598 GEORGE T. HARGITT 



while the oocytes occupy a zone toward the periphery, though 

 after growth is under way this zonal arrangement is lost and the 

 small cells are displaced by the pressure of the larger growing 

 cells. Figures 5 and 6 show the last divisions of cells in the 

 oogonial zone, the drawings having been made to show the 

 equatorial plates of the metaphase of mitosis in which these 

 cells were found. That these divisions are previous to synapsis 

 is certain since they contain twice the number of chromosomes 

 found in the polar bodies and pronuclei. These chromosomes 

 number sixteen, vary a good deal in size, somewhat in shape, 

 and show with remarkable clearness. If one attempt to match 

 these chromosomes, i.e., seeks to identify pairs,, there is some 

 difficulty which results in disappointment. For instance, the 

 smallest chromosome in each case (shown in the lower left por- 

 tion of the chromosome groups in figures 5 and 6) is clearly 

 without a mate of the same size. The one which, on account 

 of size, would most logically appear to be the mate of the small 

 chromosome is marked 'a,' in figures 5 and 6. Such a pairing 

 would involve more than the usual discrepancy in size between 

 synaptic mates. Furthermore, I can not convince myself that 

 the other chromosomes are clearly capable of being grouped into 

 similar pairs, though they would agree more closely than the 

 members of the smallest pair. 



According to the usually accepted view there should be two 

 chromosomes of a kind and their similarity should be so marked 

 as to make a pairing of them fairly easy. What does the failure 

 of these chromosomes to meet the expectation mean? Is it that 

 chromosomes are not paired and synapsis does not occur; or is 

 the conjugation between unlike chromosomes? The latter must 

 be the case since there is clearly a reduction in number of chromo- 

 somes and therefore we have no reason to doubt that a synapsis, 

 or its equivalent, takes place. The figures of the chromosomes 

 of first maturation spindles in plate 3 show that the division of 

 chromosomes in this mitosis is not always exactly equivalent. 

 This would seem to give evidence that the synapsis may be 

 between unlike chromosomes. 



