PLATE O. 



Fig. 1. Canthocamptus illinoisensis^ antenna of female. 



Fig. 2. " *' fifth foot of female. 



Fig. 3. " *' antennule. 



Fig. 4. " *' firstfoot. 



Fig. 5. " " caudal stylet. 



Fig. 6. Canthocamptus northumhricus^ var. americanus, fifth 



foot of female. 



Fig. 7. " " * antenna of female. 



Fig. 8. " " maxilliped. 



Fig. 9. " '' caudal stylet. 



Fig. 10. '* " antenna of male. 



Fig. 11. *' " firstfoot. 



Fig. 12. '' '' fourth foot. 



Fig. 13. " " fifth foot of male. 



Fig. 14. *' " frontal area. 



Fig. 15. Canthocamptus tenuicaudis, stylets. 



Fig. 16. " " fifth foot of female. 



Fig. 17. Cyclops serrulatus^ fifth foot. 



Fig. 18. '' " fourth foot. 



Fig. 19. ** " outer ramus of first foot. 



Fig. 20. Canthocamptus northumhricus^ inner ramus of third 



male foot. 



Fig. 21. " *' beak. 



Fig. 22. " " maxilla. 





I 



