196 BRITISH ENTOMOSTRACA. 



prove that they have not this faculty. He selected twelve 

 of the Cyclops qKadricornis, removed them out of the 

 water, and allowed them to remain fifteen minutes dry ; 

 seven of them he found to be irrecoverably dead ; the re- 

 maining five revived. Again, he selected twelve others, 

 and allowed them to remain twenty minutes dry ; eleven 

 out of the twelve died. A third time lie selected twelve, 

 and after exposing them to the air in a dry state for twenty- 

 five minutes, he found that all had perished.* 



These experiments, notwithstanding, are not quite con- 

 clusive, for the mud in which they are enveloped, and in 

 which they are very gradually dried, while in their native 

 habitats, might retain a certain degree of moisture suf- 

 ficient to prevent life being utterly extinguished ; and 

 I have accordingly found, upon examining ponds which 

 had been filled again by the rain after remaining two 

 months dry, numerous specimens of the Cyclops quadri- 

 cornis in all stages of growth. Their power of resisting 

 the action of cold, however, according to Midler, is much 

 greater than their power of defying drought. In an 

 experiment which he details, he says that he exposed 

 some individuals of the Cyclops quadricornis, in a glass 

 vessel, to a freezing air, and that when fully frozen, he 

 continued the exposure for twenty-fom' hours. At the 

 end of that time he placed the vessel containing 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 but although they did not all 

 recover, the greater part were restored to life. 



In some other similar experiments upon these little 

 creatures, throwing them into a state of asphyxia by 

 means of spirits of wine, and then restoring them to life 



* p. 39. t Entomost., pp. 5, 6. 



