How Animals Work. 



with her jaws (for she has not been observed to use 

 her feet or legs for the purpose). Therefore the earth 

 is dug out in little fragments, every morsel as it is dis- 

 lodged being carried to some distance from the nest. 

 As the shaft gradually deepens, the spider ceases from 

 her digging operations from time to time, to shore up 

 the walls with patches of silk, and so prevents their 

 sudden collapse, or caving in upon her. Once the 

 chamber has been completed, the spider covers the 

 walls with several dense layers of silk. 



Describing the double-doored nests, Mr. Moggridge 

 states that these " have a thin and wafer-like door at 

 the mouth of the nest, and from two to four inches 

 lower down a second and solid underground door. 

 These lower doors are characteristic of the nests to 

 which they belong that of the branched nest being 

 long and more or less tongue-shaped, while that of 

 the unbranched double-door nest is somewhat horse- 

 shoe shaped. In the branched double-door nests the 

 upper door does not fit into, but merely lies upon, the 

 mouth of the tube, the elasticity of the hinge and its 

 own weight being sufficient to keep it closed. The lower 

 door is suspended by a hinge placed at the apex of 

 the angle formed by the bifurcation of the tube, and 

 is hung in such a manner that it can either be pushed 

 upwards so as to lie diagonally across and block the 

 main tube, or be drawn back so as to fit into and close 

 the entrance to the branch. When the lower door is 

 drawn back so as to close and conceal the entrance to 

 the branch, it lies in the same plane, and closely corre- 

 sponds in curvature with the lining of the main tube, 

 and almost appears to form part of it. What, it may 



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