I. CRUSTACEA: COPEPODA 



307 



FIG. 383. Daphnia pulex. b, brood chambers with embryos; g, brain with nauplius 

 eye; go, optic ganglion; h, heart; o, ovary; s, shell gland. The eggs arise at k, and 

 separate, forming in groups of four, as at e, of which one becomes the egg, while the 

 others abort (o) and form food. The egg then passes to the brood chamber, i, 2, 

 first and second antennae; 3, mandible (maxilla rudimentary and invisible); 5-9, legs. 

 Alimentary canal cross-lined. 



basiopodite, the basiopodites of a pair being frequently united for com- 

 mon motion (fig. 374, /). Exopodite and endopodite, usually three-jointed, 

 are fringed with bristles. Usually the fifth pair of thoracic appendages 



