XII] 



COPEPODA 



211 



search the water for food. A forked limb, as we have seen, is 

 characteristic of the Crustacea, and is not met with in other groups 

 of the Arthropoda. It appears over and over again in all the orders, 



.3 1 



FIG. 82. Dorsal view of female Cyclops sp. Magnified. Partly after Hartog. 



1. 1st Antenna. 2. 2nd Antenna. 3. Eye. 4. Ovary. 5. Uterus, 

 i.e. pouch of the oviduct into which the eggs pass before being shed. 

 6. Oviduct. 7. Spermatheca or pouch for receiving the spermatozoa 

 of the male. 8. Egg-sacs. 9. Caudal fork. 10. Position of anus. 

 11. Compound segment, consisting of the last thoracic (bearing the genital 

 opening) and the first abdominal. 



retaining its primitive form in some instances, as in the abdominal 

 appendages of a Crayfish ; but more often, by the suppression of one 



142 



