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Show 398 UTRICULARIA NEG LEOTA. CHAl'. XVII. rrhe bladders are :filled with water. They generally, but by no means always, contain bubbl.es of air. A9- cording to the quantity of the eonta1ned water and air, thoy vary much in thickness, but are always sonlewhn. t compressed. At an early stage of growth, the flat or ventral surface faces the axis or stem; but tho 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. ( "Gtricularia neglecta.) Bladder; much enlarged. c, collar indistinctly seen through the wall s. plants for me in a state of nature, and found this co1nmonly to be the case, but the younger blallders 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 eells, containing chlorophyll, and bearing, chiefly on CHAP. XVII. STRUC1'URE OF THE BLADDER. 399 the outside, six or seven long, pointed, multicellular bristles. These prolongations of the bladder may b conveniently called the antennm, 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 antennoo 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 antennre, 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 |
