No. 602] SHORTER ARTICLES AND DISCUSSIONS 



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but unlike most kinds of rabbits they are strictly dependent for 

 safety from enemies upon rocks, especially where these are 

 loosely piled as in talus slopes and so alford deep retreats within 

 their interstices. The whole equipment of a rabbit is clearly 

 adapted to foraging in the open, its keen hearing and eyesight 

 quickly warning it of the approach of enemies, and giving it 

 time to escape by means of its unusual running powers. But 

 the cony is equipped in a very different way, as it has relatively 

 small ears and eyes, and small hind legs. It is compelled to 

 forage close to or beneath cover. In fact in field observations it 

 is rarely seen on the move except momentarily, and then only 

 between or beneath angular granite blocks, where it grazes on 

 such little patches of vegetation as are within immediate reach. 



It is clear from numerous observations that the cony is sharply 

 restricted in a large part of its range by the rock-pile habitat. 

 Even at favorable altitudes it is not found away from this 

 refuge. There are obviously, however, one or more additional 

 factors in its distribution. In many parts of the Sierras, talus 

 slopes occur from near the highest summits down to the foothills. 

 As examples of these, one may cite the vast earthquake taluses 

 of the Yosemite Valley proper, which occur almost continuously 

 down to and below the 4,000-foot contour. These taluses have 

 been searched diligently both by trapping and hunting, without 

 our naturalists finding a trace of conies below 8,000 feet. The 

 animals are easy to detect, by reason of their characteristic cry, 

 uttered at any time during the day, though more particularly in 

 the morning and the evening, and by the accumulations of their 

 feces, the pellets constituting which are, in size, shape and tex- 

 ture, unlike those of any other mammal. What is it, then, that 

 limits the conies downward on the western flank of the Sierras, 

 where their necessary rock habitat is continuous, and where food 

 of the right sort is also continuous ? Let us try barometric pres- 

 sure, and atmospheric density, which may properly be consid- 

 ered together. These conditions change sensibly with altitude 

 and, if we take into account California alone, the facts would 

 seem to entitle them to serious consideration as active delimitors 

 of the conies downward. But as we trace the range of the conies 

 far to the northward we are led to a different conclusion. The 

 altitudinal limits of their range is found to descend quite regu- 

 larly towards the north, until, in the case of one race, even sea 

 level is reached, at Bering Sea. Clearly, conies, generieally, are 



