$02 UTRICULARIA NEGLECTA. CHar. XVII 
tween the inner and outer surface consists of coarse 
cellular tissue (fig. 20). The inner side is thickly 
covered with delicate bifid processes, hereafter to be 
deseribed. The collar is thus made thick; and it is 
rigid, so that it retains the same outline whether the 
bladder contains little or much air and water. This 
is of great importance, as otherwise the thin and 
flexible valve would be liable to be distorted, and 
in this case would not act properly. 
Altogether the entrance into the bladder, formed by 
the transparent valve, with its four obliquely project- 
ing bristles, its numerous diversely shaped glands, 
surrounded by the collar, bearing glands on the 
inside and bristles on the outside, together with the 
bristles borne by the antenne, presents an extra- 
ordinarily complex appearance when viewed under 
the microscope. 
We will now consider the internal structure of the 
bladder. The whole inner surface, with the exception 
of the valve, is seen under a moderately high power to 
be covered with a serried mass of processes (fig. 21). 
Each of these consists of four divergent arms ; whence 
their name of quadrifid processes. They arise from 
small angular cells, at the junctions of the angles of 
the larger cells which form the interior of the 
bladder. The middle part of the upper surface of these 
small cells projects a little, and then contracts into a 
very short and narrow footstalk which bears the four 
arms (fig. 22). Of these, two are long, but often of not 
quite equal length, and project obliquely inwards and 
towards the posterior end of the bladder. The two 
others are much shorter, and project at a smaller angle, 
that is, are more nearly horizontal, and are directed 
towards the anterior end of the bladder. These arms 
are only moderately sharp; they are composed of ex- 
