CHROMATOLOGICAL RELATIONS OF SPONGILLA FLUVIATILIS. 49 
occurs in the case of many plants, the yellow chorophyll 
cannot be partially separated from the blue chlorophyll, both 
in the case of Spongilla and of many lichens. The relative 
quantity of the xanthophyll and yellow xanthophyll was 
determined by the difference in the position of the absorp- 
tion-bands, and also by the greater or less amount of the blue 
product of the oxidization of yellow xanthophyll, formed 
when the solution was treated with a little hydrochloric acid 
and nitrite of potash. The lichnoxanthine was estimated 
from the final residue after the xanthrophylls had beea 
destroyed and rendered colourless by the slow action of citric 
acid and nitrite of potash. By such means and others 
described in my paper on comparative vegetal chromatology 
I have been able to draw up a table, giving, with approximate 
accuracy, the relative amounts of the different coloured con- 
stituents ; but on the present occasion it seems to me better 
not to give the percentages, and to express the general results 
by means of the following symbols :— 
A relatively large quantity . . ‘ ee: 
A relatively moderate quantity . 3 - » ot 
A relatively small quantity . ° 
A relatively mere trace 
Table of the relative amounts of the various coloured con- 
stituents insoluble in water, that of the xanthophyll being 
taken as nearly constant. 
i ea ane 
| = = n a 
a lela Spent ls 
Bie bel te Ble 
Sele ye |, vehi jiBwle Gd 
Sue enue Shen: 
a al ° Lat ee ie A 
Highest classes of plants— 
Development perfect * | + + |x 
Development incomplete . a i (OS I 
Development still more incomplete . : ey |ae) |e 
Spongilla— 
The external deep green part . * | e e 22 || 4p || o 
The internal yellowest part + |e *x | +i + 
Lichens— 
Very green species . * |e ° ea) ise) ae 
Less green species . +]: * | + | x 
Alga— 
The green group * | * | +)e% | +i: 
The red group + : * C 
VOL. XV.—NEW SER. D 
