Larth-Worms in Fistory. 63 
As the sharply-pointed needles diverge somewhat, and as 
several are drawn into the same burrow, each tuft forms a 
perfect chevaux-de-frise. Many tufts were pulled up in the 
evening, but by the ensuing morning fresh leaves had taken 
their places, and the burrows again well protected. Impos- 
sible it would be to drag these leaves to any depth into the 
burrows, except by their bases, as a worm cannot seize hold 
of the two leaves at the same time, and if one alone were 
seized by the apex, the other would be pressed against the 
ground and resist the entry of the one that was seized. That 
the worms should do their work well, it was very essential 
that they drag the pine-leaves into their burrows by their 
bases, that is, where the two needles are conjoined. But how 
they are guided in this work was at first perplexing. The 
difficulty, however, was soon settled. With the assistance of 
his son Francis, the elder Darwin set to work to observe 
worms in confinement during several nights by the aid of a 
dim light, while they dragged the leaves of the afore- 
mentioned kinds into their burrows. They were seen to 
move the anterior extremities of their bodies about the leaves, 
and on several occasions when they touched the sharp end 
of the needle they suddenly withdrew as though they had 
been pricked, but it is doubtful that they were hurt, for they 
are indifferent to sharp objects, being known to swallow 
rose-thorns and small splinters of glass. It may be doubted 
whether the sharp end of the needle serves to tell them that 
is the wrong end to seize, for the points of many were cut off 
for the length of an inch, and these leaves were always drawn 
in by their bases and not by the cut-off ends. The worms, 
it seemed, almost instantly perceived as soon as they had 
seized a leaf in the proper manner. Many leaves were 
cemented together at the top, or tied together by fine thread, 
and these in the majority of instances were dragged in by 
their bases, which leads to the conclusion that there must 
be something attractive to worms in the base of pine-leaves, 
notwithstanding that few ordinary leaves are drawn in by 
