626 GEORGE T. HARGITT 



a group of granules is present close to the germinal vesicle. 

 These have the same appearance as the granules which were 

 present at the very beginning of growth (fig. 51), but their origin 

 is not very certain. Within the germinal vesicle the reticulum 

 is still faintly staining and similar to its earlier condition. There 

 are, however, chromatin strands in a group about the remains 

 of the nucleolus. Since this egg has reached its full growth 

 the chromatin strands represent the beginning of the formation 

 of chromosomes. 



Further stages in maturation have not been studied because 

 the material is lacking in some of the essential phases. The 

 actual formation of the polar bodies and the fertilization by the 

 spermatozoon have not been observed in any of the material 

 which I have collected. This is somewhat strange since the 

 material is abundant and shows other phases in considerable 

 number; it may be possible that there is a periodicity in the 

 formation of polar bodies and the material was not collected at 

 the correct time. Also since but two or three eggs ever develop 

 in a single ovary, the number of such eggs at command for study 

 is not very great, even in an abundant supply of medusae; the 

 number which might be expected to show maturation stages 

 would be even fewer. Muller ('08) in his paper on Hybocodon 

 also was without this stage, and probably the maturation and 

 fertilization of Hybocodon have never been observed. 



The egg remains in its place in the gonad after growth and 

 maturation are completed and the fertilization is accomplished 

 in the gonad. The egg then enters upon its cleavage, still within 

 the gonad, and finally produces a larval polyp with tentacles, 

 the actinula. A section of an actinula in position and about 

 ready to be set free is shown in figure 39. 



CONCLUSIONS 



The medusae of Hybocodon give rise to other generations by 

 budding secondary medusae from the base of the tentacle. 

 The medusae are sexual individuals and produce either eggs or 

 sperm. Sexual products are produced more or less periodically, 

 while buds arise at any time ; the sexual and asexual reproductive 

 processes often occur simultaneously. 



