402 K. MASUI: 
Fig. 26. Lateral view of metaphase of spermatogonium in the earliest generation, 
Fig. 27, Side view of anaphase of spermatogonium in the earliest generation, 
Fig. 28. Polar view of metaphase of spermatogonium in the earliest generation. 
Fig. 29. Chromosomes of spermatogonium in the earliest generation, showing thirty three 
which consist of sixteen symmetrical pairs and one odd chromosome, 
Fig. 30, Telophase of spermatogonium in the earliest generation. 
Fig. 31. : Spermatogonia and Sertoli-cell in testis of an adult animal. 
Fig. 32. Penultimate spermatogonium in the resting stage. 
Fig. 33. An ultimate spermatogonium in the early prophase. 
Fig. 34. Nucleus of spermatogonium in the early prophase, showing formation of ehromatin 
spiremes, 
Fig. 35. Side view of metaphase of an ultimate spermatogonium. 
Fig. 36. Side view of anaphase of an ultimate spermategonium, 
PLATE XV. 
Fig. 37. Polar view of metaphase of penultimate spermatogonium in an adult animal, 
Fig. 38, Chromosomes of penultimate spermatogonium in an-adu't animal, 
Fig. 39. Section of testis of an adult animal, showing the telophase of ultimate spermatogonia. 
Fig. 40. Section of testis of an adult animal, showing ultimate spermatogonia, primary 
spermatocytes and a Sertoli-cell. 
Fig. 41. Section of testis of an adult animal, showing synaptic period. 
Fig, 42. Section of testis of an adult animal, showing post-synaptic stage. 
Fig. 43. Spermatocytes in pachytene stage. 
Figs, 44, 45, Spermatocytes in diplotene stage, 
Figs, 46, 47. Nuclei of telophase of ultimate spermatogonia, 
Figs. 48—50. Nuclei of spermatocytes in leptotene stage. 
Fig. 51. A nucleus in synaptene stage. 
Figs. 52, 53. Nuclei in pachytene stage. 
Figs, 54, 55. Nuclei in diplotene stage, showing longitudinal split of chromosome and 
chromosome nucleolus, 
Figs. 56, 57, Late prophase of first reduction division. 
Fig. 58, Side view of metaphase of first reduction division. 
Fig. 59. Side views of second divisions and polar view of telophase of a second division. 
en 
Q 
ig. 60, Resting nuclei and metaphases of second spermatocytes. 
PLATE XVI, 
Figs. 61, 62. Spermatocytes in diplotene stage, showing mitochondrial granules. 
Fig. 63. Polar view of a metaphase plate of first division, showing longitudinal split of 
chromosome, 
Figs. 64, 65. Polar views of metaphase plates of first division. 
Fig. 66. Side view of metaphase of first division, showing mitochondrial granules, 
