Fig. 1. — Eight views of the maturation of the male cellg of 

 Lepidosiren paradoxa. (After Agar.) 



A, leptonema stage. B, beginning of zygonema. C, strepsiuema stage, beginning of synizesis. 

 D, separation of two chromosomes which were united in syndesis completed ; nuclear membrane dis- 

 appeared. E, second pairing of chromosomes begun, appearance of centrosoraes for the first matura- 

 tion spindle. F, later stage in second pairing of chromosomes, tlie centrosomes of the first spindle 

 now situated at opposite poles of the nucleus. G, the anaphase of the first maturation division. H, 

 the metaphase of the second maturation division. &i, a chromosome which has not yet paired with its 

 fellow ; 62j two chromosomes united end to end ; &3j two chromosomes united in a ring ; c, centrosome 

 of spindle of first maturation division ; I (in D), the two longest chromosomes, (in F), the two longest 

 chromosomes united end to end, (in G), the two longest chromosomes separating from each other in 

 the first maturation division, (in H), one of the longest chromosomes dividing into two in the second 

 maturation division ; n, nucleolus. 



5 



