Vol. XV. October, igo8. No. 5 



BIOLOGICAL BULLETIN 



A SIGNIFICANT CASE OF HERMAPHRODITISM 

 IN FISH/ 



H. H. NEWMAN. 



The subject of hermaphroditism in fish has received the 

 attention of only a few workers. Our principal information is 

 derived from the work of Stephan ('01). This author describes 

 for certain species of fish a complete and simultaneous hermaph- 

 roditism, ripe ova and spermatozoa appearing in the same 

 individual at the same time ; for other species a protandric her- 

 maphroditism, the individuals while young being males and later 

 in life becoming females ; for still others, a precocious appearance 

 of sexuality in the males and a tardy appearance of the latter in 

 the females of species still considered as unisexual. 



The condition last mentioned is interpreted by Roule ('02), on 

 the basis of rather doubtful evidence, as a true case of protandric 

 hermaphroditism. He measured large numbers of sexually 

 mature individuals belonging to several species of Cyprinidae, 

 and found that all of the individuals of small size were males 

 and all those of large size were females. Hence, according to 

 Roule, all individuals are males when young and females when 

 older. The only alternative interpretation of the facts presented 

 seems to be that these species exhibit strict unisexuality of all 

 individuals, with dwarfing of the males and precocious ap- 

 pearance of male sexuality. Roule points out, however, that, 

 on this basis, one would expect to find among the smaller 

 individuals young females with immature sex glands, and that 

 there should be at least as many of the latter as there are adult 

 females. But none such were found by him. 



1 Contribution from the Zoological Laboratory of the University of Texas, No. 94. 



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