c. pacificus. {Castor), Rhoads, Proc. Am. Philos. Soc, 1898, p. 422. 



Typi- locality. Lake Kichelos, Kittitass county, Washington. 



Geogr. Distr. Pacific slope; California to Alaska. 



Genl. Char. Size largest of species; tail long; scaly portion 

 more than twice as long as wide. Skull with narrow long rostrum; 

 nasal extending beyond premaxillaries. 



Color. Above reddish chestnut; under fur seal brown; sides of 

 body and legs and top of head walnut brown; under parts broccoli 

 brown, under fur drab gray; hind feet seal brown; fore feet dark 

 wood brown. Ears black. 



.\feasitrements. Total length, 1143; tail Vfrtebra'. 330; scaly por- 

 tion of tail, 295x122; hind foot, 185. Skull: length, 142: breadth, 

 loi; length of nasals, 53.6, breadth, 24. 



F'am. IV. ^Iiiridae. 



Lower incisors compressed: premolars none; molars with or 

 without roots, tuberculate, or with enameled folds; frontals con- 

 tracted; jugal splint-like between zygomatic processes of the maxilla 

 and squamosal; infraorbital vacuity wider above than below. 



Sub. Fam. L Muriiiae. 



Molars rooted, tubercular; root of under incisor creating a swell- 

 ing on outer side of mandible between processes of the condyle and 

 coronoid; descending process of mandible below the plane of the 

 molars. Palate nearly Hat. 



44. Mus. 



L '"'; M. 2=-' = 16. 

 !-■ 3-;- 



Mus. Linn. Syst. Nat., 1766, p. 79. Type. Mus rattus. 



Ears large, prominent; tail long, scaly; nose acute; molars with 



transverse series of tubercles, three in a series, longitudinal. 



148. rattus. {Mus\ Linn. Syst. Nat., 1766, i, p. S3. 

 Type locality. Sweden. 



Geogr. Distr. Cosmopolitan. 



Genl. Char. Tail little longer than head antl body. 



Color. .Above sooty black; beneath plumbeous: feet brown. 



Measurements. Total length, 368; tail vertebra-, 190. 



149. decumanus. {.Mus), Pall. Glir.. 1778, p. gi. 

 Type locality. Kussia. 



Geogr. Distr. Cosmopolitan. 



