DECEMBER, 1903. MAMMALS ELLIOT. 245 



pale cinnamon on sides of face beneath eyes; shoulders, flanks, and 

 sides of rump, lips, sides of nose, lower part of flanks, thighs, hands 

 and feet, and entire under parts white; base of fur plumbeous; tail 

 above dusky, beneath yellowish white. 



Measurements: Total length, 214; tail vertebrae, 119'; hind foot, . 

 23.5; ear 20.5. Skull: total length, 28; Hensel, 19; zygomatic 

 width, 13; interorbital constriction, 4.5; width of brain-case, 12.5; 

 length of brain-case, 14; palatal length, u; length of nasals, u; 

 length of upper tooth row, 4; length of mandible, angle to tip of incis- 

 ors, 16; length of lower tooth row, 4. 



With a coloring very like that of P. r. pinalis, the great difference 

 in size of skull and shape of brain-case, together with the geographical 

 distribution, shows that the two animals represent forms that are quite 

 separate from each other. These specimens were taken at the base 

 of the mountains at about 4,000 feet elevation, and no individuals 

 were seen either in the high mountains or on the desert. It would 

 appear to be local in its habitat. In a certain way, according to Mr. 

 Heller, it is something of a parasite, frequenting and taking posses- 

 sion, when possible, of the nest of the wood rats (Neotoma) dwelling 

 in the same region. It is on account of this trait in its character that 

 I have given it the above specific name. 



Peromyscus *metallicola. Sp. nov. 



Type locality: Providentia Mines, Northwestern Sonora, Mexico. 



Genl. char.: Similar to P. eremicus, but tail hairy and with a 

 pencil; sides deep orange buff, instead of pale fulvous. 



Color: Upper parts mixed black and orange buff; forehead and 

 nose gray and buff mixed: sides of face, shoulders, sides, and rump 

 about base of tail deep orange buff; orbital ring black; lips and entire 

 under parts, hands, and feet pure white; tail above dusky, sides 

 beneath white; ears brown. 



Measurements: Total length, 190.5; tail vertebrae, 101.6; hind 

 foot, 25. Skull: occipito-nasal length, 26; Hensel, 20; zygomatic 

 width, 13; interorbital constriction, 4.5; width of brain-case, 12; 

 length of nasals, 10; palatal length,, 10.5; length of upper tooth row, 

 4; length of mandible, angle to alveolus of incisor, 10; length of lower 

 tooth row, 4. 



This mouse, with a general resemblance to P. eremicus, is strik- 

 ingly different in having the tail thickly covered with hair and a pencil 

 at the tip, while the tail of the species compared is naked. The buff 



* Metallicola, a dweller in a mine. 



