CYCLOPID.B. 197 



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 the next, then the antennae, and last 

 the feet. 



De Gcer asserts, that the Cyclopidae, along with the 

 other Monoculi, are nourished by animalcules. Leeuwen- 

 hoek, in addition to this, asserts, that when deprived 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 witnessed 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 

 carried unconsciously into her mouth.* I have also ob- 

 served the sudden disappearance of the young when no 

 other animals 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 guadricornis, is the one which possesses this 

 carnivorous propensity in the greatest degree. Miiller, 

 however, maintains that the Cyclops quadricornis, as well as 

 others of the Entomostraca, live upon vegetable food ; and 

 I have mentioned above (p. 5) the experiment he insti- 

 tuted upon the subject. f But notwithstanding this, it is 

 evident he labours under a mistake and there is every 

 reason to presume, that their being carnivorous serves a 

 most useful purpose in the economy of nature. The 

 adults, in their turn, fall victims to and are devoured by 

 other insects, the chief of which are the Hydrachnae, 

 Hydras, and larvae of aquatic insects, which destroy them 

 in such vast numbers, as in some measure to counter- 

 balance the most extraordinary fertility which they 

 possess. 



* Vide the observations of M. July upon the Artemia saliva, supra, p. 59. 

 f Geoffrey also says that all the Monoculi live upon vegetable matter 

 alone. Hist, abreg. des Ins., ii, 651. 



