Vol. V] TAYLOR— NEW SUBGENUS OF PHENACOMYS I43 



always at the exact level of the nest, or the point of junction 

 of t\ie nest-limb with the tree. "Many trees were bushed out 

 at the top as though they had been cut, rotted off . . . 

 and then taken sprout; some bushing out, some forking, and 

 some growing up in a deformed top." Examination of these 

 disclosed furrow-like ridges in the bark, where Clay concludes 

 the trees had been cut many years ago. Tooth marks were 

 plainly visible in some of the more recently stripped places, 

 so that Clay is certain the cutting is done by Phenacomys, 

 though he does not know whether the bark is eaten or not. 



Because of the dead tree-tops, the semi-isolated nature of 

 the grove in which it was located, and the age of the nests, 

 it was concluded that this colony was a very old one. It is 

 implied, furthermore, though Clay does not permit himself to 

 make a positive statement in this regard, that only the trees 

 containing old nests or which had been inhabited for a long 

 time showed the phenomena of the dead tops. The absence 

 of dead-topped trees in the vicinity of Carlotta where nests 

 were studied by Wilder is explained on the supposition that 

 Phenacomys occupation in that neighborhood has been of 

 comparatively short duration; and the additional suggestions 

 are tentatively propounded, that large trees are not subject 

 to the attacks to which the smaller ones are liable; that pos- 

 sibly the tree mice feed on bark only intermittently; or that 

 it may be that the bark of older trees is not palatable. It 

 seems that the Chaparral Mountain colony was located in 

 small firs, while occupied trees at Carlotta are of larger size. 



Although it must be admitted that the circumstantial evi- 

 dence submitted by Mr. Clay is strong, still it ought to be 

 remembered that bark damage and tree destruction by Phen- 

 acomys longicaudns is unconfirmed to date by any other ob- 

 server, and it is possible, if not probable, that phenomena due 

 to some other local cause or condition on Chaparral Mountain 

 have been erroneously associated with the tree mouse. 



One animal kept by Mr. Clay in captivity would not eat 

 grain, grass, or meal, finally dying apparently for lack of 

 proper feeding. 



The area of occurrence of the tree mouse falls for the most 

 part within the humid coast province or faunal area, a region 

 characterized by frequent fogs, high relative humidity of the 



December 30', 1915. 



