102 



BIOLOGY OF THE PROTOZOA 



there are stages which have some resemblance, at least, to spireme 

 formation of the metazoan type. For Actinophrys sol, Belaf (1922) 

 has described in great detail the transformations of the chromatin 

 of the vesicular nucleus in the first maturation division. A spireme, 



bi> 



d cf 



B 



d ri- 



ff 



G 



si 



X 



%W 



C 





H 



E 



Fig. 56. — Chromosomes 1 if Aggregata eberthi. Letters a to /, or a' to /', "^designate 

 the haploid groups. .1, prophase of the first division (male); B, nuclearjplate of 

 same; C, anaphase groups at first division; E, chromosomes in macrogamete nucleus 

 before fertilization; F, chromosomes in zygote nucleus (diploid); G, paired chromo- 

 somes in nuclear plate of first zygote division; H, early anaphase groups of first zygote 

 division, and separation of homologous haploid groups. (After Dobell and Jameson.) 



passing through bouquet, pachytene, strepsineme and synapsis 

 stages, into double chromosomes of the metaphase nuclear plate, 

 are strikingly similar to analogous stages in metazoan meiosis 

 (Fig. 157, p. 309). Here there is very little to suggest individuality 



