DION^A MUSCIPULA. 343 



fringed with stiff bristles so placed as to interlock when the trap 

 is shut. The upper face of each half is somewhat convex when 

 the trap is open, and upon it there are three delicate hairs which 

 are exceedingly sensitive. Supposing the plant to be in health 

 and under favorable conditions, the lightest touch upon one of 

 the hairs upon the face of the trap will cause the valves to close 

 instantly, bringing their edges in apposition. A light touch in 

 the median line, that is, at the hinge, will produce the same 

 effect. The sensitive hairs each consist of several rows of elon- 

 gated cells so arranged as to form a conical filament resting on 

 a constricted base and attached by an articulation to a rounded 

 group of cells. This structure enables the hairs to bend when 

 the trap is shut. 



896. The digestive apparatus consists- of minute reddish 

 short-stalked glands made up of a few polyhedral cells. These 

 do not secrete any fluid unless excited by the presence of food- 

 materials, when they secrete copiously a colorless, glair}', acid 

 liquid, containing an unorganized ferment similar to that produced 

 by the stomach of animals, if not identical with it. Scattered 

 among the secretory glands are numerous compound hairs formed 

 of eight divergent cells, which are generally orange or brown 

 in color. 



897. From experiments by Darwin and others it is clear that 

 dry albuminous solids do not excite the action of the glands, but 

 if moistened very slightly, they call the glands into activity. 

 Moreover, if the bit of meat or other albuminous matter be 

 placed on the valves in such a way as not to spring the trap, the 

 valves will soon slowly close without further touch. Aggrega- 

 tion takes place in the cells of the glands in much the same way 

 as in Drosera. 



898. When a small insect is caught by the springing of the 

 trap, it can escape after a time through the spaces left between 

 the bristles at the border ; but if the insect is of moderate size, 

 its escape is impossible : the valves shut down more and more 

 tightly upon it, and digestion soon begins. 



899. The opening of the valves after digestion takes place in 

 different times according to the vigor of the plant and nature 

 of the prey. After a mere touch by which the trap is sprung 

 without anything in it, the valves will again open of themselves 

 in a day or even less. When the trap is closed by a bit of meat, 

 the valves open in from three or four days to rather more than 

 a week ; when it closes over a large insect, they remain shut for 

 a much longer time, even for a month. 



