1911] Taylor: Mammah of the 1909 Nevada Expedition. 269 



External ^Ieasurements op Ferodipus microps levipes From 

 Humboldt County, Nevada. 



F(ir method of taking measurements, see Introduction. 

 All dimensions are in millimeters. 



External Measurements of Three Young Adults of 

 Perodipus microps levipes. 



One adult specimen of our series (no. 7874) was not included 

 in the above averages, having been referred to colunibiauus. It 

 has its total length 244 mm., and its tail vertebrae 136, as might 

 be expected in that form. Its hind foot is 41, a little long for 

 cohonhianus. However, in coloration it coincides remarkably 

 with the topotypes of this species at hand, and was unquestion- 

 ably referred to it until the cranial characters were taken into 

 consideration. These lead to the conclusion that it is identical 

 with the rest of our series, which, while impossible to be referred 

 clearly to either species, has been tentatively identified as 

 levipes. There are a number of differences observable between 

 our series and either columhiamis or levipes, but they are in- 

 constant, and there is nearly as much difference between indi- 

 viduals of the same species, as represented by the topotypes, as 

 there is between our animals and either species. 



The specimens (except no. 7874) are a shade darker than 

 cohimhianus as exemplified by the typical specimens. This may 

 be due to wear and a consequent greater exposure of the plum- 

 beous bases of the hairs ; for evidently the Nevada animals have 

 not molted, while at least two of the topotypes (nos. 24182 and 



