348 G. H. PARKER 
whose cilia lash inward and might therefore be expected to 
carry water into the colony. In a corresponding fashion the 
axial angle of the mouth leads to a pair of mesenteric fila- 
ments whose cilia beat outward. Thus the autozodids are so 
organized that they might well serve as a means for the entrance 
and exit of water for the colony as a whole, as originally main- 
tained by Agassiz (’50, p. 209) for Renilla and as has recently 
been claimed by Musgrave (’09, p. 472) for sea-pens in general. 
To what extent the autozoéids of Renilla can serve the colony 
for the entrance and escape of water may be inferred from the 
following observations and tests. Wilson (’83, p. 728) noticed 
that in Renilla reniformis the eggs and sperm were discharged 
through the mouths of the autozoédids. The same is true of 
Renilla amethystina. In the early part of August, 1919, many 
females of this species were found to be spawning. From time 
to time an egg was seen to rise through the oesophagus of an 
autozooid and to shoot from its mouth into the surrounding sea- 
water. The time required for the passage of the egg through the 
length of the zoéid and for its discharge to the exterior was about 
fifteen seconds. As the egg first came into sight at the base of 
the zodid it was spherical in form and its upward motion was 
relatively slow. After it had passed the middle of the zoéid, its 
rate quickened and it became elongated in form, its long axis 
corresponding to that of the zodids. It emerged from the mouth 
as though forced out under pressure, suggesting a sphincter-like 
action for the distal half of the zodid. The whole operation gave 
the impression of a process under the control of cilia which were 
less effective in the proximal than in the distal half of the zodid, 
whereithe egg appeared to be under some pressure very likely of 
a muscular origin. The cilia most probably concerned in this 
operation are those of the mesenteric filaments, which, as already 
stated, are believed to beat toward the exterior. 
In a similar way feces were seen from time to time to be dis- 
charged from the mouths of the autozodids. If a fairly thick 
mixture of carmine and sea-water or of india ink and sea-water is 
injected into the central spaces of the colony, in about an hour 
thereafter long, thin, vermiculate lines of red or black material, 
