WORMS. 



137 



collar, and arranged somewhat like two petals of a flower, 

 with a deep bend or sinuosity where they unite. 



The extreme beauty of the display cannot but elicit 

 our admiration ; we raise a finger to point out some par- 

 ticular item to a companion, when, lo ! the whole apparatus 

 disappears like a vision j with the speed of thought the 

 whole has been retracted into the pipe, the stopper enter- 

 ing last of all, and tightly closing the aperture 



Our friend Serpula is an exceedingly prudent personage, 

 and will not soon emerge from his strong castle again, 

 after receiving such a fright as the lifted finger gave to 

 his sensitive ganglia ; and when he does, it will not be 

 without great caution. Meanwhile, as we are waiting his- 

 reappearance, we will briefly discuss some points of his 

 organisation. 



Those beautiful fan-shaped petals are gills, the breathing 

 organs of the animal, whereby he derives from the sea- 

 water the oxygen necessary for the renewal of the blood, 

 which is constantly exhausted in the bunding- up of the 

 various tissues. Their situation at the anterior extremity 

 of the body is a wise provision, since they can by this 

 arrangement be periodically bathed in the surrounding 

 water, with the least possible exposure of the animal. 

 In other species, however, which do not inhabit tubes, the 

 gills are situated on other parts of the body. Thus in the 

 common Lug (Arenicola), or Mud-worm, so well known to 

 every fisherman • for its value as bait, the gills form little 

 tufts of a crimson hue on the rings of the middle part 

 only. V^hile on the exquisite Leaf-worms (Phyllodoce) 

 they resemble heart-shaped leaves, arranged in a row on 

 each side throughout the entire length, y 



