522 
Farmer —On Spore-Formation and 
Figs. 17-35. Pellia epiphylla. 
Figs. 17, 18. Spore-mother-cell with nuclei just preparing for division. 
Fig. 19. Later stage nucleolus vacuolated, chromatin becoming more abundant, 
the nucleins drawn out into a four-armed spindle. 
Figs. 20, 21, 22. Further stages in the development of the chromosomes. In 
Fig. 21 they appear distinctly as eight rings. 
Fig. 23. The first spindle. There are eight chromosomes (four shown). 
Fig. 24. Diaster stage seen obliquely. 
Fig. 25. The second division. One nucleus only of the lower pair shown, it is 
seen in pole-field, and the fellow one is concealed. In the upper part, the other 
two daughter-nuclei are both seen in profile. The cell-walls have appeared 
dividing the spore-mother-cell into four chambers. 
Figs. 26, 27. Other views of the process. 
Fig. 28 a. The spores are formed, and are preparing to germinate. 
Fig. 28 b. Slightly later stage, showing the marking on the proper wall of the 
spores, and the disappearance of the spore mother-cell membrane. 
Figs. 29, 30. Division of nuclei in cells of the stalk of the sporogonium, a 
typical homotype karyokinesis. 
Figs. 31-35. Nuclear divisions in the gametophyte. 
Fig. 31. Nucleus in early stage of karyokinesis. 
Fig. 32. The same, showing a centrosphere at one pole. 
Figs. 33, 34. Chromosomes in equatorial plate. 
Fig. 35. Division of chromosomes. 
Fig. 36. Aneura multifield ; the division of the chromosomes in the first spore- 
mother-cell mitosis. 
Figs. 37-39. Cephalozia bicuspidata. 
Stages in nuclear division of spore-mother-cells. 
Figs. 40-49. Scapania undulata. 
Fig. 40. Spore-mother-cell with resting nucleus. 
Fig. 41. Same preparing for division. The nucleolus has fragmented ; the linin 
now forms a well-defined net- work. 
Fig. 42. Nucleus drawn out in a quadripolar spindle. The chromosomes 
beginning to form. 
Figs. 43, 44. Chromosomes form the equatorial plate. 
Fig. 45. Polar view of nucleus in same stage as in 43. The nucleolus N still 
visible amongst the eight chromosomes. 
Fig. 46. The division of the chromosomes. 
Fig. 47. First mitosis, the cell-plate divides the entire spore-mother-cell. 
Fig. 48. The second division of the spore-mother-cell. 
Fig. 49. A slightly later stage than that represented in Fig. 46. 
