PLATE 13. DiatomacesB. 



Figure 



1 . Hyalosira rectangula, front view of connected frustules. 



2. Isthmia enervis, front view. 



3. Licmophora splendida. b, side view ; c, front view of single frustule. 



4. Lithodesmium undulatum. , front view; b, side view. 



5. Melosira nummuloides, front view. 



6. Melosira varians, front view. , side view. 



7. Meridian circular e. 0, frustules united into a coil, front view ; b, side view of 



single frustule. 



8. Micromega parasitica, natural size. 5, portion of a filament containing the 



frustules ; c, side view, d, front view of a frustule. 



9. Nitzschia sigmoidea. , side view ; b, front view. 



10. Nitzschia lanceolata. a, front view; b, separate valve; e, side view of the same. 



1 1 . Nitzschia longissima. a, side view ; b, front view. 



12. Nitzschia reversa, front view of single valve. 



13. Nitzschia acicularis, left-hand frustule; N. acicularis y right-hand frustule. 



14. Odontidium turgidulum. a, frustules united, front view ; b, single valve, side 



view. 



15. Orthosira Dickieii. a, front view; b, side view. 



16. Pododiscusjamaicensis. a, side view ; b, front view. 



17. Podosphenia Ehrenbergii. a, front view; b, side view of single frustule. 



18. Rhabdonema arcuatum. a, united frustules, front view ; b, side view of single 



frustule. 



19. Ehipidopteraparadoxa. b, front view of single frustule; c, side view of the same. 



20. Striatella unipunctata. #, front view ; 5, the same ; c, side view. 



21. Surirella gemma, a, side view ; b, front view. 



22. Surirella bifrons. a, front view ; 6, side view. 



23. Synedra splendens. a, attached frustules ; b, side view of prepared frustule ; 



c, front view of the same. 



24. Synedra fulg ens. a, side view; 5, front view of a prepared frustule. 



25. Synedra capitata, side view. 



26. Sphenosira catena. , united frustules, front view; b, side view of single frustule. 



27. Tabellaria Jlocculosa. a, united frustules, front view ; 5, side view of single 



frustule. 



28. Tetracyclus lacustris, united frustules, front view. , side view. 



29. Triceratiumfavus. a, side view ; 5, front view. 



30. Tryblionella scutellum, side view. 



31. Tryblionella gracilis, front view. 



32. Tryblionella gracilis, diagram of transverse section. 



