ip 
1906] MERRIMAN—NUCLEAR DIVISION IN ZYGNEMA 53 
Fics. 16, 17, 19, 20, 21, 22, 23 show successive stages in condensation of 
chromosomes. Chromosomes all black. X 1750. 
Fics. 18, 24, 25, 26. Chromosomes and pyrenoids black. X 2440. 
Fics. 27, 28. Chromosomes becoming dissociated into smaller groups. 
Chromosomes black. x 1750. 
An ‘unusual case of division of-pyrenoids before formation of 
FIG. 29 
Chromosomes black, both in central mass 
membranes of daughter nuclei. 
and in the periphery, pyrenoids red. X 1750. 
Fics. 30, 31, 32. Chromosomes black, pyrenoids red. 1750. 
Fics. 33. Pyrenoids and central body of nucleus black, peripheral bodies 
red. X1750. 
Fic. 34. Pyrenoids red, all the nuclear bodies black. < 1750. 
Fic. 35. Nuclear bodies red, pyrenoids black. 1750. 
Fics. 36, 37, 38. All nuclear bodies red, pyrenoids black. 1 
. Nuclear bodies red, pyrenoids black, showing vestiges of connect- 
ing substance. X 1750. 
