STRUCTURE, 51 
but there are points in the structure which can best be alluded 
to here. Again taking Professor de Bary’s researches as our 
guide,* we will illustrate this by the common Jfucor mucedo: 
If we bring quite fresh horse-dung into a damp confined 
atmosphere, for example, under a bell-glass, there appears on its 
surface, after a few days, an immense white mildew. Upright 
strong filaments of the breadth of a hair raise themselves over 
the surface, each of them soon shows at its point a round little 
head, which gradually becomes black, and a closer examination 
shows us that in all principal points it perfectly agrees with 
the sporangia of other species. 
Each of these white filaments 
is a sporapgia-bearer. They 
spring from a mycelium which 
is spread in the dung, and 
appear singly upon it. Cer- 
tain peculiarities in the form 
of the sporangium, and the 
little long cylindrical spores, 
which, when examined sepa- 
rately, are quite flat and co- 
lourless, are characteristic of 
the species. If the latter be 
sown in a suitable medium, ) 
for example, in a solution of ‘ 
Pe; Fia. 31.—Mucor mucedo, with three sporangia. 
sugar, they swell, and shoot a. Portion of frill with sporangiola. 
forth germinating utricles, which quickly grow to mycelia, which 
bear sporangia. This is easily produced on the most various 
organic bodies, and Mucor mucedo is therefore found sponta- 
neously on every substratum which is capable of nourishing 
mildew, but on the above-named the most perfect and exuberant 
specimens are generally to be found. The sporangia-bearers 
are at first always branchless and without partitions. After 
the sporangium is ripe, cross partitions in irregular order and 
number often appear in the inner space, and on the upper 
* De Bary, ‘‘On Mildew and Fermentation,” in ‘‘Quarterly German Magazine,” 
or 1872. 
