PRIMARY INHIBITION OF CILIARY MOVEMENT 425 
admixture of chloral hydrate. In this liquid the ciliary activity 
becomes accelerated. At 11 h. 55 m. the animal was trans- 
ferred to another cuvette, in which to the sea water there is 
added 0.2 per cent of chloral hydrate. 
12 h. All motion of the swimming plates has stopped; the 
animal is flaccid, its mouth wide open, and it shows no reaction 
to mechanical stimulation. 
12h.2m. The animal is brought in this narcotized condition 
into a glass aquarium with plane walls. Here the sensory pole 
of the animal is removed by an operation of the same kind as in 
experiment 5, but using a punch 4 mm. in diameter. After this 
has been done one can with a suitable adjustment see from the 
animal’s aboral pole through a tunnel into its enteric cavity. 
The polar fields of the animal are situated in the piece stamped 
out. 
12h. 25m. The animal is transferred into an aquarium with 
sea-water and no chloral hydrate. 
2h.2m. The swimming plates are still motionless. After 
the animal has been transferred to a cuvette it is established by 
means of a Zeiss’ binocular lens that the cut has proceeded at 
about the termination of the ciliated furrows in the swimming 
rows, yet so that on a couple of rows up to four of the most aboral 
ciliary plates have also been removed. | 
4h.47m. Temp. in the cuvette 17°. There is now vibration 
in all the rows, but besides direct waves a few inverse ones are 
observed proceeding from the oral pole. The synchronization 
of pairs of rows has ceased. In the horizontal position no 
reduced ciliary activity is noticeable in the rows that are for the 
time being lowest. When any row has a slower ciliary activity 
it has it in all positions, as far as this can be tested merely by 
observation with the eye through a lens. 
7h. 19 m. Touching the lips of the animal causes a short 
inhibition of the ciliary action, but this inhibition is not total; it 
seems to be confined to the rows that are situated nearest to the 
place that is stimulated. 
31/7-1/8. The tunnel that existed on the 30th, of July after 
the operation is now (31/7, 11 a.m.) found to be closed. New 
