SOURCES OF MARINE FOOD. 
365 
The following table presents in order the classified distribution of total organisms 
of this cross section : 
1 Letter H (low water), September 18, 1894, 2.45 a. m., low-water slack; wind nortli-nortliwest, ) 
) force 2; sky overcast, hazy. ) 
Organisms. 
Surface. 
Middle. 
Bottom. 
Stations 
I 
11 
III 
IV 
V 
Copepods 
24 
9 
5 
7 
9 
7 
6 
9 
Peridinium 
76 
59 
27 
20 
45 
32 
29 
36 
Exuvioslla 
143 
112 
154 
91 - 
103 
52 
79 
84 
Chietoceros 
14 
119 
59 
2 
12 
5 
99 
74 
Melosira 
652 
592 
1, 160 
340 
1,081 
325 
384 
274 
14 
16 
20 
32 
7 
8 
3 
Rhizosolenia 
46 
25 
38 
64 
22 
9 
4 
10 
Navicula 
58 
68 
89 
34 
63 
39 
33 
46 
Total 
1,003 
991 
1. 547 
583 
1,333 
470 
628 
527 
Average temperature (°F.) . . 
68.1 
69 
69 
69. 1 
69 
Depth (fathoms) 
4 
7.5 
7 
0 
4 
From this table the irregularity of distribution is plainly illustrated, this being 
the first instance in which the surface organisms have not exceeded in quantity the 
mid-depth or bottom. This is evidently due to a withdrawal of organisms from the 
surface, while the peculiarly obscured condition of the light may be held responsible 
for the failure to become as regularly localized as is usual, as well as for the change 
from the ordinary daytime vertical arrangements in such a way as to well illustrate 
the effects of heliotropism, or rather the lack of the same, for the influences of so 
little light would produce weak results except in such organisms as the freeswimming 
larvie or copepods. This is well shown by the copepods, for in this cross section taken 
at nighttime 85 per cent of the whole number observed are found at the surface, while 
in all the other observations, taken as they were at daytime, only 52 per cent on an 
average were found at the surface. The night in question was unusually dark, 
with a thick haze, and in the shallow water of this bay the much disturbed verti- 
cal distribution would be expected except in the case of such organisms as the 
copepods, which can most easily change their location in the water, and are known to 
be so abundant normally at the surface during the nighttime. It is also fair to sup- 
pose that even the normal nighttime distribution would be materially affected by such 
extreme darkness as was experienced upon this course. 
This same section was retaken on the following forenoon and on high tide water 
with results represented by the following table : 
Letter H (high water), Sept. 18, 1894, 10.35 a. m., liigk-water slack; wind NE., force 3; sky cloudy. 
Organisms. 
Surface. 
Middle. 
Bottom. 
Stations. 
I 
XI 
III 
IV 
V 
Copepods 
10 
5 
4 
9 
2 
1 
3 
4 
Peridinium 
100 
46 
43 
3 
64 
23 
5T 
42 
141 
132 
1 13 
40 
162 
73 
44 
67 
ChEetoceros 
102 
81 
39 
16 
32 
9 
21 
144 
Melosira 
550 
408 
485 
234 
428 
302 
281 
198 
Lauderia 
4 
7 
24 
11 
12 
8 
3 
1 
Phizosolenia 
40 
44 
31 
12 
20 
21 
6 
6 
Navicula 
54 
59 
87 
49 
47 
27 
40 
37 
Total 
991 
777 
822 
365 
815 
463 
452 
495 
68. 3 
68. 5 
69 
69 
69 3 
Depth w (fathoins ) 
4.5 
8 
7.5 
7 
5 
