1913] MERRIMAN—SPIROGYRA 329 
4. Derscuau, M., Zur Frage eines Makronucleus der Pflanzenzelle. Archiv. 
Zellforschung 4:254-264. figs. 8. 1910. 
5. Dicpy, L., Somatic, premeiotic, and meiotic nuclear divisions of Galtonia 
candicans. Ann. Botany 24:727-757. pls. 49-53. 
6. Farmer, J. B., and Dicpy, L., On cytological features exhibited by certain 
varietal and hybrid ferns. Ann. Botany 24: 191-213. pls. 16-18. 1910. 
7. Fiscuer, A., Fixirung, Firbung, und Bau des Protoplasmas. Jena. 1899. 
8. Grécorre. V., Le reconstitution du noyau et la formation des chromosomes 
dans les cinéses somatiques. La Cellule 21: 7-90. Dis F. 2. 8903. 
9. Karsten, G., Die Entwicklung der Zygoten von Spirogyra jugalis. Flora 
99:1-11. pl. I. 1908. 
10. MERRIMAN, M. L., Vegetative cell division in Allium. Bot. Gaz. 37:178- 
207. pls. II-13. 1904. 
11. Meyer, A., Bemerkungen zur G. Lewrtsky: Uber die Chrondriosomen in 
pflanzlichen Zellen. Ber. Deutsch. Bot. Gessells. 29: 158-160. rort. 
12. Mitzcewirscu, L., Uber die Kerntheilung bei Spirogyra. Flora 85:81— 
124. pl. I. 1898. 
13. oe C., Uber Kerntheilung bei Spirogyra. Flora 872355. 
EXPLANATION OF PLATES XI AND XII 
All figures were sketched with an Abbé camera. The nuclei were stained 
oS erate hematoxylin and iron alum, or with safranin and gentian 
violet. 
hie 1~7.—Sections representing changes in nucleolus and nuclear net- 
ie up : the invasion of the spindle fibers; nuclei fixed in Bouin fluids (figs. 
ine ; ‘ ‘ : 
we oe Tomacetic (figs. 2, 3, 5, 7), in F lemming (fig. 4); Leitz oc. 4and 1/12 
gas 8, 9-—Nuclei dissected from filaments and mounted without section- 
=> ed in ae Zeiss comp. oc. 12 and Leitz 1 /12 oil im. 
G. 10.—Secti imi i i i 
Ae oi ection of stage similar to that in fig. 9; same fixing and magni- 
Pia, 13 
mae ise Whole mount of nucleus at later stage than in fig. 9; only central 
awn to show change in shape of spireme; Leitz oc. 4 and 1/12 oilim. 
- 11; fixed in Flemming; 
Fics. 13~16,.—Fj 
s «18S. 13 and 16 fixed in chromacetic, fi i 
ee Leitz oc. 4 and 1/12 oil im. Oe 
IG. 17.—Secti : 
dislodged iy k = fixed in chromacetic, in which some filaments are 
Fic oad nife; Zeiss comp. oc. 12 and Leitz obj. 6. 
Fics Astor cut obliquely; fixed in Flemming; Leitz oc. 4 and obj. 6. 
Flemming Gs 4.—Sections fixed in chromacetic (figs. 19, 20, 23, 24) and in 
8: 21, 22); Zeiss oc. 6 and Leitz 1/12 oil im, 
