PLATE 7.— Confer voidese. 



Figure 



1. Chlorococcum vulgare, Grev. a, groups in natural condition ; b, an isolated cell snow- 



ing the granular contents ; c, dividing cells treated with sulphuric acid and iodine. 



2. Protococcus viridis, noh. a, groups of cells, the upper one with eight in a linear series ; 



those to the right with the contents dividing into numerous gonidia (?) ; b, zoospores 

 set free from the cells by the solution of the cellulose membrane ; c, an isolated cell 

 dividing and about to set free its contents as two zoospores ; d, resting-cells with a 

 thick coat and reddish contents ; e, a zoospore with the cilia cast ofT; f, a zoospore 

 with imperfect or retracted cilia ; g, remains of a zoospore left on a glass slide for 

 twenty-four hours. 



3. Palmella omenta, Br. a, patch of the jelly with single cells, and dividing and divided 



pairs ; b, similar cells without the gelatinous layer, the smaller granules similar to 

 those seen in the jelly of a ; c, cells treated with sulphuric acid and iodine, showing 

 the cellulose coat and granular contents; d, diagram indicating the relative dimen- 

 sions of the cells of Palmella nivalis. 



4. Glceocapsa polydermatica, Ktz. 



5. a, b, c, Sarcina ventriculi, Goodsir. 



6. Coccochloris Brebissonii, Ktz. a, group of cells, some dividing within their cell-coat ; 



b, a linear group; c, a pair of cells conjugating; d, conjugated cells encysted and 

 passing into the resting stage. 



7. Urococcus Hookerianus, Berk. 



8. a, b, Hydrants Ducluzelii, Ag. 



9. Botrydina vulgaris, Ktz. a, b, c, d, successive stages of growth. 



10. Tetraspora gelatinosa, Ag. Four parent cells producing biciliated zoospores, imbedded 



in the gelatinous frond. 



11. Gonium pectorale, Mull, a, perfect frond ; b, the same seen edgewise ; c, a single 



zoospore. 



12. Gonium tranquillum, Ehr. 



13. Glceocapsa ampla, Ktz. 



14. a, b, Volvox globator ?, forms related to Syncrypta and Eudorina of Ehrenberg. 



15. Spirulina oscillarioides) Turp. ?). 



16. Spirulina Jenneri, Ktz. 



17. a, Bacterium termo ; b, B. catenula ; c, B. punctum ; d, B. triloculare ; e, B. lineola ; 



f, Spirillum tenue ; g, Sp. undula. 



18. Bacillus subtilis. 



19. Vibrio rugula. 



20. Bacillus ulna. 

 20 a. Vibrio serpens. 



21. Vibrio bacillus, probably Anabaina subtilissima, Kiitz. 



22. Spirochceta jjlicatilis. 



23. Spirillum volutans. 

 24-36. Volvox globator, L. 



24. A perfect family. 



2o. With fully developed young within. 



26. With yellow encysted (resting) spores. 



27. Portion of the outer wall, with zoospores, some dividing. 



28. Ditto, showing the cilia of the zoospores. 



29. Ditto, a fragment after keeping some time in chloride of calcium, the portions around 



each zoospore tumid. 



30. The same seen obliquely, with the cilia. 



31. Spore with the protoplasm dividing. 



32. Ditto, more advanced. 



33. An encysted spore with undivided contents. 



34. An encysted resting-spore with yellow contents, probably a subsequent stage of 33. 



35. Ditto, ruptured by pressure. 



36. A similar resting-spore with conical processes on the outer coat (V. stellatus, Ehr.). 



