450 
a small lead to the line also when using the apparatus in smaller 
depths. 
In my opinion this apparatus will be indispensable for the student 
of such groups as Free-living Nematods, Ostracods, bottom-Cope- 
pods, Cumaceans etc.; upon the whole we will, no doubt, thereby 
obtain a much fuller knowledge of the small, more or less micro- 
scopical organisms which inhabit the upper layer of the sea-bottom, 
be it now a soft, muddy, or a hard, sandy bottom. (On a rocky 
or stony bottom the apparatus cannot be used). As regards the 
exact quantity of these organisms the apparatus will, of course, give 
a wrong conception, just as the dredge or the trawl gives an 
unreliable conception of the quantity of the larger organisms. For 
the exact, quantative study of the bottom-organisms Dr. Peter- 
sen’s bottom-grap is and remains the means. But for the qualita- 
tive study of the smaller organisms of the sea-bottom the present 
apparatus will, I think, be as indispensable as is the dredge or trawl 
for the qualitative study of the larger organisms of the sea bottom. 
That the apparatus will be fit for using also in fresh-water I 
should think beyond doubt. I have had no opportunity, however, 
for testing itin greater depths in fresh-water. A single trial in shallow 
water (in the Tjustrup lake, at Sorø, at Professor Wesenberg 
Lund’s laboratory) did not give any noteworthy results; but con* 
ditions happened to be so exceptionally unfavourable, that it is 
hardly justifiable to draw any conclusions from that single experi- 
ment. 
The silk gauze which I have used for the net is No. 10; this 
1 have found very practical for sifting off the fine detritus and 
mud, so as to get the organisms as pure as possible. No doubt, 
however, a lot of minute organisms go through the meshes of the 
gauze of so coarse a number; but it is, of course, easy to use 
nets of various fineness, just as in plankton nets. Also it will be 
easy to make the apparatus of any desired size. (The size which 
I have used is this: length of plates 50 cm, breadth 35 cm). 
The apparatus described above was constructed especially for 
folding together, so as to be easily carried; when that is not espe¬ 
cially desired, the fixing of the plates may be made permanent, 
and more simple. It may also be suggested that, for the sake of 
securing the silknet against being torn or too much worn, it 
