276 Carter. — Studies on the Chloroplasts of Desmids. Ill . 
The axis is not usually very large, and if more pyrenoids than one are 
present they usually cause much distortion (Figs. 57 and 69). From the 
axis of each chloroplast a number of plates stretch out towards the cell-wall 
(Figs. 38-49), or in some cases, instead of definite plates, numerous thin 
strands radiate in all directions towards the cell-wall (Figs. 62-70). In 
practically every species the edges of the plates or the ends of the strands 
spread out over the internal surface of the cell- wall to form greater or smaller 
parietal extensions, but this is doubtless a feature which is subject to con- 
siderable individual variation (Figs. 37, 50, 54, 56, 67, 69, and 71). 
C. for mo sultan. 
The axis of the chloroplast in this species is provided with about four 
simple plates which radiate towards the periphery (Text-fig. 2, b), their 
edges spreading irregularly over the surface of the wall, but only covering 
a comparatively small area of its surface (Text-fig. 2, A and B). 
C. binum. 
This species, which is frequent in the tropics, has chloroplasts which are 
quite similar to those of C. formosulmn, but the radiating plates are more 
massive, and there is some attempt at branching, relatively more of the 
surface of the cell-wall being covered by their spreading extremities (Figs. 
54 and 55). The shape of the cell-wall apparently influences the develop- 
ment of the chloroplast to some extent in this species, for the broad edges 
of the four lateral plates lying under the marginal crenations of the cell-wall 
are produced to form four series of short radiating ridges, each ridge cor- 
responding to one of the crenations (Fig. 54). This relation between the 
cell-wall and chloroplasts recalls the condition described by Liitkemuller 
( 1893 ) in the parietal chloroplasts of C. tessellatum , &c. 
C. margaritiferum. 
The plates radiating from the axis in this species are much more 
irregular in form than in the two previous species (Fig. 53). In the front 
view of the cell, their widened extremities are seen running in all directions 
over the surface of the cell-wall (Fig. 52), and they are frequently seen to 
branch (Fig. 53). 
C. pachydermum. 
The axis of each chloroplast is provided with about five radiating plates 
(Fig. 72), the edges of which, on reaching the cell-wall, spread out on either 
side to form finger-like outgrowths, sometimes of considerable length and 
often branching. These flattened processes are closely adherent to the 
surface of the wall, and so in the front view the cell is seen to have several 
irregularly branching strings of parietal lobes of chloroplast (Fig. 71). The 
