PLATE 12 
EXPLANATION OF FIGURES 
91 to 94 Larval spermatocytes dividing. 
95 Single large ring tetrad. Note the size and the lugs marking the synaptic 
ends of the homologous chromosomes. 
96 to 99 Larval spermatocytes dividing abnormally. Note in figure 97 the 
great size and thickness of the central chromosome. This tetrad is cut in half 
longitudinally. 
100 and 101 Abnormal spermatocyte. Many tiny asters scattered through 
the cytoplasm. 
102 Large ring tetrad from second-year larvae. Just beneath is a small 
germ cell of the second year; note the size difference. The spermatocyte in 
which this tetrad was photographed is not shown here and was in early stages of 
degeneration. This type of tetrad rare in second-year tadpoles and found only 
in degenerating cells, which persist from first sexual cycle. 
324 
