Jexxdjgs. — Asplanchna. 



PLATE 10. 



Fig. 80. Optical section (approximately frontal) of an egg in the stage seen in 

 Figures 69-74, showing the very unequal division of d^'^. 



Fig. 81. Optical section (approximately frontal) of a stage later than Figure 80, 

 showing the five large entoderm cells. A side view of the same egg 

 is seen in Plate 9, Figure 76. 



Fig. 82. Stage slightly later than that of Figure 81. The ectoderm is supposed 

 to have been removed from the dorso-anterior part of the egg, dis- 

 closing the position of the entoderm cells. A side view of the same 

 egg is shown in Plate 9, Figure 78. 



Fig. 83. Later stage than the preceding, viewed in the same manner. A spindle 

 has appeared in each of the five large entoderm cells. 



Fig. 84. Optical sagittal section of an embryo at about the time of the beginning 

 of the formation of organs. 



