152 
THE FERN FAMILIES OF BRITAIN. 
being visible in several cases, projecting from the bifurcation 
of the prothallus, and evidently, therefore, produced from 
the archegonia by the ordinary sexual mode of reproduction; 
though the prothalli, as has been shown, had developed from 
growths that differed widely from spores in their form, their 
size, persistent adherence to the pinnae, their production of 
root-hairs from their surface, and, finally, in the development 
of the prothallus from their apices by simple extension of 
growth. 
Lest it might be assumed that these prothalli may after all 
have resulted from true spores scattered amongst the ex- 
crescences described, it should be borne in mind — first, that 
no spores or spore-cases could be distinguished when the pinnae 
were laid down ; secondly, that all attempts to raise this Fern 
from spores have failed; and finally, that the entire develop- 
ment of the prothallus from the pointed tip of the pear-shaped 
pseudo-bulb — its dilatation, bifurcation, and gradual assumption 
of the true prothallus form — has been carefully watched and 
noted step by step, not merely in one case, but in many, in 
all of which the prothallus was evolved precisely in the same 
way. 
Where, as in this case, the whole phenomenon is new to 
the observer, many points of interest are apt to be overlooked, 
their importance being unknown until too late. Another 
season’s growth may therefore confidently be expected to 
throw more light upon this development, and especially in 
relation to the first appearance of the pseudo-bulbils them- 
selves, which only came under close observation when already 
of considerable size. 
In framing this account of the occurrence, I have confined 
myself as strictly as possible to a simple, and I hope clear, 
record, of the phenomena observed during the various stages 
of growth of the abnormal sporoid excrescences under obser- 
vation. In conclusion, however, I may be permitted to point 
out, in connection with such phenomena, that, so far as formal 
records are concerned, the family of Athyria has hitherto 
been remarkable for the non-proliferous character of the fronds, 
which, considering, first, its near relation to the Asplenia, so 
