UNIVERSITY OF CALIFORNIA PUBLICATIONS 
ZOOLOGY 
Vol. 5, No. 4, pp. 271-273 August 14, 1909 
A NEW HARVEST MOUSE FROM 
PETALUMA, CALIFORNIA 
= BY 
JOSEPH DIXON. 
(A contribution from the Museum of Vertebrate Zoology of the University of California) 
Two years of intermittent collecting on the salt marshes of 
San Francisco and San Pablo bays have furnished two new forms 
of harvest nice. The first species was described as Reithrodon- 
tomys raviventris (Dixon, Proe. Biol. Soe. Wash., X XI, Oct. 20, 
1908, pp. 197-198) from the southern salt marshes of San Fran- 
cisco Bay. A series of twenty-four skins collected in the salt 
marshes of San Pablo Bay three miles south of Petaluma, Cali- 
fornia, prove to be quite distinet from either R. raviventris or 
- R. longicauda. This,new form seems to share certain characters 
of both R. longicauda and R. raviventris to a slight degree; but 
the combination of characters is such that it remains distinct from 
either of them and I therefore propose it as new, to be known as: 
Reithrodontomys halicoetes new species. 
Type—Male adult; no. 7146, Univ. Calif. Mus. Vert. Zool. ; 
three miles south of Petaluma, Sonoma County, California; orig- 
inal number 179; collected by Joseph Dixon; March 28, 1908. 
Habitat—This mouse seems to be restricted to the salt marsh, 
its range being coextensive with that of the ‘‘pickle grass’’ (Sali- 
cornia). Dilgent search and trapping failed to reveal its pres- 
ence outside the Salicornia and no specimens of R. longicauda 
could be caught in the Salicornia. The harvest mice used the 
runways of Miecrotus extensively. 
