2O6 STANISLAW SKOWRON. 



be taken as a different type from the external one. Pierantoni's 

 view, which explains the internal luminosity as the continual 

 glowing of the symbiontes inside the cells of the different tissues 

 of the body, seems to me, therefore, a very improbable hypothesis. 



DISCUSSION. 



Summing up all the characteristics of the luminescence of 

 Microscolex phosphoreus (the role of the nervous system, the 

 effect of ether, temperature, the luminosity of desiccated worms) 

 we can see that they do not agree with the observations on the 

 properties of bacterial light but point to a luminescence of its 

 own in this species of Oligochxta. It is very improbable that the 

 luminous symbiontes may change their type of luminescence so 

 completely as to behave like such animals as Cypridina, Pholas, 

 Noctiluca and others, especially as the luminous bacteria living in 

 luminous organs in some fishes and Cephalopods do not show such 

 differences, though their shape may be modified. Microscolex 

 and Chilota are therefore at least two earthworm species which 

 are certainly not infected with luminous bacteria. Allolobophora 

 Jcetida (Vejdowsky) however may be occasionally infected by 

 microorganisms or fungi, as only a few luminous specimens 

 were found. 



As I have mentioned before, the luminous material in Micro- 

 scolex consists of small granules which usually begin to glow after 

 the slime has been discharged. 11 the animal be dying however, 

 they become luminous within the body cavity. It may be 

 thought that the luminescence of the granules depends on an 

 amount of oxygen which is not present in sufficient quantity in 

 ccelomic fluid. If the worm be dying the amount of oxygen 

 may be increased, but the experiments carried out by E. N. 

 Harvey did not show any difference in the rate of permeability 

 for oxygen between living and dead cells. One may suppose 

 however that the luminescence begins when the cells disintegrate, 

 which is corroborated by the fact that on rubbing the brightness 

 of the slime increases. The process of breaking up the cells with 

 granules within was observed by me several times after the slime 

 was discharged. On one occasion Ciilchrist noticed that the 

 li.uht was given off from the glowing particles situated in cells, 



