928 LOCAL COLOUR-VARIETIES OF SCHYPIIOMEDUSvE. 



few Sydney specimens which I found were constant in this 

 particular. T consider myself justified in setting up provisionally 

 two varieties of this species : 



CYANEA ANN ASK ALA PURPUREA 



found as yet only in Port Phillip, with moutharms which avo 

 richly purple throughout, and 



CYANEA ANNASKALA MARGINATA 



found as yet only in Port Jackson with moutharms, which are 

 purple at the free margin, but otherwise appear colourless. 



The purple colour in the moutharms is very similar to the 

 brilliant purple " Sehpui'pur " in the sensitive apparatus of the 

 Retina of some animals, particularly the lizard. When the 

 Cyanea is placed in a glass aquarium this colour fades in less 

 than an hour to a dirty brickred. . When the Medusa is sick even 

 in the open sea it is always this colour, which is affected first and 

 turns into a dirty coifee colour long before the tentacles begin to 

 drop ofi", which is always a sign of approaching death. 



In my paper on the structure of Cyanea Annaskala, I pointed 

 out that no pigment occurs in the marginal bodies and that there- 

 fore the organs of sight of this si)ecies, if to be found in the 

 marginal bodies at all were not nearly so highly developed as in 

 other MedusfB, nor even as in the other species of the same genus, 

 which do not possess purple moutharms. 



Sensitive cells are very numerous, particularly in the purple 

 margin and contain the purple substance. Ganglia cells are also 

 met with there. The pigment in the other parts might be con- 

 sidered as reserve material for that, which may perhaps be used 

 up by the sensitive cells. 



I do not go so far as to draw the conclusion which the reader 

 will have inferred from the preceding lines, but I should like to 

 hint at the possibility of the moutharms of our Medusa being 

 able to perceive light. 



