iSomewhat similar to P. hoylei roirleiji, but decidedl}'^ larger 

 and grayer colored ; skull large and stoutly built, with large teeth and 

 relatively small audital bullw?. 



Color. — General color of upper parts grayish broccoli brown, produced 

 by a ground color of pinkish buff mixed with dusky ; lateral line clear 

 pinkish butf; head slightly more grayish than body, particularly on 

 cheeks ; a narrow dusky orbital ring ; lanuginous tuft at base of ear occa- 

 sionally tinged with white; under j)arts pure white; feet and ankles 

 white ; tail bieolor. 



Sknll. — Similar in general to that of rowleyi, but larger ; molar teeth de- 

 cidedly larger ; palatine slits longer ; audital bullae actually about same 

 size, relatively smaller; otherwise not peculiar. 



Mea>^iu'emenlfi. — Average of 8 adult topotypes : Total length, 218.5 

 (210-2;;4); tail vertebrie, 117 (111-120); hind foot, 25.8 (25-26). Skull 

 of type: Greatest length, 29.9 ; basilar length of Hensel, 22.9 ; zygomatic 

 width, 14.8; interorbital constriction, 4.5; interparietal, 10.5 x 2.8; 

 nasals, 11.6; bony palate, 4.4 ; palatine slits, 6x2; diastema, 7.4; post- 

 palatal length, 10; upper molar series, 4.7. 



Remarks. — This species nearly equals P. dijficllis in size, but its shorter 

 tail and ears readily distinguish it without recourse to the skull, in which 

 the audital bullae are scarcely more than half the size of those of dlfficUis. 

 Its real relationship is undoubtedly with rowleyi and atlwateri. It is appar- 

 ently an isolated species, and is not the general Mexican representative 

 of this group, for practically typical rowleyi occurs as far south at least as 

 central Zacatecas. Its pure white ankles, as well as its large size and 

 pale color, aftbrd convenient characters for readily recognizing it. 



Peromyscus gratus gentilis subsp. nov. 



Type from Lagos, Jalisco, Mexico. Adult male. No. 78,9:!7, U. S. Na- 

 tional j\Iuseum, Biological Survey Collection, June 27, 1896, E. W. Nelson 

 and E. A. Goldman. 



C/(ar((do-s.— Similar to P. grains but paler; sides of head much more 

 fulvous ; molar teeth slightly smaller. 



Color.— 'New pelage: Upper parts pale ochraceous buff lightly mixed 

 with dusky ; middle of back with a slight concentration of dusky tipped 

 hairs; top of head, ear tufts, etc., with a predominance of huffy; sides 

 of head nearly clear ochraceous buff, with a sliglit tinge of grayish be- 

 tween eye and base of ear ; eyelids black ; under parts white ; hands and 

 feet white; ankles dusky; tail bieolor, blackish above, white below. 

 Worn pelage : Upper parts varying from clear bright ochraceous buff on 

 back and rump to grayish bufl about head and shoulders, sometimes with 



