326 UTRICULARIA NEGLECTA. [Cuar. XVII. 
end of the bladder. These arms are only moderately sharp ; 
they are composed of extremely thin transparent membrane, 
so that they can be bent or doubled in any direction without 
being broken. They are lined with a delicate layer of 
protoplasm, as is likewise the short conical projection from 
which they arise. Each arm generally (but not invariably) 
contains a minute, faintly brown particle, either rounded 
or more commonly elongated, which exhibits incessant 
3rownian movements. These particles slowly change their 
positions, and travel from one end to the other of the arms, 
but are commonly found near their bases. They are present 
in the quadrifids of young bladders, when only about a third 
of their full size. They do not resemble ordinary nuclei, but 
I believe that they are nuclei in a modified condition, for 
when absent, I could occasionally just distinguish in their 
places a delicate halo of matter, including a darker spot. 
Moreover, the quadrifids of Utricularia montana contain 
rather larger and much more regularly spherical, but 
otherwise similar, particles, which closely resemble the 
nuclei in the cells forming the walls of the bladders. In the 
present case there were sometimes two, three, or even more, 
nearly similar particles within a single arm; but, as we shall 
hereafter see, the presence of more than one seemed always 
to be connected with the absorption of decayed matter. 
The inner side of the collar (see the previous fig. 20) is 
covered with several crowded rows of processes, differing in 
no important respect from the quadrifids, except in bearing 
only two arms instead of four; they are, however, rather 
narrower and more delicate. I shall call them the bifids. 
They project into the bladder, and are directed towards its 
posterior end. The quadrifid and bifid processes no doubt 
are homologous with the papillee on the outside of the bladder 
and of the leaves; and we shall see that they are developed 
from closely similar papille. 
The Uses of the several Parts— After the above long but 
necessary description of the parts, we will turn to their uses. 
The bladders have been supposed by some authors to serve 
as floats; but branches which bore no bladders, and others 
from which they had been removed, floated perfectly, owing 
to the air in the intercellular spaces. Bladders containing 
dead and captured animals usually include bubbles of air, but 
these cannot have been generated solely by the process of 
decay, as I have often seen air in young, clean, and empty 
