CH.VIIT.—-MORPHOLOGY AND COURSE OF DEVELOPMENT.—MVYXOMYCETES. 433 
these movements:the branches of the plasmodia all change their previous distribution 
through the whole of the thickness of the body and creep to the periphery, where they 
form a net-work stretching only in the direction of the surface and formed of threads 
which become successively broader and meshes growing narrower and narrower 
(Fig. 188 a). The whole is covered on the outside by a thin layer of the hyaline 
protoplasm which alone forms the whole of the inner portion of the body. When 
these processes are completed, the net-work of protoplasm breaks up simultaneously 
into numerous polyhedral portions of nearly uniform size (Fig. 188 4). They contain 
each a nucleus, become flattened from without inwards, and remain grouped in a 
simple layer which follows the surface like an epithelium. Then each of these proto- 
plasmatic bodies begins at once to grow convex towards the outside, and to lengthen 
out at right angles to the surface of the whole body into the shape of a sphere borne 
on a slender conical stalk (Fig. 188 4). A delicate membrane is formed at the 
same time within which all 
the protoplasm passes through 
the stalk into the spherical 
expansion at the extremity. 
The latter then becomes in- 
vested all round with a söme- 
what thicker membrane with 
an ellipsoid outline, and thus 
becomes a mature spore which 
is readily detached from the 
empty;hyaline stalk. The entire 
gelatinous sporophore under- 
goes no further changes, but 
in most cases soon dissolves 
and disappears. 
The other known ecto- 
. FIG. 188. a Ceratium hydnoides Piece of a sporophore in the act of forming: 
Se een 
ee ee 
the species just described only woronin. a magn. about 68 times, b 120 times. 
by the yellow colour and by 
the shape of its sporophore, which resembles in form the hymenium of a Polyporus 
(see page 288). 
The development of the sporophores and receptacles as just described runs its 
course rapidly if the conditions are favourable. According to a series of observations 
on spontaneously developed Physareae, species of Trichia, Stemonitis and others, the 
complete development from the commencement of the formation to maturity requires 
an interval on the average of about 12 hours; the development is quicker or slower in 
particular species, or according to the temperature and moisture of the environment. 
The sporophores of Ceratium are perfectly formed according to Famintzin 
and Woronin in the course of a summer night. The entire development of the 
species may also be accomplished very rapidly. Cienkowski obtained in four days 
fully formed plasmodia of Chondrioderma difforme when grown on microscopic 
slides, and these formed sporangia on the fifth day. 
[4] Ff 

