280 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. i. 



process from angle, 15. Greatest length of under jaw from outer 

 edge of condyle to alveolus of incisors inside, 30. 



This handsome wood rat was procured by Mr. Surber in a 

 rocky canon a few miles from Alva in the northwestern part of 

 Oklahoma Territory. It appears to be scarce, only three indi- 

 viduals having been seen, two of which were secured. But as 

 Mr. Surber is still working in the Territory it is hoped he may 

 obtain additional specimens. N. m. surberi is related to the N. 

 macropns and N. m. canescens style of wood rat, but can readily 

 be distinguished from both, by its larger size, much longer tail, 

 and darker color. Not having any specimens of N. m. canescens, 

 I sent one of my specimens to Dr. Allen and it was compared 

 with his type, and he states that surberi is a darker gray with 

 the upper surface of the tail much darker. His specimen was 

 taken in May, the type of surberi in February. A point not 

 touched upon in his letter, but which has a specific value is, 

 in his description of canescens Dr. Allen states that the hairs 

 on the lower surface of the body are pure white to the base. 

 In surberi the entirely white hairs are confined to the breast, 

 throat and space between hind legs, the remainder having 

 plumbeous bases. The difference in the length of tail is very 

 great. That of canescens $ , presumably the type, being 135 mm., 

 while that of $ surberi type is 197 mm. The tail of 9 surberi, 

 which is much shorter than that of the male, is yet 23 mm. longer 

 than the $ canescens, being 158 mm. to 135 mm. The length of 

 tail of M. macropus is about the same as that of N. m. canescens, 

 seven specimens averaging about 136 mm. 



I have named this animal after Mr. Thaddeus Surber, the offi- 

 cial collector of the Field Museum. 



2. Scalops machrinus intermedius. 



Type locality. Alva, Oklahoma Territory. Adult $ . Collected 

 February 23, 1899, by Thaddeus Surber. 



Characters. Similar in color to 5. m. texanus Allen, but much 

 larger, being nearly of the same size as average specimens of 6". 

 a. machrinus from Arkansas, and other Southwestern States, but 

 quite differently colored from them. 



Color. Entire upper parts silvery-brown, somewhat lighter 

 than the hue exhibited by S. m. texanus, but in some lights this is 

 obscured by a beautiful light purple sheen. Cheeks, chin and 

 upper part of throat brownish-green, a color difficult to define as 

 it is constantly changing according to the light, occasionally 



