250 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



larger, hind foot shorter; skull narrower across mastoids and parietals; 

 nasals shorter. 



Color: Upper parts pinkish buff, palest on the head and darkest 

 on rump, the plumbeous under fur showing in places; no black streaks 

 on face; white spots behind ears and above eyes; upper parts of sides 

 from eye to rump, like color of rump; nose, sides of face, lower part 

 of flanks, entire under parts and limbs, pure white; a narrow line of 

 pinkish buff across thighs; hands yellowish white, feet white; tail with 

 a bushy pencil, the upper parts to tip pale drab, sides and beneath 

 white; ears naked, yellowish. 



Measurements: Type. Total length, 225; tail vertebras, 134; hind 

 foot, 36; ear, 15. Average of ten specimens: total length, 234.7; 

 tail, 137.3; hind foot, 36.7; ear, 14.1. Skull: total length, posterior 

 line of mastoids to anterior end of nasals, 34; Hensel, 20; zygomatic 

 width, 15 ; width of mastoids, 22 ; greatest width of parietals, 15 ; length 

 of nasals, 12; greatest width of rostrum, 5; palatal length, n; length 

 of upper tooth row, 3 ; length of mandible, condyle to tip of incisors, 

 16; length of lower tooth row, 3. 



In my paper on the Mammals of the San Pedro Martir Mountains 

 (Field Museum Publication, Vol. III., p. 220), I referred the ten speci- 

 mens of Dipodomys from San Felipe and Canon Esperanza to D. m. 

 simiolus. Since that paper was issued, I have received from Mr. E. 

 Heller, series of Dipodomys from Palm Springs (Agua Caliente), and 

 Whitewater, type localities of D. m. simiolus and D. m. similis respect- 

 ively. On comparing the Lower California examples with these, it is 

 at once seen that the Mexican animal is lighter and more pink in color, 

 very much smaller in all its measurements, and is without the dark 

 streak on the lower side of the tail. These ten specimens represent a 

 well-marked diminutive race of D. merriami, nearest allied to D. m. 

 simiolus. 



Dipodomys merriami mortivallis. Subsp. nov. 



Type locality: Furnace Creek, Death Valley, Inyo County, Cali- 

 fornia. 



Genl. char.: Similar to D. m. simiolus, but the dorsal and 

 ventral stripes and pencil of the tail vary from a purplish drab to a 

 pale russet, quite different from the blackish tail of D. m. simiolus. 

 The general color of the upper parts of the body is darker than that 

 of the sub-species just named. The skulls of the two forms are much 

 alike, save the new race has much longer and broader nasals widening 

 at the anterior end; the extreme width of the parietals is greater, and 

 the mastoids are broader. 



