380 JACQUES LOEB AND F. W. BANCROFT 



the percentage of the eggs which underwent early segmentation 

 was possibly augmented by this procedure, the percentage of the 

 eggs which developed into tadpoles was not increased in this way. 

 Practically all the eggs of the same females that had been fertilized 

 with sperm developed into tadpoles, many of which are healthy 

 and alive today. 



2. We were anxious to obtain parthenogenetic frogs in order to 

 test the statement of Kuschakewitsch,^ to which Professor Mor- 

 gan called our attention, that the young frogs are often hermaph- 

 rodites, or intermediate forms. If Kuschakewitsch's statement 

 is correct, the presence of ova in the genital glands is not sufficient 

 proof that the young frog is going to develop into a female. He 

 gives some criteria for the discrimination between real females 

 and the intermediate form which may develop into males. On 

 the basis of his statements we examined once more the sec- 

 tions of the sexual glands of last year's parthenogenetic frog. We 

 also utilized the slides we had made from the sexual glands of a 

 young frog produced by fertilization with sperm from an egg of 

 the same female from which the parthenogenetic tadpole and frog 

 originated. 



The gonads of the parthenogenetic frog which died at the close 

 of metamorphosis were fairly well preserved. An examination 

 showed that there were eight or nine genital spaces. According 

 to Kuschakewitsch eight genital spaces are characteristic for the 

 intermediate form while six are characteristic for the pure female. 

 In addition there were many degenerating ova, which Kuschake- 

 witsch mentions as a characteristic for the intermediate form. 

 Comparatively few of the oocytes had entered the growth period. 

 The right gonad, which was smaller and in an earlier develop- 

 mental stage than the left one, had nineteen larger oocytes while 

 the left gonad had only fifteen. Most of the oocyte nests (or 

 oogemmae as Kuschakewitsch calls them) did not contain any 

 large oocytes. If Kuschakewitsch's criteria are correct, the 

 parthenogenetic frog which we described is a hermaphrodite or 

 intermediate. 



^Festschr. f. Richard Hertwig, Bd. 2, p. 61. 



