3*20 History of British Entomostraca. 
ing them in a state of dryness for twenty-five minutes, he found that 
all had irrecoverably perished.* 
Their power of resisting the action of cold, however, according to 
Muller, is much greater than their power of defying drought. In 
an experiment which he details, he says, that he exposed some in- 
dividuals of the C. quadricornis in a glass vessel to a freezing air, 
and that when fully frozen, he continued the exposure for twenty- 
four hours. At the end of that time he placed the vessel contain- 
ing their frozen bodies in a warm bath, watching the effect of this 
upon them frequently during the succeeding twenty-four hours, but 
without seeing any motion. Next morning, however, upon looking 
into the vessel, he observed, not without wonder, the insects alive, 
and swimming about as before congelation, the females with their 
bags of eggs adhering to them as usual ; t they did not all recover, 
but the greater part were restored to life. In some other similar 
experiments upon these insects, especially the C. castor, throwing 
them into a state of asphyxia by means of spirit of wine, and then 
restoring them to life again, Jurine found that the first part of the 
body to show irritability and a return of motion was, not the heart, 
as perhaps might be expected, but the alimentary canal the heart 
seems to be next then the antennae, and last, the feet. 
De Geer asserts that the Cyclopes, along with the other Mono- 
culi, are nourished by animalcules. Leeuwenhoek, in addition 
to this, asserts that when in want of other food they devour their 
own young. De Geer also says, that he has seen this frequently 
to be the case. Jurine has repeatedly seen the same, but says, 
in vindication of his beloved insects, that it would appear from 
what he has noticed, that they do not do so from taste, but that 
the helpless young cannot resist the action of the whirlpool the 
mother causes around her, and are thus carried unconsciously in- 
to the old one's mouth. I have also frequently noticed the sud- 
den disappearance of the young when no other insects were in the 
vessel but their mother, and who, it is most probable, must have 
devoured them, and from what I have noticed, I think the variety 
albidus of the species quadricornis is the one which possesses this 
carnivorous propensity in the greatest degree. Muller, however, 
maintains that the C. quadricornis, as well as others of the Ento- 
mostraca, live upon vegetable food ; and I have mentioned in my 
former paper (page 40) the experiment he instituted upon the sub- 
* Hist, des Monoc. p. 39. f Entomostraca, pp. 5, 6. 
