88 University of California Publications in Zoology [Vol. 27 
swimming in a creek in the redwoods of Mendocino County with a 
white-footed mouse ( Peromyscus ) in its mouth. 
These fragmentary data indicate that the species is a ‘carnivore’ 
with respect to amphibians and land mollusca, and possibly small 
mammals. In this connection it is interesting to note that more species 
(and probably also individuals) of salamanders (Plethodontidae and 
Ambystomidae) occur within the range of Dicamptodon ensatus than 
in any other area on the Pacific slope. 
The life-history in relation to the environment:. — Dicamptodon 
ensatus is an inhabitant of the northwest humid coast belt. Its range 
embraces nearly all of the area occupied by the coast redwood and in 
addition the western portions of Oregon and Washington. It inhabits 
the territory occupied by the shrew-mole (Neurotrichus) , Townsend 
mole ( Scapanus townsendii) , mountain beaver (Aplodontia) , winter 
wren ( Namnus hiemalis), and other species of vertebrates whose prime 
environmental requirement seems to be moisture in large amount. 
Its habitat is at all times moist with respect both to atmosphere and 
soil. The coastal region from Monterey Bay northward to Puget 
Sound experiences a large amount of rainfall (26.8 inches at Santa 
Cruz to 78.2 inches at Astoria and 37.0 inches at Seattle) ; and through 
the year, particularly in the summer season, there are many days with 
heavy fog. The mat of leaf mold on the ground in the redwood- 
Douglas-spruce forest is at all times damp. Further, there is heavy 
deposition of dew almost every night during the year. In consequence 
of these features it is possible for a moist-skinned animal the size of 
Dicamptodon ensatus to forage at night and even in the daytime with- 
out danger of desiccation. The restriction of the species to the humid 
area here indicated and the large size to which it attains are probably 
closely related circumstances. This, so far as the writer knows, is 
the largest Nearctic species of urodele exclusive of the permanently 
aquatic Necturus, Amphiuma, and Crypt ohranchus. 
In the developmental program a few features of possible adaptive 
significance may be noted. The firm texture of the egg mass, in con- 
junction with its large size and its fixation below the surface of the 
water, together with the probability of a prolonged developmental 
period, would seem to indicate effective protection for the eggs and 
embryos prior to hatching, more necessary here than in a short em- 
bryonic development, as in the Salientia. The green algal coating in 
the egg capsule may be of advantage in disposing of waste products 
of metabolism resulting from development. The active nature of the 
