The minute two-armed glands on the valve were also affected by the solution; for they now contained several, sometimes as many as six or eight, almost spherical masses of translucent matter, tinged with yellow, which slowly changed their forms and positions.  Such masses were never observed in these glands in their ordinary state.  We may therefore infer that they serve for absorption.  Whenever a little water is expelled from a bladder containing animal remains (by the means formerly specified, more especially by the generation of bubbles of air), it will fill the cavity in which the valve lies; and thus the glands will be able to utilise decayed matter which otherwise would have been wasted.

Finally, as numerous minute animals are captured by this plant in its native country and when cultivated, there can be no doubt that the bladders, though so small, are far from being in a rudimentary condition; on the contrary, they are highly efficient traps.  Nor can there be any doubt that matter is absorbed from the decayed prey by the quadrifid and bifid processes, and that protoplasm is thus generated.  What tempts animals of such diverse kinds to enter [page 439] the cavity beneath the bowed antennae, and then force their way through the little slit-like orifice between the valve and collar into the bladders filled with water, I cannot conjecture.

Tubers.—­These organs, one of which is represented in a previous figure (fig. 26) of the natural size, deserve a few remarks.  Twenty were found on the rhizomes of a single plant, but they cannot be strictly counted; for, besides the twenty, there were all possible gradations between a short length of a rhizome just perceptibly swollen and one so much swollen that it might be doubtfully called a tuber.  When well developed, they are oval and symmetrical, more so than appears in the figure.  The largest which I saw was 1 inch (25.4 mm.) in length and .45 inch (11.43 mm.) in breadth.  They commonly lie near the surface, but some are buried at the depth of 2 inches.  The buried ones are dirty white, but those partly exposed to the light become greenish from the development, of chlorophyll in their superficial cells.  They terminate in a rhizome, but this sometimes decays and drops off .  They do not contain any air, and they sink in water; their surfaces are covered with the usual papillae.  The bundle of vessels which runs up each rhizome, as soon as it enters the tuber, separates into three distinct bundles, which reunite at the opposite end.  A rather thick slice of a tuber is almost as translucent as glass, and is seen to consist of large angular cells, full of water and not containing starch or any other solid matter.  Some slices were left in alcohol for several days, but only a few extremely minute granules of matter were precipitated on the walls of the cells; and these were much smaller and fewer than those precipitated on the cell-walls of the rhizomes and bladders.  We may therefore con- [page 440] clude that the tuber do not serve as reservoirs for food, but for water during the dry season to which the plant is probably exposed.  The many little bladders filled with water would aid towards the same end.