234 



Comparative Animal Physiology 



class may show considerable variation in cyanide sensitivity; Fundnliis eggs are 

 particularly resistant to cyanide and azide in concentrations which are very 

 toxic to the pelagic eggs of the cunnar, mackerel, and scup.-"*- With develop- 

 ment, however, the Fundidus eggs too become sensitive to the respiratory 

 poisons, indicating a change in respiratory pattern. Frog eggs can cleave under 

 anaerobic conditions to form blastulae, but oxygen is necessary for complete 

 gastrulation and subsequent development.^"^ Cyanide sensitivity in Para- 



4000 



9000 



u 2000 



300 



200 



2 4 6 8 10 12 14 16 



TIME IN DAYS 



Fig. 52. Oxygen consumption during larval and pupal development in the honeybee, 

 showing the increased rate ot the queen compared with that of the workers, on both a 

 weight (upper curves) and an individual (lower curves) basis. P, time of pupation. 

 After Melampy and Willis.^"'' 



mecium may be correlated with food supply, well-fed (younger) individuals 

 being more sensitive than starved (older) animals.-^" 



Total metabolism is of course the sum of the individual tissue metabolic 

 activities, and it is not surprising that certain tissues show a variation in oxygen 

 consumption with age. Investigations on the gill tissues of Venus are con- 

 sistent with the bulk of the literature in demonstrating that tissues of younger 

 animals respire at a higher rate than do those of older animals.^''- However, 



