Apogamy in Ferns . 199 
Fig. 42. Nucleus in equatorial plate stage. In this and the preceding figure the postmeiotic 
number of chromosomes are shown, x 1500. 
Fig. 43. Nucleus, in same stage as the last, from prothallial cell, but containing increased 
number of chromosomes due to fusion with a nucleus of adjacent cell, x 1500. 
Fig. 44. Nucleus in same stage from cell of embryo, x 1500. 
PLATE XIX. 
Figs. 45, 46, 47, 48, 49, 50, 51 illustrate stages in the migration and fusion of nuclei from 
adjacent prothallial cells. The empty cell is drawn, but the surrounding cells, every one of which 
contains a nucleus, are not included in the figures : the figures are all drawn to a magnification of 
1500 diam., and are reduced to \ size. 
Figs. 52, 53. Unusual types of nuclear migration. In Fig. 52 three nuclei have collected into 
one cell ; in Fig. 53 a nucleus is seen passing from one cell, traversing the next, and entering the 
third cell beyond. 
Figs. 54, 55. Apogamous outgrowth with tracheids arising from the prothallium. 
Fig. 56. Embryo formed from the apogamous peg. The prothallium shows tracheids in the 
anterior end. 
Lastrea pseudo-mas var. polydactyla , Dadds. 
Fig. 57. Dividing nucleus from young archesporial tissue, x 1500. 
Fig. 58. Heterotype mitosis in spore-mother-cell. X 1500. 
Fig. 59. Mitosis in the antheridial rudiment. The antheridium arises as a small pouch-like 
upgrowth from the prothallial cell, shown in the Fig. pr. x 1500. 
Fig. 60. Prophase of mitosis in embryo, x 1500. 
Fig. 61. Migration of nuclei in prothallium. Note the wall separating the cell is breaking down. 
Fig. 62. Archegonium. v.c.c., ventral canal-cell ; b, the ‘ body 1 in the oosphere. 
PLATE XX. 
Fig. 63. The central cell (oosphere) with ‘body‘ (b), and the ventral canal-cell, {v.c.c.) (more 
highly magnified than the last figure). 
Fig. 64. The apogamous protuberance ( sp ), situated close to an abortive archegonium ( Ar ) (the 
latter is cut obliquely). 
Fig. 65, a and b. Two consecutive sections cut through older sporophytic growth (sp). In 
Fig. 65 a the apex of the root, in Fig. 65 b the adjacent archegonium, is shown. 
Nephrodium pseudo-?nas var. cristala apospora , Druery. 
Fig. 66. Edge of pinna with aposporous prothallial outgrowth. 
Fig. 67. End of pinna with brush-like outgrowth of marginal cells. 
Fig. 68. End of pinna with marginal (m) and with superficial (s) prothallial outgrowths. 
Fig. 69. Prothallial cell and nucleus, x 1500. 
Fig. 70. Mitosis in nucleus of prothallial cell, x 1500. 
Fig. 71. Somewhat later (equatorial plate) stage in mitosis of prothallial nucleus, x 1500. 
Figs. 72, 73. Nuclear division in Embryo, x 1500. 
Fig. 74. Section through a young apogamous outgrowth on the prothallium. 
Fig. 75. Section through an older apogamous embryo cut obliquely, and showing the apex of 
the root. 
Fig. 76. Aposporous prothallium and apogamous embryo still attached to it. 
