Phosphorescence in Ctenophores. II5 



SUMMARY. 



1. The dead matter originating from ctenophores is not 

 phosphorescent, i. e., only Hving ctenophores or parts of them 

 phosphoresce. 



2. Phosphorescence appears along the rows of paddle plates 

 and no phosphorescence was obtained from jelly free from paddle 

 plates. 



3. The smallest piece from which phosphorescence was 

 obtained consisted of four connected paddle plates. 



4. Movement of the paddle plates is not always accompanied 

 by phosphorescence. 



5. No phosphorescence was obtained from the excised 

 auricles having cilia but no paddle plates. 



6. The sense-organ is not phosphorescent. 



7. Phosphorescence does not depend upon correlation of the 

 part with the sense organ. The sensory-motor circuits for phos- 

 phorescence are local in character. 



8. No phosphorescence could be obtained from the eggs of 

 Mnemiopsis before segmentation. 



9. The early cleavage stages (without cilia) are phosphores- 

 cent. 



10. Gastrulae (ciliated) are phosphorescent, as are also all 

 stages in which paddle plates are present. 



11. The phosphorescence of embryos is easily exhausted. 



12. The deposition of eggs can be retarded by light. 



13. Direct sunlight prevents the appearance of phosphores- 

 cence, but in darkness, the power to phosphoresce upon stimula- 

 tion, is acquired. 



14. Direct sunlight inhibits a previously acquired power to 

 phosphoresce. Diffuse daylight of sufficient intensity has the 

 same effect. 



15. Phosphorescence has a proportionate relation, in a nega- 

 tive sense, to the intensity of light. 



16. Mechanical stimulation accelerates the appearance of 

 phosphorescence in darkness. 



17. Non-phosphorescent ctenophores do not become phos- 

 phorescent by mechanical agitation alone. 



18. Long-continued mechanical stimulation reduces the inten- 

 sity of phosphorescence but does not easily inhibit the phenomenon 

 entirely. 



