686 
Frit sc h and Haines.—The Moisture-relations 
Hormidium ftaccidum the minimum was 2*5 per cent., but with a 5 P er 
cent, solution contraction was little marked in the granular cells (cf. 
below). 
Table I. 
Comparison of plasmolysis of identical material of various terrestrial 
forms in different strengths of sea-salt. 
Material. 
Expt. 
No. 
Cells 
counted. 
Strength 
of sol. 
O/ 
Strongly 
J plasmolysed . l 
Of 
Slightly 
plasmolysed} 
0/ 
Unaffected. 
°/ 
Zygogonium 
XVI 
1,104 
/o 
3 -o 
fo 
1.9 
Zo 
6o*6 
Zo 
37 * 6 
55 
1,185 
4.0 
12.9 
61.7 
25.2 
J 5 
yy 
1,226 
5 -o 
71.8 
16-7 
11.4 
Hormidium 
11 
4 2 3 
3 -o 
°*7 
37*3 
61.9 
>> 
1 ) 
757 
5 *° 
20.9 
68.6 
10.6 
J 7 
y y 
1,023 
3 -o 
45*8 
32-7 
21 *6 
?? 
yy 
I , OI 9 
5 *° 
91-2 
3-6 
5 * 2 
Prasiola 
XXVII 
382 
10-0 
7*6 
54*2 
38*2 
yy 
L 449 
20-0 
74-6 
11*0 
I 4*4 
Protonema 
XV 
811 
3 -o 
1 7.8 
6o* 1 
22.2 
yy 
yy 
851 
4 *o 
62*8 
247 
12-6 
yy 
yy 
764 
5 *o 
VI 
9 
6 
17-8 
I 2*2 
Plasmolysed. 
0 / 
Unaffected. 
V 
Pleurococcns 
VII (1) 
687 
T 5 ‘° 
/o 
27T 
/o 
72-9 
>> 
yy 
661 
17-5 
39 -o 
6 i*o 
»? 
yy 
669 
20*0 
39’9 
6o*i 
>> 
yy 
643 
2 2*5 
50 * 1 
49*9 
y y 
645 
25*0 
50-2 
49*8 
j > 
VII (2) 
1,002 
15-0 
i 9'9 
8o*i 
y y 
yy 
1,007 
I 7‘5 
22*5 
77-5 
yy 
yy 
1,004 
20-0 
26*9 
73 * 1 
yy 
yy 
1,003 
2 2*5 
33-6 
66-4 
yy 
yy 
J, 5°2 
25*0 
457 
54*3 
Many of the cells of these terrestrial algae include larger or smaller 
numbers of highly refractive granules, which appear in part at least to 
be fatty in nature (cf. p. 721). The feature in question is often so marked 
that one can broadly classify the cells in a given mass of material into 
‘granular’ and ‘non-granular’; a classification often employed below. 
In the filamentous forms whole threads may be granular, non-granular, 
or mixed. The granular cells, as found in nature, differ somewhat among 
one another in character, some containing more or less uniform, rather 
evenly distributed granules, others such as are of very unequal size and 
often very uneven shape. But one of the most distinctive types of granu¬ 
lar cells—apparently especially prevalent during mild periods of drought in 
1 In many cases it has been found desirable to distinguish between £ strongly plasmolysed ’ and 
‘ slightly plasmolysed’ cells, the latter being those in which only a slight shrinkage of the proto¬ 
plasts away from the corners of the cells was recognizable. The distinction is somewhat arbitrary, 
but in practice not difficult to draw. It was, however, impossible to make the distinction in the 
unicellular forms owing to the small dimensions of the cells. 
1 
