Fossombronia longiseta , A list . 103 
and Pallavicinia , and Moore 1 for P allavicinia. Following this the nucleus, 
in which the nucleolus is relatively very large, shows a delicate, reticular 
structure and assumes an equi-four-angled form (Fig. 55, PL VI). Here 
again no radiations were perceptible, although different stains were 
employed. In one case the anilin-safranin— -gentian-violet — orange G com- 
bination was employed, but more satisfactory results were obtained with 
the iron haematoxylin, using erythrosin as a contrast stain. A little 
later the nuclear protuberances are considerably elongated, extending well 
into each lobe of the cell. At this stage there seems to appear an 
accumulation of cytoplasm at the four poles, but nothing like definite 
radiations could be made out. At this time in all cases examined the 
nucleolus had begun to undergo change, in some instances appearing 
vacuolated, while two of the nuclear arms were somewhat longer than the 
others, which corresponds with Farmer’s account of the spore-mother-cell 
nucleus in F. Dumortieri just preceding the appearance of the bipolar 
spindle. Satisfactory stages of the further behaviour of the nucleus were 
not obtained, so we pass to the events following mitosis. The ultimate 
outcome of the division in the spore- mother-cell is the tetrad, each cell 
of which has it own nucleus, equaling in size that of the archesporial cell, 
though the nucleus is relatively smaller than is true of the spore- mother- 
cell. Protoplasmic granules in the cytoplasm lie disposed irregularly, 
giving the protoplasm a somewhat vacuolated appearance. Each spore 
now becomes surrounded by its own proper wall, and a little later 
a distinct endospore becomes differentiated. Judging from its staining 
qualities the old spore-mother-cell wall becomes mucilaginous, and by 
breaking down the spores become liberated within the capsule, in which 
respect it agrees with the other Jungermanniaceae, with the exception 
of Sphaerocarpus . The spores have already been described by Howe 2 
as showing considerable variation in external appearance, which leads 
him to think that this is significant of a possibility that we may be 
including under the head of F. longiseta more than one species. The 
writer’s investigation can throw no light upon this point. He has found 
the echinate and cristate types of spores produced on plants that in no 
other respects appeared to differ. In the majority of cases the inner faces 
of the spore are nearly smooth in comparison with the outer face ; the 
cristate ridges of the latter, at times, apparently being continuous near the 
limits of the inner faces, as seen in Fig. 59, PI. VI. 
Normally the spores are somewhat compressed and round-tetrahedral 
in outline, measuring from 38 to 50 /x in greatest diameter. The ripe 
sporogonium by the rapid, and relatively very great, elongation of the 
seta reaches a total length of 10 to 16 mm. For some time previous 
1 Moore, vol. xxxvi, Fig. i of plate. 
2 loc. cit., p. 82. 
