GAMETIC MEIOSIS IN MONOCYSTIS. 



395 



(Fig. 10) and when two gametes come together, fusion begins at 

 this nucleated end. The nuclei fuse and the zygote secretes a 

 delicate plastic membrane which is transformed later into the 

 rigid sporoblast capsule (Figs, n, 12 and 13). At this early 



Skdlp^ 



'"*''.' .' >r--j:' -*!*""::. V--"",^ 



^ 



llr 



i : -i 

 ifc . ..*=*.. ' 

 \ v -~"- 



-r^. 

 FIG. 10. Group of gametes. Smear. Camera lucida. X 900. 



period of the zygote the form is quite variable owing to the 

 plasticity of the membrane (Fig. 15). The amphinucleus swells 

 and becomes more conspicuous by reason of the more intensely 

 staining chromatin. The chromomeres become arranged in a 

 loose spireme which appears to be continuous (Fig. 14). The 



f*^\ .-:.,. -^....'*.:.'i. "C X ... v -' ..'-/VV.l 



flfcV -y. f" v . .*..:.-..; "'. ',.,^. $&'*'*:. -.''. ^"N/. W 



i , |-;-4i-%,. ':'. . ?. ,: / . . /:, ~\'!$ 1 



V,*^ . *,-:.?;. .*!.., .'.-:'':/'<: A:' .&S-iiivf%z&p 



FIG. ii. Characteristic grouping of gametes and zygotes about gametocyte. 

 Section. Camera lucida. X 600. 



threads are double and break up into 10 chromosomes. A 

 spindle is formed with definite poles and fibrils but the latter are 

 not as sharply defined as in the progamous divisions (Fig. 15). 

 In the anaphase stage 10 chromosomes are present in each 

 daughter plate (Fig. 14). 



After this first metagamic division, which is not accompanied 

 by cell division, we were unable to make out any definite spindle 



