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FERNANDUS PAYNE. 



These are now arranged in a pentad group, which always shows 

 the same composition and occupies the same position. Four of 

 these five chromosomes are grouped very closely together and 

 lie in one plane, while the other one is either above or below this 

 group of four, lying close to them on the other side of the equa- 

 torial plane (Fig. 2, A, polar view of the equatorial plate ; Fig. 

 2, E, and Fig. 3, C, side views). The fifteen chromosomes in 

 the ring divide equally, while the chromosomes of the central 

 pentad do not divide individually, but the group as a whole sep- 

 arates in such a manner that one chromosome passes to one pole 



FlG. 3. Galgulus oculatus. A, metaphase figure of the second division, polar 

 view, showing the ring of fifteen and the four chromosomes of the pentad group near 

 the middle — the fifth chromosome of the pentad group could not be shown, as it lies 

 beneath the four ; B, early anaphase of the second division, polar view, showing the 

 nineteen chromosomes which go to one pole ; C, metaphase of the second division, 

 side view, showing the'typical position and arrangement of the chromosomes of the 

 pentad group ; D and E, anaphases of the second division, side view, showing the 

 manner of separation of the pentad group, four chromosomes of which go to one pole 

 and one to the other — only three chromosomes of the four group show, as all of them 

 do not lie in the same plane. The photographic enlargement is i,5°° diameters. 



and the other four to the other pole (Fig. 2, F, and Fig. 3, D 

 and E). Two classes of spermatozoa are thus formed, which 

 contain sixteen and nineteen chromosomes respectively. The 

 early anaphase illustrating these two classes is shown in Fig. 

 2, G, //and /, and Fig. 3, B ; the later anaphase in Fig. 2, C 

 and D. 



