2q8 Rivet t .— The Cytoplasm in the Cells of A licularia sea laris. 
In a slightly older cell of the same leaf, the first traces of the oil-bodies 
(visible in living material) are to be found ; they appear as small refractive 
drops, similar to the minute granules of the smaller cells, but larger in size; 
they may be scattered throughout the protoplasm or be limited to a small 
patch in the cell; where they occur they give the cytoplasm an emulsified 
appearance similar to that of the oil-bodies in Radiila complanata. They 
lie within the protoplasm and do not push through into the developing 
central vacuole. These oil-drops are in many cells continually in motion, 
rotating and revolving with the granules first seen in the younger cells, 
though less rapidly and in a smaller orbit. Owing to the high refractive 
index of the oil, the actual limits of their margins are obscured and they 
appear spherical with a dark edge. From their first appearance, their 
Text-FIG. i. Cells taken from mature leaf mounted entire in water and viewed from the 
surface, a = oil-bodies; b — chlorophyll-granules. 
method of movement, they appear simply as drops secreted by the proto¬ 
plasm within its own substance. There is no specialized external covering 
visible, for the protoplasmic surface from which they were secreted is blurred 
by the refractive glimmer of the oil (PI. VI, Figs. 3 and 4). 
In a cell which is a little more advanced than the previous one, the oil- 
drops have grown larger and their motion has diminished ; a few still appear 
to rotate slowly, but the revolving movements about the cell have ceased 
and each drop remains in its own place. In some cells at this stage there 
are distinctly two patches of oil-drops, foreshadowing the formation of two 
oil-bodies ; but this is not regularly so, and the whole surface of the cell may 
appear as one emulsified patch. At this stage the central vacuole of the cell 
is well developed and the protoplasm is retreating towards the cell-wall. 
In a cell of an older leaf the central vacuole is nearly fully formed and 
the pressure exerted on the protoplasm also affects the collection of oil-drops. 
