1892. | NEW YORK ACADEMY OF SCIENCES. 13 
greatest sensitivity, judging from the results of experiments 
hereafter given. The traps are not usually open wider than an 
angle of 90°. Should, from its crowded position, the trap be 
disposed sidewise the supine valve loses its concavity, flattens 
or becomes convex, and the spikes adjust themselves to the 
ground and may even be of service as skids to facilitate 
entrance from the side; the overhanging lobe meanwhile 
retains its inner concayity, its spikes pointing downward. 
In the process of closing, the important part played by the 
marginal spikes has already been discussed by Darwin ; the 
closing, possibly by altering the convexity of the lobes, causes 
the spikes to rotate rapidly inward (90°), gently interlocking. 
The actual process of digestion has already been carefully 
followed, (Ins. Pl. 295-304). Under native conditions the plant’s 
power to emit rapidly the digestive juice, is worthy of note. 
Several of the leaves that had been fed with bits of earthworm 
and examined at the end of a half-hour had already exhibited 
the stout incurving of the lobe, the secretion was noticable and 
evenly distributed, the basal glands assuming the yellow tone, 
a change apparently more marked in deeply pigmented leaves. 
During the process of digestion the pressure of the lobes, as 
notéd by Darwin, is sufficiently strong to outline the enclosed 
object. It may further be noted that at a later stage one of the 
lobes laps out irregularly, displayed lke a protruding lip, the 
spines bending outward, the digestive juice sometimes oozing 
out, The final stage in the recovery of the leaf follows the out- 
rolling of the margins and the subsequent constricting of the 
angle of the lobes at the midrib. 
In regard to time of closing the traps are irregular even to a 
noteworthy degree. The sensitivity, in addition, does not 
depend entirely upon irritation of the filiaments. 
Varying sensitiveness is exemplified in the following experi- 
ments : 
1. Twenty-five full grown and similarly opened traps were 
irritated by several strokes of wisp passing across the sensitive 
filiaments. Three traps failed to close ; fifteen did not close 
sufficiently to allow the spikes to interlock, time from 2 to 10 
seconds ; seven interlocked firmly, time from 2 to 5 seconds, 
Of these seven five were but feebly pigmented and perhaps had 
not as yet fed. 
2. A-similar experiment irritating the filiaments somewhat 
more slowly, gave the following results: twenty-four closing, 
five firmly interlocking. It should be noted, however, that in 
these experiments the irritation had been far more severe and 
constant than could under ordinary circumstances be caused by 
