Female Organs 



III 



a multitude of short tubes opening into one central 



passage. 



The essential reproductive organs are the ovaries and 

 testes, within which the ova 

 and sperm-filaments (spermato- 

 zoa) are formed. Particular 

 germinal cells, formed within a 

 part of the ovary distinguished 

 as the germarium, are converted 

 into ova, nutritive cells, or folli- 

 cular epithelial cells ; particular 

 cells of the epithelium of the 

 testis undergo repeated division, 

 and form multitudes of seminal 

 filaments. In Chironomus we 

 find the remarkable and almost 

 unique phenomenon, that the 

 eggs or sperm-filaments are de- 

 veloped from cells which have 

 never formed part of a perma- 

 nent tissue ; they are believed 

 to be merely handed on from 

 generation to generation, and 

 though some of the cells to 

 wdiich they give rise are differ- 

 entiated for special purposes 

 and used up, others undergo no 

 change except division ^. 



Let us now examine the struc- Female 

 ture of the female organs in the 



Pig. 79.— Ovary from fuU-grown n (> r\\ • mi 



larva. The external envelope is lly 01 UllironomuS. lilC OVariaU 



tubes (fig. 79) are short and ex- 

 tremely numerous, radiating from a central axis which 

 takes the place of an oviduct, or else of a primary 



^ Weismann, 1889. 



organs. 



