37 2 Mij/ake . — On Fertilization in Picea excelsa. 
represents an archegonium which has nearly approached to its full size, but its 
cytoplasm is still quite vacuolate, x no. 
Fig. 32. A still later stage, little before the division of the central cell, x no. 
Fig- 33. An archegonium showing the division of the central cell, x no. 
Fig. 34. An archegonium just after cutting off the ventral canal-cell. 
Fig. 35. Mature archegonium; the ventral canal-cell is shown right below the 
neck-cells, x no. 
Fig. 36. Upper portion of an archegonium, showing the nucleus of the central 
cell shortly before division, x 500. 
PLATE XVII. 
Fig. 37. Nucleus of the central cell preparing to divide, x 500. 
Fig. 38. The same, later stage; a rupture in the upper right-hand corner of the 
nucleus was probably made during preparation of the section, x 500. 
Figs. 39-45. Various stages of the division to form the ventral canal-cell. 
X 500- 
Figs. 46, 47. Formation of the two daughter-nuclei, x 500. 
Fig. 48. Early stage in the development of the egg-nucleus, showing also the 
disorganizing ventral canal-cell, x 500. 
Fig. 49. Entire egg-cell, showing the first sperm-nucleus approaching the egg- 
nucleus. The second sperm-nucleus, which is located near the top of the egg, 
is found in other section, x no. 
Fig. 50. A later stage, showing the first sperm-nucleus just coming into contact 
with the egg-nucleus. The second sperm-nucleus is found in other section near 
the top of the egg. x no. 
Fig. 51. A still later stage; the first sperm-nucleus has partly imbedded itself in 
the egg-nucleus. The second sperm-nucleus is found in the upper portion of the 
egg. x no. 
Fig. 52. The spindle of the first segmentation, x no. 
Fig. 53. The two daughter-nuclei resulting from the first segmentation, x no. 
Fig. 54. A later stage, with the four segmentation-nuclei. One of the nuclei 
is not shown in this figure, being found in other section, x no. 
Fig- 55- The four free nuclei at the base of the archegonium ; only two of them 
are shown here, x no. 
Fig. 56. Basal portion of an archegonium ; the four nuclei are dividing, 
x no. 
Fig. 57. A later stage, showing the eight nuclei of the proembryo; the walls 
are laid down between the nuclei, x no. 
Fig. 58. A still later stage, showing the division of the nuclei of the upper 
incompletely walled cells, x no. 
Fig. 59. Formation of the proembryo is nearly completed; the nuclei of the 
lower tiers are in the late telophase of division, x no. 
Figs. 60-64. Abnormal archegonia. Figs. 60, 61. Archegonia without neck- 
cells; in Fig. 61 the ventral canal-cell is formed at the side of the egg instead of 
the top. Figs. 62-64. Double archegonia in various stages of development, 
x no. 
