58 



Fio. R. — Supposed course of oogenesis and 

 spermatogenesis in hermaphroditism. 



Diagram 6 shows the 

 course of oogenesis and sper- 

 matogenesis in hermaphro- 

 ditism. 



Here it will be seen 

 " that instead of the produc- 

 " tion and maturation of two 

 " kinds of eggs, male and 

 " female in destination, we 

 " witness the maturation of 

 '' one kind only, the female 

 " egg. The germ-cells, which 

 " here should have become 

 " male-eggs, are converted 

 " into spermatogonia, and from these spermatozoa are ultimately 

 " produced." '■''■ 



According to Beard, any one or more of the four 

 gametes may be suppressed at any period of the life history. 

 This faculty supplies the explanation of the phenomena of 

 hermaphroditism and parthenogenesis. In hermaphroditism 

 there is the partial or complete suppression of the male-egg, 

 or rather its conversion into spermatogonia and (ultimately), 

 sperms. In parthenogenesis there is the occasional or cyclical 

 arrestment of one or other of the gametes of the female. 



" A comparison of parthenogenesis and hermaphroditism 

 " demonstrates that in the former there is what may be 

 " termed a precocious development of an embryo, male or 

 " female. In the latter, the precocious development of male- 

 " eggs or their forerunners to form male gametes or sperma- 

 " tozoa without the intermediation of the otherwise necessary 

 " male embryo or sexual person. In hermaphroditism the 

 " males tend to disappear, because the male-eggs, which 

 " should have gone to form them, have been used in the 

 " development of spermatozoa. In parthenogenesis the males 

 " disappear for another reason, because their production may 

 " become unnecessary." *" 



* John Beard, "The Determination of Sex, etc.." p. 715. 

 ♦'^ John Beard, " The Detcrminalion of Sex, etc.," p. 71(i. 



