266 ZOOLOGY 
the sixth and last thoracic. It bears a pair of appendages 
which are reduced to a small valve-like structure overlying 
the sexual aperture. In the female this last thoracic segment 
is fused with the first abdominal. . The four abdominal seg- 
Fic. 158.—Dorsal view of male Cyclops. The 
reproductive organs are diagrammatic. 
After Hartog. 
1. Antennae. 
2. Carapace. 
. Testis. 
3 
4, Vas deferens. 
5. Vesicula seminalis. 
6 
. Kye. 
ments are cylindrical! in shape, and are entirely devoid of 
appendages ; the last, however, bears the caudal fork. 
The mouth leads into a narrow gullet which ends in the 
anterior end of the stomach, an oval sac extending back to 
about the second thoracic segment. The chitinous cuticle 
