Hargitt: Pennaria tiarella and Tubularia crocea. 



PLATE 7. 



Tubularia crocea. 



All eggs killed in corrosive-acetic. 



Fig. 55. Cross section of gonophore near the end of the growth period, 

 showing oocyte with pseudopodia, also spadix and other oocytes, 

 which serve as food. The spherical bodies in the egg are nuclei 

 of absorbed oocytes, "pseudo-cells." The germinative vesicle 

 is represented by the small circle at the edge of the oocyte oppo- 

 site the spadix. Auerbach's acid fuchsin and methyl green, 

 X 51. 



Fig. 56. Like Figure 55. Ehrlich's hematoxylin and eosin. X 51. 



Figs. 57a, 57b. Daughter nuclei of first cleavage; each shows two vesicles. 

 In Figure 57a one polar cell is shown. Iron hematoxylin. 

 X 1200. 



Figs. 58a, 58b. Two sections from an egg which is in an early cleavage stage. 

 The nucleus has completed its second division. First cleavage 

 furrow incomplete, second just started. Iron hematoxylin and 

 Congo red. X 51. 



Fig. 58c. Part of Figure 58b enlarged, showing interzonal filaments, inter- 

 zonal body, one daughter nucleus, and the beginning of the sec- 

 ond cleavage furrow. X 1200. 



Fig. 59. Egg still in gonophore. Second nuclear division completed and a 

 small blastomere forming; first cleavage furrow incomplete. 

 In another section a similar small blastomere is found. Picro- 

 hematoxylin. X 51. 



Fig. 60. Early cleavage; 20 nuclei present, but cytoplasmic division slightly 

 retarded. Nuclei all on the same side of the egg, and cleavage 

 planes meridional. Cleavage cavity represented by spaces 

 between the cells. Pseudo-cells present, but not represented in 

 the figure. Ehrlich-Biondi mixture. X 51. 



