ITS STOPPER. 289 



branchial currents is to bring a powerful vortex into 

 the enclosed funnel, the bottom of which terminates in 

 the mouth. The food which sustains nutrition is thus 

 brought to be swallowed, a large quantity of water being 

 at the same time constantly poured into the body ; this 

 is discharged (by the agency of a ciliated lining of the 

 hinder parts) in the form of a strong current, which, im- 

 pinging against the closed end of the tube, is turned 

 upward, carrying with it all extraneous or foecal mat- 

 ters, and is ever pouring out of the frontal extremity 

 around the neck of the creature. What a beautiful and 

 effective contrivance is this for constantly keeping in a 

 state of the most unsullied cleanness the interior of the 

 house ! It reminds one of the fabled Hercules cleans- 

 ing the Augean stable by driving the river Peneus 

 through it. 



On each side of the mouth there springs a length- 

 ened horny thread, appearing to answer to the antennae 

 which in other Worms, as well as in Insects and Crus- 

 tacea, project from the front of the head. Such seems 

 their true relation considered structurally, but in func- 

 tion and office they are very remarkable and quite 

 peculiar. To these organs is assigned the duty of 

 closing up the tube when the animal has withdrawn its 

 gaily-coloured plumes ; and for this end, one of these 

 antennae is much lengthened, and at the end is ex- 

 T 



