JS^otes on j\fi/n'npoda. 



21 



A Comparison, 



We may add here that crystals have been observed in the 

 dried films of excretion obtained in our holder, not only from 

 the ventral surface o£ luminous specimens of G. cnrpophagus^ 

 but also in one case from a non-luminous specimen of 

 Gec/fhilus insculptas, Attems, taken in a Darwen garden 

 28. vii. 1919. 



The Incidence and Decline of Light Production. 



Quite roughly we have prepared a number of curves to 

 sliow the incidence and decline of luminosity v/hich follows 



Fig, 14. 





100 

 90 



70 



eo 



50 



40 



^^30 

 i5 ■"> 20 



5 



ro 



10 20 30 40 50 60- 70 80 90 100 110 ISO 13a 140 150 ISO 170 160 190 



T/me in seconds 



Curve to show incidence and decline of luminosity in Gcophilus carpo- 

 ph'^KjiiK. Description in the text. Tlie data employed are tl^ose of 

 Experiment 2 (see Table). S. G. I3.-B. del. 



the electrical stimulation of a specimen of Geophilus carpo- 

 phar/ns. Although the curves plotted are only roughly 

 estimated, it seems worth while to give the figures of three 

 experiments carried out in our own laboratory and to accom- 

 pany them by a drawing (fig. 14) of one curve which serves 

 as a type. Here it will be noticed that there is a short 

 S|)ace of time between the sudden shock of electrical stimu- 

 lation, which is only momentarily applied, and the incidence 

 of light-productifju. The light is brightest when it is first 

 oljservcd, and it fades suddenly at first and more slowly later 



