421 
Embryo of Sciadopitys verticillata. 
cell, which proves quite clearly that no membrane separates them from one another. It may be 
seen also that the nucleus of the top cell of the axial row shows signs of disorganization. June 4. 
Fig* 35* The same at a later stage. Here we see the two nuclei of the middle cell and the 
nucleus of the top cell showing signs of disorganization, and the basal cell considerably enlarged, 
with its nucleus in a normal active condition. June 4. 
Fig. 36. A longitudinal section of the axial row. It will be seen that the basal cell has 
enormously enlarged and becomes really the functional megaspore. The middle and top cells show 
no growth whatever, and their nuclei are very much disorganized. June 12. 
Fig* 37* A longitudinal view of the very large functional megaspore and the three abortive, 
more or less disorganized, functionless spores at the top. It will be noted also that the functional 
megaspore consists for the most part of a large central vacuole, and the relatively small amount of 
cytoplasm present is parietally placed. June 19. 
Fig* 38. A more highly magnified view of the three abortive megaspores. The three nuclei 
become crowded together and altogether difficult to recognize as nuclei. The two free nuclei of 
the middle cell become flattened against one another. June 19. 
Fig. 39. A part of the megaspore membrane as seen in longitudinal section. June 19. 
Fig. 40. A longitudinal section of a very young archegonium, which at this stage consists of 
a central cell and two neck-cells. April. 
Fig. 41. The same, showing the enlargement of the central cell and the differentiation of the 
jacket cells. May 15. 
Fig. 42. A longitudinal section of two young archegonia, showing the great increase in length 
and breadth of the central cell. May 15. 
Fig. 43. The same at a later stage of development, when the cytoplasm of the central cell has 
become very much vacuolated, and the sterile tissue at the apex of the prothallium has grown forward, 
leaving the archegonium behind, and forming a single archegonial chamber leading to the neck-cells 
of each archegonium. May 25. 
Fig. 44. Two mature archegonia ready for fertilization, each containing a large central vacuole 
in the rear of the egg nucleus. June 19. 
Fig. 45. The nucleus of the central cell in process of division. The spindle is formed directly 
under the neck-cells. June 15. 
Fig. 46. The ventral canal spindle with the chromosomes at the poles. June 15. 
Fig. 47. The neck region of an archegonium, showing the relative size and position of the 
ventral canal nucleus and egg nucleus soon after they are formed. June 15. 
Fig. 48. A longitudinal section of the apex of the nucellus and upper part of the prothallium, 
to show the penetration of the pollen-tube through the nucellar tissue and archegonial chamber to 
the neck-cells of the archegonium. June 19. 
Fig. 49. A longitudinal section to show the relative size of the two male nuclei as they lie 
in the upper cytoplasm of the archegonium immediately after their discharge from the pollen-tube 
through the neck-cells. June 27. 
Fig. 50. A longitudinal section of the fusion-nucleus immediately after fertilization, to show the 
position and form of the first sporophyte-spindle within the confines of the membrane of the egg 
nucleus. June 29. 
Fig. 51. A surface view of the chitinous-like reticulated thickenings on the inner walls of 
the jacket cells during the period of fertilization. June 29. 
Fig. 52. A longitudinal section of a pro-embryo, showing four free nuclei descending to the base 
of the archegonium. June 29. 
Fig. 53. The same at a later stage, to show the arrangement of the free nuclei in three tiers just 
previous to the formation of walls between them. July 2. 
Fig. 54. A later stage in the development of the embryo after the elongation of the suspensors. 
The embryo proper at this time consists of several layers of cells which are carried forward into the 
prothallial tissue by the elongated suspensors. July 7. 
