PLATE 7 



EXPLANATION OF FIGURES 



99 Photograph of a smear of first spermatocyte prophase of Hippiscus, showing 

 the early longitudinal division of the tetrads, the early concentration of certain 

 tetrads, and the homogeneous appearance of the accessory chromosome. X 875. 



100 Photomicrograph of a smear of a first spermatocyte prophase complex of 

 Trimerotropis maritima. One of the twelve chromosomes, near the metaphase 

 chromosomes, is very dim, due to spreading. Of particular interest are the four 

 chromosomes on the left. The upper one is a typical rod; the second, a cross; 

 the third, a ring. In each of these the structure is very clear. Just below the 

 prophase ring is another from a metaphase complex. That the latter represents 

 merely a more condensed condition of the former is very evident. The three 

 lower rings are much extended by smearing, but still show their composition. 

 There is no indication of crossed-over ends — they are true rings. X 875. 



101 Photomicrograph of a smear of a Hippiscus first spermatocyte prophase. 

 The longitudinal division in the tetrads is very clear. X 875. 



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