1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 441 
PLATE XIX. 
The first mitosis in the germinating tetraspore. 
Fic. 1. Nucleus in resting stage, showing delicate linin network and nucleolus. 
Fics. 2a-2c. Three sections of the same nucleus, showing segregation of 
chromatin material into about 20 groups, probably prochromosomes, before the 
formation of chromosomes. 
Fics. 3a, 3b. Two sections of the same nucleus, early prophase; 20 chromo- 
Somes may be counted. 
1G. 4. The late prophase; centrosome-like bodies lying at Mom ee 
Fic. 5. Metaphase showing equatorial plate; nuclear still present; 
neuclear cavity considerably smaller than in the preceding stage. 
Fic. 6. Membrane dissolving; centrosphere-like structures present at the 
Poles of the spindle. 
1c. 7. The polar view of an equatorial plate showing 20 chromosomes and 
the remains of nucleolar material. 
Fic. 8. Anaphase, showing groups of daughter chromosomes assembled Bt 
the iis of the spindle 
ae 9. La oa the original nuclear membrane entirely dissolved; 
— structures passing into vaguely outlined kinoplasmic masses, 
Fic. 10. Polar view of late anaphase; space within the group of chromosomes 
probably ; thai the first appearance of nuclear sap within a vacuo a 
Fie. rr. Telophase; the membrane of the daughter nucleus is roe errs ; 
1G. 12. Resting condition of daughter nucleus, showing linin network an 
two nucleoli, ; : 
Fic. 13. Cleavage furrow appearing at the periphery of the cell in the middle 
region, 
Fic. 14. The cleavage furrow has penetrated almost to the sone the = 
leaving only a Narrow passage admitting of protoplasmic continuity between 
daughter cells. 
PLATE XX. 
The first mitosis in the germinating car pospore. 
rk. 
Fic. 15. Nucleus in the resting condition, showing linin netwo. ; 
ie 16a-16c. Three sections of the same nucleus, showing 40 prochromo 
ition 17a, 17b. Two sections of the same nucleus, eatly prophase; 40 chromo- 
eg a. im Two sections of the same nucleus; centrosome-like bodies 
oc 
ie showing equatorial plate; centrosphere-like structures 
at t 
F ea Pile ee of an equatorial plate showing group ‘of 40 chromosomes 
and the remains of nucleolar material. 
