Hakgitt: Pennaria tiarella and Tubularia crocea. 



PLATE 6. 



Tvbularia crocea. 

 All eggs killed in corrosive-acetic. All Figures X 1600. 



Fig. 45. Egg about full grown ; nucleolus of germinative vesicle fragmented 

 into a chain of vacuolated pieces. Ehrlich's hematoxylin and 

 eosin. 



Fig. 46. Similar to Figure 45, with nucleolus in several irregular fragments. 

 Ehrlich's hematoxylin and eosin. 



Fig. 47. Extreme case of fragmentation of the nucleolus. Drawing com- 

 piled from all the sections of the germinative vesicle containing 

 nucleoli. Ehrlich's hematoxylin and eosin. 



Fig. 48. Germinative vesicle of full grown egg before polar-cell formation; 

 chromatin in beaded strands; cytoplasm concentrated around 

 the vesicle. Iron hematoxylin and Congo red. 



Fig. 49. Germinative vesicle in prophase of maturation mitosis. The 

 surface of the egg is raised into an elevation containing the 

 ovoidal germinative vesicle with radiations at its peripheral end, 

 but not directed to a visible centrosome. Cytoplasm only slightly 

 concentrated around the vesicle. Iron hematoxylin and Congo 

 red. 



Fig. 50. Another germinative vesicle, to which the description of Figure 49 

 also applies. 



Fig. 51a. First maturation spindle; chromosomes at the equator. Iron 

 hematoxylin and Congo red. 



Fig. 51b. Sperm nucleus of the same egg as Figure 51a, no centrosome nor 

 aster. 



Fig. 52. The two polar cells already detached ; the second still connected to 

 the egg by interzonal filaments. (The polar cell shown in dotted 

 outline occurs in the following section.) Egg nucleus near sur- 

 face of the egg. Iron hematoxylin and Congo red. 



Fig. 53. Somewhat oblique, nearly tangential, section. Two polar cells on 

 the surface of the egg, and egg nucleus close to the surface. Iron 

 hematoxylin. 



Fig. 54. Sperm head with accompanying aster near the surface of the egg. 

 Iron hematoxylin. 



