426 E. R. Downtne, The spermatogenesis of Hydra. 
(Fig. 16—67, 2684: 1.) 
Fig. 16. Spireme in spermatogonia outside the spermary. 
Fig. 17. Late prophase of same. 
Fig. 18. Equatorial plate of same. Top of cell cut away. 
Fig. 19. Metaphase of same. 
Fig. 20. Anaphase, reduction in number of chromosomes foreshadowed 
by fusion of adjacent ones. 
Fig. 21. Telephase of same. 
Fig. 22. Schematic equatorial plate of same, showing chromomeres. 
Fig. 23. Two of the V-shaped chromosomes dividing (heterotypic 
mitosis). 
Fig. 24. A later phase of same. 
Fig. 25. The V-shaped chromosomes appear rod shaped. 
Fig. 26. The anaphase: real longitudinal division appears transverse. 
Fig. 27. The late anaphase, reduction in number of chromosomes 
foreshadowed. 
Fig. 28. Fusion of adjacent chromosomes complete. 
Fig. 29—39. Division of a spermatogonium within the spermary. 
Fig. 40. A spermatogonium of the second order. This becomes the 
spermatocyte of the first order, Fig. 41. 
Fig. 41—45. Division of the spermatocyte of the first order. 
Fig. 46—48. Synapsis stages of spermatocyte, second order. 
Fig. 49—59. Division of spermatocyte of second order. 
Fig. 60—67. Transformation of spermatid to spermatozoon. 
Fig. 
68. Adult sperm. 10736:1. 
