98 How to obtain it. 







Mr. G. E. Simms, of Oxford, who had the plant growing in an 

 aquarium in which the fry of perch and roach were also kept. 

 Seeing some little fish apparently lying dead amongst the 

 bladderwort, Mr. Simms endeavoured to remove them, and found 

 that they were firmly held by the plant. The latter may be 

 briefly described as a floating species growing in ditches, ponds, 

 and other still waters. The stem lies in a somewhat prostrate 

 position, from which numerous thread-like leaves grow out in 

 whorls. Amongst these leaves are found a number of tiny 

 vesicles, which were formerly supposed to be air-bladders by 

 means of which the plant floated to the surface. These now 

 come out in their true character as traps for living creatures, 

 including fish, upon which the plant probably feeds. The 

 vesicles are somewhat pear-shaped, and possess an opening at 

 the smaller end which is closed by a valve. This valve opens on 

 pressure from without, and closes upon any unfortunate creature 

 that may enter. Young fish have been found caught by the head, 

 tail, and umbilical sac. Crustaceans, larvce, and other organisms, 

 are entrapped by these vesicles, or so-called bladders, from which 

 the plant derives its name. In summer it sends up a flower stem 

 some five or six inches high. The blossoms are yellow streaked 

 with purple. 



Mr. Simms tells me that experiments have shewn that it is 

 very seldom, indeed, that young roach become entangled in the 

 bifid processes with which the quadrangular mouth of the vesicle 

 is furnished ; young perch, however, succumb freely to its 

 influence, which is a purely mechanical one. Under a high 

 power microscope, the vesicles appear perfectly smooth and 

 polished, and they seem to be armed with a series of reversed 

 serrations, pointing towards the opening. These serrations catch 

 the delicate skin of the fry, whose every struggle only sends them 

 further on towards the opening, and so on until the posterior wall 

 of the vesicle is reached, when the fish is prevented from making 

 its exit by the closing of the trap. Sooner or later the fish dies, 

 decomposition sets in, the tail drops off, that is, as much of it as 

 is exposed outside the vesicle, whilst the portion that remains 

 within is largely utilised for the future support of the plant. 

 Owing to its having no root, it is dependent to a con- 



