216 Proceedings of the Biological Society of Washington. 



moderately worn). Collected September 26, 1913, by E. A. Goldman. 

 Orig. No. 22234. 



Diagnosis. — Coloration much like that of Onychomys leucogaster ruidosse; 

 but size less, and skull considerably smaller and weaker. Darker than 

 0. 1. metanophrys; lighter, more reddish-brown, than 0. l.fuliginosus. 



Color. — The color, in all pelages, closely resembles that of 0. I. ruidosse. 



Measurements of type. — Total length, 142; tail vertebrae, 4.'!; hind foot, 

 21 ; ear from notch in dry skin, 14. (5. Skull: Condylobasal length, 25.1; 

 zygomatic breadth, 14; breadth of braincase, 13.0; maxillary tooth 

 row, 4.3. 



Onychomys leucogaster breviauritus subsp. nov. 



Type from Fort Reno, Oklahoma. U.S. National Museum, No. 'M:.!. 

 skin and skull of adult 9 (teeth moderately worn). Collected February 

 16, 1S90, by Dr. J. C. Merrill. Orig. No. 18. 



Diagnosis. — Most like Onychomys leucogaster longipes, but darker and 

 richer colored, with shorter tail, smaller hind foot, and smaller cars. 



Color of adult in full winter pelage: Head and hack a rich blackish- 

 brown, the ground color pinkish-cinnamon, the overlying hairs with 

 long blackish tips which streak and darken the ground color; cheeks and 

 sides with less of the dark streaking, the hips and lower rump almost 

 pure pinkish-cinnamon. Center of nose gray; cinnamon spots at base of 

 whiskers, between the gray of nose and white of lips. Ear tufts cinnamon- 

 bull'; tail grayish-brown above to near tip, sharply bicolor, the underside 

 and tip white. Arms, hands, lower legs, and entire underparts white, 

 with dark gray underfur everywhere except on chin. 



Measurements of type. — Total length, 164; tail vertebrpe, 42; hind foot, 

 21; ear from notch in dry skin, 13.2. Skull: Condylobasal length, 27.4; 

 zygomatic breadth, 15.1; breadth of braincase, 12.5; maxillary tooth 

 row, 4.7. Average measurement of ear from notch in dry skin in seven 

 adults is 12.8; in twelve adults of 0. I. longipes, 16.1. 



