Castle. — Ciona iutestinalis. 



PLATE VI. 



Magnification of all Figures, 315 diameters. Arrows indicate the direction of 



spindles. 



Fig. 33. Later stage of the same egg as that sliown in Fig. 32, Plate V. Iti-celi 



stage, just formed. 

 Fig. 34. The same egg, passing into 24-cell stage. 

 Figs. 35-38. Ventral aspect of four successive stages of a living egg. 

 Fig. 35. 4-cell stage. 

 Fig. 36. 8-cell stage, just formed. 

 Fig. 37. 8-cell stage, a few minutes later. 

 Fig. 38. 12-cell stage, just formed. 



