The Reproduction of Ahnfeltia plicata. 19 
been ascertained. The number of chromosomes in the young 
still dividing end-cells of the nemathecium being four, it 
must be supposed that the vegetative cells of the nema- 
thecium and probably also of the frond have the same 
number of chromosomes, but owing to the small size of 
the vegetative nuclei, the chromosomes are very difficult 
to distinguish. Some observations seem, however, to show 
that there are really four chromosomes in the nuclei of 
the cortical and the medullary cells of the frond'. 
The nemathecia ripen in winter and are still to be found 
with ripe spores in May, but then they die and in summer 
Ahnfeltia is always sterile. The ripe nemathecia are hemi- 
spherical or usually elliptical or obiong, their long axis 
being parallel to the axis of the frond (fig. 1). The colour 
is yellowish’. 
The ripe monosporangia are ellipsoidie or obovate, but 
the spores set free are globular, about 8.5 w in diameter. 
They contain numerous small refractive bodies (starch) 
and one single yellow-brown chromatophore, situated a little 
excentrically, and beside it a hyaline round spot the nature 
of which was not ascertained (nucleus or vacuole?) (fig. 16). 
3. Germination of the spores. 
Spores were sown in May 1927, fronds of Ahnfeltia with 
ripe nemathecia being put down on slides, partly sand- 
blown, at the bottom of glass-vessels filled with sea-water 
from the Great Belt, where the fronds had been collected, 
and placed in a room facing north. The presence of the 
1 I am indebted to Dr. C. A. JØRGENSEN, to whom I have shown 
some of my slides, for having called my attention to such nuelei, but 
the observations still need confirmation. 
? GREVILLE (1830 p. 150) described them as dark coloured. 
