72 SEA-SIDE STUDIES. 



which carries the chyle directly to the tissues. An 

 image may render the mechanism intelligible. Sup- 

 pose a worm suspended in a phial of water. Let the 

 worm represent the intestinal canal, and the glass phial 

 represent the external integument, the 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 subser- 

 vient to the purposes of nutrition. It also serves an- 

 other purpose, acting as an internal skeleton. You are 

 surprised at the idea of a liquid skeleton .? yet you 

 sit on a cushion of air, without the least astonish- 

 ment. The fact is positive : the Annehd employs its 

 chylaqueous fluid as a fulcrum by which it moves ; let 

 the fluid out, and all power of locomotion vanishes. 



The two bloods have two methods of aeration. The 

 " chylaqueous fluid " rushes into the lovely tentacles 

 which in many species wave above the head, and there 

 is aerated, aided by the action of the cilia which line 

 the inner surface of the tentacles. The " blood '' is 

 carried to those arborescent tufts without cilia, which 

 branch from each side of the head beneath the ten- 

 tacles. But although the respiratory process does un- 

 doubtedly take place in these organs, yet in animals so 

 simply constructed, each organ performs more than one 

 function. Let us hear Dr Williams on the tentacles : — 



" From theii' extreme length and vast number they 

 expose an extensive aggregate surface to the agency 

 of the surrounding medium. They consist of hollow, 



