EXPLAISTATIOISr OF THE PLATES. 



ILLINOIS CRUSTACEA. 



1, 2, 3, 4, 5, 6, 7, (Jrangoiiijx mucronatus^ Forbes. 



1. Head of female, with pedicels of antennae. 



2. Posterior abdominal segments of male, with their appendages. 



3. One of Ist pair of hands of male. 



4. One of "id pair of hands of .male. 



5. Telson and last pair of stylets of female. 



6. One of 1st pair of hands of female. 



7. One of 2d pair of hands of female. 



8, 9, 10, 11, Asclhis hrericanda, Forbes. 



8. Hand of male, )< 20. 



9. One of 1st pair of genital plates of male, x 38. 



10. One of 2d pair of genital plates of male, X ^9- 



11. One of caudal st3'lets. 



12, 13, 14, 15, 16, AseUas uitermcdiiiti, Forbes. 



12. Hand ©f male, X 45. 



13. Hand of female. 



14. Last segment of abdomen, with caudal stylets, X !"• 



15. One of 1st pair of genital plates of male, X 38. 

 1(5. One of 2d pair of genital plates ot' male, X 38. 



17, 18, Asellus communis, Say. 



17. One of 1st pair of genital plates of male, X ^8. 



18. One of 2d pair of genital plates of male, X 18. 



19, 20, Asellus st^ghis, Pack. 



19. One of 1st pair of genital plates of male. 



20. One of 2d pair of genital plates of male. 



21, 22, 25, Euhrunchipus serratus, Forbes. 



21. Abdomen, x 3. 



22. Frontal ajipendage of male, X ^^• 

 25. Claspers of male, from before, X 6. 



