356 JOHN F. FULTON, JE. 



the eighth day the third specimen, which had shriveled to about 

 one-tenth its normal size, was placed in water, and, though more 

 slowly, it too revived." Several other specimens were placed 

 in direct sunlight (out of contact with water) ; they lived but four 

 days. It would seem, therefore, that death occurs as soon as the 

 water in the gastrovascular fluid has disappeared. This obser- 

 vation brings up many interesting problems which would well 

 repay further investigation. In the first place, an anemone out 

 of contact with the water cannot obtain food. How long, then, 

 can an actinian live without food? Does the anemone ingest 

 the Zooxanthellae themselves, as Keeble and Gamble ('07) have 

 shown to be the case with the green cells in the turbellarian worm 

 Convoluta roscoffensis? Since it is known that the internal 

 fluids of nearly all of the marine invertebrates are isotonic with 

 the sea-water in which they live (Fredericq, '85), what occurs 

 when the gastrovascular fluid of a sea-anemone evaporates; does 

 the saline concentration increase, as one might expect, or does 

 the organism possess some compensatory mechanism for pre- 

 venting such an increase? 



The control specimens, which were placed in the dark room, 

 survived a period of six days without water, and at the end of that 

 period showed a degree of vitality which was as great as, if not 

 greater than, that of the corresponding ones in the hght. 



This, again, throws doubt upon the symbiotic character of the 

 organisms which are harbored in the gastrovascular fluid, and it 

 also gives fair indication that life continues so long as there is 

 sufficient water present to carry on the metabohc activities. 



From the two experiments just recorded it was at once evident 

 that A. bermudensis is capable of existing upon a remarkably 

 small amount of oxygen, since the animal remained alive for six 

 days upon the quantity of oxygen which is normally dissolved in 

 100 cc. of water. 7 It was therefore of interest to see how long an 

 animal could exist in the complete absence of oxygen. 



6 It died, however, the following day. 



^ In this connection it may be noted that, according to Vernon ('96), the 

 respiratory exchange is lower for coelenterates than for any other group of ani- 

 mals, save possibly certain ascidians. For further details see Krogh's ('16, p. 

 144) monograph on the respiratory exchange of animals. 



