PLATE VL 



Fig. 



1. Cytheridea punctillata. Carapace of female, seen from left side. 



2. . — — „ „ above. 



3. — — ,, „ below. 



4. — — Carapace of male, seen from left side. 



5. — — ,, female (variety). 



6. 7. — — Carapaces in early stages of growth. 



8. — — Right valve, seen from outside. 



9. — — End-view of adult carapace. 



10. — — Hinge-margin of left valve, seen from above. 



11. — — „ „ „ inside. 



12. Cytheridea papulosa. Carapace of female, seen from left side. 



13. — — „ ,, above. 



14. — — „ „ below. 



15. — — ,, „ front. 



16. Cytheridea lacustris. Carapace, seen from left side. 



17. — — „ „ above. 



18. — — „ „ below. 



19. — — „ „ front. 



20. — — Hinge-margins, seen from above. 



21. Krithe glacialis. Carapace, seen from left side. 



22. — — „ „ above. 



23. — — „ ,, below. 



24. — — „ ,, front. 



25. — — Left valve, seen from inside. 



26. — — Right and left valves, separated, and seen from above. 



(All magnified 40 diameters, except 10, 11, and 20, wliich are on a larger scale.) 



