104 Mottier.—Chondriosomes and the Primordia 
It seems reasonable to conclude from the foregoing that in the growing 
root-tip of Adiantum there are two distinct organs in the cytoplasm, namely, 
the primordia of plastids and other bodies, which I have spoken of as 
chondriosomes. The latter vary in shape from spherical granules to short, 
delicate rods, the former always exceeding the latter in number. They 
divide rapidly with the growth of the cell, thereby becoming very numerous, 
especially in the large, rapidly elongated cells of the central cylinder. The 
primordia of leucoplasts, on the contrary, develop in the root-cap into bodies 
resembling certain chloroplasts, which contain one or more lenticular inclu¬ 
sions of starch. In the root proper these primordia remain in their original 
form as small, elliptical bodies, or develop into starch-bearing plastids, or in 
the plerome cylinder they may become large, elongated rods, which do not 
give rise to leucoplasts but continue to elongate into long-drawn-out threads 
which finally disappear. 
Pinus . In the Gymnosperms, the young seedlings of Pinus Banksiana 
that did not exceed a centimetre in length supplied the material for study. 
In the cells of the growing point of the stem all primordia of cytoplasmic 
differentiations are small. Two kinds may be recognized in the groundwork 
of cytoplasm, which appears as a network in preparations stained with the 
haematoxylin method,—namely, very small round or globular bodies with 
a colourless centre, which may be represented by drawing a very small circle 
with a hard pencil, the primordia of leucoplasts and chloroplasts, and very 
small, densely-staining black specks, those of the chondriosomes. Passing 
to older parts of the seedling, as, for example, to the cortex of the young 
stem or to the cotyledons, we see that the circular and almost colourless 
primordia develop into the chloroplasts or leucoplasts, while the densely- 
staining bodies, which appeared as minute black specks, have become 
larger granules or rods, as shown in Fig. 10. I have not been able to 
convince myself that these minute bodies ever develop into leucoplasts or 
chloroplasts. The large densely-staining rods, so conspicuous in the roots 
(P"igs. 2 , 15 ), are not present in the parts of the seedling observed. The 
chloroplasts in such cells are rounded, oval, or lenticular bodies with 
colourless inclusions. In some the inclusion constitutes the bulk of the 
object; in others it is smaller, lying near one end. The form of the individual 
chloroplasts differs somewhat in the same and in different cells. In some 
cases they seem to be thinner and flatter ; in others, thicker and more 
rounded. It cannot be stated with certainty that the lenticular form is 
merely an edge view of a flattened, oval, or rounded chloroplast as seems 
to be true in some cases. The small, densely-staining, and homogeneous 
granules and rods are very numerous in the cortical cells of the stem and the 
cotyledons (Fig. 10). Their number seems to vary considerably, however, 
in different cells. Both rods and granules seem to multiply actively by 
division, for division stages are readily observed. It seems reasonable to 
