. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN WATER 37 of pleopods. The frequency of this beating has been studied repeatedly (F. Peters, 1938; Fox and Johnson, 1934), and Lindroth () succeeded in placing a crayfish so that the flow could be measured (Fig. 12). The curve, Fig. 13, shows the effect of oxygen concentration upon the ventilation. At high oxygen concentrations in the water down to about atmospheric tension the effect is slight only, but at lower concentrations the ventilation rises abruptly, and the animal is characterized as dyspnoeic wh
. The comparative physiology of respiratory mechanisms. Respiration. RESPIRATION IN WATER 37 of pleopods. The frequency of this beating has been studied repeatedly (F. Peters, 1938; Fox and Johnson, 1934), and Lindroth () succeeded in placing a crayfish so that the flow could be measured (Fig. 12). The curve, Fig. 13, shows the effect of oxygen concentration upon the ventilation. At high oxygen concentrations in the water down to about atmospheric tension the effect is slight only, but at lower concentrations the ventilation rises abruptly, and the animal is characterized as dyspnoeic when the exertion. kzzzzzzzzzzzzzzzz; V///.V/////////ZZ? Fig. 12. Determination of ventilation in the crayfish. A, box with one rubber wall; B, fixation plate; C, connections to flow meter; D, aeration. (Lindroth.) of breathing is a conspicuous item in the general behaviour. It is a very characteristic feature that the utilization of the oxygen is only slightly reduced in dyspnoea. In one case, for instance, the oxygen concentration was reduced in the passage through the gill chamber from ml/1 to when the ventilation was 6 ml/minute, a utilization of 70%, while in another with a ventilation of ml/min it was reduced from to , a utilization of 59%. Somewhat lower utilizations, 49% on an average, were observed by Hazelhoff (1938) on a number of marine Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Krogh, August, 1874-1949. Philadelphia, University of Pennsylvania press
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