RESEARCHES ON THE DEVELOPMENT OF STARCH-GRAINS. 297 
and they consist of innumerable minute polyhedral grains. 
In ripe seeds these minute grains have always become 
separate. 
Immediately before the first formation of the starch-grains 
the starch-forming-corpuscles are spheres of rather larger size 
and lower refrangibility than those in the epidermis of PAzlo- 
dendron grandifolium. They are very numerous, and they are 
especially collected on the lateral walls of the cells. The 
mode of their development differs but little from that which 
has already been described in other cases. In the youngest 
cells the nucleus, which is usually suspended in the cavity 
of the cell, is surrounded by a very thick layer of peculiarly 
glistening protoplasm. This becomes paler, and a number 
of bright points become apparent in it; these enlarge into 
spheres, and the remainder assumes the appearances of ordi- 
nary finely granular protoplasm. Some spheres also make 
their appearance in the strands of protoplasm which connect 
the protoplasm around themselves with the parietal layer, 
and some appear also in this layer itself. The corpuscles 
enlarge, their refrangibility diminishing at the same time, 
and the protoplasm with the nucleus coalesce with the 
parietal layer. 
The first starch-grains are apparently formed in the peri- 
pheral portion, but this has not yet been quite definitely 
ascertained. ‘The corpuscle soon becomes turbid in con- 
sequence of the presence of a number of minute granules 
which increase in size and become starch-grains. The 
whole body increases considerably in size, and it may either 
retain its spherical form or become more or less elongated. 
The substance of the corpuscle diminishes, and finally 
disappears altogether, whilst the starch-grains fill up the 
whole space, and become polyhedral in consequence of 
mutual pressure. In this way the above-mentioned com- 
pound grains are produced, which must therefore be regarded 
as spuriously compound. 
The starch-grains in the endosperm of Melandryum 
macrocarpum (figs. 24—29) are large, spherical, or ovoid, 
and consist of innumerable minute grains, which, as in 
Beta, separate as the seed ripens. 
The starch-forming-corpuscles which produce them are 
moderately large, spherical, or spindle-shaped, and lie in the 
parietal protoplasm upon the nucleus. They are few in 
number. They differ from those which have been already 
described in that they are formed at various points in the 
protoplasm, which is, from the first, parietal. The process 
isin other respects essentially the same in all cases, The 
VOL, XXI,——NEW SER. U 
