_Fig._ 1. Peziza bicolor--2. Truffle: _a._ ascus of spores; _b._ mycelium--3. Sphæria herbarum: _a._ piece of dead plant, with S. herbarum natural size; _b._ section of same, slightly magnified; _d._ Ascus with spores, and paraphyses more magnified--4. Peziza pygmæa--5. Apical form of same--6. P. corpulasis: Ascus with spores and paraphyses, merely given as a further illustration of structure in Peziza--7. Yeast healthy--8. Yeast exhausted--9. Phyllactinia guttata--10. Yeast with favus spores and mycelium of fungus--11. Favus ferment, with oïdium and bacteria--12. Puccinia spores, growing in a saccharine solution--13. Aerobic bacteria--14. Spores and mycelia from eczema produced by yeast--15. Volvox globator--16. Amœboid condition of portion of volvox--17. Puccinia buxi--18. Ditto, more enlarged--(17 to 20 illustrate Ascomycetes.)--19. Æcidium grossulariæ from transverse section of leaf of currant: _a._ spermogones on upper surface; _b._ perithecia with spores--20. Phragmidium bulbosum, development of--21. Palmella parietina, trans. section through a spermogone, showing green gonidia and spermatia escaping--22. Æcidium berberida, from leaf of berberry--23. Vaucheria sessilis--24. Stephanosphæra pluvialis: _a._ Full-grown example, germ cells spindle-shaped with flagella; _b._ Resting-cell; _c._ division into four; _d._ Free-swimming ciliated young specimen; _e._ Amœboid condition--25. _a_, _b_, _c_, _d_, _e_, _f_ and _g_, Development of lichen gonidia--26. Palmella stellaris (lichen), vertical section through apothecium, showing asci, spores, and paraphyses, with gonidia and filamentous medulla: _a._ Spermatophore with spermatia--27. Moss gonidia assuming amœboid form. Typical forms of Protophyta; 7 to 14, modes of development or rudimentary conditions; Confervoideæ, 23; Vaucheria, Stephanosphæra, 24; Volvox, 15, &c. PLATE II.--_Page_ 412. PROTOPHYTA. ALGÆ. _Fig._ 27. Ceramium acanthonotum--28. Closterium, Triploceras gracilis--29. Cosmarium radiatum--30. Micrasterias denticulata--31. Docidium pristidæ--32. Callithamnion plumula--33. Diatoma, living: _a._ Licmophora splendida; _b._ Achnanthes longipes; _c._ Grammatophora marina. These figures are intended to show the general character of the endochrome and growth of frustule--34. Callithamnion refractum--35. Jungermannia albicans; _b._ representing elater and spores--36. Leaf with antheridia, or male elements, represented more magnified at _a_ to the left of the figure--37. Ceramium echinotum--38. Pleurosigma angulatum, side view--39. Delesseria hypoglossum--40. Pleurosigma angulatum, front view, endochrome not represented--41. Ceramium flabelligerum. PLATE III.--_Page_ 479. PROTOZOA.