CYCLOPID.^. 189 



The species belonging to this family are to be found 

 both in fresh water and in the sea. The fresh-water 

 species abound in the muddiest, most stagnant pools, and 

 in the clearest springs, and the ordinary water with which 

 the inhabitants of London are supplied for domestic 

 purposes often contains them in great numbers. The 

 marine species are to be found frequently in immense 

 quantities in small pools on the sea shore, within high- 

 water mark, living among the sea-weeds and coral- 

 lines, which so elegantly fringe the beautiful little wells 

 and clear round pools which are hollowed out in the rocks 

 on the coast, and are to be met with in equal profusion 

 in the open ocean, where, by the cmious luminous pro- 

 perties they possess, they assist in producing that beautiful 

 phosphorescent appearance of the sea, which formerly 

 puzzled naturalists to discover the cause of. It is 

 amazing when we examine the pools of water in our 

 fields or sea shores, to find such infinite myriads of little 

 creatures sporting about in all the enjoyment of existence; 

 and it is exceedingly curious and interesting to know the 

 extraordinary fertility of such apparently insignificant 

 creatures. Specimens of the Cj/cio])S quadricornis are 

 often found carrying thirty or forty eggs on each side ;* 

 and though the other species, which have only one external 

 ovary, do not carry so many, still the number is very 

 considerable. Jurine has with great fidelity watched the 

 hatching and increase of the Cyclops quadricornis in par- 

 ticular, and has given a calculation which shows the 

 amazing fertility of the species. He has seen one female 

 isolated lay ten times successively, but in order to speak 

 within bounds, he supposes her to lay eight times within 

 three months, and each time only forty eggs. At the 

 end of one year this female would have been the progenitor 

 of 4,442,189,120 young!! The first mother lays 40 



* Leeuweulioek says, that in the specimens which occurred to him of the 

 quadricornis, he counted the eggs iu tlic ovary and found them arranged 

 three or four in breadth, and nine or ten in length. — Epist. ad Soc. Reg. 

 Aug., p. 138. 



