SEA-WORMS. 



119 



Lose no time in examining it. See how it crawls along the 

 bottom of the vessel, with its thousand feet moving rapidly 

 forwards. See what beautiful plumes adorn the sides of the 

 body; these are the branchiae, or organs of respiration, which 

 become vermilion as they are swelled by the blood, the course 



RAINBOW LEAF-WORM. 



of which you may trace all along the back. Look at that 

 head enamelled with the brightest colours ; here are the few 

 tentacles, delicate organs of touch, and here, in the midst of 

 them is the mouth, which, at first sight, seems merely like an 

 irregularly puckered slit. But watch it for a few moments ; 

 see how it opens and protrudes a large proboscis, furnished 



