6 BRITISH ENTOMOSTRACA. 



Then, when life liad fairly ceased, they rioted upon their 

 flesh, and in a few hours little but the external covering 

 was left. 



I have no doubt that most of the Entomostraca are 

 essentially carnivorous, and I have frequently seen speci- 

 mens of Cypris in their turn, as soon as dead, attacked 

 immediately by quantities of the Cyclops quadricornis, 

 who in a few minutes had fastened themselves upon the 

 dead animal, and were so intent upon their prey, that they 

 were scarcely frightened away from it by being touched 

 with the brush. In a short time the Cypris might be seen 

 lying at the bottom of the vessel, the valves of the shell 

 separated and emptied of tlieii* contents. Leeuwenhoek 

 and De Geer not only maintain that the Cyclops quadri- 

 cornis lives upon animalcules, but that it even preys upon 

 its own young, a fact which I have also noticed myself. 

 Jurine asserts that the Cyclops quadricornis is carnivorous 

 from taste, and only herbivorous from necessity ; while 

 the Daphnia p>ulex, he distinctly affirms, lives upon ani- 

 malcules. Place a few Entomostraca, such, for example, 

 as theDaphniai, Chirocephali, Lyncei, &c., in a vessel with 

 clear pure water, and only some vegetable matters in it, 

 and they gradually become languid, transparent, and finally 

 die ; but mix with this water some which contains nu- 

 merous Infusoria, and the Entomostraca will then be seen 

 speedily to assume another aspect. They become lively and 

 active, and the opacity of their alimentary canal testifies 

 sufficiently the cause of it. When, indeed, we consider the 

 amazing quantity of animals which swarm in our ponds 

 and ditches, and the deterioration of the surrounding 

 atmosphere which might ensue from the putrefaction of 

 their dead bodies, we see a decided fitness in these Ento- 

 mostraca being carnivorous, thus helping to prevent the 

 noxious effects of putrid air which might otherwise ensue ; 

 whilst they in their turn become a prey to other animals, 

 which no doubt serve their purposes also in the economy 

 of nature. The fresh-water Gannnari seem to prey upon 

 them, and the Hvdrachnae are their decided enemies ; 



