CHAP. II. THEIK INTELLIGENCE. 89 



consider the broad triangles by themselves, 

 59 per cent, were drawn in by the apex, 25 

 per cent, by the middle, and 16 per cent, by 

 the base. Of the narrow triangles, 65 per 

 cent, were drawn in by the apex, 14 per cent, 

 by the middle, and 21 per cent, by the base ; 

 so that here those drawn in by the apex were 

 more than 3 times as many as those drawn 

 in by the base. We may therefore conclude 

 that the manner in which the triangles are 

 drawn into the burrows is not a matter of 

 chance. 



In eight cases, two triangles had been drawn 

 into the same burrow, and in seven of these 

 cases, one had been drawn in by the apex and 

 the other by the base. This again indicates 

 that the result is not determined by chance. 

 Worms appear sometimes to revolve in the 

 act of drawing in the triangles, for five out of 

 the whole lot had been wound into an irregular 

 spire round the inside of the burrow. Worms 

 kept in a warm room drew 63 triangles 

 into their burrows ; but, as in the case of the 

 pine-leaves, they worked in a rather careless 

 manner, for only 44 per cent, were drawn in 

 by the apex, 22 per cent, by the middle, and 



