PHYSIOLOGY OF THE INVERTEBRATA. 



139 



The Maja squinado of Naples lives in sea water which is 

 exceptionally rich in saline matter ; 20.669 grammes of this 

 water yielded 0.821 gramme of saline residue, equal to 3.9 

 per cent ; 14.807 grammes of the blood of Maja yielded 

 0.498 gramme of soluble salts, equal to 3.37 per cent. 



Not only has Fredericq examined the blood of various 

 Crustaceans inhabiting sea water but he has also examined 

 the blood from those living in brackish and fresh water. 



6.48 grammes of the blood of Carcinus mcenas inhabiting 

 brackish water yielded 0.096 gramme of soluble salts, equal 

 to 1.48 per cent. 



To examine the blood of fresh water Crustaceans seven 

 crayfishes {^Astacus fluviatilis) were used in the experiments. 

 A large quantity of blood was obtained by making an incision 

 in the claws. Its taste was only slightly saline ; 23.453 

 grammes of it yielded 0.221 gramme of soluble salts, that is 

 less than one per cent. (0.94 per cent.) 



The following table gives a summary of the results 

 obtained concerning the saline matter of the blood of various 

 Crustaceans and the medium in which they live : — 



