308 Microscopic Life. [Sess. 



good look at them, we have generally to put a good deal of 

 chloroform on the slide. Daphnia pulex and D. vetula are 

 particularly interesting, as they have two kinds of eggs. The 

 summer eggs develop in the usual way within the parent's 

 shell, till the young are able to look after themselves. The 

 winter eggs, however, are contained in a case called the 

 ephippium, which after a time falls off the Daphnia's back, 

 and floats about in the water by itself while the eggs within 

 it are developing. The winter eggs are larger, and fewer in 

 number, than the others. 



The water-bear deserves mention, though we have only 

 found it once or twice. It is a curious little creature be- 

 longing to the Arachnidas, and has eight short thick legs 

 furnished with strong claws. It appears to walk slowly 

 about among the algae, catching hold of them with its claws, 

 and biting them in a most businesslike way, and really gives 

 one the impression of being an intelligent little animal. 



We were for a time chiefly interested in vegetable life, but 

 here the difficulty of identification is much greater, as many 

 of the algae, for instance, can only be identified when in fruit. 

 Diatoms are by far the commonest vegetable organisms in the 

 microscopic world : we must have found a good number of 

 different kinds, but we have only identified a few, such as 

 Meridion circulare, Melosira varians, Diatoma vulgare, Gom- 

 phonema, and Cocconeis. We found half-grown specimens of 

 Meridion circulare over and over again for some time, and 

 were uncertain of its identity ; and when we at last came 

 across a specimen which completed and more than completed 

 the circle, we wrote down the name triumphantly, feeling that 

 it was quite a red-letter day. Diatoma vulgare is interesting 

 on account of the curious way in which its frustules are 

 united : we have often found this species in horse-troughs, 

 which are generally good hunting-grounds, as the water is 

 clear and in constant motion. Cocconeis sometimes grows 

 so thickly on an alga as to cover it almost completely with its 

 little oval shells. We tried some time ago to mount an alga 

 overgrown with it, but not with much success : it would be 

 much easier to mount the Cocconeis separately. 



In the marl pit at Davidson's Mains we have several times 

 found quantities of a filamentous diatom, which we think is 



