ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
583 
collected. Fig. 49 a shows the mouth of the net closed. By letting 
fall the weight G f , the lever H' releases the bolt R', which in turn 
releases the ring r', and so opens the mouth of the net as shown in 
fig. b. The mouth of the net, which has a width of 30 cm., is made of 
hinged metal bars V Jcl, contained in the sliding frame Vs. To close 
the net again, the larger weight G" is let fall ; this, through the lever 
R" and bolt R", releases the ring r", when the portion Ys of the sliding 
Fig. 49. 
frame falls down. The weights G' and G" are made in two parts, so 
that they can be put on the cable and then bound together by wire 
round the grooves shown in the figure. The author has used this net in 
the Traun Lake in Upper Austria, and finds that the plankton is not 
evenly distributed in depth, but shows a distinct zoning, the depth of 
which varies with the time of year and day. The apparatus could be 
slightly modified for deep sea purposes. 
1897 r 2 S 
