LUMINESCENCE OF MICROSCOLEX PHOSPHOREUS DOUG. 2(>7 



which were in process of breaking up. I do not think that the 

 granules can be luminous only during the time when they begin 

 to be thrown off from the cells, for the centrifuged extract con- 

 taining the free granules alone gives off light if ether be added, 

 but it may be that they become luminous after they are liberated. 

 It is possible that if the worm be dying the cells break up inside 

 the body cavity. This process never occurs if the animal is in 

 good condition. The accelerating effect of the rubbing may be 

 explained by the increase of the process of breaking up the cells. 

 In favor of such a view it may be noticed that the ejaculated 

 slime which glows brightly always contains free granules in 

 abundance, and their amount increases with time when the cells 

 dissolve. It was impossible to prove this directly as the light 

 of the granules is not strong enough to be seen under the micro- 

 scope. 



I wish to express my sincerest thanks to Professor E. N. 

 Harvey for many suggestions and criticism. My thanks are also 

 due to Professor R. Dohrn, Director of the Zoological Station in 

 Naples and his staff for many courtesies shown me during my 



stay there. 



SUMMARY. 



Microscolex phosphoreus is characterized by an external lumi- 

 nescence (except the steady death glow) which begins upon 

 stimulation. All the properties of its light seem to show that this 

 species has a luminescence of its own. The luminous material 

 is represented by small granules situated in the protoplasm of 

 the cells, which take their origin from the body cavity. The 

 luminescence begins probably after the granules are liberated 

 from the cells. 



BIBLIOGRAPHY. 

 Beddard, F. E. 



'99 A Note upon Phosphorescent Earthworms. Nature, Vol. LX. London. 

 Benham, B. W. 



'99 Phosphorescent Earthworms. Nature, Vol. LX. London. 

 Dubois, R. 



'14 La lumiere et la vie. Paris. 

 Friend, H. 



'93 Luminous Earthworms. Nature, Vol. XLVII. London. 

 Gilchrist, J. D. F. 



'19 Luminosity and its Origin in a South African Earthworm (Chilota sp.?). 

 Trans. Roy. Soc. South Afr., Vol. VII., part 3. 



