ILLUSTRATIONS 



TO 



THE FIRST VOLUME. 



(The Author is indebted to the works of Dr. Carpenter, Eev. M. J. Berkeley, Mr. 

 Gosse, and Mr. Darwin, for the larger part of these Illustrations.) 



PIG. PAGB 

 89. Eucyrtidium cranoides ..... frontispiece 



1. Form of stratified discharge in a vacuum tube . . . 79 



2. Form of stratified discharge in a vacuum tube, as affected by an 



electro-magnet . - . . . v .81 



3. Development of Ulva . . . . . .171 



4. Vertical section of the cuticle of Iris germanica . . .173 



5. Longitudinal section of stem of Italian reed . . .176 



6. Palmoglcea macrococca .- . . . . .182 



7. Protococcus pluvialis . . . . . .184 



8. Volvox globator . . . . . . .189 



9. Various species of Staurastrum . . . ,. .192 



10. Economy of Closterium Lunula . . . . .193 



11. Diatoma vulgare and Grammatophora serpentina -v'- s . 197 



12. Biddulphia pulchella -. . . . . .198 



13. Pleurosigma angulatum . * . -. t .199 



14. Actinocyclns undulatus * . . '... . 200 



15. Meridion circulare . -# .' . .- . 201 



16. Bacillaria paradoxa . ^ . . .. - r 203 



17. Cell multiplication in Conferva glomerata r . . 207 



18. Zoospores . . . . , . . . 208 



19. Threads of Eivularia nitida . . .- .- .215 



20. Trichodesmium erythraeum . . . -. - . 216 



21. Conjugation of Zygnema quininum . . . .217 



22. Ulva latissima ....... 225 



23. Polyides rotundus and Furcellaria fastigiata ... -^.., . 229 



