but they were all inactive or depressed (Table 28), None showed nor- 

 mal behavior. 



Combinations of extreme salinity and temperature test conditions 

 caused the shrimp to undergo some unusual contortions. Normally, in 

 the resting posture the pleopods extend forward with the exopodites 

 angled down. But in 2.5°/ooS some shrimp rested with the exopodites 

 curled forward, while in 42,5°/ooS the exopodites were angled back- 

 ward with the tips curled up. This was noticed in animals acclimated 

 to 5 and 10°/ooS. Abdominal cramps were seen in both test salinity 

 and temperature combinations. Some shrimp were also cramped in the 

 control salinities (5 or 10°/oo) at 18° but not at 32°C. 



In 5 or 10°/ooS most of the shrimp survived but they were in- 

 active. There was a higher mortality at 32" than in 18°C, 



Oxygen Consumption in Deviated Ion Media 



The respiratory rates of brown shrimp were determined in rela- 

 tion to deviated ionic ratios of calcium, magnesium, and potassium 

 in the seawater. Within the concentration levels used in our studies, 

 sodium had no apparent adverse effect on the behavior or survival of 

 shrimp during a 24 hour period. Therefore, sodium was excluded from 

 these studies. 



Oxygen consumption in synthetic seawater 



Oxygen consumption rates were determined at test temperature 

 18°, 25°, and 32°C by directly transferring brown shrimp from 15°/ooS 

 and 25°C, The control test medium (15°/ooS) was prepared with syn- 

 thetic sea salt and contained the normal ion ratios. The purpose of 

 these experiments was to determine whether the respiratory rates ex- 

 hibited significant differences from the rates in natural salt water. 



265 



