CYCLOPS. 203 



pletely oval in form, and more romided than in preceding 

 varieties. The caudal segments and filaments are rather 

 shorter and thicker, and the antennae longer. It varies in 

 colour according to locality, &c. Sometimes it is of a red 

 colour, sometimes of a dull white; and at others of a green, 

 more or less deep. The external ovaries are carried 

 diverging out from the abdomen more or less at a right 

 angle with it (t. XXIV, f. 4.) 



Cyclops quadricornis, vars. rubens, albidus, and viridis, Jurine, 

 Hist. Monoc, t. 1, f. i-11 ; t. 2, f. 1-9 ; t. 2, f. 10, 11; 

 t. 3, f. 1-3. 



Cyclops pictus, Koch, 1. c, h. xxi, t.l. 



Cyclops pulchellus, Koch, 1. c, h. xxi, t. 2. 



Cyclops vulgaris, Koch, 1. c, h. xxi, t. 4. 



Cyclops obsoletxjs, Koch, 1. c, h. xxi, t. 5. 



Cyclops bistriatus, Koch, 1. c, h. xxi, t. 7. 



Cyclops lucidulxjs, Koch, 1. c, h. xxi, t. 10. 



Var. c. — The figm'cs given by Jurine of his varieties 

 fuscus and prasinus agree with this variety. It differs 

 from the last, chiefly in its carrying the external ovaries 

 close upon and covering part of the abdomen. They do 

 not appear ever to divaricate, either when the animal is at 

 rest, or swimming. The inner edge of the caudal seg- 

 ments are beset with short, stout setse ; the antennae are 

 somewhat longer, and the last two joints of the antennules 

 are considerably longer than in either of the two preceding 

 varieties (t. XXIV, f. 5.) 



Cyclops quadricornis, vars. puscus aticl prasinus, Jurine, Hist. 



Monoc, t. iii, f. 5. 

 Cyclops phaleratus, Koeh, Deutsch. Crust., h. xxi, t. 9. 



Hab. — In ponds and ditches; common everywhere, 

 almost aU the year round. 



