70 POND LIFE 



unable to break the water-film, carefully washes its face like 

 some diminutive cat. 



The eggs are laid on or in the leaves of water-plants, and 

 when about to hatch are transparent. The young are very 

 similar to their parents in appearance. During the winter, 

 springtails hibernate in the mud. 



The following incident is of interest. On the surface of the 

 aquarium some peculiarly long springtails were noticed, which 

 on examination turned out to be two springtails, one leading 

 the other by the hand. By means of a dissecting needle the 

 leader was persuaded to relinquish hold. The other, left to its 

 own devices, seemed perfectly incapable and at a loss as ta 

 direction. The microscope revealed no trace of eyes, and it 

 can only be surmised that the creature was blind. 



CHAPTER VII 



AQUATIC WORMS 



THE members of the " Vermes " inhabiting our ponds and 

 streams are usually very different to what one imagines a worm 

 to be. 



All the vermes are soft-bodied animals, and in this respect 

 no one breaks the rule. 



When examining weeds under the microscope, minute trans- 

 parent slug-like creatures may often be seen. They glide 

 along, altering their shape on meeting obstacles : swelling, 

 elongating, and behaving altogether in a quite unique manner. 

 These little creatures are members of a family of worms known 

 as Rhabdocoelida, a branch of the Turbellaria, of which there 

 are many and various kinds. They all bear a ferocious expres- 

 sion, and one is little surprised to learn that they are car- 

 nivorous. 



On first seeing these Turbellaria, one is liable to mistake 

 them for members of the Protozoa, owing to their minute size 

 and general appearance. Members of the Tricladida, another 

 sub-order of the Turbellaria, are very common in every pond 

 and stream. In fact in some districts, depending on the 

 season, their numbers are legion. These little black shining 

 animals, known as Planarians, are familiar objects on the leaves 

 of watercress and other plants, and may also be seen wander- 

 ing slowly over the mud and stones at the bottom of the 

 stream. When at rest their shape is not constant, sometimes 



