722 



THE NATURE BOOK 



transparent membrane or door ; this can 

 be pushed inwards by any small creature 

 desiring to enter, but it closes again, and 

 cannot be opened from the inner side. 

 Whether the Water Fleas, like most 

 creatures, are imbued with the sense of 

 curiosity or not, it is chfficult to say, but 

 that they are attracted to the bladders 

 is very evident. They swim about with 

 their curious jerky motion amongst the 

 bladders, and finally push open the alluring 

 trap-door, and discover too late that 

 they are within a prison from which 



ONE OF THE "BLADDERS" IN WHICH THE 

 BLADDERWORT ENTRAPS WATER FLEAS. 



escape is impossible. Within these curious 

 bladder-like prisons the Water Fleas soon 

 die, their bodies are decomposed by bac- 

 teria, and the products of decomposition 

 are absorbed by the plant and stored 

 within its tissues to be utilised in the 

 process of nourishment and growth. 



The beautiful little Water Mites, cousins 

 of the Water Spider, abound in the 

 ponds throughout the summer months. 

 Some idea of how numerous these Water 

 Mites are. may be gathered from the fact 

 that Mr. Saville Kent has detected about 

 forty British species. Perhaj)s the most 

 conspicuous is the Round Red Water Mite, 

 which has a rather convex, ]:)ur])lish red 

 bod}^ and red feet and palpi, and is present 

 in most ponds. The Great Water Mite 

 (Hydrachna geographica) is one of the 

 largest species ; it has a black, nearly 

 spherical body marked with red spots, 

 and the ends of its legs are red in colour. 

 A rather common Water Mite, called the 



Harlequin {Atax histrionica) , has an 

 oval, dark red body, and blackish green 

 palpi and legs. Other Water Mites well 

 worth seeking are the Hunchback 

 [Arrenunis glohator) ; the Walking Mite 

 {Limnochares holosericeiis), which crawls 

 about instead of swimming ; the Claret 

 Mite {Hydrachna criienta), which attaches 

 its eggs to the stems of the Potamogeton ; 

 the Furrowed Mite {Eylais extendens), 

 and the Yellow Mite {Aiax Intescois). 

 To the amateur microscopist the Water 

 Mites will be found a very interesting 

 group for investigation, and will yield a 

 large number of beautiful objects with 

 which to enrich his cabinet of slides. 



Attached to the submerged stems of 

 various water-weeds, and more particu- 

 larly to old stems, we shall find the tiny 

 towers which form the home of the Brick- 

 maker Rotifer ; one of the most beautiful 

 and wonderful inhabitants of ponds and 

 slow-moving streams. 



The Brickmaker and its tower are of 

 diminutive proportions, and therefore 

 easily escape notice unless careful search 

 be made amongst the tangle of stems. 

 The best plan is to place two or three 

 stems at a time in a wide-mouthed glass 

 jar, and to examine them critically with 

 a hand magnifying glass for the little 

 Rotifer tubes, which rarely exceed an 

 eighth of an inch in length. The selected 

 stems should be carried home in a glass 

 jar or tube filled with water, and then 

 placed in a small aquarium. To appre- 

 ciate fully the beauties of the Brick- 

 maker, we should place a brandi bearing 

 some of the tubes in a zoophyte trough, 

 and examine them under a low-power 

 object glass of the microscope. And what 

 a wonderful sight is then revealed ! The 

 tiny tube is seen to be composed of row 

 upon row of minute round pellets or 

 " bricks," each with a central hole. As 

 we watch, a silvery mass is seen slowly 

 to rise from within the tube, and gradu- 

 ally to expand like some dainty, fragile 

 flower. The petals open until the whole 

 reminds us of a miniature, silver pansy 

 blossom. 



Around the edges of the shining petals 

 constant movement is taking place, as if 

 some invisible hand were at work, wind- 

 ing a tiny chain. This motion is due 

 to a fringe of delicate hairs, moving 



