410 GUSTAF FR. GOTHLIN 
pole, but that the succeeding ones travel successively farther and 
farther toward the oral pole and finally throughout the whole 
row. 
6h.3m. In the animal that is weakly poisoned with chloral 
hydrate it is now observed that a weak current accelerates the 
frequency of the ciliary waves. For instance, in one row with- 
out any current there is a number of waves expressed by 10/13 
sec. = 46 per min., but when a current of density 0.93m.amp/cm.? 
is closed, the waves are at least 180 per minute. 
6 h. 10 m. The animal is transferred into another cuvette, 
which contains sea-water with 0.2 per cent of chloral hydrate 
added. 
6h. 54m. Onall the rows the waves are now only partial, con- 
fined to a small portion nearest to the sensory pole. One row is 
observed to be still sending out regular waves. The latter are 
not inhibited now even by suddenly injecting an oro-central cur- 
rent of density 2.7 m.amp./cm.?, nor by leaving the density unal- 
tered and making the direction of the current centro-oral. 
4. 19/7 Beroé, 23 mm. long, takes up a vertical position in 
the aquarium at the surface of the liquid with the oral pole up- 
ward. The ciliary motion is lively, but varies very much in 
frequency. The ciliary waves are for the most part uncount- 
able, but on one occasion on the slowest striking row the number 
of waves was found to be 21/7.5 sec. = 168 per min. A primary 
stoppage can be produced by touching the edges of the mouth or 
the polar fields, assuming that this takes place with a suitable 
strength. 
5h.42m. The animal is transferred to a cuvette containing 
sea-water with 0.1 per cent of chloral hydrate. 
5h.43 m. The animal goes to the bottom of the cuvette and 
takes up a vertical position there with its mouth downward. 
5h.58m. As the animal is not more strongly affected by the 
concentration of poison used, it is removed to another cuvette, 
in which the sea-water has 0.2 per cent of chloral hydrate added 
to it. 
5h.59m. The animal now keeps at the surface. In the row 
that strikes most slowly the ciliary waves now have a frequency 
