Miyake, Tlie development of the gametopliytes etc. 
23 
Fig. 39. The same, in spindle of first division; equatorial-plate stage. 
X 1330. 
Fig. 40. The same, in telophase. X 1330. 
Fig. 41. Functional megaspore with two disorganizing spores above. 
X 660. 
Fig. 42. Outline of longitudinal section of young ovule; megaspore 
mother-cell in metaphase of first division. Fig. 39 is sketched from the same 
preparation. X 50. 
Fig. 43. The same at a later stage; integument is not shown. Female 
prothallium probably in four-nucleated stage. Tapetum is shaded. X 50. 
Fig. 44. Four-nucleated stage of female gametophyte. X 660. 
Fig. 45. Longitudinal section of ovule slightly older than that offig. 43. 
Tapetum is shaded. April 30. X 50. 
Fig. 46. Longitudinal section of central portion of young ovule, showing 
the arrangement of tapetum-cells around young gametophyte. X 240. 
Fig. 4 (. A portion of young prothallium whose nuclei are in division. 
X 660. 
Fig. 48. Longitudinal section of nucellar part of ovule, showing young 
gametophyte and well-developed tapetum. Tapetum is shaded. X 50. 
Fig. 49. The same, in a later stage. May 17. X 50. 
Fig. 50. The same, in a much later stage. Tapetum, which now consists 
mostly of a single layer of cells, is not shown. June 8. X 50. 
Fig. 51. A part of fig. 50 highly magnified, showing a parietal layer of 
free nuclei, tapetum and nucellar cells. X 660. 
Fig. 52. Surface view of free-nucleated prothallium as shown in fig. 51* 
X 660. 
Fig. 53. Slightly later stage than in fig. 51; beginning of wall-formation 
between the nuclei. X 660. 
Fig. 54. Still later stage. X 660. 
Fig. 55. Surface view of the same. X 660. 
Fig. 56. A part of the base of mature prothallium, showing the structure 
of megaspore-membrane at this stage. X 660. 
Plate III. 
Fig. 57. A part of growing prothallial tissue as it half way advanced 
toward the center of vacuole. X 160. 
Fig. 58. Solid prothallial tissue just formed. X 50. 
Fig. 59. Tip of the same more highly magnified. X 160. 
Fig. 60. Archegonial initials. X 160. 
Fig. 61. Tipper part of the same more highly magnified. X 660. 
Fig. 62. The same, with dividing nucleus. X 660. 
Fig. 63. Young archegonium with a single primary neck-cell. X 160. 
kig. 64. Upper part of a similar archegonium, more highly magnified; 
neck-cell is dividing. *X 660. 
Fig. 65 a. A little later stage. X 160. 
Fig. 65 b. Upper part of the above. X 660. 
Figs. 66 68. Later stages in the development of archegonia. Fig. 68 
represents an archegonium which has nearly reached to its full size. X 160. 
Fig. 69. Upper part of female prothallium, showing a young archegonial 
complex. X 50. 
