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Rhabditis, Diplogaster and Cephalobus. De Man, who in his 
large Monograph exclusively deals witli the ,,in der reinen Erde 
und im sussen Wasser lebenden Nematoden“ divides these in the 
i 
strictest sense of the word free-living forms, after the different soil 
in which they live. He establishes five groups, namely: 
Om ni vage-Arten, 
Wiesennematoden, 
Sandnematoden, 
Brachwassernematoden, 
Susswassernematoden. 
With the word „Brachwassernematoden 11 de Man indicates 
the forms living in earth, saturated with brackish water; he tells 
himself that the word is an abbreviation of „Brachwassererdenema- 
toden“. This sort of soil which is, of course, fo'und to a great 
extent in Holland has its own fauna containing forms which are 
neither to be found in the sea nor in freshwater. The Sand- 
Nematodes are especially found in dunes; the omnivaging forms 
occur in all sorts of earth besides fresk-water and the sea. A faet 
which would be of great interest to get explored, is the extension 
downwards in the soil of the different species of Nematodes'. It is 
connected with the question of their dependence on the plants and 
could possibly also throw light upon their relation to organic sub- 
stances in the earth as well as to other in the earth living 
organisms. 
As to collecting and preparation I shall notice the following: 
I immediately put the gathered material which has to be examined 
for Nematodes in tin-boxes or in glasses with tight-fitting covers 
or corks; then it will not dry up and the animals will keep living 
for a long time. This summer I have re-examined some of'the 
material which I gathered last summer on a journey in Jutland and 
which has been standing during the winter in such boxes or glasses 
and it proved that it still contained lots of Nematodes besides 
Oligochetes, Tardigrades, Podura and larvæ of Insects, in short 
the whole fauna which is commonly found in such ‘ material, ap- 
