ON THE LUMINESCENCE OF MICROSCOLEX 

 PHOSPHOREUS DUG. 1 



STANISLAW SKOWRON. 



FROM THE ZOOLOGICAL STATION, NAPLES, ITALY, AND THE BIOLOGICAL 

 LABORATORY OF THE UNIVERSITY, CRACOW, POLAND. 



In spite of several papers describing observations on the 

 luminescence of different species of earthworms, there are still 

 some uncertain points which deserve further investigation. In 

 Mangold's ('14) article, which discusses thoroughly the power of 

 luminescence in all groups of plants and animals, the conclusions 

 lead to the assumption that the production of light in these 

 animals is due to infection by luminous microorganisms or fungi, 

 which may be present in places where earthworms obtain their 

 food. Dubois ('14) and Linsbauer ('17) were unable, however, 

 to show in the luminous slime any luminous microorganisms, 

 which is a strong argument against the view of the bacterial 

 origin of luminescence in this group of the animal kingdom. 

 Gilchrist ('19) working on the South African earthworm species 

 Chilota, describes many observations and experiments which 

 seem to show that the luminescence in this species is not bacterial. 

 Quite recently, however, Pierantoni ('24), according to his 

 "hereditary symbiosis theory," believes that Microscolex phos- 

 phoreus owes its luminescence to symbiotic bacteria living inside 

 the cells of its body. It is the purpose of this paper to show 

 how the luminescence in Microscolex originates, and which 

 opinion rests upon a sounder basis. 



OBSERVATIONS AND EXPERIMENTS. 



Microscolex phosphoreus- a small earthworm with clitellum 

 situated near the anterior part of the body is easily to be found 

 in Naples and its environs. If the animal be kept undisturbed, 

 one cannot observe the production of luminous slime, which is 



1 This work was done while holding the International Education Board Fellow- 

 ship. 



" I wish to thank Mr. G. E. Hutchinson for his help in identifying the earthworms. 



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