The spermatogenesis of Peripatus (Peripatopsis) balfouri. 365 



Eigs. 193, 194. Lateral views of anaphases of the 1st maturation 

 division, in each only one pole of the spindle shown on account of the 

 obliquity of the section. Cytoplasmic details not given. 



Figs. 195, 196. Lateral views of anaphases of the 1st maturation 

 division. 



Fig. 197. Latero-polar view of the chromosomes at one pole of 

 the spindle, 1st maturation dyaster. 



Fig. 198. Lateral view of anaphase of the 1st maturation division. 



Fig. 199. 1st maturation dyaster, pole view of one plate of 

 chromosomes. 



Figs. 200 — 202. Successive dyaster stages of the 1st maturation 

 division ; chromosomes very closely approximated ; in Fig. 201 only half 

 of the cell lies in the plane of the section. 



Fig. 203. Lateral view of 2nd spermatocyte , preparation for 

 monaster stage; only a few chromosomes shown. 



Fig. 204. Two sister 2nd spermatocytes, lateral view of monaster 

 stage ; onty a few chromosomes shown. These cells have revolved 

 around one another. 



Figs. 205 — 207. Lateral views of 2nd spermatocytes, metakinesis. 



Figs. 208 — 210. Lateral views of successive anaphases of 2nd 

 spermatoc3^tes, only a few of the chromosomes shown. 



Fig. 211. A mature (?) spermatozoon from the vas deferens, showing 

 the whole proximal end and a portion of the flagellum. 



Fig. 212. Spermatogonium nucleus, probably the beginning of the 

 prophase of a giant spermatogonium. 



Fig. 213. Giant nucleus in rest stage from the zone of resting 

 spermatocytes. 



Fig. 214. Giant spermatogonium, late prophase. 



Fig. 215 A and B. Two sections of a giant spermatogonium, pro- 

 phase, showing all the chromosomes. 



Fig. 216. Giant spermatogonium, prophase of monaster, showing 

 lateral view of achromatic spindle ; on another section of the same cell ' 

 6 chromosomes were seen. 



Plate 23. 



Fig. 217 A and B. Two sections, including all the chromosomes, 

 of a giant spermatogonium, prophase of monaster; the pair of minute 

 bodies in 217 A marked C? may be centrosomes. 



Fig. 218 A and B. Two sections, including all the chromosomes, 

 of a giant spermatogonium, pole view of monaster. 



Fig. 219 A and B. Two sections, including all the chromosomes, 

 of a giant spermatogonium, pole view of monaster. The chromosomes 

 in B are apparently parts of some of those in A. 



Fig. 220. Giant spermatogonium with 28 chromosomes, pole view 

 of monaster: x a large, deep-staining, degenerated body. 



Figs. 221, 222. Giant spermatogonia, lateral views of metakinesis 

 stages: in 222 the greatest diameter of the cell not shown. 



