1911] Taylor: Mammals of the 1909 Nevada Expedition. 279 



when we trapped in the vicinity of some water-course. Several 

 individuals were caught on the open desert far from water. A 

 couple of juvenals, and these happen to be the specimens taken 

 at the greatest altitude, were secured on exposed rocky ridges. 

 Two were caught near a ditch in an alfalfa field at Big Creek 

 Ranch. So the species may be said to be quite generally distrib- 

 uted in different types of habitat. 



A Perognathus was seen at dusk hopping rapidly along- 

 through the brush, apparently covering twelve or fourteen inches 

 at each jump. 



As regards breeding habits, I have already mentioned the 

 taking of a series of nine young animals. The first is dated June 

 1-4, and was taken at Big Creek Ranch. The last was secured on 

 Leonard Creek August 8. None of these are in the very young 

 stage, but might be more properly termed "adolescent." A 

 female taken at Quinn River Crossing on May 18 contained six 

 embryos, and another secured June 10 at Big Creek Ranch con- 

 tained eight. A female taken JNIay 26, and two secured July 7, 

 at Quinn River Crossing (4100 feet), and Big Creek (6000 feet), 

 respectively, were suckling young. Two females caught ^lay 26 

 and June 10, respectively, possessed three pairs of mammae, of 

 which two were abdominal and one pectoral. Numbers of the 

 sexes in our material are nearly evenly divided, fourteen of the 

 series being females and eighteen males. 



Perognathus nevadensis C. H. Merriam. 

 Nevada Pocket INlouse. 



Status. — The size of the specimens collected at Quinn River 

 Crossing and Big Creek Ranch averages slightly greater than 

 that of the type of nevadensis C. H. ^Merriam (1894a, p. 264), but 

 smaller than average measurements of twenty-four topotypes. 



All our series have a very definite buffy tinge dorsally. No. 

 8113 is much paler buffy than the others. Every specimen except 

 one (no. 8120) is in process of assuming the post-breeding pelage. 

 The molt appears to start at the nose and proceed posteriorly in 

 an irregvilar fashion. The post-breeding pelage is evidently ap- 

 preciably darker than the breeding coat. The type of nevadensis 



