F. Cavers. 
276 
become gregariniform, strongly suggesting the attached juvenile 
phase of many Gregarinida ; the gregarinoid or euglenoid 
movements of Gregarinida and of the spores or other phases of 
Coccidia and Haemosporidia, which are quite comparable with the 
contractile and metabolic movements of Flagellates; and the 
exogenous type of reproduction, which is easily derived from the 
multiple fission of certain Hsemoflagellates, and this in turn from 
the typical binary longitudinal fission of Flagellata in general. On 
the other hand, the Endospora have probably arisen from the 
Rhizopoda or, perhaps more probably, from those members of the 
Azoosporeae division of Proteomyxa which appear to lead to the 
Rhizopoda and other Sarcodina. A Flagellate ancestry is 
apparently excluded by the entire absence of a flagellate or even 
gregariniform phase and by the simple type of spore formation 
characteristic of the primitive Endospora. Some of the latter, 
belonging to the group Haplosporidia, are apparently very closely 
related to Proteomyxa. In some cases (e.g., Bertvamia) the indi¬ 
vidual begins life as a small uninucleate body which later becomes 
multinucleate, then the protoplasm becomes segregated around the 
nuclei so as to produce a mulberry-like form, and the uninucleate 
spores thus formed are set free by the breaking-up of the parent 
body. In other cases the sporulating parasite becomes rounded 
off and forms a protective cyst; in others the spore mother-cells, 
instead of producing a single spore, give rise to several, e.g., four 
in Haplospovidium, many in Rhinosporidium. In Scheviakovclla the 
amoeboid individuals become aggregated to form plasmodia, and the 
spores divide by binary fission. Some of these simpler types of 
Sporozoa show striking resemblances to certain of the “ primitive 
fungi,” with which we now proceed to deal. 
VI.— The Chytridiales. 
On the view here adopted there may be traced from the 
Proteomyxa a series of lines, or possibly a single line which 
branched early into diverging lines, leading to a multitude of forms 
which may be included in four main groups—Myxomycetes, 
Chytridiales, Plasmodiophorales and Acrasiales. Of these groups, 
representing a rough though probably fairly natural division of the 
“ primitive fungi,” the two first are very much larger than the two 
last, and they are also marked by the invariable presence of a 
flagellate phase; flagella are sometimes found in the Plasmodio¬ 
phorales, but not in the Acrasiales. In all four groups the 
vegetative body is naked and usually capable of amoeboid movement 
except in various Chytridiales where a cell-wall is present in the 
vegetative phase so that a mycelium is formed like that of the 
typical Eumycetes. In other respects also the Chytridiales show a 
far wider range in structure and development than is to be found 
in the other three groups, and yet the various members of this group 
are so closely connected that one hesitates to break it up, at any 
rate to the extent to which some writers have proposed to do. In 
any case, we shall see that the four groups are so closely related 
to each other that they must be considered together, and that to 
separate off the Chytridiales as a group derived from algal ancestors 
and to combine the remaining three groups as “ Myxomycetes ” 
derived from Amoeba -like Protozoa, as is done by Schroter and 
others, is quite unjustifiable. 
