Jeniokos. — Asplanchna. 



PLATE 5. 



Fig. 35. Ventral view of a stage similar to that seen in Figures 33 and 34, Plate 4, 

 showing the antero-posterior position of the spindle in c?^i. 



Fig. 36. Transverse optical section of the sixteen-cell stage, tlirough the cells of 

 the third layer, exhibiting the position of the spindle in #3. The 

 section is viewed from the dorsal side. (Compare Plate 2, Fig. 8.) 



Figs. 37-42. Twenty-cell stage. 



Fig. 37. Completion of the fifth cleavage in quadrant D. Note the oblique posi- 

 tion of the elongated aster in d^-^. 



Fig. 38. Sagittal optical section of tlie egg shown in Figure 37. The section 

 passes, on the anterior side, between the cells of quadrants A and B, 

 showing the cells of quadrant A. 



Figs. 39-42. Different views of one and the same egg. 



Fig. 39. Left side, showing the asters and spindles for the fifth cleavage in quad- 

 rants A and B. 



Fig. 40. Right side of the egg shown in Figure 39. Observe the more advanced 

 karyokinetic stages in quadrant C, as compared with quadrant A, 

 Figure 39. 



Fig. 41. View looking down upon the animal pole. 



Fig. 42. View of the same egg from the ventral pole, showing the oblique posi- 

 tion of the asters in d^'^. 



Fig. 43. An older stage than that given in Figures 39-42 ; the fifth cleavage in 

 progress ; the egg contains twenty-seven cells. The cells c^-s and 

 J6-3 are forced apart by the cell c®-". 



