232 MANTON COPELAND AND H. L. WIEMAN. 



muscular contraction. Nereis responded in the same way to 

 all other forms of animal food which were offered, viz., crushed 

 clam [Mya arenaria Linn.], mussel [Mytilus edulis Linn.], bits 

 of fish [Fundulns heteroclitus (Linn.)], and meat of the blue 

 crab [Callinectes sapidus Rathbun] . When the food was grasped 

 it was always pulled to the mouth of the burrow and, unless 

 too large, into the interior of the burrow itself. In no case was 

 a worm observed to leave the burrow entirely and move about 

 freely in the water. 



In order to learn something of the extent to which the animals 

 depend upon a chemical sense in such reactions a number of tests 

 were made, one of which was carried out in the following man- 

 ner. The position of a worm was first determined by baiting 

 with a piece of clam which was removed before the animal had a 

 chance to seize it. Some fragments of the same food were 

 then wrapped in cheese cloth and dropped into the water about 

 five centimeters from the opening of the burrow. Equidistant 

 from the burrow and one centimeter from the first packet was 

 placed a second, consisting of a white pebble done up in cheese 

 cloth. Each packet measured slightly over two centimeters in 

 diameter and both had essentially the same appearance. The 

 worm soon responded by emerging from the burrow and, ad- 

 vancing in a straight line toward the baited packet, seized it 

 and dragged it down almost out of sight. The packet was then 

 dug out and replaced in its former position. In a few minutes 

 the worm reappeared and repeated the reaction in every detail. 

 Again the food was recovered, and this time the positions of 

 the baited and unbaited packets were interchanged. Within 

 several minutes the anterior end of the worm came out of the 

 sand somewhat nearer to the packets than before and moved 

 forward in a course which, if adhered to, would have brought it 

 between them. However, when close to the packets the animal 

 suddenly turned and fastened its jaws in the baited one and for 

 the third time pulled it into the sand. 



The results of this experiment indicate that sight plays little 

 or no part in the worm's food reactions under the conditions 

 prevailing. Tests were also made by dropping pebbles near 

 occupied burrows to ascertain if agitation of the water, or some 



