2Ci Dr. ^^L- the Rev. S. Graham Pjiade-Birks — 



niisleadinf;; factors : Ford (9) has devoted some space to 

 tliein iu the case of insects. 



(i.) Photudermatic seyisatlons. 



When we speak of tliese Geopliilomorphs as blind animals, 

 we must remember that thougli it is true that they have no 

 eyes, no specialised organs of sight, they may be able to 

 appreciate light l)y a general absorption of its waves throai;h 

 the surface of the body. Pigment-cells, which we have 

 found abundantly present in the connective tissue close to 

 the chitin of both dorsal and ventral surfaces of the trunk 

 ill luminous specimens of G. carpophagus, might play an 

 important part in such au absorption. 



(ii.) Smell. 



Again, as we speak of the odour of the luminous fluid in 

 G. carpophcKjHs^ we must not foi'get that the odour, as we 

 perceive it, may have no counterpart in the experience of 

 the animal producing it. 



Sexual Significance. 



Young and adult, male and female alike, exhibit lumi- 

 nosity, and we have already stated (2) that it seems unlikely 

 that the character is a sexual one. In Kent luminous 

 specimens of G. carpophagus have been taken in ])cceml)er, 

 January, February, and April, and in Lancashire we have 

 collected specimens which were afterwards luminous upon 

 stimulation from April this year (1919), fairly frc(]ueutly up 

 to the month of writing this paper (September). Gazagnaire 

 (lOj based his theory of the sexual significance of this phe- 

 nomenon upon records which only covered, a limited period 

 of the year. 



Prulection. 



I>oth the light and the odour may be protective against 

 enemies. 



Accidental Piajicrti/. 



We must not lose sight of the fact tluit luminosity may 

 be an entirely neutral factor in the economy of this animal, 

 and thai the product of the " white glands" nuiy be entiiely 

 accidentally photogenic. 



