1914.] 



EEITHRODONTOMYS PULVESCENS GROUP. 



43 



raviventris and longicaudus, being larger than either mth upperparts 

 fully as dark as raviventris. The underparts are whiter than in 

 longicaudus, the latter usually being more or less tinged with pale 

 ochraceous-buff . The close resemblance between lialiccetes and ravi- 

 ventris in skuU characters and the fact that nearly half of the speci- 

 mens of Tialicmtes examined from Petaluma are more or less suffused 

 beneath with ochraceous (though never so completely as in raviven- 

 tris) leads to the belief that the two are subspecifically related. 

 Specimens of lialiccetes in worn pelage are much redder (less blackish) 

 than those in fresh pelage, thus rather closely resembling in color 

 certain specimens of longicaudus. 



Mr. Joseph Dixon, who collected the type series of this mouse, 

 states: 



This mouse seems to be restricted to the salt marsh, its range being coextensive with 

 that of the ''pickle grass" (Salicomia), Diligent search and trapping failed to reveal 

 its presence outside the Salicomia and no specimens of R. longicauda could be caught 

 in the Salicomia. The harvest mice use the runways of Microtus extensively.^ 



Specimens examined. — Total number, 56, from the following locali- 

 ties: 



California: Brentwood, 1; Cordelia, Solano County, 6;^ Grand Island (2 miles 

 north of Knights Landing, Yolo County), I f Grizzly Island, Solano County, 

 27 f Petaluma, 21. ^ 



REITHRODONTOMYS FULVESCENS GROTTP. 



REITHRODONTOMYS FULVESCENS FULYESCENS Allen. 

 SoNORAN Harvest Mouse. 



Reiihrodontomys mexicanus fulvescens Allen, Bull. Am. Mus. Nat. Hist., VI, 1894, 

 p. 319. 



Reiihrodontomys fulvescens Allen, Ibid., VII, 1895, p. 138. 

 Type locality. — Oposura, Sonora, Mexico. 



Distribution. — Mountainous parts of southern Sonora, western Chi- 

 huahua, and northern Durango. 



Characters. — Size medium — a little larger than R. m, megalotis, with 

 decidedly longer tail; prevailing color of upperparts ochraceous-buff 

 with a pronounced lateral line. 



Color. — ^Upperparts light ochraceous-buff, sparingly mixed with 

 blackish brown ; buff color most strongly marked on sides where it 

 frequently forms a pronounced lateral line, unmixed with brown; front 

 and sides of face tinged with grayish; underparts white, sometimes 

 faintly tinged with pale buff; feet buffy white; ears hair-brown 

 externally, clothed on inner surface with ochraceous-tawny hairs; 

 tail hair-brown above, grayish white beneath. 



Slcull. — Similar to that of R. m. megalotis but slightly larger; inter- 

 pterygoid fossa broader. 



1 Univ. of Cal. Pub. in Zool., V, 1909, p. 271. 



2 Collection Mus. Vert. Zool., Univ. of Cal. 



