Clurtoptcrus Variopedtitus. 41J1J 



podia. The three palettes are in rhythmic motion so long as the 

 animal is undisturbed, Init when disturbed, as by the addition of 

 carmine or masses of sand, the motion ceases for a time or its direc- 

 tion may even be reversed. Under normal conditions the palettes 

 cause the water to flow over the animal from the anterior to the pos- 

 terior end. The incurrent end of the tube is therefore nearest the 

 mouth of the animal and the excurrent orifice is nearest the posterior 

 end. 



When finely divided carmine in w^ater is permitted to enter at 

 the incurrent end of the tube it is seen that some of its larger par- 

 ticles touch the ventral lip of the buccal funnel and there remain 

 imbedded in the layer of mucus which is extruded. Others pass in 

 the current of water over the dorsal side of the anterior region, 

 thence through the arch formed by the joined notopodia of the twelfth 

 segment ; they are then swept around or over the posterior region, 

 and expelled from the excurrent opening. When large granules of 

 carmine or masses of sand are dropped into the incurrent opening 

 the palettes beat only feebly or cause a weak reverse current, as 

 stated above. This response occurs when the sand touches the ven- 

 tral lip of the funnel or the tentacles. The animal then shrinks 

 backwards in the tube and the palettes vibrate forwards with such 

 energy that the irritating material is expelled to a distance of sev- 

 eral centimeters above the "incurrent" end. 



When a larger amount of sand and diatoms was added the method 

 of expelling it varied somewhat from that just described. The ani- 

 mal moved slowly forwards toward the incurrent tube. Here it 

 contracted the anterior region and caused its margin to roll dorsal- 

 wards so that it took the form of a cylinder. The anterior margin 

 of the buccal funnel and the tips of the tentacles were pushed a few 

 millimeters beyond the periphery of this end of the tube. The 

 body w^as dra^vll forwards till it passed the mass of sand. The 

 palettes of the middle region and the neuropodia of the posterior 

 region then began to vibrate rapidly wdiile, at the same time, the 

 body of the worm lengthened backwards. The animal expelled the 

 sand and diatoms, partly by means of the strong current which was 

 ])roduced by the palettes, and in part by the rhythmic movement of 



