COLLECTED IN THE SOUTH ORKNEYS. 305 
the oval cell as a uniform expansion of the body (1 & 2 in figs. 7, 8, 9, & 11, 
p. w. in fig. 8), this expansion being rather wider at the sides than at the 
two ends of the cells. In the other two pairs of wings (lateral wings) the 
wings of each pair form an angle of 60? with one another and with the 
principal wings, these pairs being 3, 4 and 5, 6 in fig. 11*. Atthe two ends 
of the cell the wings of each lateral pair become very slightly arched out and 
then dip in suddenly and meet together, so that a kind of apparent sinus is 
formed at the two ends on either side of the principal wings (cf. fig. 7, and 
especially figs. 8 & 9, which are oblique end-views of S. antarctica showing 
only the course of the wings ; see also Pl. 11. phot. 4). The customary 
position of an individual of ©. antarctica 18 with the principal wings parallel 
to the substratum, as shown in fig. 7 (also Pl. 11. phot. 4) ; in this саке, as 
the figure indicates, the two ends of the cell appear completely rounded. 
Dut not uncommonly individuals are to be found in which wings 3, 6 or 4, 5 
are parallel to the substratum (cf. fig. 10), and in such cases there is a 
prominent papillose protrusion at each end of the cell, due to the fact that 
the principal wings project further at these ends than do the lateral wings; a 
glance at figs. 7 & 9 should make this quite clear. The wings themselves 
are solid extensions of the wall, into which the cell-cavity does not penetrate 
(cf. fig. 11); they are conical in section, being broadest where they arise 
from the main body of the cell and gradually narrowing down to a rounded 
edge (fig. 11). In the side-views of the cell a very faint stratification of the 
solid wings could occasionally be observed, especially in stained preparations. 
At the middle of its longitudinal course each wing is provided with a slight 
but perfectly distinct notch (РІ. 10. figs. 7, 10, 12; Pl. 11. phot. 4), which 
divides it into two symmetrical halves ; this is an absolutely eonstant feature. 
The wings are quite rigid and stand off stiffly and at right angles to the 
surface of the cell ; in a drop of water the cells can be made to roll over 
and over without any apparent bending of the wings taking place. 
The cell-contents of Scotiella antarctica were very difficult to decipher. 
It has been impossible to make out any details as to the shape of the chloro- 
plast, which, however, appears to be single. Staining with iodine or 
hematoxylin sometimes brings out a small round body (figs. 11 & 13), which 
may be either a nucleus or pyrenoid, probably the latter. As a general rule, 
very little or no starch was demonstrable in the cell-contents, although 
occasional cells contained quite a lot, The abundant presence of the yellowish- 
white fat in the contents makes them astonishingly similar to those of 
Chlorosphera antarctica. As in the latter case, the distribution of the fat 
shows considerable diversity. The contents mostly occupied the whole body 
of the cell, and in such cases the granular protoplasm is found in the middle 
* In an optical section, such as fig. 11, there is nothing to distinguish the different wings 
from one another, and the numbering is purely arbitrary for the purposes of description, 
