The spermatogenesis of Peripatus (Peripatopsis) balfouri. 363 



In Figs. 113, 114, 121, the sphere is shown as a solid object, in the 

 other figures as a section. All these spheres with one exception (Fig. 125) 

 from the same testis and by the same preparation. In Fig. 115 the 

 dotted line represents the margin of the lower lip of the aperture. In 

 Figs. 112 — 124 the outline of the distal pole of the nuclear membrane 

 is shown. 



Fig. 127. Lateral view of spermatocytes at the commencement of 

 the prophase of the 1st maturation division ; the idiozome spheres not 

 delineated on account of their obscurity in this preparation. 



Figs. 128 — 130. Lateral views of successive early prophases of 

 spermatocytes. 



Fig. 131. Lateral views of spermatocytes, early prophases; details 

 shown only in cell A; the idiozome sphere of cell C does not lie in 

 the plane of the section. All pairs of centrosomes lie close to the 

 surface of the spheres. 



Figs. 132, 133. Lateral views of spermatocytes in the early pro- 

 phase, only in Fig. 133 the details of the nucleus shown; in both ceils 

 the centrosomes lie close to the surface of the sphere. 



Fig. 134. Lateral view of spermatocyte in prophase ("dense 

 spirem"). 



Fig. 135. Nucleus of 1st spermatocyte, prophase, showing G entire 

 bivalent chromosomes. In this as in all other figures of the prophases 

 of the 1st maturation division, only such chromosomes are drawn as 

 could be seen plainly in their entirety. 



Fig. 136. Idem, showing 2 whole bivalent chromosomes. 



Fig. 137. Idem, showing 3 whole bivalent chromosomes; about 

 10 other chromatin segments were present in this nucleus. 



Fig. 138. 1st spermatocyte, lateral view of prophase, all the 

 chromatin drawn in. 



Fig. 139. Nucleus of 1st spermatocyte, prophase, showing 4 whole 

 bivalent chromosomes. 



Fig. 140. Idem, showing 2 whole bivalent chromosomes. 



Fig. 141. Idem, „ 3 „ „ „ 



Fig. 142. Idem, „ 5 „ 



Fig. 143. A single bivalent chromosome, early prophase of 1st 

 maturation division. 



Fig. 144. Nucleus of 1st spermatocytic prophase, showing 3 whole 

 bivalent chromosomes. 



Fig. 145. Idem, showing 4 whole chromosomes. 



Fig. 14G. One bivalent chromosome, early prophase of 1st matur- 

 ation division. 



Fig. 147. Nucleus of 1st spermatocyte, early prophase, showing 

 3 whole bivalent chromosomes. 



Fig. 148. Idem, showing 3 whole chromosomes. 



Fig. 149. Idem, „ 3 „ 



Fig. 150. Idem, „ 4 „ „ 



Fig. 151. 5 whole bivalent chromosomes from 2 nuclei, prophase 

 of 1st maturation division. 



