MIGRATION OF REPRODUCTIVE ORGANS IN HYDRA. 421 



bud in Diagram C was seventy hours. Diagram D, I, 2 and 3 

 shows the position taken by the ovary, at the different stages in 

 the development of the bud. The rate of growth and migration 

 of the ovary is the same as in the case of the spermary. 



The position taken by the reproductive organs during the 

 different periods of growth in the formation of the buds, indicate 

 beyond question, that the region around the base of the buds, 

 contributes almost entirely to the formation and growth of the 

 buds, and that the cells of the buds contribute but little to their 

 own development. The cells in the growth region not only 

 divide mitotically, but migrate from the parent hydra to the 

 buds and carry the reproductive organs with them. 



It was not an unusual thing to find hydra that were produced 

 by budding in the different cultures, which showed either ovaries 

 or spermaries at their extreme distal or proximal end. Dia- 

 grams A, 3, and C, 4, are good examples of these conditions. 



In a few instances where the spermary was situated equi- 

 distant between two forming buds, the spermary became divided 

 through the central region, either half reformed into a distinct 

 spermary and migrated towards the corresponding bud. In 

 these particular cases the spermaries were in their early stages of 

 development. But in those spermaries that were completely 

 formed and contained mature sperm, no division occurred. 

 They either remained in their former position equidistant be- 

 tween the two buds, or migrated in toto towards one or the 

 other. 



The migration of the reproductive organs as observed in 

 hydra is rather an interesting phenomenon, and occurs quite 

 frequently, especially in budding hydra that are rich in sex 

 organs. This process of migration however, is directly asso- 

 ciated with asexual reproduction and can not be considered as 

 having any very special significance, since the reproductive 

 organs migrate in conjunction with the surrounding cells and 

 not independently of them. 



LITERATURE CITED. 

 Downing, E. R. 



'04 The Spermatogenesis of Hydra. Zool. Jahr., Band 21. 

 Lang, Albert 



'92 Uber die Knospung bei Hydra und einigen Hydropolypen. Z. wiss. Zool., 

 Vol.' 54- 



