404 POLYMORPHIC FUNGI. 
tin box, but that the Mucor afterwards appeared on the same 
leaves, sometimes from the same patches, and from the same my- 
- celium. The great difference in structure of the two species lies 
in the fructification. In Penicillium, of which fig. 76 is a good 
illustration, the spores are naked, and in moniliform threads, 
whilst in Mucor the spores are enclosed within globose membra- 
nous heads or sporangia, as shown in fig. 77. The moulds, or 
Mucedines to which Penicillium belongs, are included in one of 
the large families of fungi termed Hyphomycetes, and the Mucors | 
belong to another family, the Physomycetes. We entertain no — 
doubt whatever, that the Mucor, to which we have alluded as — 
growing on box-leaves, intermixed with Penicillium roseum, is no 
other than the higher and more complete form of that species, and 
that the Penicillium is only its conidiiferous state. The presump- 
tion in this case is strong, and not so open to doubt as it would 
k 
: 
be, did not analogy render it so extremely probable that such is 
the case, apart from the fact of both forms springing from the 
same mass of mycelium. In such minute and delicate structures — 
it is very difficult to manipulate the specimens so as to arriveat 
positive evidence. If a filament of mycelium could be isolated 
successfully, and a fertile thread, bearing the fruit of both forms, 
could be traced from the same individual mycelium thread the 
evidence would be conclusive. In default of such conclusive evi- 
dence, we are compelled to rest with the assumption until farther 
researches enable us to record the assumption as fact. 
In Lewis’s recent “ Report on Microscopie Objects found in 
Cholera Evacuations” (Calcutta, 1870), a similar instance of pre 
sumed dimorphism between precisely the same genera is thus Te — 
corded. ‘‘@n a preparation preserved in a moist chamber, on the 
numerable ‘ yeast’ cells with some filaments, branching in all di- 
rections. On the fourth day, tufts of Penicillium had developed 
— two varieties, P. glaucum and P, viride. This continued until 
cases they seemed to be derived from the same filament as others 
bearing the ordinary branching spores of Penicillium, but of this 
I could not be positive. This kind of fructification increased rap- 
idly, and on the fourteenth day spores had undoubtedly developed 
