246 SELIG HECHT 
Fig. 7 Apparatus to record the movements of Ascidia. 
In order to analyze the movement of the siphon rims, I secured 
kymographic records of their activity. The apparatus which 
was employed is represented in all essentials in figure 7. The 
drawing needs little explanation. The long, light, aluminum 
lever was nearly, but not quite, balanced by the weight on the 
short arm. This slight excess on the long arm kept the pendant 
vertical rod in continual contact with the right edge of the siphon 
rim. Such a procedure proved more effective and less disturb- 
ing to the animal than actually attaching the lever to the tissue. 
In addition the vertical arm was curved so as to fit into the 
cavity of the siphon. To keep the animal in place, it was fixed 
to a piece of plate glass, which was heavy enough so that éven 
a vigorous movement of the entire animal did not change its 
position. 
Fig. 8 Record of siphon rim contraction, and record of body bending. The 
base line marks one minute intervals. 
