1911] Taylor: 3Iammals of the 1909 Nevada Expedition. 299 



cicognani group (Boreal), and arizonensis belonging to the 

 frenatus and longicauda series (Austral); These species are ana- 

 logous in their comparative characteristics to rixosiis and arcticus 

 of the far north (see C. H. Merriam, 1896, p. 7), their habits 

 probably being sufficiently divergent so that they occupy different 

 niches in the economy of nature and so are able to live in the 

 same region. 



Putorius arizonensis ^Nlearns. 

 JNIountain Weasel. 



Status. — The two specimens of mountain weasel collected by 

 the Nevada Expedition (nos. 8220, 8221) were identified by Dr. 

 C. Hart Merriam as belonging to this species. The specimens 

 themselves are very dissimilar. Their data are as follows: no. 

 8220, female, July 13, 1909, 7000 feet. Alder Creek, Pine Forest 

 Mountains, Nevada; no. 8221, adult male, July 23, 1909, 8000 

 feet, head of Big Creek, Pine Forest Mountains, Nevada. The 

 first measures : total length, 311 mm. ; length of tail vertebrae, 

 117 ; hind foot, 35, while the second is, respectively, 326, 98, and 

 37. ^leasurements of arizonensis as given in C. H. ^lerriam's 

 characterization of it (1896, p. 24) are, respectively, total length, 

 385 mm. ; tail vertebrae, 144 ; and hind foot, 44.5. Thus neither 

 of our specimens is very close to the average of "specimens from 

 the Rocky ^Mountains" as measured by him. 



An adult male specimen of arizonensis (no. 2167) collected by 

 Harry S. Swarth on July 23, 1908, in the San Jacinto Moun- 

 tains (8000 feet altitude), southern California, is at hand, and, 

 together with the two specimens from Nevada, exemplifies the 

 wide range of intraspecific variation. In the California animal 

 and in the male from Nevada the ventral parts are in coloration 

 a shade intermediate between buff and ochraceous buff ; the Cali- 

 fornia animal presents a slightly paler tone, but has more yel- 

 lowish ventrally on the neck. In the female from Nevada the 

 lower surface is straw yellow. This animal has the proximal 

 third of the tail yellow ventrally, and a considerably larger black 

 tip to the tail. The chin is white in all three specimens. The 

 throat also is white in the two Nevada specimens, but the buffy 



