CYCLOPS. 
297 
the female of the Cyclops quadricornis may be the progenitor 
in the course of one year of 4,442,189,120 young. The 
young are so unlike the adults, that some naturalists have 
formed different genera for their reception. 
Muller has shown that the Cyclops above mentioned has 
great power of resisting cold. He froze some in a glass ves- 
sel, and exposed them for twenty-four hours in a state of 
congelation ; on thawing them he was surprised to find them 
alive, the females swimming about with their bags of eggs. 
Plate XVII. fig. 3 c, d, shows some of the changes they 
assume before acquiring their perfect form. 
Gen, 160. CYCLOPS, Muller . 
Poot-jaws large and strong, branched; antennules sim- 
ple; ovaries double (fig. 3 b). The male has both antennae 
swollen. (Plate XVII. fig. 3 a .) 
Cyclops quadricornis, L. (Plate XVII. fig. 3.) — 
Thorax and abdomen very distinct from each other, the 
former twice the size of the latter. It is a variable species, 
differing much according to age, locality, and other circum- 
stances ; it is sometimes white, at other times tawny, green, 
or red. 
Hab. Ponds and ditches. Common everywhere. 
