198 DROSERA ROTUNDIFOLIA. [Cmar X. 
a large object is placed on their glands, or when an insect is 
caught by them. In this latter case we can see that the 
inflection of the short central tentacles would be useless, as 
their glands are already in contact with their prey. 
The result is very different when a single gland on one 
side of the disc is excited, or a few in a group. These send 
an impulse to the surrounding tentacles, which do not now 
bend towards the centre of the leaf, but to the point of ex- 
citement. We owe this capi- 
tal observation to Nitschke,* 
f and since reading his paper a 
\ I 2 few years ago, I have repeat- 
é > edly verified it. If a minute 
bit of meat be placed by the 
a aid of a needle on a single 
gland, or on three or four 
T together, halfway between 
the centre and the circum- 
i ference of the disc, the di- 
5 rected movement of the sur- 
rounding tentacles is well 
exhibited. An accurate draw- 
ing of a leaf with meat in 
this position is here repro- 
duced (fig. 10), and we see 
the tentacles, including some 
of the exterior ones, accu- 
rately directed to the point 
where the meat lay. But a 
Leaf (enlarged) with the tentacles inflected much better plan as +0 place 
over a bit of meat placed on one side of  & particle of the phosphate 
the disc. of lime moistened with saliva 
on a single gland on one side 
of the disc of a large leaf, and another particle on a single 
gland on the opposite side. In four such trials the excitement 
was not sufficient to affect the outer tentacles, but all those 
near the two points were directed to them, so that two wheels 
were formed on the disc of the same leaf; the pedicels of 
the tentacles forming the spokes, and the glands united in 
a mass over the phosphate representing the axles. The 
precision with which each tentacle pointed to the particle 
Fic. 10. 
(Drosera rotundifolia.) 
* ‘Bot. Zeitung,’ 1860, p. 240. 
