Jbknisos. — Asplanclma. 



PLATE 9. 



Fig. 71. Left side of the egg shown in Figures 69-74. Ninety-four cells. 

 Fig. 72. Dorsal view of tlie egg represented in Figures 69-74. The small 

 cells in the centre, at the point of meeting of the four quadrants, are 



„7.16_(f7.16. 



Fig. 73. Ventral end of the same egg, showing the crowding together of the 

 cells of the quadrants A, B, and C in this region. 



Fig. 74. Posterior view of the same egg, showing spindles for the ninth cleavage 

 in some of the cells of quadrant D, and the ninth cleavage completed 

 in other cells of that quadrant. 



Fig. 75. Anterior surface of a later stage, containing about 120 cells. At the ven- 

 tral end (lower part of the figure) the cells are much crowded and 

 many of them are very small. The vesicles immediately below the 

 cells b^^^, a8'i\ and aS-n are the small ventral products of the cleav- 

 age of a"°-c""^ and a'-'-c'-', the spindles for which are shown in 

 Figures 69 and 70, Plate 8. 



Figs. 76-79. Successive stages in which the ectoderm is conceived to have been 

 removed from the riglit side, to show tiie entoderm cells. 



Fig. 76. Egg at tlie stage shown in P'igure 75. A frontal section of this egg is 

 given in Plate 10, Figure 81. 



Fig. 77. Shghtly older stage than Figure 76, viewed in the same way. 



Fig. 78. Slightly older stage than Figure 77, showing the change in the position 

 of the cells of the entoderm and of those at the animal pole. A view 

 of this egg from the animal pole is shown in Plate 10, Figure 82. 



Fig. 79. Later stage than Figure 78. Tlie entoderm cells have changed position 

 still further, and are approaching cleavage. 



