92 University of California Publications in Zoology [Vol. 10 



within. We did not examine into the internal arrangements of 

 the structures, as we were desirous of obtaining more specimens, 

 but made our observations and took our photographs with the 

 least noise possible. 



At another part of the valley there was a pond formed by a 

 prodigiously large beaver dam, evidently once occupied by a 

 large number of animals, but at the time of our visit apparently 

 by one solitary old beaver, who was far too wary to venture into 

 a trap. 



It was no easy task to obtain an adequate series of specimens 

 of this animal, but one calling for an immense amount of labor 

 and no small degree of skill in trapping; and we were fortunate 

 in haying in the party a man possessing the requisite ability and 

 energy. It took days of tramping before any occupied houses 

 were found, while the intervals at which they were scattered and 

 their distance from our camp made it an all-day tramp to make 

 the round of the traps. Then, too, it was disagreeable work, 

 wading for hours in the cold streams, or struggling through dense 

 and frequently dripping vegetation. 



When they were finally located several discouraging days 

 passed before any were trapped. Finally Despard obtained some 

 oil of rhodium (largely used among trappers to attract the 

 smaller carnivores, but something of an experiment as regards 

 beaver) and secured one the first night he used it. After that 

 they came more easily, for the castor" obtained from the first was 

 a most efficient lure to draw others into the traps. 



Steel traps were used, placed in shallow water or on the dams, 

 and set in such a way that the captured animal could flounder 

 into dec]) water, where he would speedily drown, hampered as he 

 was by the weighted trap. Otherwise an adult beaver will in- 

 variably cut off the pinioned foot and make his escape. One of 

 the younger animals secured had the front leg and breast cut to 

 ribbons, as Despard supposed, by an older one endeavoring to 

 effect its release. 



Ten specimens were collected at Beaver Creek during June 

 (nos. 12101-12110), three adult males, three adult females, and 

 four juvenals. Besides these, two young ones were caught, too 

 small to drag the traps into deep water; and as they were un- 



