OCT., 1899.1 MAMMALS. 93 



In Ash Cteek Canyon Walter Fisher found their cuttings to consist 

 chietiy of ferns and willows — tlie latter carried from a long distance. 

 In Mud Creek Canyon the cuttings consisted chietiy, according to 

 W. H. Osgood, of thimble-berry bushes, mountain ash, and brake 

 ferns — the latter predomiiuiting, and in one place forming a pile as big 

 as a bushel basket. The animals commonly live in colonies, but Osgood 

 concluded that in Mud Creek Canyon only one individual, or at most, 

 a pair, lived in one [)lace, ''though several may be distributed among 

 the branches of a stream.'' 



Mus museulus Linn. House Mouse. 



Abundant at Sisson, and running wild like the native s])ecies. R. 

 T. Fisher reported them as constantly getting into his traps, partic- 

 ularly in the weeds and sedges in wet places along the banks of Cold 

 Creek, where he caught a dozen or more. 



Reithrodontomys klamathensis sp. nov. 



Typv from Big Spring ('May ten'), Sliasta Valley, Calif. No. 95444, ^ ad., U. S. 

 Nat. Mus., Biological Survey Coll. Collected Sept. 18, 18i»S, by W. H. Osgood. 

 Orig. No. 281. 



Characters. — Size medium; ears and hind feet large; tail long, only 

 slightly shorter than in longicauda; color grayish or brownish gray, 

 decidedly paler than loncjicauda. 



Color. — Summer pelage: Upperparts pale grayish brown, washed 

 with butfy on sides; underparts white, tail bicolor, dusky above, 

 whitish below. 



Cranial characters. — Skull rather large; braincase and rostrum rel- 

 atively broad; audital bulla" small. The skull as a whole agrees better 

 with that of iiicf/alotis than with that of Io)igic((V(h(, particularly in the 

 length of ]nilate and breadth of braincase; but the rostrum is broader 

 and the audital bulhe are smaller than in either. 



Measureinents. — Type: Total length, 14!>; tail vertebra', 71; hind foot, 

 19. Average of 2 adults from type locality: Total length, 144; tail 

 vertebra', 6G; hind foot, 18.5. 



Remarhs. — Both in color and cranial characters Reithrodontomys 

 Mamathensis resembles the pale grayish R. megalotis of the desert 

 region of the southern part of the Great Basin much more closely than 

 it does the dark brownish R. longicauda of California west of the 

 Sierra. 



This new harvest mouse is common in wet places in Shasta and Lit- 

 tle Shasta valleys, where four specimens were obtained by W. H. 

 Osgood and K. T. Fisher. They were caught in little runways in wet 

 grass near tules. The species doubtless reached Shasta Valley by way 

 of the open Klamath country. During our explorations in eastern 

 Oregon in 1890, numerous specimens of the same species were caught 

 by my assistants, E, A. Preble and Cleveland Allen, in the tule marshes 

 bordering the streams connecting Malheur and Harney lakes. 



