GEOMETRICAL SPIDERS 105 



limbs, the spider hurried away along the foundation- 

 lines to a place of shelter outside the snare. After a 

 lapse of fifteen minutes the spider again returned, 

 remained motionless for about two minutes at the 

 centre of the snare, and then moved out along a radius 

 to continue the work of construction. It was distinctly 

 evident that the movements of the spider were greatly 

 hampered by the mutilation. It advanced slowly, 

 deliberately and more laboriously than before. There 

 was a complete absence of all skill and agility in its 

 motion. It approached the point where the work had 

 been interrupted and again took up the thread of its 

 labour. Away it started on its spiral round, strug- 

 gling with difficulty from radius to radius and trying 

 in vain to attach a spiral at equidistant radial points. 

 There was no mistaking the fact that the spider was 

 at a great disadvantage after the loss of its organs 

 of measurement, and that it was quite unable to ensure 

 the parallelism of its lines, It attempted to use its 

 amputated stump, waving it helplessly in the air, but 

 its efforts were in vain. Yet the spider was more 

 adaptable than I thought. Finding itself unable to 

 measure after the loss of its fore limbs, it began now 

 to try and estimate the distance by the use of its hind 

 limbs. In this way a limited degree of compensation 

 took place. It made some attempt at measurement, 

 but with indifferent success. Yet the spider circled on. 

 Laboriously it plodded round and round the snare, 

 continually measuring its distance incorrectly and 

 making the adhesions in the wrong place. Three 

 times it neglected to insert a whole spiral ; again and 

 again it made attachment to the spiral instead of to 

 the radius, and sometimes it passed by a radius with- 



