402 S. J. Holmes 



to either side, or twist about on its long axis. It is almost con- 

 stantly bending and writhing about in various ways. The ante- 

 rior extremity is the most active as well as the most sensitive part 

 of the organism. It is continually executing small movements, 

 bending back and forth or up and down as if attempting to explore 

 its environment. The oral margin of the body at times performs 

 a sort of undulating movement, usually when it is lifted up free 

 from the surface. This motion when the animal is largely free 

 from contact with the substrate may become a vigorous and rapid 

 one and serves to turn the body about in the water. When slight 

 the fluttering movements are confined to near the anterior end of 

 the body but when more decided they involve a considerable part 

 of the oral margin. 



When turned over so as to lie on its left or unciliated side 

 Loxophyllum may right itself in several ways. At first it writhes 

 about for a little while, but it is usually only a short time before 

 one of its methods of turning over is hit upon. One common 

 method is to raise up the ends of the body more or less, twisting 

 about the anterior end until its right side touches the bottom. 

 The rest of the body is then pulled over much as in the common 

 righting movements of a planarian. Often, but not always, this 

 is accompanied by a rapid undulation of the oral margin which 

 apparently aids the turning. Generally Loxophyllum raises the 

 oral side and twists about aborally, but it not infrequently turns 

 over in just the reverse direction. Frequently the body is twisted 

 about when the two ends are free in the water, the turning begin- 

 ning at the anterior end and continuing until the whole body is 

 twisted about. 



When placed on its left side Loxophyllum sometimes bends the 

 anterior end of its body upward at right angles to the long axis, 

 raising it until it stands erect, and then toppling over upon the 

 opposite side. In one instance I saw both ends raised up to about 

 the same extent until they nearly met, forming a sort of hoop; then 

 the animal rolled over, through the force of ciliary action until 

 the anterior end touched the bottom, when it attached and glided 

 ahead, thus straightening out the body into its normal position. 

 Loxophyllum is, as a rule, rather reluctant to swim through the 



