CHAPTER X.—MORPHOLOGY OF THE BACTERIA. 459 
terminology adopted in the case of the Scytonemeae is also applied to this form of 
branching in the Schizomycetes, which has therefore been designated by the really in- 
correct or at least unnecessary name of false branching (pseudo-ramification). 
In some of the larger forms of this group, Crenothrix for example, Cladothri‘x, 
and species of Beggiatoa, the filaments attach themselves by one extremity to fixed 
bodies, while the other extremity stretches free into the surrounding fluid; here 
therefore there is a distinction between base and apex, and this is accompanied by 
certain corresponding phenomena of growth, such as the direction of the branches 
and some others. . 
The formation of filaments occurs in those Schizomycetes in which growth and 
divisions advance only or chiefly in one, and that the longitudinal direction. If these 
take place alternately in two or three directions while the genetic connection is 
maintained, then , 
3. Groups of cells are produced forming flat surfaces or masses. The 
dice-shaped pockets of Sarcina ventriculi are the best-known examples of this kind. 
Figs. 170 x and 175 a will give an idea of their appearance. 
4. The isolated and connected forms of each of the kinds described above may 
again be united by coherent mucilage into larger gelatinous masses, which are known 
by the older and more general name of Palmella, or by the ‘more recent term ‘of 
Zoogloea. These masses form gelatinous layers or pellicles according to the 
species or culture-form, and cover the surface of the solid or fluid substratum ; or 
if suspended in a fluid they form lumpy bodies of very various shapes and are often 
lobed and branched. The gelatinous cell-membranes in these masses are either 
fused together into a homogeneous structure, or show a Stratification which varies 
in the different isolated cells or aggregates of cells. In the larger and more firmly 
united masses the cells, whether isolated or connected together, have not the power 
of locomotion which many of them, as we have seen, possess in the free state. 
All these varieties of shape and connection are merely growth-forms like those 
designated Filamentous Fungi, Sprouting Fungi, Compound Fungus-body, &c. 
(see section I). But the Bacteria were at first distinguished into species 
and genera according to these forms of growth, and on the too hasty assump- 
tion that the forms produced from them were always like the parents, and 
since the year 1872 these distinctions have been precisely defined by Cohn. But 
it is obvious from what has now been stated that we are dealing in the present case 
with /orm-species and form-genera only, using these words in the sense assigned 
to them on page 120; the names Micrococcus, Bacillus, Spirillum, Spirochaete, 
Vibrio, Leptothrix, Zoogloea and others, applied above to the Schizomycetes, were 
in this sense used originally as names of genera and not as designations of forms 
of growth. The relations of these form-genera to the natural genera, that is to the 
genera founded on the entire course of development, will be considered presently. 
Section CXXX. The forms comprised under the name of Bacteria or Schizo- 
mycetes may be distributed, in accordance with the course of their development. 
and with the facts as at present known to us, into two groups, and such is to some 
extent the course adopted by Van Tieghem in his new text-book. The first group 
will contain the species which have their spores formed endogenously, the Endo- 
