On the Behaviour of the Nuclei during the Conjugatoin of Zygnema. 


(192) 
Explanation of Plate V. 

All figures drawn from Picro-nigrosin preparations (except Fig. 8, which is dvawn from Chromic-Haematoxylin preparations) with Abbe’s 
camera lucida under the magnification by Zeiss, Homog. Immers, abs + Oeular 2. 
Fig, 1. Cells preparing to conjugate; two processes produced from them about to meet each other. p signifies pyrenoid; ¢, chromato 
wa 明 
phore ; n, nucleus ; ik, nucleolus. 
ーー 
—_— 
Fig, 2. Two processes fused, and common wall yet present, 
Fig, 8. Common wall already disappearing. 
4. Nuclei connected by the so-called “ thread” (processes of two nuclei) (t), 
Fig, 42. In the uppermost and the lowest pair of celis, which are concerned in conjugation, chromatophores are large, whereas in the 
middle cell not concerned in conjugation they are small. 
Fig, 5. Thread now becoming a band; two nucleoli yet distinct. 
F 6. Two nucleoli approaching each other. 
Fig. 7. Chromatophores passing into the common bladdery canal ; two nuclei, together with their respective nucleoli, fusing. 
Fig, 8 
Represents various stages of conjugation in a species of Zygnema belonging to the first class :— 
BBAT-~ AR t + 
a, Cell not concerned in conjugation ; 
b, Contents of one cell on the way of passing towards the other cell; two nuclei distinet ; 
ec, Contents of two cells found together in one of them; both nuclei yet distinct ; 
d, da.’ Nuclei coming into contact with each other ; : 
e, Nuclei fusing together, both nucleoli yet distinct ; 
f. Nuclei and nucleoli fusing; 
go, 
。 Abnormal form, in which both nuclei and nucleoli fuse together already before the contents of one cell have not yet com- 
pletely passed away into the other cell, 
ee at OE ee 一 ーー 一 - 一 ーーーーーーーーーーー- 

