CASH AND HICK '. ON FOSSIL FUNGI. 
117 
conditions and circumstances under which it was preyed 
upon by the parasite. 
The tissue attacked bears obvious marks of the ravages 
which the fungus has made upon it. Its walls are corroded 
and less sharply defined than those of the unaffected part, so 
that the two can be readily distinguished, even under the 
lower powers of the microscope. The tissue itself may be 
cellular or it may be vascular. From a transverse section 
only it is hardly safe to speak with any degree of confidence; 
but we incline to the opinion that it is vascular. 
The vegetative part of the fungus consists of a large 
number of very delicate hyphae, which the section has cut 
through in almost all possible directions. The majority of 
these are even finer than the threads of Penicillium c/laiicum, 
and can scarcely be more than 7 0 \ 0 inch in diameter. A 
few are somewhat stouter, and in these so perfectly have the 
structural details been preserved, it is quite possible to dis- 
tinguish the protoplasmic contents from the enclosing cellulose 
wall. Where this occurs the protoplasm appears as a mere 
line occupying the centre of the thread. Branching has 
been freely indulged in by the hyphae, but it is very irregular. 
In one respect the hyphae differ from those of most fungi 
with which we are acquainted, in exhibiting at different 
points what appear to be a number of closely approximated 
constrictions, which give the filaments at these points a 
moniliform character. We are not sure, however, whether 
this may not be due to extraneous influences rather than to 
the nature of the fungus, though it is quite possible that the 
constrictions may be closely set transverse septa. Whatever 
be the nature of these constrictions, transverse septa are 
present in the hyphae, though they can only be demonstrated 
with considerable difficulty. In individual hyphae there are 
appearances which even in the absence of demonstrable 
septa would lead to the opinion that they had originally 
