MORPHOLOGY AND DEVELOPMENT OF EUDENDRIUM. 4! 



During the stay of the ovum in the pedicel there is an occa- 

 sional absorption of neighboring ectoderm cells. It is indicated 

 by the presence of degenerating nuclei within the ovum. At 

 first they differ little from the nucleus of an ectoderm cell. At 

 a later stage the nuclear membrane disappears leaving a vacuole 

 larger than the original nucleus and containing deeply staining 

 chromatin rods surrounded by a non-staining watery substance. 

 Similar nuclear degeneration may be traced more completely in 

 the general ectoderm tissue up to the formation of the vacuole. 



A more active cell absorption takes place when the egg reaches 

 the hydranth (Fig. 10). As much as half of the egg membrane 



^^'^<y;^^->(.C^^ni^rrr Ji ^r--r^'' ; " '^"*?~-~~~~*^. 



^- -SKI 



FIG. 10. 



on one side may disappear in company with part of the walls of 

 neighboring entoderm cells. A thin cuticular film stretching 

 over the inner side of the egg separating it from the enteric cavity 

 is all that remains of the walls of the nearest cells. The more 

 distant cells retain the part of their wall farthest from the egg. 

 There is no break in the continuity of the ooplasm and the 

 fused cytoplasm of the entoderm cells. Nuclei are scattered 

 about irregularly. Some occur definitely within the confines of 

 the egg. As soon as the egg becomes enclosed in the gono- 

 phore it presents an unbroken periphery. When it has been 

 carried away from the surface of the hydranth its nutriment 

 comes by way of the spadix lumen which is a prolongation of 

 the enteric cavity of the hydranth. Part of the columnar cells 



