CHÄPTER V.—COMPARATIVE REVIE W.—CHYTRIDIEAE. 161 
though close affinities. With this reservation we will first proceed to describe the 
points of form which are common to them all. See the Figs. 75-77 below. 
The sporangia are cells of varying shape and diameter in the different species, 
and are often furnished with one or more wart-like or neck-like processes, which 
finally discharge the spores from their swollen and projecting apex, or which, as in 
Chytridium Olla, are cast off like a lid for the same purpose. They are furnished 
when fully grown with a moderately thick wall of cellulose, and densely filled with a 
uniformly finely-granular fatty protoplasm, which at length divides simultaneously into 
numerous spores. In most species the division is preceded by separation of the pro- 
toplasm-granules, which are colourless or coloured yellow, orange, or rose, according 
to the species, into as many groups divided by narrow hyaline streaks, in each of which 
the granules then coalesce to form bodies of successively larger size, and ultimately a 
single sphere consisting chiefly of fatty matter. This sphere of fatty matter then lies, 
usually excentrically, in the body of the swarm-cell, which otherwise consists of 
hyaline protoplasm and allows a nucleus to be seen in the larger forms’. Such a 
swarm-cell when set at liberty is roundish or elongated in shape, and is furnished 
with one cilium which is several times longer than the diameter of the body, The 
sphere of fatty matter is much more frequently, but not always, brought near the point 
of insertion of the cilium; exceptions to this structure occur in most of the species 
only as monstrosities. But in some there is no fatty sphere (Chytridium macrosporum, 
Ch. roseum, &c.). The spores of Olpidiopsis Saprolegniae, Woronina, and Rozella 
have according to A. Fischer always two cilia. 
The spores are discharged from the sporangia by the process of swelling 
described in section XX, and in some species are at first held together in a mass 
by mucilage, from which they are afterwards gradually set free one after another; 
in other species they leave the cavity of the sporangium one by one. Where the 
dimensions and the speed of their movements allow of exact observation, the cilium 
is usually seen to follow the body in the process ofrelease from the sporangium. The 
movement in the water is described as being clearly in many species a hopping 
movement; a progression by hops in no strictly determinate direction alternates 
in longer or shorter periods with a state of quiescence and each hop is associated 
with a stroke of the cilium like the stroke of a whip. But this kind of movement is 
not found in all the species. The spores of Nowakowski’s Chytridium Mastigotrichis 
and the highly phototactic spores of Polyphagus Euglenae and of Strasburger’s 
Chytridium vorax move forward with moderate speed and uniform rotation round 
their longitudinal axis and with the extremity that has no cilium in front, while the 
cilium follows passively behind. The time that the movement continues varies in 
each case, being seldom more than an hour, often much less; in a few cases, as 
in Synchytrium Taraxaci, it is considerably more. Towards the end of the period 
of movement an undulating change in the outline of the body often takes the 
place .of the phenomena which have been described, together with an amoeboid 
creeping on a firm substratum, in which the cilium is dragged behind. 
The resting-cells or resting-spores of the Chytridieae are on an average nearly or 
quite as large as the sporangia, and are distinguished from them by thick, often 

? See above, pp. 107-109. 
[+] M 
