The bladders are filled with water. They generally, but by no means always, contain bubbles of air. According to the quantity of the contained water and air, they vary much in thickness, but are always somewhat compressed. At an early stage of growth, the flat or ventral surface faces the axis or stem; but the footstalks must have some power of movement; for in plants kept in my greenhouse the ventral surface was generally turned either straight or obliquely downwards. The Rev. H.M. Wilkinson examined FIG. 18. (Utricularia neglecta.) Bladder; much enlarged. c, collar indistinctly seen through the walls. plants for me in a state of nature, and found this commonly to be the case, but the younger bladders often had their valves turned upwards. The general appearance of a bladder viewed laterally, with the appendages on the near side alone represented, is shown in the accompanying figure (fig. 18). The lower side, where the footstalk arises, is nearly straight, and I have called it the ventral surface. The other or dorsal surface is convex, and terminates in two long prolongations, formed of several rows of cells, containing chlorophyll, and bearing, chiefly on [page 399] the outside, six or seven long, pointed, multicellular bristles. These prolongations of the bladder may be conveniently called the antennæ, for the whole bladder (see fig. 17) curiously resembles an entomostracan crustacean, the short footstalk representing the tail. In fig. 18, the near antenna alone is shown. Beneath the two antennæ the end of the bladder is slightly truncated, and here is situated the most important part of the whole structure, namely the entrance and valve. On each side of the entrance from three to rarely seven long, multicellular bristles project out- FIG. 19. (Utricularia neglecta.) Valve of bladder; greatly enlarged. wards; but only those (four in number) on the near side are shown in the drawing. These bristles, together with those borne by the antennæ, form a sort of hollow cone surrounding the entrance. The valve slopes into the cavity of the bladder, or upwards in fig. 18. It is attached on all sides to the bladder, excepting by its posterior margin, or the lower one in fig. 19, which is free, and forms one side of the slit-like orifice leading into the bladder. This margin is sharp, thin, and smooth, and rests on the edge of a rim or collar, which dips deeply into the [page 400] bladder, as shown in the longitudinal section (fig. 20) of the collar and valve; it is also shown at c, in fig. 18. The edge of the valve can thus open only inwards. As both the valve and collar dip into the bladder, a hollow or depression is here formed, at the base of which lies the slit-like orifice. The valve is colourless, highly transparent, flexible and elastic. It is convex in a transverse direction, but has been drawn (fig. 19) in a flattened state, by which its apparent breadth is increased. It is formed,