PLATES 
All the figures have been drawn to the same scale with the aid of the camera 
lucida at the level of the base of the microscope, with. the Zeiss apochromatic 
immersion objective 1.5mm., and ocular 12; the original dimensions have been 
reduced one-fifth. 
The following abbreviations have been employed: 
c. centriole m. minute chromosome 
ch. c. chromatoid corpuscles mit. mitosome (spindle remains) 
D. larger idiochromosome pf. perforatorium 
d. smaller chromosomes pl. plasmosome 
id. idiozome sp. sphere 
PLATE 1 
EXPLANATION OF FIGURES 
1 and 8 from testis no. 103, all others from testis no. 282. 
1 Penultimate spermatogonium, rest; (follicle 5). 
2 The same, pole view of equatorial plate; (follicle 6). 
3 Portion of a rosette of ultimate spermatogonia; (follicle 6). 
4 Anaphase of ultimate spermatogonium; (follicle 4). 
5 Later anaphase of the same; (follicle 4). 
6-41 Successive stages of the early growth period of the first spermatocytes. 
All the cells from follicle 4 except the following: Figs. 23, 24 from follicle 5; figs. 
10, 11, 15, 22 from follicle 6. 
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