PRIMARY INHIBITION OF CILIARY MOVEMENT 429 
edge of the mouth and touching the surface of the wound caused 
primary inhibition in the swimming plates, as well as that trans- 
mission of an oro-central current produced primary inhibition at 
an equally low density of current and also in other respects in 
the same way as in an intact animal. 
When one considers the ease with which by suitable electrical 
stimulation one can produce a primary inhibition in a Beroé 
row, it seems very remarkable that I was never able to observe 
that a similar electrical stimulus had an inhibitory effect on an 
isolated, spontaneously striking, swimming plate. My experi- 
ments as to this were carried out by following through the micro- 
scope, the movements of a spontaneously vibrating ciliary plate 
and suddenly exposing it to the influence of a cathodic field. 
Such observations are described in experiment 9. Neither in 
this nor in other experiments where satisfactory precautions have 
been taken to prevent electrolytic products from reaching the 
preparation have I observed that a spontaneously vibrating 
swimming plate of a Beroé has moved more slowly or stopped 
under the influence of a cathodic field, but I have certainly 
observed that spontaneously striking swimming plates have 
accelerated their activity and that previously stationary plates 
have begun to vibrate when a cathodic field has arisen around 
them. 
From observations on shaken preparations of Beroé it seems to 
me to appear that isolated swimming plates of Beroé have, as a 
rule, a rather small degree of automatism, especially in compari- 
son with isolated plates of Bolina. The assumption that the 
automatism in the swimming plates of Beroé is relatively slight 
in comparison with that of other etenophores seems also to be 
supported by a statement of C. F. W. Krukenberg (’80, p. 17) 
that ‘“‘abweichend von dem Verhalten der Beroé, bei Chiaja der 
Ruderschlag an allen Theilstiicken seinen vollig normalen Char- 
acter, gleich von der Zeit ihrer Abtrennung an, bewahrt.’’ One 
may also compare the result I have described in experiment 9 
of shaking to fragments a Beroé in full ciliary activity with a 
slight quantity of sea-water with Parker’s observation (’05, p. 
413) on Mnemiopsis under similar conditions. He writes: 
