68 SEA-SIDE STUDIES. 



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 Annelids have two 

 difierent 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 tJiis 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 

 circulating in a system of closed vessels, but a fluid which 

 carries the chyle directly to the tissues. An image may 

 render the mechanism intelligible. Suppose a worm sus- 

 pended in a phial of water. Let the worm represent the 

 intestinal canal, and the glass phial represent the external 

 integument, tlie water will then represent the chylaqueous 

 fluid, which moves with every motion of the intestine, and 

 fills up every cavity made by its motions. The albuminous 

 and corpuscular nature of the chylaqueous fluid prove it to 

 be subservient to the purposes of nutrition. It also serves 



