88 HABITS OF WORMS. Chap. 11. 



33 per cent, by the base. In five cases, two 

 triangles were drawn into the same burrow. 



It may be suggested with much apparent 

 probability that so large a proportion of the 

 triangles were drawn in by the apex, not from 

 the worms having selected this end as the 

 most convenient for the purpose, but from 

 having first tried in other ways and failed. 

 This notion was countenanced by the manner 

 in which worms in confinement M^ere seen to 

 drag about and drop the triangles ; but then 

 they were working carelessly. I did not at 

 first perceive the importance of this subject, 

 but merely noticed that the bases of those tri- 

 angles which had been drawn in by the apex, 

 were generally clean and iiot crumpled. The 

 subject was afterwards attended to carefully. 

 In the first place several triangles which had 

 been drawn in by the basal angles, or by the 

 base, or a little above the base, and which 

 were thus much crumpled and dirtied, were 

 left for some hours in water and were then 

 well shaken while immersed ; but neither 

 the dirt nor the creases were thus removed. 

 Only slight creases could be obliterated, 

 even by pulling the wet triangles several 



