194 



NORTH AMERICAN FAUNA 



[No. 55 



The females have 2 pairs of inguinal and 2 of pectoral mammae, 

 and the young, as shown by embryos, are usually 4 to 6. Probably 8 

 is the maximum number, as occasionally recorded in related forms. 



Their stomachs are usually filled with green pulp, and many bits 

 of cut grass and small plants, cut and drawn under cover to be eaten 

 In safety, are found under the logs where they feed. Traces of grass 

 and other plant seeds are also found in the stomachs, and rolled oats 

 or other grains are eagerly taken as trap bait. 



Very little mischief can be ascribed to these beautiful little forest 

 dwellers, and their value as food for fur-bearing mammals may well 

 overbalance any destruction of vegetation. 



PHENACOMYS LONGICAUDUS TRUE 

 RED TREE MOUSE 



Phenacomys longicaudus True, U. S. Natl. Mus. Proc. 13: 303, 1890. 



Type. Collected at Marshfield, Coos County, Oreg., by Aurelius Todd, in 

 1890. 



General characters. Next to the largest of the genus; tail hairy, about as 

 long as body without head; legs short, toes long, and claws sharp and well 

 curved; eyes small; ears low, nearly concealed in fur; fur long, fine, and 

 soft; upper parts uniform light rusty or cinnamon rufous; lower parts washed 

 with buffy white over plumbeous underfur ; tail dark brown or blackish above 

 and below. 



Measurements. Average of 5 adult females : Total length, 182 mm ; tail, 73 ; 

 foot, 21; ear (dry), 11. Weight, 27 g (A. B. Howell, 1926, p. 52). 



Distribution and habi- 

 tat. Specimens of the 

 red tree mouse have been 

 taken in western Oregon 

 at or near Marshfield, 

 Coos County; Port Or- 

 ford, Lobster Creek, and 

 Agness, in Curry Coun- 

 ty; Salt Creek, north of 

 Bybee Springs, in Jack- 

 son County ; Meadow, 

 Eugene, and Mabel, in 

 Lane County; and near 

 Marmot, i n Clack ; iamas 

 County (fig. 41). The 

 animals or their unmis- 

 takable nests (pi. 33) 

 have been reported on the 

 Coquille River, in Coos County; on Elm Creek and at Melrose, in 

 Douglas County ; on the Willamette, at Cottage Grove, and at Vida, 

 in Lane County; on the upper Clackamas Eiver, in Clackamas 

 County; and near Bonneville, in Multnomah County. 



These localities indicate a range over most of the timbered parts 

 of western Oregon, from the foothills to the coast, unless, as seems 

 probable, its place is taken west of the Willamette Valley by the 

 darker colored dusky tree mouse. To the south the species ranges 

 down the timbered coast region of northwestern California as far 

 as Mendocino County. 



FIGURE 41. Range of four forms of the genus Phc- 

 nacomys in Oregon : 1, Phenacomys silvicola; 2, 

 P. longicaudus; 3, P. intemnedius intermedius; 4, 

 P. i. olympicus. Type localities circled. 



