492 Wisconsin Academy of Sciences, Arts, and Letters, 
Table 16. The average number of individuals per square meter at the 
various depths in the intermediate zone and at the regular stations. The 
data for the 5- -7- meter region are taken from Muttkowski’s table 5 
a, p. m>. 
Depth, 
Meters 
Number of 
Samples 
Oligochaeta 
Pisidium 
Chironomus 
Oorethra 
Protenthes 
5-7. 
10 
19 
15 
10 
24 
8... 
21 
311 
157 
519 
747 
280 
9.. 
24 
805 
374 
291 
2,907 
196 
10..... 
27 
1,004 
330 
557 
1,005 
370 
11. 
16 
1,321 
413 
953 
3,930 
200 
12. 
21 
1,253 
230 
716 
1,800 
340 
13. 
13 
1,535 
286 
1,409 
1,470 
130 
14. 
5 
2,215 
502 
1,220 
3,720 
202 
15. 
18 
1,750 
380 
1,815 
3,430 
350 
16. 
9 
2,466 
420 
1,585 
4,830 
359 
17. 
5 
4,148 
295 
2,203 
10,500 
240 
18. 
31 
2,370 
416 
2,300 
5,500 
195 
19. 
3 
2,785 
605 
1,972 
5,850 
260 
20. 
17 
2,800 
506 
1,650 
7,630 
195 
8-20. 
210 
1,485 
352 
1,200 
3,460 
258 
Sta. I..... 
64 
2,320 
570 
871 
5,571 
432 
Sta. II.... 
95 
3,000 
600 
549 
12,890 
191 
Five sta... 
263 
3,500 
557 
593 
10,830 
185 
