Fossombronia longiseta , A ust. 
105 
Summary. 
1. The apex of each leaf-lobe terminates in a single, smaller cell, 
void of chlorophyll, though always containing a few oil-globules and 
considerable mucilaginous fluid. These cells bear a strong resemblance to 
the mucilaginous hairs, and are, doubtless, of the same physiological signifi- 
cance to the plant. 
2. The plants are susceptible to great desiccation without material 
injury. On being moistened they revive in a few hours. Plants that have 
passed through a dry season are often found bearing sex-organs in an 
advanced stage of development. 
3. The germinating spore produces normally a germ-tube of con- 
siderable length, containing little chlorophyll, but rich in oil-globules, which 
diminish in number as the growth of the young plant advances. The 
segmentation of the germ-tube shows variation, sometimes taking place 
very early, as in Text-Fig. 4, D. The first rhizoids commonly appear at 
a later stage ; these are colourless, while those of older plants are vinous 
purple. 
4. The antheridium mother-cell divides once horizontally ; this 
is followed by a horizontal division in the basal cell, the uppermost 
segment of which becomes active in forming the stalk. Following 
horizontal division of the mother-cell are two vertical divisions, giving rise 
to octants. Further divisions in the spermatogenous tissue occur with 
marked regularity. 
5. The development of the antheridium in Fossombronia longiseia 
shows it to have a certain morphological relationship with such forms as 
Geothallus and Sphaerocarpus. 
6. No centrosome was observed at any stage of nuclear division in 
spermatogenesis. The spermatid mother-cell divides to form two sper- 
matids, between which no wall is formed. 
7. Blepharoplasts appear apparently de novo in the cytoplasm of the 
spermatid. These migrate to one of the spermatid poles and later develop cilia. 
8. A ‘ Nebenkorper ’ appears in the cytoplasm of the spermatid, and 
migrates towards the pole occupied by the blepharoplast. Here it elongates 
and appears to connect up with the cytoplasm and blepharoplast, thus 
forming the middle piece of the spermatozoid. 
9. The mature sperm forms a spiral of about one and one-half turns. 
10. The first division in the archegonium-mother-cell is horizontal, 
followed by three nearly vertical divisions in the upper cell. This is 
followed by horizontal and vertical divisions in the stalk-cell. Later 
divisions result in the formation of cap and axial-cells. The latter divide 
to form six canal-cells, a ventral canal-cell, and relatively large egg, bearing 
a well-defined receptive spot. 
