the type of distribution, &c., of the cilia for each species when growing
at its best. The chief results may be summed up as follows: some species,
_e.g._ _B. anthracis_, have no cilia; others have only one flagellum at one
pole (_Monotrichous_), _e.g._ _Bacillus pyocyaneus_ (fig. 1, C, D), or one
at each pole; others again have a tuft of several cilia [v.03 p.0160] at
one pole (_Lophotrichous_), _e.g._ _B. syncyaneus_ (fig. 1, E), or at each
pole (_Amphitrichous_) (fig. 1, J, K, L); and, finally, many actively
motile forms have the cilia springing all round (_Peritrichous_), _e.g._
_B. vulgaris_ (fig. 1, G). It is found, however, that strict reliance
cannot be placed on the distinction between the _Monotrichous_,
_Lophotrichous_ and _Amphitrichous_ conditions, since one and the same
species may have one, two or more cilia at one or both poles; nevertheless
some stress may usually be laid on the existence of one or two as opposed
to several--_e.g._ five or six or more--at one or each pole.

[Sidenote: Vegetative State.]

In _Beggiatoa_, a filamentous form, peculiar, slow, oscillatory movements
are to be observed, reminding us of the movements of _Oscillatoria_ among
the _Cyanophyceae_. In these cases no cilia have been observed, and there
is a firm cell-wall, so the movement remains quite unexplained.

[Illustration: FIG. 4.--Types of Spore-formation in Schizomycetes. (After
Zopf.)

A. Various stages in the development of the endogenous spores in a
_Clostridium_--the small letters indicate the order.

B. Endogenous spores of the hay bacillus.

C. A chain of _cocci_ of _Leuconostoc mesenterioides_, with two "resting
spores," _i.e._ arthrospores. (After van Tieghem.)

D. A motile rodlet with one cilium and with a spore formed inside.

E. Spore-formation in _Vibrio_-like (c) and _Spirillum_-like (a b, a)
Schizomycetes.

F. Long rod-like form containing a spore (these are the so-called
"_Koepfchenbacterien_" of German authors).

G. _Vibrio_ form with spore. (After Prazmowski.)

H. _Clostridium_--one cell contains two spores. (After Prazmowski.)

I. _Spirillum_ containing many spores (a), which are liberated at b by the
breaking up of the parent cells.

K. Germination of the spore of the hay bacillus (_B. subtilis_)--the axis
of growth of the germinal rodlet is at right angles to the long axis of the
spore.

L. Germination of spore of _Clostridium butyricum_--the axis of growth
coincides with the long axis o