Vol. V] TAYLOR— NEW SUBGENUS OF PHENACOMYS I39 



companied the shipment of the first specimen it is asserted 

 that so far as could be found out, Phenacomys longicaiidus 

 Hves exclusively among the boughs and branches of Abies 

 douglassi (= Pseudotsuga taxifolia). Farther on Todd 

 modifies this statement by remarking that tracks, which he 

 thought were made by these little animals, had been seen 

 in the snow around the trees. "They could be tracked," says 

 Todd, "up and down the tree, but to no great distance from 

 it, and were most likely in search of food." In a contribution 

 to the -West American Scientist (1891, p. 242) Todd again 

 calls attention to the tracks he has seen around the trees, but 

 specifically disclaims positive knowledge that they were made 

 by Phenacomys. 



Wilder gives it as his opinion that they must occasionally 

 come to the ground, though it is to be doubted whether they 

 spend much time there. 



Clay says that in order to reach the tree containing the 

 family nest, the males in some instances would have to 

 descend to the ground. This is on the theory (see p. 153) 

 that males live for at least a part of the time in small nests 

 separate from those of the females. 



All the clear evidence at hand shows that tree mice are 

 dependent on the trees in which they live for food, home 

 and drink. I have not seen nor can I find any record of 

 any object found in any nest of Phenacomys indicating that 

 it visits the ground. All nests at Mendocino City were found 

 in grand firs {Abies grandis). The only piece of nest ma- 

 terial not derived from this tree was a twiglet of Bishop pine 

 (Pinus miiricata), which was probably brought in by way of 

 the tree branch route. 



2 KINDS OF TREES INHABITED 



Nests of Phenacomys longicaiidus have been found in three 

 conifers, Picea sitchensis, Abies grandis and Pseudotsuga taxi-' 

 folia. Our field party in 1913 found nests in both the latter- 

 named species, those at Mendocino City being in grand firs, 

 while those at Lierly's and elsewhere were in Douglas firs. 



So far as Todd was aware (1891, p. 240) the tree mouse 

 was found only in the branches of the Douglas fir. In fact, 

 all published records of nests which I have seen refer to their 



