578 Jobn Beard, On the Life-History and Development of the Genus Myzostoma. 



matozoa , and thiis tlie number of yoimg arising from the union of her- 

 maphrodites , wheu hermapbrodites are once formed, will greatly 

 increase and probably in the end crowd out of existeuce the young pro- 

 dueed by the union of males with hermapbrodites. 



Thus as the result the follo wing conclusions may be drawn. 



The term complemental male adopted by the great naturaUst is 

 probably not an expression of the true morphological meaning of the 

 phenomenon , physiologicaily it may be correct. Morphologically it is 

 rather the male organs of the hermaphrodite , which are complemental 

 to those of the male. The males are really primitive, and refer us back 

 to a time when the parent stock was unisexual. 



Hermaphroditism . probably all hermaphroditism, had its origiu in 

 a unisexual condition. It has been gradually acquired, in some cases 

 perhaps as the result of a tendency in the sexual organs towards her- 

 maphroditism. in others in order to provide for the continued existence 

 of the form. In some cases it is the females, which bave become her- 

 maphrodite as , for example , Myzostoma , in others it is probably the 

 males , in others still both males and females. In those cases where 

 ouly one sex has become hermaphrodite , the other sex has probably 

 in most cases become either periodic in its appearauce if male , or else 

 extinct. 



The foregoing researches were in great part carried out at the 

 Zoological Station of Naples. On the recommendation of Prof. Sempek, 

 to whom my best thanks are due, the Senate of the University of Würz- 

 burg approved my application for the Bavarian table at Naples during 

 several of the wiuter months. But as the contract for the table was in 

 October last not yet renewed, I journeyed to Naples without the no- 

 mination of the Bavarian government. Prof. Dohrn however very 

 kindly received me and gave me a place in the Station, where I worked 

 from November tili the middle of April. For this and many other acts 

 of kindness I beg to tender him my best thanks. 



I should like further to express my thanks to the staff of the Station 

 and more especially to Drs. Paul Mayer, Eisig , Brandt and to the 

 Couservator Sig. Salvatore Lo Bianco. 



F r e i b u r g i. B. , July 1 7th 1 SS4 . 



