290 FEESH-WATEK AQUAEIA. 



speaking of tke profusion of ttese creatures, says : " I Lave 

 frequently seen large patches of water in different ponds 

 assume a ruddy hue, like the red rust of iron, or as if blood 

 had been mixed with it, and ascertained the cause to be an 

 immense number of Daphnia Pulex. The myriads necessary 

 to produce this effect are really astonishing, and it is extremely 

 interesting to watch their motions. On a sunshiny day, in 

 a large pond, a streak of red a foot broad and ten or twelve 

 yards in length, will suddenly appear in a particular spot, 

 and this belt may be seen rapidly changing its position, and 

 in a short time wheel completely round the pond. Should 

 the mass come near enough to the edge to allow the shadow 

 of the observer to fall upon them, or should a dark cloud 

 suddenly obscure the sun, the whole body immediately 

 disappears, rising to the surface again when they have reached 

 beyond the shadow, or as soon as the cloud has passed over." 

 The male Water-flea is rarely found, and then only during 

 the latter part of the year. It may be known by its smaller 

 size and its larger superior antennae, which are situated beneath 

 what may be called the beak. In the female these antennae 

 are very small. It has been calculated that a Daphnia may 

 have three broods during a month, each brood numbering 

 from forty to fifty. No wonder that these tiny crustaceans 

 are so numerous in our ponds ! The Daphnice are said to 

 eject ephippia, or " vrinter eggs," which are said to be protected 

 with an envelope of extra hardness, so that they wUl be able 

 to bear without damage a degree of cold which would prove 

 fatal to the crustaceans themselves. The food of these Water- 

 fleas consists, for the most part, of minute infusoria. Dr. 

 Baird enumerates at least six other species besides the one 

 just described. The Parrot-beaked Water-flea (D. psittacea) 

 receives its name from the formation of its beak, which is 

 shaped somewhat like that of a parrot. The margin of its 

 shell at the back is serrated. The Large Water-flea {D. 

 Schcefferi) is the largest British species, and has its shell 

 almost circular. Dr. Baird speaks of it as having a heavy, 

 tumbling sort of movement in the water. It is not very 

 common. However, from its size it is certainly worth the 



