364 . Prof. Ehrenberg on the Microscopic Life 
Cymboplea, and Phalarina amongst the Diatomexe; Chetotrochus 
amongst the Polythalamia; and Lithosema amongst the Phyto- 
litharia. 
In all, there are 29 forms out of the 154 which have never 
been observed elsewhere by me; namely, 15 Polygastria, 11 
Phytolitharia, 1 Polythalamion and perhaps more, and 2 Rota- 
toria. Of these 18 are independent organisms. 
If they be divided into terrestrial and marine forms, 48 out of 
the 154 organic forms belong to the sea, the remaining 106 being 
land and freshwater organisms. 
As Tardigrada and Rotatoria were to be detected in some of 
the specimens, I immediately tried with great care whether they 
would give any signs of life in water, or whether they could 
be brought to full vital activity, which has usually been erro- 
neously described as a resuscitation from death. The dry mate- 
rials, which were collected in December 1857, and reached me 
in 1861, and were consequently more than three years old, ex- 
hibited no signs of vitality in any of the forms in which these 
were expected, although in previous experiments with materials 
from other localities I had been able to observe life still retained 
even for four years. We can revive no dead organisms, even 
the smallest ! 
There is, however, no doubt that the independent microscopic 
life of the island cannot be regarded as completed by these 
76 independent forms. By observations quietly and specially 
directed to them, the stagnating snow and rain-water or the 
muddy earth, however little it may strike the eye, may present 
numerous other forms which disappear after death, as I found 
to be the case in the deserts of Africa forty years ago. 
Of the 76 independent minute forms, 8 are shelless animals 
(Anguillule, Rotatoria, and Tardigrada), 13 Arcellina with mem- 
branous carapaces, 40 silicious-shelled (Diatoms and Polycys- 
tina), and 15 calcareous-shelled (Polythalamia and Bryozoa). . 
Several of the independent forms bearing silicious shells are 
very numerous in their localities; but there exists no Kiesel- 
guhr, tripoli or polishing-slate formed by them. On the con- 
trary, the so-called humus-soil is formed principally of the 57 
silicious particles of grasses, some, however, with Naviculacee. 
As, according to the investigations of the botanists of the 
expedition, there were only 11 indigenous Phanerogamiec plants 
and only 7 grasses upon the island, the whole of the 57 silicious 
particles of grasses which form the upper soil under the turf 
are undoubtedly derived from these 7 grasses. The few isolated 
Spongolithes belong to the sea, and never contribute much to the 
mass. 
The grassy soil or humus, which in the upper parts of the 
