Il6 A 7710 s W. Peters. 



19. Darkness accompanied by mechanical stimulation is at 

 least one combination of conditions which produces phosphores- 

 cence, but these two factors acting singly cannot produce this 

 result. 



20. The phenomenon of phosphorescence was observed at 

 temperatures ranging from about 9° C. to 37° C, with an optimum 

 at or near 21°. 5 C, the temperature of the sea-water. 



21. The intensity of phosphorescence diminishes as physiologi- 

 cal extremes of temperature are approached. 



22. The phosphorescence of Mnemiopsis is probably a meta- 

 bolic reaction which is dependent upon the formation of a sub- 

 stance in darkness the katabolism of which takes place upon 

 mechanical stimulation and becomes evident to observation as the 

 energy of light. 



BIBLIOGRAPHY. 



Agassiz, a., '74.— Embryology of the Ctenophorae. Mem. Amer. Acad. Arts and 



Sci., vol. X, pt. 2, no. 3, pp. 357-398, 5 pi. 

 Allman, G. J., '62. — Note on the Phosphorescence of Beroe. Proceed. Roy. 



Soc. Edinburgh, vol. iv, no. 57, pp. 518-519. 

 Chun, C, '80. — Die Ctenophoren des Golfes von Neapel und der angrenzenden 



Meeres-abschnitte. Fauna und Flora des Golfes von Neapel. 



Monographic I. xvii + 313 pp., 18 Taf. 

 Panceri, p., '72. — La luce e gli organi luminosi dei Beroidei. Atti R. Accad. 



Sci. fis. e mat. Napoli, vol. v, no. 20, 15 pp., i tav. 



