ON THE CONVERSION OF ASCI INTO SPORES. - 321 
The case, however, of Spheria inquinans, which we have now to 
bring forward, is still stronger. This species and Stilbospora macro- 
sperma were extremely abundant on an old elm at Batheaston in 
January last. Not only were they so intermixed as to make it difficult, 
from the close resemblance of the fruit, that of the one being merely a 
little more elongated, and in a very slight degree more attenuated at 
either extremity, with rather a browner tinge, to say at once which was 
the Spheria, which the Séilbospora, but the same orifice in the bark gave 
egress both to the sporidia of the one and the spores of the other. At 
the base of the spores of the Sfi/bospora, where seated on their sporo- 
phores, from one to three short sheaths were observed, as if the spore 
had burst through one or more enveloping membranes. But not only 
was the Stilbospora produced in the same portion of the bark as the 
Spheria, or perhaps, to speak more correctly, in the same stroma, but 
in one case it was actually developed on the external surface of a peri- 
thecium, the inner surface giving rise to perfect asci, with their proper 
sporidia. Ina certain stage of growth the sporidia of the Spheria are 
furnished at either extremity with a cirrhiform appendage, but this is 
not always visible in the ejected mass which surrounds the common 
orifice of the perithecia. Analogous appendages occur in some other 
species, 
The third case to which we invite attention is Hendersonia mutabilis, 
a species which occurs on twigs of Plane. The main perithecium con- 
tains one or more cavities, more or less isolated, which produce far 
smaller hyaline bodies, and which do not accord with the genus Hen- 
dersonia but rather with Phoma. This is not indeed a case bearing 
upon the conversion of asci into spores, but is interesting as exhibiting - 
one perithecium within another; and whether considered as a new cell 
developed within the old one, and consequently containing younger 
spores (a view at first adopted, but which, on maturer consideration, 
seems scarcely tenable), or as two forms of spores both belonging to 
the same species but produced in distinct cavities, or finally as two 
genera united within the same common receptacle, it is full of interest. 
We are not prepared, as in the last case, to say that the same wall 
from its two sides produces different forms of fruit, though in some 
sections the two fertile surfaces are so confluent above that it is very 
probable that the same fact will be found to obtain here also. 
These instances certainly seem to indicate rather a transformation of 
