388 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



animals in turn fed upon microscopic plankton or upon 

 vegetation along the shore or an the sea-bottom. 



In order to approach the matter more closely, it 

 became desirable to estimate in several types of marine 

 animals the daily rate of oxidation and output of carbon- 

 dioxide necessary for the maintenance of the animal, so 

 as to arrive at the daily food quantity necessary in each 

 case. 



In the previous paper observations of this kind were 

 made in the case of Sponges, Ascidians, Aplysia, Eusus, 

 Buccinum, Echinus, Asterias, Cancer, Eupagurus, and 

 Blennius (a small fish). It was impracticable at that stage 

 in our work to continue the experiments for a period of 

 much over 24 hours, the maximum period of observation 

 in one case being 48 hours. Also, as no suitable large 

 glass reservoirs were then available, the amount of 

 dissolved oxygen of the sea-water in which the animals 

 were immersed, in certain cases where more active animals 

 were concerned, fell to a very low figure, indeed almost to 

 zero. 



These preliminary experiments yielded remarkable 

 results as to the minute amounts of respiratory oxygen 

 upon which marine animals can subsist for a rather 

 prolonged period, but, so far as our immediate quest is 

 concerned, can only be taken as demonstrating the 

 respiratory exchanges during the initial hours in a limited 

 supply of sea-water, and, while giving an approximate 

 idea of the rate at which such animals oxidise their food 

 supply, do not give clear figures as to results over pro- 

 longed periods when there is a sufficient supply of oxygen 

 maintained in the water. 



Other results of bio-chemical interest were observed 

 in this shorter initial period with rapidly decreasing 

 oxygen supply. It was found, for example, that a large 



