Cuar. XVI. MOVEMENTS OF THE LEAVES. 379 
and probably more important way. We have seen 
that when large bits of meat, or of sponge soaked 
in the juice of meat, were placed on a leaf, the margin 
was not able to embrace them, but, as it became 
incurved, pushed them very slowly towards the middle 
of the leaf, to a distance from the outside of fully 
‘1 of an inch (2:54 mm.), that is, across between 
one-third and one-fourth of the space between the 
edge and midrib. Any object, such as a moderately 
sized. insect, would thus be brought slowly into contact 
with a far larger number of glands, inducing much 
more secretion and absorption, than would otherwise 
have been the case. That this would be highly ser- 
viceable to the plant, we may infer from the fact that 
Drosera has acquired highly developed powers of move- 
ment, merely for the sake of bringing all its glands 
into contact with captured insects. So again, after 
a leaf of Dionza has caught an insect, the slow 
pressing together of the two lobes serves merely to 
bring the glands on both sides into contact with it, 
causing also the secretion charged with animal matter 
to spread by capillary attraction over the whole sur- 
face. In the case of Pinguicula, as soon as an insect 
has been pushed for some little distance towards the 
midrib, immediate re-expansion would be beneficial, as 
the margins could not capture fresh prey until they 
were unfolded. The service rendered by this pushing 
action, as well as that from the marginal glands being 
brought into contact for a short time with the upper 
surfaces of minute captured insects, may perhaps 
account for the peculiar movements of the leaves; 
otherwise, we must look at these movements as a 
remnant of a more highly developed power formerly 
possessed by the progenitors of the genus. 
In the four British species, and, as I hear from 
