392 The Botanical Gazette. [December, 
modification of the individual rods at the period of encyst- 
ment. For while in one group (Myxococcus), they become 
transformed into definite spores, in the other (Chondromyces 
and Myxobacter), the rods are encysted as such with little 
apparent modification, as far as the writer has been able to 
ascertain. : 
Without entering into further details of structure or devel- 
opment, which will be found below, sufficient has been said 
to make intelligible a brief comparison between the course of 
development of these plants and that of other organisms 
which may seem to possess certain characteristics in common 
with them. 
The general character and structure of the rod-like individ- 
_ uals, together with their vegetative multiplication by fission, 
renders their schizomycetous nature as individuals a matter 
hardly to be doubted: but, on the other hand, the question 
may fairly be asked whether the remarkable phenomena 
which they present, not as individuals, but as aggregates, 
may not indicate a possible relationship in other directions. 
In the account just given it is hardly necessary to point out 
the evident similarity between the course of development 
described and that which occurs in the Mycetozoa, and more 
particularly in the Acrasiee. In no other group, as far as 
the writer is aware, does there exist a similar concerted 
action of aggregates of individuals towards a definite end, 
namely, the production of a more or less highly differentiated 
resting state. Setting aside for the moment the fundamenta 
differences presented by the cell characters in either group, 
the vegetative condition of the Acrasiee and that of the 
Myxobacteriacee may be considered strictly comparable. In 
both cases multiplication by bipartition, followed by the 
complete separation as individuals of the two parts thus 
formed is followed in turn, after a period of successive bipat- 
titions, by a swarming together of distinct individuals ite 
aggregates of distinct individuals having a definite end in 
view. Apart from differences of cell structure, therefore, 
the essential characters of a pseudo-plasmodium are common 
to both groups. 
Following the analogy to later stages of development 4 ce 
tain similarity may be noted between the steps which lead in 
either case from the simpler to the more complicated forms. 
In both instances a transition is observable from a mere heap- 
