PHYSIOLOGY OF THE INVERTEBRATA, 167 



and it has nothing to do with the change in the colour of the 

 blood. 



It may be remarked in passing that Dr. W. D. Halliburton^ 

 F.R.S.,* has shown that the blood plasma of T/t^^z/'^fyv^s contains 

 a red pigment, which is soluble in alcohol, ether, and chloro- 

 form ; but it is possible that this pigment belongs to the 

 histohasmatins which Dr. MacMunn has found to be pretty- 

 generally distributed in the tissues and organs of the 

 Iiivcrtcbrata. 



The blood of Homarm, Cancer, Carcinus, and Astacus does 

 not show any absorption bands when examined by the 

 microspectroscope. The blood in all these animals contains 

 ha)moc3'anin. 



The blood of Ajyus, one of the Plti/llopoda, is of a red colour, 

 and, according to Lankester, this colour is due to ha3moglobin. 

 Another Crustacean which has red or violet blood is (Tarii- 

 riurrus. 



(6) The Pohjzoa. — Several of the Pohfzoa contain lipo- 

 chromes ; and in Flustra foliacca MacMunn f has shown 

 there exists a chlorophylloid pigment which is soluble in 

 alcohol. The spectrum of this pigment somewhat resembles 

 that of modified chlorophyll. The alcoholic solution is a yellow 

 colour, and has a red fluorescence. Its chief dark band reads 

 from X 681*5 to X 656, its darker part from X678 to X 662. 

 " It showed another before D ; the third chlorophyll band 

 was missing, and there was one lipochrome band." 



(7) The MolUtsca. — The blood of many Molluscs contains 

 the pigment ha^mocyanin. 



In 1 8 16, Erman simply recorded the fact that the blood of 

 Hdw^ was of a blue colour. Harless and Von Bibra| (in 

 1847) stated that the blood of Hdic iMvudia acquired a blue 

 colour on exposure to air, but this colour was discharged by 

 shaking the blood with carbonic anhydride. They also 



* British Medical Journal, 1885. 



t I'roc. Fhysiol. Soc, 1887 ; and Quart. Juttrn. Micro. Science, vol. 30, p. 79. 



X 3Iuller'8 Arcliiv, 1847, p. 148. 



