CH, X.—MORPHOLOGY OF THE BACTERIA.—ARTHROSPOROUS BACTERIA. 475 
simply Nostocaceae or Schizophyta which contain no chlorophyll; at the same time 
the position of the entire group in the general system remains still undetermined’. 
Of the forms which are here termed Endosporous Bacteria it can only be said at 
present that they come nearest of all known forms to the Arthrosporous Bacteria, and 
apparently are very nearly allied to them. It may be repeated in this place that the 
sharp separation between the two groups rests on the knowledge of them which we at 
present possess, and may disappear with its extension. Till then the separation must 
be maintained, and it must remain an open question whether the resemblance between 
the two groups really implies close affinity, or whether the endosporous forms may not 
stand in still nearer relationship to other members of the system. If we look around 
us under the guidance of ascertained facts for such affinities, we are led once more, 
as Biitschli has also pointed out?, to the Flagellatae. The arthrosporous form 
such as Beggiatoa, with their generations alternating between a state of rest and one 
of swarming movement by aid of cilia, show an unmistakeable resemblance to the 
simpler forms of that varied group. The mode, of forming their spores which is 
characteristic of the Endosporous Bacteria finds its analogue, as far as we can 
venture to speak in the present state of our knowledge, only in the formation of the 
spores or cysts, to use the customary phrase, in the simple Flagellatae * known as 
Spumella vulgaris, Cienk., and Chromulina. In these species the spore is formed, 
as in the Bacteria in question, inside and from a portion of the protoplasm of a 
cell, and this mode of formation occurs nowhere else among the lower Thallophytes. 
We may at least suspect that a homology is indicated by this in itself only analogous 
phenomenon, but the facts which have been observed lend no support to the 
assumption. In dealing with this question we must keep well in mind that we are 
not equally well acquainted with all portions of the range of organisms included 
under the name Flagellatae, especially as regards the course of development of the 
species, and that their affinities must be to some extent obscure and uncertain. For 
this reason we will not add anything further to the remarks which have now been 
made. 
But if we assume for a moment a connection between the Bacteria and the 
Flagellatae, it is evident that as a consequence the following series of forms converge 
to the Flagellatae: firstly, the series of Bacteria and Nostocaceae; secondly, that 
of the Mycetozoa (see page 445); Zhirdly, that of the chlorophyllaceous Algae, 
with which are connected in ascending line the main series of the vegetable kingdom 
and of the Fungi as one or more lateral branches‘, and perhaps also side by side 
with the chlorophyllaceous Algae some smaller groups which are now placed with 
the -Chytrideae ; fourthly and lastly the Rhizopoda and the Protozoa with the 
Animal Kingdom which connects with these in an ascending line. On the above 
assumption the position of the series of Bacteria in the whole system would be the 
definite one of a gropp of organisms linking with the Flagellatae as a common 
point of commencement and departure, and coordinating with the series of the Algae 

"2 Bot. Ztg. 1881, 1. 2 Bütschli (as cited on page 453), p. 808. 
3 Cienkowskiin Schulze’s Archiv f. mikr. Anat. VII, p. 434.—Biitschli, (as cited on page 453), 
PP. 797, 816, t. 45. 
* Bot. Ztg. 1881. 
