JsKNixes. — Asplanchna. 



PLATE 2. 



Four-cell stage, viewed as a transparent object from the animal pole. 



The anterior end is above. 

 Four-cell stage, later than Figure 8, seen from the right side. Spindles 



in C^ and I>^ ; spherical nucleus in B^. 

 Four-cell stage, optical section through the cells B^ and D^, showing the 



division of the asters in preparation for the third cleavage. 

 Five-cell stage, from tlie ventral side. The anterior end is above. The 



aster in c?^i has divided laterally, the two parts being still connected. 



Spindles in A^, B^, and 0'^ seen endwise. 

 Optical section, approximately sagittal, through the quadrants B and D, 



from the egg shown in Figure 11. 

 Oblique view of the eight-cell stage, shortly after the third cleavage. 



The animal pole is marked by the polar cell ; the anterior median 



line by the boundary between quadrants A and B. 

 Dorsal view of the egg represented in Figure 13, showing the oblique 



position of the asters in d^-, and the lateral extension of the aster 



in c*"2. 

 Ventral view of the egg seen in Figures 13 and 14, showing the oblique 



position of the asters in c/*i, and the lateral extension of the aster 



in c*''^. 

 Optical, nearly sagittal, section of the eight-cell stage, through the quad- 

 rants B and D, showing the dorso-ventral direction of the spindles in 



c?*'i and d*-^. Notice also the change of form of the quadrant B, as 



compared with the same quadrant in Figures 10 and 12. 



