END OF THE EXPERIMENT. 233 



Several BerpiilcB. 



Acarida. 



Entomostraca. 



Infusoria. 



Grantia nivea. And other smaller zoophytes and 

 sponges which I could not identify. 



Soon after this examination I went on a journey, 

 and did not return till the 7th of July. The weather 

 had set in very hot : whether this, combined with the 

 closeness of the room, had had any effect I do not 

 know; but on my return I found the water beginning 

 to be offensive, a sort of scum forming on the surface, 

 and the animals evidently dying. Some were already 

 dead, but most of the others recovered on being 

 removed to fresh sea-water. This result, though it 

 puts an end to my experiment at this time, I do not 

 regard as conclusive against the hypothesis ; for of 

 course animals are liable to death under any circum- 

 stances, and the corrupting body of one of these in so 

 limited a volume of water would soon prove fatal to 

 others, even though there might be no lack of oxygen 

 for respiration. It is possible that one of the large 

 Actinim may have casually died during my absence, 

 the timely removal of wliich might have averted the 

 consequences to the others ; but this is only conjec- 

 ture. Perhaps there was too large an amount of 

 animal life in proportion to the vegetable ; but the 

 maintenance of all these in health and activity for 

 nearly nine weeks seems hardly to agree with such a 

 supposition. 



Should these experiments be perfected, what would 

 hinder our keeping collections of marine animals for 



