Castle. — Ciona iutestinalis. 



PLATE V. 



Six successive views of a living egg, seen from the anterior end ; magnification, 

 315 diameters. Figs. 27-31 show the egg viewed as a transparent object. 

 Fig. 32 is a surface view. 



Fig. 27. 2-cell stage, newly formed. 



Fig. 28. 2-cell stage, a few minutes later. 



Fig. 29. 2-cell stage, a few minutes later still. 



Fig. 30. 4-cell stage. 



Fig. 31. 8-cell stage, just formed. 



Fig. 32. 8-cell stage, a few minutes later. 



