322 CALIFORXIA ACADEMY OF SCIE\CES [Proc. 4iH Se». 



Epimys norvegicus (Erxleben) 

 Norway Rat 



Original description — "Mus uon\-gicus Erxleben, Syst. 

 Regni Anim., 1. 1777, p. 381." 



Type locality — "Norway." 



S\uo)iyms — Brown Rat, part; Wharf Rat: Mus dccumauus. 



Range — Almost everywhere in the settled portions of the 

 state, chiefly in towns and cities. In the San Joaquin and 

 Sacramento valleys, rats have invaded marshy tracts and occur 

 along- sloughs far from human habitations. This is the most 

 abundant species of non-native mammal outside of the house 

 mouse. 



Epimys rattus (Linnaeus) 



Black Rat 



Original description — j\Iits rattus Linnaeus, Syst. Nat.,1, 

 1758, p. 61. 



Type locality — Sweden. 



Range — Occurs in relatively small numbers in ^an Francisco 

 and neighboring cities of the San Francisco Bay region. Not 

 native. 



Epimys alexandrinus (GeofTroy) 

 ' Roof Rat 



Original description — "Mus alexandrinus Geoffroy, De- 

 scription de I'Egypte, Mammiferes, 1818, p. 735." 



Type locality — "Alexandria, Egypt." 



Synonym — Brown Rat, part. 



Range — Occurs commonly in the larger cities of west-cen- 

 tral California. Not native. 



Mus musculus musculus Linnaeus 

 House Mouse 



Original description — Mus musculus Linnaeus, Syst. Nat., 

 1, 1758, p. 62. 



Type locality — Sweden. 



Range — Practically throughout the state around human 

 settlements ; in the thickest settled valleys occurs widely over 

 uncultivated land, often a mile or more from the nearest build- 



