Oxygen and Carbon Dioxide Transport by Blood Containing Haemocyanin 



branchial artery. Redfield and Goodkind 1 (1929) determined the gas 

 content of arterial and venous blood of the squid and found that the 

 blood delivers to the tissues practically all the oxygen acquired in the 

 gills, while the shift in pH accounts for about 30 per cent of the total 

 amount delivered. 



100 



Figure 6. Oxygen dissociation curves of ink fishes 



Octopus vulgaris t 14° (Wolvekamp) 



Sepia officinalis t 14° t 20° 



(Wolvekamp, Baerends, Kok and Mommaerts 5 ) 



Loligo vulgaris • — t 20° ( „ ) 



Loligo pealei / 23° (Redfield and Ingalls 1 ) 



The acquisition and distribution of oxygen in the cephalopods is 

 furthered by a highly developed circulatory system and an efficient 

 respiratory mechanism. The utilization of the oxygen dissolved in the 

 respired water may amount to 80 per cent 11 . In collaboration with 

 Mrs. J. Baerends-van Roon I determined the respiration volume of 

 resting cuttle fish. The animals were clamped in a specially devised 

 stand. A glass canula was tied into the funnel and connected with 

 rubber tubing of a very wide bore in order to collect the total quantity 

 of expired water. At a temperature of 15°-17°C animals of about 

 500 gm weight would respire 300-600 cm 3 of water in one minute. 



We determined the oxygen consumption in well aerated water and 

 found that animals of tins size would consume about 100 cm 3 per kg 

 per hour when at rest, that is about the same amount as used by some 

 fresh water fish, while man at rest consumes twice as much. Redfield 

 and Goodkind found for the American squid an oxygen consumption 

 about six times higher than that found by us for Sepia. 



By what means do Sepia and Loligo succeed in transporting these 

 rather considerable quantities of oxygen to their tissues ? We have 

 seen that the respiratory mechanism is efficient. Is the transporting 

 system as efficient ? In the first place it must be pointed out that the 

 oxygen capacity of the blood, though higher than that of other inverte- 



307 



