142 
Ohservaiions on Mucor Mucedo. 
fMonthly Mlcroscopirai 
L Journal, Sept. 1,1869. 
plasma (germinal matter), and continuous with that in the tuhular 
stem. If a little more advanced, the head has enlarged, the con- 
tents are more differentiated, and a rather dense granular mass 
occupies the interior with a still denser mass towards its centre, 
this showing, in mxany cases, a pale cell within, or perhaps several, 
the plasma still communicating with the filament on which the head 
is expanding (h) ; on another filament we may find the pear-shaped 
head covered with closely applied dark spores, somewhat variable 
in size, those towards the neck often of an oblong or irregular 
shape (^), and the "core" with the stem darker in colour and 
denser in structure. 
Various effects may have been noticed according to the parti- 
cular head under examination. If sufiiciently matured, on the 
approach of water, the outer membrane enlarges, suddenly bursts, 
and a grumous semi-cellular substance flows out (u) at the same 
time that the contents of the tube pass up into the head ; when 
well-emptied, sundry cells come into view, seated close to the inner 
surface of the membrane or still deeper within ; there is no septum 
visible between the head and filament. At a later period, as 
growth progresses, within are numerous rounded granular cells of 
nearly equal size as well as the hyaline cells, a globular head fills 
the centre, and the outer surface is seen freely covered with fine 
points (t) ; a little below the head may be noticed a very faint line 
which marks the point of attachment between the " core " and the 
outer membrane. I find no direct septum through the filament. 
Under compression the outer membrane shows hexagonal areolar 
structure, and this also is occasionally evident at a later period on 
the membrane of the " core " or column. When rather more ad- 
vanced, well-marked spores are seen on the surface, which, by 
making their way towards the free surface, have ruptured the fine 
outer membrane, which may sometimes be found still retaining its 
hexagonal areas (d), but generally broken up entirely, the small 
points lying scattered about, whilst within the " core " everything, 
in well-nourished healthy plants, seems in activity. The hyaline 
cells are still seen, and if the specimen be ruptured these will some- 
times float out with fine molecular matter, which fills the " core," 
and on being set free exhibits active molecular movements, though 
I have not been able to satisfy myself of any circulation proper of 
this molecular matter in the stem.* The globular spores adhere 
by contact for some time while the ripening takes place, and 
eventually fall away, leaving the central column collapsed but 
* The circulation may be describerl as of two kinds : one general, the contents 
of the tubes of tlie mycelium, enclosing air-spores of varying shapes and sizes, 
sweeping somewhat rapidly and irregularly along the threads, even for consider- 
able distances ; the other, special, the small granules moving slowly along and 
round the fine threads, forming a loose net-work in the interior of many of the 
tubes ; no mantle or other fluid was seen in conjunction with them. 
