ACTIVITIES OF COLONIAL ANIMALS 485 
When a Renilla is divided into pieces by cuts transverse to its 
chief axis, a very different condition from that just described is 
to be seen. Each piece continues to exhibit contractions, but 
these contractions have a very different rate in the different re- 
gions. Thus in a Renilla cut in two transversely through the 
center of its rachis the peduncular piece was found to contract 
on the average once in 115 seconds and the apical piece at the 
lower rate of once in 205 seconds. ‘The same condition was met 
with in a Renilla that had been cut into five instead of two trans- 
verse pieces (fig. 6). These five pieces may be conveniently 
designated as the peduncle, the proximal rachis, the middle 
rachis, the subapical rachis, and the apical rachis, and their 
several rates of contraction are recorded in table 3. 
TABLE 3 
Rates in seconds at which one wave follows another in separate transverse pieces of 
Renilla 
PIECES INTERVALS IN SECONDS BETWEEN WAVES | AVERAGES 
HZecuimele samme ete eae cae evs, fe cis tone 125 160 185 170 | 180 164 
Proximal rachis.... : Sie rp Sees Re Sale Hg? 175 180 190 165 160 174 
NMiiddllesna chistes: . e825 aceite: 205) 225) 230) |) 200) || 210 214 
‘Sil ogyoncnll teVelatise Gass seen o age oa ane 250) | 225 | 230) 210 |) 240 231 
XS SSCGE II TRACI DTS RE Seer Ae 280 | 250 | 300] 260) 310 240 
As table 3 shows, the peduncular waves have on the average 
the shortest interval, 164 seconds, and the farther a piece is re- 
moved from the peduncle the longer that interval, till the long- 
est one encountered is 240 seconds, in the apical rachis. 
It is worthy of note in passing that, excepting the peduncle, 
the fragments of colonies such as those on which the tests just 
recorded were made, were easily kept alive in aquaria for fully 
a week, during which time they continued to exhibit their differ- 
ences in rate of contraction. 
From these and the preceding observations it appears that 
rachidial peristalsis may take its origin from almost any section 
of the colony, but that the rates at which the waves emanate 
become successively lower as one proceeds away from the pedun- 
