14 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 
Pieces of the sides connected only with the stomach and suspen- 
soria, or with the margin (Experiment 47 (?)) twitched spontaneously, 
but seldom did so when these were removed. In one instance the 
whole side was cut out so as to exclude the radial ganglion but still 
connected with a portion of the suspensorium. This pulsated, or 
contracted, but on being halved transversely, the lower half ceased to 
contract while the upper half connected with the suspensorium, 
continued to contract. 
Cutting off the whole stomach end of the animal excited to very 
rapid pulsations of the remaining part, with the stream of water 
stronger out the aboral end than past the velarium. 
Conant says, “It seems I get no good evidence of the subumbrella 
without connection with special nerve centers being able to contract 
by itself.” The piece in which he did get contractions he suspects 
may have been intimately associated with some part of the frenula 
or the suspensoria. In Polyclonia no such doubt exists, for small 
pieces of subumbrella were seen to contract. A small piece of 
subumbrella of Charybdea with a sensory club attached could contract 
by itself. 
From the above it would seem that a center capable of inciting 
to contractions resided in the suspensoria as well as in the sensory 
clubs, and this may be one of the centers that becomes potent upon 
the removal of the clubs. This is further supported by Conant’s 
observation (Introduction and “Cubomeduse”’) that an extra large 
number of ganglion cells is found under the epithelium of the 
suspensoria. A somewhat similarly located center of spontaneity 
described by Romanes for Stawrophora laciniata (Hydromedusa) has 
already been noted. 
As to the rapid pulsations of the bell after cutting out the 
stomach end, this also is similar to Romanes’ results on Aurelia and 
other Scyphomeduse, when he cut off parts of the manubrium or an 
aboral ring out of the bell. In these instances, however, Romanes 
soon obtained a slackening of the rhythm following the temporary 
acceleration. The temporary acceleration he attributes to the stimulus 
of cutting, and the slackening to a lack of some afferent stimulus 
from the removed tissue. Conant obtained the same results on 
Polyclonia by removing the oral arms (see Polyclonia) but says 
nothing about a slackening of the rhythm in Charybdea. I believe 
the increased rhythm in Charybdea was in part due to the decreased 
