Paramylon
Most cells from treatment ponds contained numerous rod-shaped paramylon grains (Figs. 1A, lI O. In some cells these were concentrated in two regions (Figs. lr, ln, lI), in a few specimens surrounding a dense accumulation of orange- coloured droplets. This latter disposition was shown very well in one specimen (Fig. 1n) that contained only five chloroplasts.
On a number of occasions during July and August 1966 and October 1967, cells from the Mangere ponds and lagoons were observed to contain distinctive ovoid paramylon grains (Figs. lo, 1E). In some of these cells a few rod-shaped grains were also present. The chloroplasts were in intimate contact with these unusual grains while there appeared to be no association of the plastids with grains in normal cells (compare Fig. 1J with 1K). Only a very few cells in an otherwise normal population showed this characteristic. It seems that the ovoid form of these grains was not a permanent condition, since samples left overnight and examined the following day failed to show any cells with this feature, even though several had been seen in the freshly collected material.