94 



TISSUE RESPIRATION IN INVERTEBRATES 



the transmission of the solvent being set at 

 unity or at 100 per cent. 



stellar nerve (see Connelly, 1952): In cepha- 

 lopod mollusks; this term presumably re- 

 fers to the large nerve trunks that run from 

 the brain to each stellate ganglion; these 

 nerve trunks are usually called the mantle or 

 pallial nerves. 



subumbrella: In jellyfishes; the concave or oral 

 surface of the umbrella (see definition). 



succinoxidase system: An enzyme system that 

 includes succinic dehydrogenase and part of 

 the electron transport system; catalyzes the 

 oxidation of succinate to fumarate and trans- 

 fers the electrons so removed to oxygen via a 

 portion of the terminal electron transport 

 system. 



Thunberg respirometer: A type of differential 

 respirometer. 



tricarboxylic acid cycle: See citric acid cycle. 



triphosphopyridine nucleotide (TPN): Or co- 



enzyme II; a hydrogen acceptor which is re- 

 duced by a variety of substrates in the pres- 

 ence of specific dehydrogenases; in turn, it 

 reduces a flavoprotein. 



umbrella: The gelatinous bell-shaped or disk- 

 shaped structure that comprises the greater 

 part of the body of a jellyfish. 



volumeter: A closed-system, constant-pressure 

 respirometer with two flasks connected by a 

 manometer and with an additional calibrated 

 arm permitting direct measurement of changes 

 in volume that result from respiration in one 

 flask; the second flask serves as a thermo- 

 barometer. 



Warburg respirometer: A single-flask, constant- 

 volume manometer in which the consumption 

 of oxygen is measured as a function of a 

 change in pressure. 



Winkler method: A chemical method for the 

 determination of dissolved oxygen based on 

 the oxidation of manganese. 



