Castle. — Cioua intestinalis. 



PLATE VII. 



Magnification of all Figures, except 43 and 44, 315 diameters ; magnification of 

 Figs. 43 and 44, about 300 diameters. 



Figs. 39-42. Four later views of the egg shown in Figs. 35-38, Plate VI.; same 



(ventral) aspect. 

 Fig. 39. 16-cell stage, just formed. This view five minutes later than that in 



Fig. 38. 

 Fig. 40. 16-cell stage, five minutes later. 

 Fig. 41. 16-cell stage, ten minutes later still. Arrows indicate the direction of 



spindles. 

 Fig. 42. 24-cell stage, just formed, some minutes later than the last view. 

 Fig. 43. A late 24-ceIl stage, viewed from the right side. 

 Fig. 44. Optical section of the same egg, near the median plane. The cells of the 



dorsal hemisphere are in mitosis. 



