MAMMALS OF TIIK MEXICAN BOUNDARY 



365 



sionally seen dead in the streets of E] Paso, Nogales, and Tucson, 

 where it appeared to be less aumerous than the roof rat I Mus alex 

 tini/riiiiis). In San D*egO, rats were very abundant. Score- of 

 black, white, or, more often, particolored ones, were seen about sta- 

 bles or slaughterhouses, and were said to have been recently imported 

 from China. Among ten specimens collected about the wharves of 

 San Diego, was a single plumbeous-black individual, which agreed in 

 all respects, except color, with eastern specimens of Mus norvegicus. 

 The remaining nine had unusually long tails, in some instances longer 

 than the head and body. They were grayer than .New York exam- 

 ples of Mus norvegicus. Large brown rats, probably this specie-, 

 were feeding about my camp, in Flagstaff, Arizona, dime I to 3, L887. 

 I saw dead Norway rats lying in the streets of Bisbee, Arizona, in 

 October and November, L892. None were seen or heard of on the 

 Sonoyta River, Sonora, Mexico, no species of Mus having reached the 

 Mexican villages of that region. 



Record and measurements <>( 10 specimens <>( Mus norvegicus. 



" Color, white. 

 '' Cnlcr. brown. 



■ ( !olor, brow n. ( Contained I fctu e 

 -' < ol< 'i' plumbeous black. 



MUS RATTUS Linnaeus. 



BLACK RAT. 



[Mus] rattus Linx.f.cs, Syst. Nat., 10th ed., L758, p. 61 (original description . 



Elliot. Field Col. Mus., II, 1901. p. 117. fig. 28 (skull 1. (Synop. Mam. X. Am ; 



IV, 1904, p. 163, fig. ."51 (skull), fig. 25 1 animal) (Mam. Mid. Am 

 Musrattus, Miller and Rehnt, Proc. Bost. Sue. Nat. Hist.. XXX. No. 1. Dec. 27, 



1901, p. 56 (Syst. Results Study X. Am. Mam. to close of 1900 



Type-locality. Sweden. 



Geographical range. Cosmopolitan, bul does not thrive where Mus 

 norvea'niis is abundant, usually disappearing before it. 



