COLOUKING MATTER OF THE BLOOD. 71 



There is one remark I wish to make in passing, 

 respecting the colomiess blood of the majority of in- 

 vertebrate animals, and that is the proof it affords of 

 the error, not uncommon, in attributing the colouring 

 matter of animals to the colouring matter of their 

 blood. It is now known that the colour of the 

 muscles is due to a peculiar pigment, far more than 

 to the blood which is in them. It is quite clear that 

 the purple fluid ejected by the Sea-hare, or the inky 

 fluid ejected by the Cuttle-fish, cannot derive their 

 colour from colourless blood. There are muscles in 

 several Molluscs — for instance, those of the oesophagus 

 in the Slug and Water-snail — which are of reddish 

 hue, yet the blood of these animals has no colour. 

 And, as a final argument, the integument of the 

 Anemones is richly coloured, yet they have no blood 

 at all. 



To return to our Annelids. If we grant that the 

 fluid hitherto universally regarded as blood is truly 

 blood, we shall have to acknowledge that these Anne- 

 lids have two different kinds of blood ; for over and 

 above the fluid which we see circulating in the vessels, 

 there is a fluid circulating, or, more correctly speaking, 

 oscillating, in the general cavity of the body, and this 

 fluid carries with it what are called the blood- corpuscles. 

 It consists of albumen and sea water ; and is by Dr 

 Williams named the " Chylaqueous fluid,'' the simplest 

 form in which blood makes its appearance, distin- 

 guished from the " Blood-proper,'' in not being a fluid 

 cii'culating in a system of closed vessels, but a fluid 



