PHYSIOLOGY OF THE INVERTEBRATA. 211 



matter. Hydrochloric acid did not discharge the colour at 

 first, although it became much lighter ; strong sulphuric acid 

 and nitric acid discharged it after some time. Absolute 

 alcohol also precipitated the pigment, the fluid becoming 

 flocculent after a while. The colouring matter in the fresh 

 state showed no bands except some shading at the blue 

 end of the green; it also absorbed the violet end of the 

 spectrum." 



Dr. MacMunn's investigations on the respiratory pigment 

 of Chrysaora confirms those of Dr. J. G. M'Kendrick, F.R.S.,* 

 who has also investigated the pigments from Cyanea and 

 Aurelia by allowing fragments of these organisms to 

 macerate in sea-water for about thirty-six hours. " In these 

 cases ammonia precipitated the colouring matter from its 

 solutions, and it dissolved in acids." Dr. M'Kendrick states 

 that after death " the body becomes slightly acid, the 

 protoplasm disintegrates, and the colouring matter difEuses 

 out." 



When examined by the microspectroscope the fresh pig- 

 ment from Cyanea, as well as an infusion of the organism, 

 gave two bands, one in the orange and the other in the 

 red. 



The spectrum of the blue pigment of Mhizostoma Ciovieri 

 consists of three bands, one in the red, a dark one 

 at D, and an extremely faint band in the green. There 

 is little doubt that the same colouring matter occurs in 

 Bhizostoma as in Cyanea. This pigment has been termed 

 cyanein by the late Dr. Krukenberg,t and he compared 

 it with the blue pigment found in Velella limhosa by A. and 

 G. De Negri.J Cyanein is soluble in water, insoluble in 

 benzene, ether, carbou disiilphide, and chloroform. On the 

 addition of alkalies, cyanein is changed into an amethyst 

 colour, while acids colour it red. 



* Journal of Anatomy and Physiokigy, vol. 15, p. 261. 



t Vergl. Physiol. Studien, zweite Beihe, dritte Abfch., 1882, B. 68. 



t Oaitett* Ohimica Italiana, vol. 7 [1877]. 



