15. Meridion circulare 201 16. Bacillaria paradoxa 203 17. Cell multiplication in Conferva glomerata 207 18. Zoospores 208 19. Threads of Rivularia nitida 215 20. Trichodesmium erythræum 216 21. Conjugation of Zygnema quininum 217 22. Ulva latissima 225 23. Polyides rotundus and Furcellaria fastigiata 229 24. Vertical sections of conceptacles of Gracilaria 230 armata, Grinnelia americana, and Corallina officinalis 25. Callithamnion corymbosum 232 26. Rhabdonia Coulteri, Sphærococcus coronopifolius, 236 Wrangelia penicillata, and Cruoria pellita 27. Dictyurus purpurascens 242 28. Polyzonia cuneifolia 243 29. Fruit of various species of Ectocarpus 245 30. Dictyota dichotoma 247 31. Vertical section of receptacle of Fucus 254 platycarpus 32. Various species of Pucciniæi 276 33. Puccinia Graminis 280 34. Various species of Mucedines 286 35. Torula Cerevisiæ, showing successive stages of 287 cell-multiplication 36. Various species of Sphæriacei 294 37. Various species of Lichens 299 38. Sporopodium Leprieurii, Coccocarpia smaragdina, 300 and Lecanora affinis 39. Paulia perforata, Calicium tympanellum, and 301 Graphis Leprevostei 40. Nitella flexilis 302 41. Antheridia of Chara fragilis 314 42. Further development of antheridia of Chara 315 fragilis 43. Marchantia polymorpha 317 44. Anatomy of frond of Marchantia polymorpha 318 45. Archegonia of Marchantia polymorpha 319 46. Elater and spores of Marchantia 319 47. Funaria hygrometrica 324 48. Polytrichum commune, group of antheridia 325 49. Polytrichum commune, development of spermatozoids 325 50. Microscopic structure of leaves of mosses 330 51. Development of spores of Pteris serrulata 336