328 UTRICULARIA NEGLECTA. (Cuar. XVII. 
minute and weak animals, as are often captured, could force 
their way into the bladders, I tried many experiments to 
ascertain how this was affected. The free margin of the 
valve bends so easily that no resistance is felt when a needle 
or thin bristle is inserted. A thin human hair, fixed to a 
handle, and cut off so as to project barely } of an inch, en- 
tered with some difficulty ; a longer piece yielded instead of 
entering. On three occasions minute particles of blue glass 
(so as to be easily distinguished) were placed on valves 
whilst under water; and on trying gently to move them 
with a needle, they disappeared so suddenly that, not see- 
ing what had happened, I thought that I had flirted them 
off; but on examining the bladders, they were found safely 
enclosed. ‘The same thing occurred to my son, who placed 
little cubes of green box-wood (about z} of an inch, 423 mm.) 
on some valves; and thrice in the act of placing them on, or 
whilst gently moving them to another spot, the valve sud- 
denly opened and they were engulfed. He then placed 
similar bits of wood on other valves, and moved them about 
for some time, but they did not enter. Again, particles of 
blue glass were placed by me on three valves, and extremely 
minute shavings of lead on two other valves ; after 1 or 2 brs. 
none had entered, but in from 2 to 5 hrs. all five were 
enclosed. One of the particles of glass was a long splinter, 
of which one end rested obliquely on the valve, and after a 
few hours it was found fixed, half within the bladder and 
half projecting out, with the edge of the valve fitting closely 
all round, except at one angle, where a small open space was 
left. It was so firmly fixed, like the above-mentioned larve, 
that the bladder was torn from the branch and shaken, and 
yet the splinter did not fall out. My son also placed little 
cubes (about s of an inch, +391 mm.) of green box-wood, 
which were just heavy enough to sink in water, on three 
valves. ‘These were examined after 19 hrs. 30 m., and were 
still lying on the valves; but after 22 hrs. 30 m. one was 
found enclosed. I may here mention that I found in a 
bladder on a naturally growing plant a grain of sand, and 
in another bladder three grains; these must have fallen by 
some accident on the valves, and then entered like the par- 
ticles of glass. 
The slow bending of the valve from the weight of particles 
of glass and even of box-wood, though largely supported by 
the water, is, I suppese, analogous to the slow bending of 
