264 CHAS. W. HAUGITT, 



tainty l)e recognized. And it is hardly necessary to suggest that its 

 observation in living eggs is all but impossible. The same is to a 

 certain extent the case with other hydroids of similar character. Even 

 with forms in which the eggs are set free the phenomenon is rarely 

 conspicuous. As I have elsewhere noted, in only a few cases have I 

 identified these cells with certainty in Pennaria ova, which are freely 

 discharged before fertilization occurs. 



Similar difficulty exists in most cases in reference to the internal 

 features of maturation. This has been already hinted at in a pre- 

 vious paragraph. With Eudendrium it is particularly difficult owing 

 the massing of yolk spheres of very opaque nature in the egg, and 

 to the distortion, or apparent disintegration of the nucleus during the 

 growth of the egg. Hickson has found a similar condition in the 

 growth of the egg of Disticliopora. Indeed, many of Hickson's figures 

 would serve to portray with fair accuracy the prevalent condition found 

 in the hydroid just cited. The migration of the nucleus to the periphery 

 of the egg and the amoeboid aspect of the nucleus during this time 

 and its subsequent apparent disintegration and dissii)ation through 

 the cytoplasm of the egg have seemed to me to be associated with 

 maturation, rather than with fertilization as Hickson has suggested. 



CoE (1898), has shown that in Cerebratulus maturation of the 

 egg is accompanied with the discharge of no inconsiderable portion of 

 the chromatin and its disintegration and distribution through the egg 

 cytoplasm. Something similar to this apparently occurs in Euden- 

 drium and several other hydroids and hydromedusae, perhaps in a 

 considerable number. In these cases however it is not necessary to 

 assume that the chromatin thus dissipated through the cytoplasm 

 finds no further use in nuclear activity, as Coe has suggested con- 

 cerning Cerebratulus. Its dissipation is only a phase in the maturation 

 of the egg associated with the dissolution of the nucleus and its 

 probable distribution throughout the cytoplasm. 



So far as I have been able to follow the course of maturation 

 phenomena in Eudendrium they are substantially as follows: 



Following the migration of the nucleus toward the periphery of 

 the egg, as previously intimated, there is complete dissolution of the 

 nuclear membrane, and the total disappearance of the nucleolus, 

 whether as a whole, or by dissolution and dissipation I have not been 

 able to demonstrate certainly, but failure to trace its discharge as a 

 distinct body leads me to infer its fragmentation and gradual dis- 

 sipation. Fig. 7 shows a final condition of the nucleus, apparently 



