SEX REVERSALS 265 



of the sex-chromosomes, because only very rarely is there 

 indication of asymmetry of the accessory organs outside 

 the gonads, and the gonad tissue is frequently irregu- 

 larly distributed. Furthermore, if the evidence that the 

 sperm and eggs of hermaphrodites are both homogametic 

 is valid, the ground of a possible explanation due to chro- 

 mosome elimination is removed. 



From a hermaphrodite (Hh) Witschi was able to ob- 

 tain ripe sperm and eggs. He tested these with sperm 

 and eggs from a differentiated race with the following 

 results 



(1) Eggs dif. 9 by sperm from herm.= $ 2 



(2) Eggs herm. by sperm from dif. 3 = 50%9 + 50%3 



The eggs of the hermaphrodite were also fertilized by 

 sperm of the same individual and gave 45 $ and one her- 

 maphrodite, thus 



(3) Eggs herm. by sperm from herm.=45 $ -fl herm. 



These results can be interpreted to mean that the original 

 hermaphroditic female was XX. Each ripe egg carried 

 one X. Likewise each functional sperm must also have 

 carried one X. There seems to be no escape from one or 

 the other conclusion, either that every sperm carries an 

 X, or else half carry X, half no X, but the latter die in the 

 female (i.e., never become functional). 4 



4 Crew (1921) has also reported the result of successful fertilization of 

 the eggs of a hermaphrodite (Fig. 14) with its own sperm. In each tadpole 

 the development of the gonad was direct. All the offspring (774) that were 

 sufficiently developed to determine the sex were female. The mother may be 

 regarded as a true XX female that produced eggs and sperm, each with an 

 X-chromosome. 



It is conceivable, but perhaps not probable, that the testis in the her- 

 maphroditic females is due to elimination of one of the X-chromosomes in a 

 somatic division, and that the no X-sperm die. (See above.) 



