PHYSIOLOGY OF THE INVERTEBRATA. 



M7 



matter was then separated from the other ; and about one- 

 sixtli of its volume of pure absolute alcohol was added. After 

 tiltration the alcoholic extract was exposed to - 12° C, when 

 red crystals were obtained. These crystals yielded the 

 following results on analysis : — 



The above analyses prove that the colouring matter of the 

 blood of LiunhricUH is comparable chemically to that of a 

 Vertebrate animal, like the dog.* 



Although ha?moglobin is present in the blood of certain 

 Invertebrates, the chief constituent in the blood of the 

 majority of these animals is h^mocyanin, a compound said 

 to be analogous to hasmoglobin, but containing copper instead 

 of iron. 



It is well known that "the blood of many Molluscs and 

 Arthropods is of a blue colour after exposure to the air, and 

 this is in most cases due to the presence of hfemocyanin." 



(1) The Erldnodcrmata. — Dr. MacMunnf has examined 

 the blood of Holotlmria nigra. It does not contain heemo- 

 globin, but when examined with the spectroscope it strongly 

 absorbed the violet end of the spectrum but gave no bands. 

 The colouring matter of the blood '' is soluble in absolute 



* Grittiths in Proc. Hoy. ISoc. Kdlnb., 1891 (June l). 



t Quarterlij Journal of Microicupical /Science, vol. 30, p. 60. 



