20 JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 
regained its normal rate of pulsation and continued to live over two 
weeks. A long latent period followed the cutting of an arm, before 
the stimulation of cutting manifested itself. 
An Aurelia, with all its ithocysts removed, still gave spontaneous 
and coordinated contractions after allowing time for recovery from 
the operation. This was the result in one instance, while in several 
others only a few contractions were observed. Removal of the 
sixteen marginal bodies (lithocysts) in a Cassiopcea produced paralysis 
for a time but recovery soon followed. A Polyclonia with its entire 
margin removed was paralyzed but had so far recovered in a day 
as to be able, at intervals, to give spontaneous pulsations. 
The removed margin of a Polyclonia pulsated vigorously. This 
margin was then split so as to make a ring within a ring but 
connected at one point by a small bridge of tissue. The waves of 
contraction, which always originated on the ring with the lithocysts, 
passed the bridge to the inner ring quite as Romanes experienced. 
The outer ring was next split so as to separate the exumbral 
portion from the subumbral, when it was found that the contractions 
always originated from the latter. Seven days after its removal, 
this same margin was still alive and pulsating vigorously, and 
broken-off pieces of the subumbral portion were pulsating by 
themselves. Fifteen of the ganglia were removed. It was then 
found that while most of the pulsations originated at the remaining 
ganglion, now and then contractions originated in other parts where 
no ganglion remained. Two days later this margin was still alive 
with contractions originating as often from other parts as from the 
ganglion. A similar observation was made on a margin of Cassiopcea. 
A Polyclonia with the eight lithocysts of one side removed, to 
compare with a normal one, gave no evidence of affected coordination. 
An oral lobe from an Aurelia could give contractions some 
minutes after removal. 
In another Aurelia a circular cut was made about the base of 
the oral lobes through the epithelium of the subumbrella. The 
animal could pulsate well enough but coordination seemed a little 
affected, while in another one with a like cut but semicircular, no 
effect was noticed. 
These results on the removal of the lithocysts (and margin in 
Polyclonia) in Aurelia, Polyclonia and Cassiopasa agree quite with 
those on Charybdea and, of course, also with Romanes’ and Eimer’s 
