490 G. H. PARKER 
anchoring and burying a colony and rachidial peristalsis with 
elevating it, it is natural that the two sets of waves should not 
be running at the same time. In a purely accidental way I 
discovered a means, however, by which these two operations 
might be made to occur simultaneously. If a ligature is tied 
firmly about the peduncle of an inflated Renilla at a position 
not far from the proximal end of that part and the colony is 
returned to a basin of sea-water, after an interval of half an hour 
or more two sets of waves may appear: peduncular waves run- 
ning over the peduncle distally from the ligature and rachidial 
waves beginning in the base of the peduncle and passing in the 
usual direction over the rachis. The simultaneous occurrence of 
these two sets of waves is due, I believe, to the separation of the 
colony into two parts by the ligature which is so effective as to 
bring about a complete physiological dissociation of the regions 
concerned. 
PHOSPHORESCENCE 
As early as 1850 Agassiz made the observation that Renilla 
reniformis ‘‘shines at night with a golden green light of a most 
wonderful softness,’’ a peculiarity which is apparently common 
to most sea-pens (Mangold, ’10-14; Dahlgren, 716). If a fresh 
specimen of Renilla amethystina that has been exposed to ordi- 
nary daylight is carried into a darkroom and stimulated by being 
prodded gently, no phosphorescence is observable. On trying 
the same experiment at night, the colony glows with a wonder- 
fully clear blue-green light. During August in La Jolla this 
phosphorescence made its first appearance about half past eight 
o’clock in the evening and could be excited any time during the 
. hight until toward sunrise. 
If during daylight non-phosphorescent colonies are transferred 
to a dark room and kept there, they begin to show phosphor- 
escence on stimulation in about half an hour and attain what 
seems to be their maximum. capability under these circumstances 
in from fifty-five to sixty-five minutes. The phosphorescence 
thus developed seemed never to reach the degree of brightness 
seen during the night. This is not easy to judge by the eye, but 
