504 Howard Edwin Enders. 



bled about by the peristaltic movements of its walls. In the narrower 

 portion of the intestine of a well-fed individual from four to six 

 of the food masses lie side by side in the lumen. They are some- 

 times discharged from the anus singly, but more frequently by twos 

 and threes. The ciliated groove which I described within the intes- 

 tine probably aids in the movement of the food masses. 



The medium in which the animals live normally is heavily charged 

 with food in suspension. In order to make the diatoms of the 

 aquarium available as food for the young worms I agitated the 

 water several times daily. When the water has not been agitated 

 for twenty-four hours or more the faeces which were discharged con- 

 sisted mainly of the pellicle of mucus with only a few diatoms and 

 the shells of young gasteropods or veligers that breed in the aquaria. 

 An hour after the water has been thoroughly agitated the fseces 

 which are discharged are filled with diatoms. Finely divided car- 

 mine that is permitted to enter the incurrent tubes is usually dis- 

 carded from the tube in less than ten minutes as boluses of red 

 mucus. I have repeatedly dropped these boluses into the tubes for 

 an hour, but they were discharged in each case a few minutes after 

 their entry. Some of the granules of carmine were ingested and 

 then were discharged to the exterior an hour or more after their 

 introduction and the thorough agitation of the water. The finely- 

 divided gelatinous egg-masses of the gasteropods were also rejected 

 in the same way and were not accepted as food. 



The amount of fsecal matter discharged and the rapidity of its 

 movements through the animal are proof of the efficiency of the 

 ciliary grooves and the accessory feeding organ as organs of pre- 

 hension. The water which passes through the tube is strained sev- 

 eral times, as, by the cilia of the buccal funnel, the groove of the 

 mid-dorsal side, the complicated ciliary grooves of the arch within 

 the notopodia of the twelfth segment and the cowl-shaped accessory 

 feeding organ of the thirteenth segment. 



In the closely related sedentary annelid, SpiochcBiopterus ocul- 

 atus ( ?) the tentacles have undergone a considerable specialization. 

 They have the same form as those of Chsetopterus, but they are as 

 long when extended as the body of the annelid. The straight, 



