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The Ovogenesis of Hydra. 

 By 



Elliot K. Dowuiug, Ph. D. 



The Northern State Normal School, Marquette, Mich. U. S. A. 

 With plates 11—12 and 2 figures in text. 



The earliest recorded observations on the eg-g production of 

 Hydra were made during- the fifth decade of the eighteenth centuiy. 

 Since then, many investigators have studied the ovogenesis of this 

 fascinating animal. The volume of earlj' publications regarding the 

 formation of the ^g^ and its development is much greater than that 

 regarding the development of the sperm, summarized by the author 

 in a preceding paper. In fact a fairly complete ovogenesis of hydra 

 can be patched together from the accurate but scattered facts 

 already recorded. 



It has seemed a not altogether thankless task to summarize, 

 in one article, these data, spread through several languages and 

 some two centuries. Abundant material gave promise of clearing 

 up, also, some of the conflicting statements and unsettled points. 

 The study was deemed worth while, too, because the remarkable 

 disintegration, recorded by Hargitt in the nuclei of the oocytes of 

 some of the coelenterates , makes it desirable to further study this 

 group with especial reference to the nuclear changes in ovogenesis. 



Zool. Jahib. XXVIII. Abt. f. Anat. 20 



