266 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



plumbeous; tail hairy and penicillate, with a pale dusky line on 

 top, rest white; ears large, naked, dusky brown. 



Measurements. Total length, 208; tail vertebrae, 105; hind 

 foot, 24; ear from notch, 27.5. Skulk total length, 29; Hensel, 

 21.5; zygomatic width, 14; interorbital width, 4; length of 

 nasals, 9.5; length of braincase, frontal suture to occiput, 18.5; 

 width of braincase above zygomata, 13.5; width at auditory 

 meatus, 12; palatal length, n; length of upper tooth row, 4; 

 length of mandible, 12.5; length of lower tooth row, 4. 



Out of a series of 32 specimens the one selected for the type 

 has most of its measurements greater than those of any 

 other. The average of twelve adults with perfect tails is 194; 

 97; 23.4; 26.7. This would show that beside the difference in 

 color the present form is considerably larger than P. truii, a 

 series of 16 of which from Anderson's Ranch, Nevada, before 

 me, give much smaller measurements than even those of the 

 average sized stated above, especially as regards total length, 

 and that of the tail vertebras. The only other species with 

 which the present form requires comparison is P. megalotis 

 Merriam, from Black Tank, Little Colorado Desert, Arizona, and 

 by the kindness of Dr. Merriam, who loaned me three specimens 

 of his species, I have been able to bring the two forms together. 

 While resembling each other in color, P. lasius has a generally 

 paler hue on the upper parts, pure white hands and feet (these 

 in Dr. Merriam's examples being decidedly buff), a very differ- 

 ently colored tail on its upper side, and with a heavier skull, 

 having a larger and longer braincase, longer and stouter ros- 

 trum, and with a heavier mandible, especially between the 

 angle and coronoid process; the horizontal portion is also 

 stouter. P. megalotis has the tail above seal brown, like the 

 tail of P. truii, while the upper part of the tail of P. lasius is a 

 rather pale dusky. Altogether the California mountain species 

 seems to be a somewhat larger, heavier animal with marked 

 differences in color and also in cranial character from both its 

 relatives, the two species with which it has been compared. 



ORYZOMYS. 

 Oryzomys jalapae *apatelius, Subsp. nov. 



Type locality. San Carlos, State of Vera Cruz, Mexico. 

 Genl. Char. Similar to O. jalapce in color on upper parts, 

 grayish buff beneath ; tail shorter ; hind foot longer. Skull with " 

 * axaTrhos , deceitful. 



