6 
BRITISH ENTOMOSTRACA. 
Then, when life had 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 their 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 pulex, he distinctly affirms, lives upon ani- 
malcules. Place a few Entomostraca, such, for example, 
as theDaphnise, 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 Gammari seem to prey upon 
them, and the Hydrachnse are their decided enemies ; 
