i66 PHYSIOLOGY OF THE INVERTEBRATA. 



their food, because of the protective * colour which they 

 acquire from its presence in their blood and tissues. 



(4) Th.eA/-f(cJnii(/((. — Professor Ray Lankester f has shown 

 that the blood of Scorpio becomes blut- on exposure to air. 

 It contains hasmocyanin. The blood of Eix'ira^ Tegcnaria, 

 and Pholcus also contains hasmocyanin. 



(5) The CrvMacca. — Concerning the blood of the Crustacea, 

 Genth in 1852 first observed the blue colour of the blood of 

 Limulus Cyclops; and in 1857, Professor Haeckel ]: observed 

 that the blue blood of Jlomartts became, after many hours' 

 exposure to the air, a violet colour. 



In 1873, P-abuteau and Papillon § experimented on the 

 blood of crabs, and found that it became blue in contact 

 with air, but lost this property when submitted to the action 

 of carbonic anhydride. It, however, recovered its blue colour 

 on shaking with air. " Jolyet and Pegnard || showed in 1877 

 that on shaking crabs' blood with air it showed a beautiful 

 blue or brownish colour, according to the manner in which it 

 was examined; it gradually loses this colour, becoming reddish 

 and then feebly yellow ; but on treatment with pure oxygen 

 its original colour is restored. They found two colouring- 

 matters in crabs' blood : one is blue, and is precipitated by 

 alcohol with the albumin of the blood ; the other is reddish, 

 and remains in the alcoholic filtrate." 



In 1879, Dr. Leon Predericq IF j)roved that the blue blood of 

 Homarus contained hasmocyanin, and that it was blue with 

 reflected and brown with transmitted light. The blue pigment 

 — hsemocyanin — is a proteid containing copper. The red pig- 

 ment in crabs' blood is also present in the blood of Hornarii.s. 

 But this pigment does not belong to the proteid constituents 

 of the blood ; it does not contain copper, iron, or manganese, 



* From enemies. 



t Quarterhj Journal of JMicroscoincal Science, 187S, p. 453. 



% Midler's Archiv, 1857, p. 511, Anm. i. 



§ Coi)ij)fes-Beiuh(s, t. 77, p. 137. 



II Archives lie Physloloyie, 2 serie, t. 47. 



•|[ Bulletins de VAcud6mie Boyale de Belgique, 2 serie, t. 47. 



