56 



THE POPULAR SCIENCE MONTHLY. 



vvlgaris, the result being to establish beyond question the predatory 

 practices of the bladderwort, a plant which had hitherto enjoyed a 

 good name. 



It is not provided with any irritable filaments, the sensitiveness 

 residing in the surface of the leaf, which is set with two kinds of gland- 

 ular hairs secreting an extremely viscid fluid which seems to be the 

 only agent for entrapping the insects. When once caught they are 

 detained by the slowly-inflecting leaf. Here, too, contact with nitro- 

 genous bodies changes the nature of the secretion, so that it becomes 



Fig. 7. Pinguicttla vulgaris. Outline of 

 leaf with left margin inflected over a 

 row of small flies. 



FiQ. 8. PiNGUicuxA VULGARIS. Outline of 

 leaf, with right margin inflected aguinet 

 two square bits of meat. 



capable of dissolving and digesting insects and other nutritious sub- 

 stances, when the secretion and the digested matter are reabsorbed 

 by the glands. When the objects are too large to be inclosed by the 

 inflected leaf, they are by its incurving pushed along over the sur- 

 face, constantly coming in contact with fresh and hungry glands, 

 subserving the needs of the plants as well as by the other method 

 {see Fig. 8). 



Utricularia neglecta and TJ. vulgaris {common Bladderwort'). It 

 will be a new revelation to most readers to be told that the bladders 

 of this plant are not, as the manuals have always stated, filled with 

 air and intended to float the plant, but that their real use is to cap- 

 ture small aquatic animals, which they do on a large scale. 



The general appearance of a bladder is shown in the figure (10) 

 given below. The lower side is straight, the other surface convex 

 and terminating in two long prolongations bearing six or seven long 

 pointed bristles. The prolongations are called antennae, for, as ]\lr. 

 Darwin says, " the whole bladder curiously resembles the entomo- 

 stracean Crustacea " upon which they prey so freely. 



Under these antennas, where the bladder is slightly truncated, is 

 situated the most curious and important part of the whole structure, 

 namely, the entrance and valve. 



