156 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



of its ears and their uniform coloration, there being no black 

 spot, the edges only being black. It must be rare in the San 

 Pedro Martir mountains, as only four specimens were taken. 



PEROMYSCUS. 

 Peromyscus *perimekurus. Sp. nov. 



T\pe locality. Goldbeach, Oregon. 



Geogr. distr. Coast region of Oregon, extent of range not 

 yet known. 



Gen. char. Similar to P. austerus, but lighter in general color 

 and larger; tail very long, 107-116. Skull with larger bullae, 

 wider pterygoid fossa, and somewhat narrower rostrum. 



Color. Back of head and dorsal region buff, heavily lined 

 with black; fore part of head, nose, sides of head and body, 

 grayish buff; lateral line bright buff, more distinct in some speci- 

 mens than in others; lips and entire under parts plumbeous, 

 washed with white; hands and feet white; tail brown above, flesh 

 color beneath, with 27 millimeters of the end blackish; ear, inside 

 orange at base, remainder black, outside pale brown for basal 

 half, rest blackish with white edge. 



Measurements. Total length, 220; tail vertebrae, 116; hind 

 foot, 23; ear, 19. Extreme measurements of seven specimens: total 

 length, 206-220; tail vertebrae, 107-116; hind foot, 22-24; ear, 

 18.5-22. Skull: occipito-nasal length, 25.5; Hensel, 19: zygo- 

 matic width, 12; interorbital constriction, 4; palatal arch to 

 alveolus of incisor, 9.5; width of brain case, 11.5; length of 

 nasals, 9.5; width of rostrum, 3; length of upper tooth row, 3; 

 length of mandible, angle to alveolus of incisor, 11.5: height at 

 condyle, 4.5; at coronoid process, 6. 



In the series of Peromyscus obtained by Mr. Heller of the 

 austerus style there seems to be two forms, the one here described, 

 characterized by greater size and a very much longer tail, with a 

 general lighter colored pelage, and the typical style. Mr. Heller 

 noticed the difference and in his notes stated that the larger form 

 was the rarer of the two, which seems to be the fact, for out of 

 fifty-eight specimens I can only find seven that can be assigned 

 to the new form, the rest being P. austerus, all, however, being 

 larger than Baird's type. The exceedingly long tail of the 

 present form makes it at once conspicuous among specimens of 

 austerus, the tail of which appears rarely to exceed 100 millimeters 

 in length. 

 *-*p2// ?/*?/?, very long; ovpd, a tail. 



