LUMINESCENCE OF MICROSCOLEX PHOSl'HORKUS DOUG. 2C>5 



Pierantoni states that the addition of sodium chloride to the 

 water in which the living specimens of Microscolex phosphor eus 

 are kept inhibits their luminescence. In spite of many trials I 

 have not been able to demonstrate the effect of different salt 

 solutions when added to the powder from desiccated earthworms. 

 The observations on Microscolex agree therefore with those of 

 E. N. Harvey on Cypridina where the effect of different ions was 

 not to be found. Pierantoni in his paper distinguishes two types 

 of luminescence in Microscolex. Besides the external secretion 

 of luminous slime he describes a general luminescence of the 

 whole body, first visible at the posterior and anterior part, which 

 takes place within the different tissues. This internal lumi- 

 nescence may be produced by the strong stimulating action of 

 ammonia or alcohol. It seems to me that in many cases the 

 ejaculated slime, through the movements of the animal, spreads 

 over the whole body and sticks to the skin, thus imitating an 

 internal luminescence. By rubbing the worm over the filter 

 paper or cloth all the slime can be removed but in water, however, 

 the viscous slime does not dissolve easily. In ammonia of the 

 proper strength the motionless animal begins to glow, the pos- 

 terior part glowing first. After some time the luminosity spreads 

 over the whole body even if the animal be apparently dying. The 

 same effect can be obtained with alcohol solution. With ether 

 or chloroform I noticed only the external luminescence, the 

 movements of the worm being for a longer time very energetic. 

 Ammonia arrests almost immediately the muscular action. It 

 is therefore to be understood that only in a few cases the ejacu- 

 lation of the slime on application of ammonia was observed. 

 The luminosity of the dying animal may be compared with the 

 steady death glow as noticed in Noctiluca (E. B. Harvey, '17) 

 and other forms. This internal luminescence may be hastened 

 if the worm be rubbed gently with the finger when in ammonia 

 or alcohol. If the animals are in a very poor condition they can 

 also be made luminous by rubbing them, even without ammonia 

 or alcohol. Sometimes the worms already luminescent can, if 

 slightly pressed, throw the luminous slime through the anal or 

 oral aperture. After the ejaculation of slime the animal loses its 

 luminosity, which indicates that the internal luminescence cannot 



