1914.] 



EEITHKODONTOMYS MEGALOTIS GEOUP. 



33 



Specimens examined. — Total number, 36, from the following locali- 

 ties: 



Washington: Prescott, 7. 



Oregon: Narrows, Malheur County, 11; Vale, 1. 

 California: Bieber, 1; Brownell, 4. 

 Idaho: Nampa, 5; Payette, 5; Weiser, 2. 



REITHRODONTOMYS MEGALOTIS LONGICAUDUS (Baird). 

 Calefornia Harvest Mouse. 

 Reithrodon longicauda Baird, Mamm. N. Am., 1857, p. 451. 



Oc?ietodon longicauda Coues, Proc. Acad. Nat. Sci. Phila., 1874, p. 186; Mon. N. Am. 



Rodentia, 1877, p. 126. 

 Reithrodontomys 'pallidus Rhoads, Am. Nat., XXVII, 1893, p. 835 (Santa Ysabel, 



Cal.). 



Reithrodontorays longicauda Allen, Bull. Am. Mus. Nat. Hist., VII, 1895, p. 129. 

 Reithrodontomys MainatJiensis Merriam, N. Am. Fauna No. 16, 1899, p. 93 (Shasta 

 Valley, Cal.). 



Reithrodontomys megalotis longicauda Grinnell, Proc. Cal. Acad. Sci., Ser. 4, III, 

 1913, p. 303. 



Type locality, — Petaluma, Cal. 



Distrihution. — Greater part of western California, east to the foot- 

 hills of the Sierra Nevada, San Bernardino, and San Jacinto Eanges; 

 north to Grants Pass, Oreg., and south into northwestern Lower 

 California to about latitude 32°. 



Characters. — Slightly smaller than megalotis; colors darker and more 

 intense. 



Color. — Fresh winter pelage: Upperparts mixed blackish and ochra- 

 ceous-buff, the black predominating on dorsal area, shading to nearly 

 pure ochraceous-buff on sides; lateral line of buff often well defined; 

 ears same color as back, clothed with scattering ochraceous hairs; 

 feet grayish white; tail sharply bicolor, hair-brown or fuscous above, 

 grayish white below; underparts grayish white, usually mth a tinge 

 and often with a strong wash of ochraceous-buff. Fresh summer 

 pelage: Similar to the winter pelage, but decidedly paler and lacking 

 most of the black on the dorsal area. 



STcuU. — Similar to that of megalotis, but smaller. 



Measurements. — Adult topotype: Total length, 152; tail vertebrae, 

 75; hind foot, 17.5. Average of 13 specimens (mostly young adults) 

 from vicinity of San Francisco Bay: 139 (130-146); 73 (68-79); 

 17 (16-18). Skull: (See table, p. 81). 



Remarlcs. — This form has a wide range on the Pacific coast and inter- 

 grades with megalotis at various points along the edge of the deserts. 

 Intermediate specimens have been examined from Barstow, Mojave, 

 Tehachapi, Santa Paula, Kern River, Bieber, etc. The form from 

 Shasta Valley described under the name "Mamathensis^^ is likewise 

 intermediate between longicaudus and megalotis, specimens from there 

 agreeing exactly in color with summer specimens of longicaudus from 



28657°— 14 3 



