92 MORPHOLOGY OF THE BACTERIA. : 
veloped, from the Vibrio rugula, which only pre- 
sents a single curve in its centre, to certain species 
of Spirillum which have numerous turns of the 
spiral. In several species, cilia, or a flagellum, have 
recently been observed. | 
We divide them into three genera : — 
Fil. short, slightly sinuous . . . VIBRIO. 
Fil. short, spiral, rigid . . . . SPIRILLUM. 
Fil. long, spiral, flexible. . . . SprrocH#TE. 
g. Vibrio, Auct. emend. 
Body filiform, more or less distinctly articu- 
lated, always undulating, having serpentine 
movements. This genus forms the transition 
between the Desmobacteria and Spirillum “from 
which it cannot be separated’ (Warming). 
Fil. thick, with a single curve . . . V. RUGULA. 
Fil. slender, with several undulations . V. SERPENS. 
V. rugula, Miiller (V. lineola, Duj. ex parte). 
Filament presenting in its centre a single curva- 
ture, feeble but distinct; length 8 to 16 yw. The 
shortest are slightly curved (= 6 ~ Warming), the 
larger, which may attain 17.6 uw (Cohn), 35 » (Warm.), 
are about to divide. Movements of rotation more or 
less rapid around their longer axis; of progression 
forward, giving then the idea of a serpentine move- 
ment: having a cilium (Warming). 
V. rugula is commonly found in swarms, in 
infusions, in deposits upon the teeth, in intes- 
tinal matters (Leewenhceck), in choleraic dis- 
charges (Pouchet). 
