POND LIFE 



721 



with short hairs. The three forms most 

 frequently met with are the Green, the 

 White, and the Brown Cypris ; all to 

 be found swimming in ponds. 



THE WATER FLEA. 



The most familiar Cyclops, and one that 

 is to be found in most ponds, is the Four- 

 horned Cyclops {Cyclops qiiadricornis), 

 which has an oval head and tapering 

 body terminating in two groups of stout 

 bristles. This Cyclops has gained its 

 popular name from the four horns or 

 antennae which adorn its head. The 

 female is easily distinguished, as she carries 

 two pear-shaped egg-sacs or ovaries, one 

 on each side of her tapering body. Besides 

 the common Four-horned Cyclops, Lord 

 Avebury has described si.x or seven short- 

 horned species as being fairly common in 

 the Kentish ponds. 



It is well for the Water Fleas that they 

 are such a remarkably prolilic tribe, for 

 otherwise they would soon become extinct, 

 so numerous and voracious are their foes. 

 Xor are the enemies of the Water Flea 

 confined to the animal kingdom, for there 

 is one remarkable pond plant which must 

 account for a comparati\'ely large number 

 in the course of the year. This is a 

 plant called the Bladderwort (Utriciilaria 

 vulgaris), frequently to be found growing 

 in ponds and sluggish streams. It is a 

 curiously interesting plant, living and 

 floating at the surface of the pond during 

 the spring and summer, but sinking to 

 the bottom at the approach of winter. 



Its straggling stem bears numerous, much- 

 divided slender leaves, and for a few weeks 

 in the summer it sends up a flower-stalk 

 bearing quaint orchid-like golden bhjssoms. 

 But the most remarkable feature of the 

 plant consists of the numerous little oval 

 bodies attached to the sul)merged stem, 

 which look like tiny bladders or floats, 

 and from which the plant has gained its 

 name of Bladderwort. At one time it was 

 generally supposed that these processes 

 acted as bladders to buoy up the }jlant and 

 keep it afloat near the surface of the water. 

 Modern scientific research has pro\'ed, 

 however, that this is not the case, but 

 that these bladders {)lay a very impor- 

 tant part in providing certain forms of 

 food necessary for the growth of the plant. 

 Indeed, we now know that the Bladder- 

 wort belongs to that curious and intensely 

 interesting group— the carnivorous plants. 

 All these plants grow in more or less 

 marshy situations, where the supply of 

 nitrogen in the soil— so necessary to their 

 growth— is low; as a consequence of this 

 environment, they ha\'e, in the course of 

 ages, gradually e\-olved special organs for 

 obtaining the required supply of nitro- 

 genous material by other means than from 

 the soil. 



In the case of the Bladderwort, the 



THE FEMALE CYCLOPS. 



supply of nitrogenous material, required 

 by the plant for the building up of its 

 tissues, is obtained through the agency 

 of the blatlder-like processes. \\'lien we 

 come to examine these '* bladders " closely, 

 we find that tlic}' are really very com- 

 plex organs. Each is a hollow chamber, 

 the entrance to which is closed by a semi- 



