498 G. H. PARKER 
enon in Pennatula by Panceri (’71), namely, 5 em. per second, 
and is approximately sixty to sixty-five times as fast as the 
rachidial (1.2 mm. per second) and the peduncular rates (1.1 
mm. per second). This indicates that the process of transmission 
that underlies the waves of luminosity is probably entirely dif- 
ferent from that which controls peduncular and rachidial peri- 
stalsis. 
Other evidence that is in favor of the view that these two 
forms of transmission are essentially distinct is seen in a certain 
kind of mutual independence that they sometimes show. When 
TABLE 4 
Times in seconds for the passage of waves of luminosity over strips of Renilla 
rachis. The stimulus, pressure of a rod, was applied first at the right-hand end 
of the preparation and then at the left-hand end. Temperature of water 21°C. 
‘\ 
NUMBERS OF THE TESTS 
ce | wveac® | axa 
1 2 3 4 5 6 7 8 9 10 
cm 
A 105) 5 Om alee lee ale ale ete 2 al Os) 1 Os eat 9.3 
B ICO |e aE Lh |p WR] TL 2a a) ahh fea EO] 1.18 9.2 
C EM) pi (18) eget Fo Pl 1 i Mea Ga a 0 es 9.3 
D LOR RISE 2 AOR Se SL Oa ea Aes tO eel 1.14 9.2 
By | 1 Andee eos lek | bBo) BiG) ed) leGe) dad 1.58 9.2 
General Syersieeaeee ess se eke ae Seo ce eee 1.25 9.24 
a strip of tissue is prepared from the margin of the rachis of Ren- 
illa for the measurement of the rate of the phosphorescent 
waves, it is not uncommon to find that after a time rachidial 
peristalsis appears on it. When this occurs at night, an inter- 
esting comparison between the two sets of waves can be insti- 
tuted. In one preparation where this occurred, the rate of the 
rachidial wave was measured and found to be approximately 
1 mm. per second. The preparation was then placed in a dim 
light, and just after a rachidial wave had started from one end 
that end was stimulated mechanically and a rapid wave of 
phosphorescence was made to run over the whole strip. On 
quickly throwing a bright light on the preparation the rachidial 
