Shape
Most cells were elongate spindles (Figs. 1A, 1D, IF) but in a few cases there was a significant proportion (10-20 ~) of cells which were variously bent about the long axis. At least one of these specimens (Fig. 10 took the form of a spiral. A few ridged cells were present in many populations and these appeared to conform with E. acus vat. angularis Johnson. Occasionally up to 40 ~o of the cells had these ridges. In the more extreme examples of ridged forms, the cells were somewhat flattened (Fig. lc) and could therefore be regarded as being close to E. platydesma Skuja.
A few distended cells were often seen, particularly in samples that had been left standing overnight. These cells showed only weak locomotory powers. Striae were quite easily seen on these specimens, usually running obliquely to the long axis of the cell in contrast to the striae of healthy cells which were very faint and almost parallel with the long axis. In markedly inflated cells (Fig. 1G) the neck and tailpiece were not distorted but the disposition of the paramylon grains suggested torsion had occurred throughout the cell contents as well as in the pellicle. This condition is thought to have occurred at or just prior to the death of a cell.
None of the cells that were examined showed signs of euglenoid movement. However, in one sample that was treated with a few drops of sulphuric acid which brought the pH down from 9.0 to 6.6, the cells showed marked movement, while quiescent (encysted .9) cells of other species of Euglena became quite active.