HETEROMORPHOSIS 155 



Five minutes later -the foot reached the bottom of the test- 

 tul>e (Fig. 34, c). The bending spread gradually to elements 

 lying nearer the head; as the foot could no longer advance 

 vertically, it was pushed horizontally over the bottom of the 

 test-tube; and at the same time the head, which until now 

 had played no active part, was slightly raised (2:35 P. M., 

 Fig. 34, d). The bending then passed from one element of 

 the body to another, until the head was brought into an 

 erect position (Fig. 34, e}. Finally the entire animal righted 

 itself so that at 1 o'clock it had the position shown in Fig. 

 34,/). The whole righting process had therefore occupied 

 an hour. The animal remained in this position for two days, 

 when it crawled out of the test-tube. I have repeated the 

 experiment many times, but always with the same result. 



5. If a Cerianthus is divided transversely in the middle, 

 and both pieces are laid upon the wire screen, they work 

 their way (often immediately after the division) through the 

 screen with their aboral ends directed downward. If the 

 head and foot of an animal are amputated, the middle piece 

 may still show this reaction. When this occurs, the amoral 

 cud always bends downward, and works its way through 

 the wire screen. Never have I seen the reverse occur- 

 that such an animal assumes a position in which the oral 

 pole is directed downward and the aboral pole upward. I 

 wished to determine whether light or gravity had any effect 

 upon the position of the new organs formed in these headless 

 and footless animals when fixed vertically in sand, with 

 their aboral ends directed upward; in no case, no matter how 

 often I fixed the animals in an inverted position in the sand, 

 did I succeed in retaining them in this position longer than 

 two days. Nor did they remain with their aboral cut ends 

 directed downward in a narrow test-tube the long axis of 

 which stood vertically. In all cases they turned their oral 

 poles upward. 



