nvestigations of the former on the number and
distribution of cilia (see fig. 1) led him to propose a scheme of
classification based on these and other morphological characters, and
differing essentially from any preceding one. This scheme may be tabulated
as follows:--

I. ORDER--HAPLOBACTERINAE. Vegetative body unicellular; spheroidal,
cylindrical or spirally twisted; isolated or connected in filamentous or
other growth series.

1. _Family_--COCCACEAE. Vegetative cells spheroidal.

(a) Sub-family--ALLOCOCCACEAE. Division in all or any planes,
colonies indefinite in shape and size, of cells in short chains,
irregular clumps, pairs or isolated:-- _Micrococcus_ (Cohn), cells
non-motile; _Planococcus_ (Migula), cells motile.

(b) Sub-family--HOMOCOCCACEAE. Division planes regular and
definite:--_Sarcina_ (Goods.), cells non-motile; growth and
division in three successive planes at right angles, resulting in
packet-like groups; _Planosarcina_ (Migula), as before, but motile;
_Pediococcus_ (Lindner), division planes at right angles in two
successive planes, and cells in tablets of four or more;
_Streptococcus_ (Billr.), divisions in one plane only, resulting in
chains of cells.

2. _Family_--BACILLACEAE. Vegetative cells cylindric (rodlets),
ellipsoid or ovoid, and straight. Division planes always perpendicular
to the long axis.

(a) Sub-family--BACILLEAE. Sporogenous rodlets cylindric, not
altered in shape:--_Bacillus_ (Cohn), non-motile; _Bactrinium_
(Fischer), motile, with one polar flagellum (monotrichous);
_Bactrillum_ (Fischer), motile, with a terminal tuft of cilia
(lophotrichous); _Bactridium_ (Fischer), motile, with cilia all
over the surface (peritrichous).

(b) Sub-family--CLOSTRIDIEAE. Sporogenous rodlets,
spindle-shaped:--_Clostridium_ (Prazm.), motile (peritrichous).

(c) Sub-family--PLECTRIDIEAE. Sporogenous rodlets,
drumstick-shaped:--_Plectridium_ (Fischer), motile (peritrichous).

3. _Family_--SPIRILLACEAE. Vegetative cells, cylindric but curved more
or less spirally. Divisions perpendicular to the long axis:--_Vibrio_
(Mueller-Loeffler), comma-shaped, motile, monotrichous; _Spirillum_
(Ehrenb.), more strongly curved in open spirals, motile, lophotrichous;
_Spirochaete_ (Ehrenb.), spira