Jennings. — Asplanchna. 



PLATE 4. 



Figs. 26-29. Ten-cell stage. 



Fig. 26. Left side of an egg in a ten-cell stage, slightly older than that shown in 



Figures 20-25. Note the dorso-ventral elongation of the cells a^'i 



and a*-, as compared with tiie same cells in Figure 22. 

 Fig. 27. Right side of the egg shown in Figure 26. The cytoplasm is beginning 



to become constricted in the cells of quadrant C 

 Fig. 28. Dorso-ventral, approximately frontal, optical section of the egg shown in 



the two preceding figures, viewed from the anterior side, to show the 



greatest dorso-ventral extent of the quadrants A and C at this stage. 

 Fig. 29. Right side of the egg of Asplanchna priodonta Gosse, in the ten-cell 



stage, showing the spindles in the shorter axes of the cells. 

 Figs. .30-36. Sixteen-cell stage. 



Fig. 30. Resting condition, seen from the anterior side. 

 Fig. 31. Left posterior view of the egg seen in Figure 30, showing the position of 



tiie asters in all tiie cells of quadrant D. 

 Fig. 32. Dorso-ventral, nearly sagittal, optical section through the quadrants B 



and D, from the egg shown in the two preceding figures. 

 Fig. 33. Posterior view of an egg slightly older than that shown in Figures 30-32. 

 Fig. 34. Nearly sagittal optical section, through the quadrants B and D, in the 



same stage as that shown in Figure 33. 



