220 
bulletin of the bureau of fisheries. 
In another experiment an oyster was kept three days in the first desiccator full of 
pumped-out water, three days in the second, two days in the third, two days in the fourth, 
and two days in the fifth. By that time it was black and unable to close properly. 
After a few hours in the aquarium it showed disintegration, so that twelve days of life 
in oxygen-poor water proved fatal. Time and facilities for carrying out many of these 
experiments were missing, although the seven-day experiment was practically dupli- 
cated by one in which an oyster was kept in the same desiccator full of water six days 
with no ill effects. That the fatal effect of a twelve days’ exposure was not due to 
insufficient renewal of the water was shown by control experiments in which several 
oysters were kept in the same water during fourteen days while air was bubbled through 
it. The oysters survived this treatment uninjured. 
OXYGEN REQUIREMENTS OF CLAMS. 
Measurements on clams were made by the same method used for oysters. The 
results of successful experiments are embodied in table vi. They show a general agree- 
ment with measurements on oysters. The amount of oxygen used by clams weighing 
about 6o grams is somewhat higher per loo grams than that used by an oyster of about 
the same weight and observed at the same temperature. Computed per gram of dried 
shell contents, however, the oxygen requirements of the clam seem somewhat smaller 
than those of the oyster. Here, as with oysters, the amount of oxygen used is more 
or less proportional to increase in the temperature, though sufficient data to show a sim- 
ple relationship were not obtained. In this case, also, the oxygen requirement per gram 
is less in the larger individual than in the smaller, again like the oyster. 
Table VI. — Oxygen Used by Clams. 
Note. — F igures in parentheses are averages of measurements under approximately uniform cx>nditions. 
Weight 
whole 
clam. 
DecimilUgrams of oxygen used 
per hour. 
Averages of same per hour per 
100 grams. 
Weight 
dried 
clam. 
Average mgr/io used per hour 
per gram, dried weight. 
At 20° to 
21° c. 
At 22® to 
22.5® C. 
At 24® to 
24-5’ C. 
At 20® to 
21® C. 
At 22® to 
22.5® C. 
At 24® to 
24 .S*C. 
At 20® to 
21® C. 
At 22® to 
22.5® C. 
At 24® to 
24.5^ c. 
Grams. 
7.0 
19- 5 
21.0 
28. 0 
57-0 
57-5 
60. 0 
63. 0 
I. 2 
3-0 
(2. i) 
5-19 
9.2 
6 . 7 
(7-9) 
8.2 
II. 0 
12.4 
(ii- 7) 
29. 6 
26. 7 
26. 9 
29-3 
20. 7 
Grams. 
9-7 
iS-i 
49-7 
77-4 
1.32 
3-93 
7- 35 
11.4 
17. 2 
19- I 
30*0 
30*0 
31 - 9 
52. 2 
3-97 
■ 4-34 
7 -SS 
17 - 7 
15-2 
(16.4) 
25.8 
