Campylonema Lahorense. 37 
Perennation and Multiplication. In unfavourable conditions 
such as drought, as a rule, the filaments lie enclosed in their thick 
sheaths, thus giving the stratum a dark-brown colour. They are 
very fragile in this condition. When the favourable conditions 
recur, trichomes, generally broken up into a number of 
hormogones, slowly come out of the sheaths and lie more or less 
parallel to one another, thus forming a fresh bluish-green stratum. 
These hormogones may consist of even one or two cells. They 
resemble the filaments of Oscillatoria in general appearance and may 
be easily mistaken for the latter. They are produced generally by the 
secretion of an inter-cellular substance or sometimes by the death 
of vegetative cells here and there. The inter-cellular substance is 
dark-green in colour and is in the form of a biconcave disc (Fig. 2). 
Fig. 3. A filament showing many heterocysts (het.), and a single pseudo¬ 
branch (p.b.), at the base of one of them. ( x 450j. 
Rarely spores were seen forming a chain inside the sheath. 
The sheath in these cases was found to be thin and smooth, though 
firm and brown (Fig. 6). Each spore has a thick smooth outer 
membrane and a very thin inner membrane. It is about 8/x long 
and about 6/x broad and has homogeneous or very finely granular 
contents. The ejection and germination of these spores have not 
yet been seen by the writer. 
Systematic. The alga described above, although to some extent 
it resembles Tolypothrix arenophila W. and G. S. West, and was 
to that species by the writer in a former paper (2), shows 
many characters which render it hardly possible of reference 
even to the genus Tolypothrix. Firstly, heterocysts are 
frequently found at intervals during the whole length of the 
filament as in Scytonewa, and are seldom confined to the base of a 
