16 
Notes on the Archegonium of Ferns. 
I. Ina memoir on the Ostrich Fern*, 
published some time since, the statement 
was made that the ventral canal-cell was 
wanting. This decision was based on 
numerous sections of the living prothal- 
lium, and has since been found to be in- 
correct. In microtome sections, (see fig. 
a.) the ventral canal-cell (b.) is very evi- 
dent, and is plainly derived from the cen- 
tral cell. In the upper canal-cell, two 
nuclei may usually be readily seen, but 
in no cases observed was the cell divided. 
2. On sectioning one prothallium, 
perfectly developed archegonia were 
noticed both above and below (Fig. b.) 
and subsequent examination showed 
numerous other instances of the same 
thing; in several of these prothallia, embryos developed from 
archegonia upon the upper surface. Is this a case of reversion to 
an ancestral form having archegonia above as in liver-worts ? 
Unfortunately the fern from which these came could not be de- 
termined. 
DoucLas H. CAMPBELL. 
Bloomington, Indiana, October, r8go. 
EXPLANATION OF FIGURE. 
a,—Vertical section of the full-grown archegonium of Onoclea Struthiopteris. 
o.—Central cell of the archegonium. 
é.—Ventral canal-wall. 
n-ni—The two nuclei of the upper canal-cell. 
6,—Vertical, longitudinal section of a fern-prothallium sp. (?) with archegonia up- 
on both surfaces, 
_ a,—One of the apical cells. 
Virginia Creeper, | 
Many years ago the late Dr. Warder called my attention to 
the two supposed forms of Ampelopsis (see BULLETIN xvii. 269) in 
*The Development of the Ostrich Fern, D. H. Campbell, Memoirs, Boston So- 
ciety of Natural History, 1887. 
