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PHYSIOLOGY OF THE INVERTEBRATA. 



Professor Huxley considers that the perivisceral fluid 

 represents ordinary blood as far as being a carrier of a utri- 

 mcnt to the tissues ; and that the pseudo-htemal fluid is 



probably only engaged in the function of respiration ; hence 

 the reason that he calls it '' respiratory blood." 



After these general remarks we proceed to detail at length 

 the pseudo-htemal systems of Lumhicus and Hiriido. 



(ji) In Lumhriciis, there are three principal vessels which 



