Centimeters 



Figure 183. — Metabolism chamber for determining the oxygen uptake of an oyster kept in continuously renewed filtered 

 sea -water. A — respiratory chamber (for details see figure 184); B — glass coil (placed horizontally on bottom) to 

 bring the sea water to a desired temperature; C — constant temperature water bath; D — thermometer for recording 

 the temperature of water before it enters the respiratory chamber; E — thermometer for recording the temperature 

 of water in the bath; F — slow-motion kymograph; G — supply of filtered sea water of known oxygen content; H— 

 constant level tank which regulates the flow of sea water through the chamber; I — T-tube connection leading to the 

 sampling cylinder; J — two-way stopcock; K — two sampling cylinders which receive water from the respiratory 

 chamber; I, — sampling cyhnder which receives sea water directly Irom supply G; M — water bath in which the sampling 

 cylinders are suspended; N — counter weights to balance the sampling cylinders; O — capillary tubing for regulating 

 the rate of flow of sea water. Constant temperature regulator, heater or cooler in bath 0, are not shown. 



short strokes directed away from the edge of the 

 shell to avoid accidental sealing of the valves. 

 After careful examination and removal of superflu- 

 ous paraffin the oj'ster was placed in the oval 

 respiratory chamber (figure 184), which was built 

 of hea\^ plastic with a removable slanted top (E) 

 kept in place by two metal clamps (F). The 

 capacity of the chamber, which rests on two heavy 

 lead bars, is about 800 ml. When it is in opera- 



tion, filtered sea water of known oxygen content 

 is delivered through inlet B and is discharged 

 through outlet C on the top. 



The chamber is filled with filtered sea water, 

 the oyster is placed inside, and the cover clamped 

 down. All air bubbles are carefully evacuated. 

 To record the shell movements a glass test tube 

 (H) is lowered through the wide neck of the 

 cover E until it rests on the oyster valve; the 



202 



FISH AND WILDLIFE SERVICE 



