PLATE 4 
EXPLANATION OF FIGURES 
16 Section of a more typical spermatophore. X 1250. 
17 A giant spermatogonium. > 1800. 
18 A giant spermatogonium dividing, the two-cell stage. 
19 A giant spermatogonium dividing, the four-cell stage, polar view. 
20 A giant spermatogonium dividing, the eight-cell stage, side view. 
] A giant spermatogonium dividing, the eight-cell stage, polar view. 
2 A giant spermatogonium dividing, the sixteen-cell stage, polar view. 
23 A later stage in segmentation of a spermatogonium, a spermatophore from 
the body fluid of A. cristata. 
24 The ‘invagination’ of the forming spermatophore in A. cristata. 
25 Section through the saucer-shaped spermatophore of A. cristata. The cells 
are spermatids, 1} X 4yu. 
1050 
