308 THE ZOOLOGIST. 



In the ■ Report of the British Association' for 1887 (p. 767) 

 we have a note by Mr. Harker "On a Luminous Oligochsete." 

 But here again the same remark applies. Much good work, 

 alas ! is rendered valueless for want of a little accuracy in 

 nomenclature. 



It now becomes a question what end could be served by the 

 possession of this property. The philosopher no sooner learns 

 a new fact than he begins to pry into the secret which lies 

 beneath, and stands to it as cause to effect. We have analogy to 

 guide us. The water worms may be compared with the marine 

 animals which produce phosphorescence, while the Brandling 

 may be studied in the light of a Glowworm. It may be objected 

 that as worms, except in a few rare cases, have no eyes there can 

 be no advantage in their luminosity. But such an argument 

 would be based on the erroneous assumption that a creature 

 without eyes is incapable of receiving impressions from light. 

 That worms are influenced by light is proved both by their habit 

 of avoiding it, and by the experiments which have been carried 

 out by various students. Darwin remarks that as worms are 

 destitute of eyes he at first thought that they were quite in- 

 sensible to light. He found, however, that " light affects worms 

 by its intensity and by its duration." Hoffmeister states that, 

 with the exception of a few individuals, worms are extremely 

 sensitive to light, and from my own observations I have been 

 able to demonstrate that there are marked differences in the 

 susceptibility of the different species — some being very much 

 more susceptible than others. 



Now it follows that if a number of species of worms lived 

 together in one place, as they usually do in a manure-heap, it 

 would be a great advantage for a given species to possess a 

 distinguishing feature, such as that of luminosity, to enable two 

 individuals to discover each other's whereabouts, just as the male 

 Glowworm detects the female by the light emitted from her 

 upturned abdomen. 



Viewed in this light, a new field of research is opened up 

 which hitherto has been totally unworked, but which may be 

 hoped to yield remarkable results if diligently, patiently, and 

 intelligently tilled. 



It will not be out of place in this connection to quote from 



