BESCEIPTION OF THE EXGEAVINGS. 957 



PLATE XX. (PiiYTOzoA). 



Figures 1-14. Polytoma Uvella, forms and development of: 1. Perfect form; 2. 

 Same, acted on by chromic acid, which has separated the primordial cell from the external 

 envelope; 3-6. Stages of fission-process ; 7. Resting stage ; 8. External membrane broken 

 up into granules ; 9. Pission into foiu- ; 10-12. ilrrangement of secondary or " daughter " 

 cells ; 13. Contraction of body witliin external envelope ; 14. Body retracted from ante- 

 rior extremity: x300 (Schneider), 15-21. Fission and formation of microgonidia in 

 Chlorogonium euchlorum. 22, 23. Pandorina Morum (?) ; 22. A presumed form of, 

 with encysted immature fronds, Xl50; 23. Another presumed form, x220. 24. 

 Chlamydococcus (?), a presiuned form of; the two internal globular cells of a clear 

 ruby-crimson ; the moving granules pi'obably monads ; suggested to be Spermatozoa, X 220 

 (Currey). 25. Yolvocina, a developmental phase of one of the, having encysted gonidia. 

 26-28. SyncryptaVolvox, x2G0. 29,30. Synura Uvella : 30. Section of a group (Ehi-.). 

 31. Uroglena Yolvox. 32. Yolvox G-lobator. 33-49. Illustrations of structure and 

 development of Yolvox Globator (Busk and V\'illiamson) : 33. A section showing parietal 

 cells and contained gemmffi ; 34. Portion of edge of an embryo Yolvox viewed in the 

 equatorial plane to show the common envelope and the position of the subjacent cells or 

 gonidia ; the last not passing beyond the external gelatinous (?) coat (Busk) ; 35. Highly 

 magnified view of tlu*ee cells ; the faint lines between indicate the limits of the gelatinous 

 envelope of each cell ; 36. Section of a specimen momited in glycerine (Will.) ; 37. Cells 

 seen from above, shoeing radiating threads ; 38. Oblique section, mounted in glycerine ; 

 39-41. Single cells ; 42-44, 46, 47. Progressive development of Yolvox by fission ; 45. 

 Diagi-am of a superficial view of a portion of a globe (Will.); 48, 49. Wiiiter spores of 

 Yolvox aiu'eus: 48. An earlier ; 49. A later and mature condition (Busk). 



PLATE XXI. (Protozoa). 



Figure 1. Amoeba Schultzii, x330. 2. A. globularis, x330. 3. A. porrecta, x330. 

 4. A. princeps, xlOO. 5 a. b, c. Amoebiform germs or "Proteans" of Spongilla. 6. 

 Miliola vulgaris. 7-9. Arcella vulgaris ; 8. A side view ; 9. Empty shell. 10. Difilugia 

 globulosa, xl50. 11. Euglypha alveolata, empty shell, x340. 12-14. Gromia oviformis : 

 12. A young specimen ; 13,14. Nuclear bodies found in (Schultze), x300. 15. Arcella 

 Okeuii. 16. Gromia oviformis, x300. 17. Difflugia pyriformis. 18 a, h. Supposed 

 young forms of Gromia Dujardinii : a, x72; b, x 180. 19 a-f. D. Enchelys : a, b. Difi'erent 

 forms ; c. Contents resolved into granules ; d, e. Fission into two and four portions ; 

 /. Two individuals coherent. 20 a, b. Early stage of an undescribed Miliola : a, x 72 ; 

 b, x330 (Schultze). 21, 22. Miliola obesa : 21. A yoimg specimen, x72; 22. Shell, 

 after the removal of the calcareous matter by dilute acid. 23. M. Anconensis. 24. 

 Animal contents of a Miliola after dissolution of the shell by acid ; displaying a constric- 

 tion at each half turn, and the delicate membranous envelope at the lower and larger 

 extremity. 25. Cornuspira perforata. 26. Eotalia Yeneta, seen in front. 27. Eosahna 

 omata. portion of shell of, X 100. 28. Polystomella venusta, X 72. 29, 30. P. Stella- 

 borealis, seen in front, x72; 30. Portion of cell to show structui'e, Xl80. 31. Rotalia 

 Yeneta, shell after action of acetic acid, X 180. 32. Nuclear body from the last chamber 

 of Textilaria picta, x330. 33. Rotalia Yeneta, XoO. 34 «, b. Acervulina acinosa; 

 b. Natm*al size. 35. Acervulina globosa, portion of shell, x300. 36. Textilaria picta, 

 Xl80. 37. Acervulina globosa, section through thickness of shell, x300. 38. Polymor- 

 phina eihcea, silicious matter detached by pressure, x300. 39. Polystomella strigilata, 

 animal substance with attached particles apparently assmning an independent existence, 

 x330. 40. Portion of contents of Gromia Dujardinii. (Figures 20 to 40, Schultze.) 



PLATE XXII. (Protozoa). 



Figures 1-3. Amoeba radiosa ; 2. An older specimen ; 3. One nearly divided into 

 two. 4, 5. A. Limax. 6. A. guttula. 7-11. A. bilimbosa : in 7 and 9 the external 

 envelope strongly marked by a double outline ; a clear zone witliin it ; 9. First stage 

 of encysting ; 10. A nucleus with a central clear space, and one with two nucleoli ; 

 11. A specimen acted on by solution of iodine ; contained starch-granules coloured blue. 

 12-18. A. actinophora : in 13 two pulsating vesicles occur ; 15. Specimen acted upon by 

 acetic acid, showing double outline of integument ; 16 contains refracting particles of a 

 crystalline form ; 17. Some such particles isolated, and more highly magnified ; 18. Two 

 coherent individuals, indicative either of fission or of conjugation. 19. Cadium marinum. 

 20-23. Amceba bilimbosa: 20. Treated with iodine, the starch-granules coloured blue; 



