2 28 
Ward . — Thames Bacteria , III. 
elongated colony of about 20-25 rodlets (perhaps more 
behind ; it was impossible to count accurately) had formed, 
and some were slowly wandering off (Fig. 39 e). At 10 p.m. 
the initiation of a colony as a beautiful double-fan or con- 
stricted bundle of parallel or intertwining filaments breaking 
up into rodlets was established (f) } and next morning this 
appeared as an extremely tenuous cloud of slowly wandering 
rodlets, filaments and tresses of the types Figs. 36 and 37 
Some of these filaments intertwine to curious serpentine 
zoogloea-tresses, like those shown in Fig. 36 b , the frayed 
ends of which go on emitting rodlets (Fig. 37 e). 
Tracing the colony of No. 23 further in gelatine it begins 
as coloured mycelium-like tresses, radiating offshoots in all 
directions from the one or more denser coiled and serpentine 
central zoogloea-tresses, and in forty-eight hours the whole 
of the circular and extremely tenuous cloud-like colony is 
built up of the radiating strands branching from the central 
zoogloea-mass (Fig. 37 b). 
On the third day in ro per cent, gelatine the marginal 
strands become closely serried, and radiate like flames (see 
Fig. 37 d)\ or if the surface of the gelatine is suitable, these 
marginal filaments grow out on the moist surface as coiled 
islets, or compact contoured films. 
In this way the different marginal zones shown in Figs. 
36-38 are produced, the last-mentioned thin filmy borders 
(e. g. Fig. 37 d) being very iridescent. 
The central portion of the colony breaks up into cloudy 
masses arranged more or less like a network, and very often 
this more or less membranous part looks just like a sieve, fine 
or coarse, as the case may be (Fig. 38). The differences in 
colour, iridescence, zoning, &c., are entirely due to the rate 
of liquefaction and attendant pigmentation, the amount of 
flowing of the contoured margin, and the mode of breaking 
up of the tresses into radiating spokes, networks, sieves, or 
mosaics, according to the distribution of the clouds of 
segments into which they disintegrate. 
The behaviour of the colonies of No. 23 in 5 per cent. 
