338 Saxton . — Contributions to the Life-history of 
nuclei is more pronounced. A few starch grains are seen in the suspensor 
in this figure, but are seldom found at such a late stage. 
After this the suspensors rapidly elongate and their walls thicken, and 
they form an intertwining mass of long tubes in the region previously 
occupied by the disorganizing, unfertilized archegonia, eventually breaking 
down nearly all the apical tissue of the prothallus (PI. XXVIII, Fig. 54). 
The large nucleus of the suspensor is very persistent, as well as con- 
spicuous, and may be identified for quite a long time in the development of 
Text-fig. 3. Series of diagrams to illustrate the development of the proembryo, formation of 
embryo cells, and elongation of the suspensors. x about 350. (The apex of the prothallus is 
supposed to be to the left , in these diagrams.) 
the embryo. It remains near the embryo, embedded in a small mass of 
cytoplasm, the rest of the suspensor being devoid of contents. 
A group of four suspensors and embryo initials is shown in P"ig. 48, 
shortly after the suspensors have begun to elongate, and two at a later 
stage in Fig. 49 ; a somewhat similar group is shown in the microphoto- 
graph (Fig. 54). 
The embryo initials remain undivided for a considerable time, some- 
thing like ten days or a fortnight, and the first division wall is vertical, as 
shown in Figs. 50 and 55 (microphotograph), this being quickly followed by 
