OXYGEN AND LUMINESCENT!-:. 97 



Radiolaria and Coelenterates it would certainly he worth while 

 to test the luminescence of dinoflagellates, hydroids, sipho- 

 nophora? and medusae in absence of oxygen. Many other higher 

 forms await careful experimental investigation. 



SUMMARY. 



Simple methods for completely removing oxygen from bio- 

 logical fluids are described and indicators for absence of oxygen 

 discussed. 



Most luminous animals require free gaseous dissolved oxygen 

 for luminescence but a few can luminesce without such oxygen. 

 These are the Ctenophores; the medusa, Pelagia noctiluca; and 

 Radiolarians. Pennatulids require oxygen as do all annelida, 

 ophiurians, cephalopoda, copepoda, and balanoglossids tested. 



It is found that in Bero'e and Pelagia the photogenic granules 

 (without cells) luminesce in absence of oxygen, and it is suggested 

 that the proper amount of oxygen for luminescence is bound up 

 in the photogenic granule, and cannot be removed by the drastic 

 methods of oxygen-removal herein described. 



LITERATURE. 

 Clark, W. M. 



'23-'25 Public Health Reports, Washington, especially XL., 1139. 

 Harvey, E. N. 



'17 Amer. Journ. Physiol., XLII., 349. 

 Harvey, E. N. 



'20 Amer. Journ. Physiol., LI., 580. 

 Harvey, E. B. 



'17 Carneg. Inst. Wash., Pub. No. 251, p. 244. 

 Harvey, E. N., and Morrison, T. F. 



'23 Journ. Gen. Physiol., VI., 13. 



