Some Notes on Alcippe lampas (Hanc.). 197 
The animal performs rhythmical movements. The caudal end 
with the cirri is protruded and withdrawn. The cirri force the free 
edge of the mantle lips out and open a little and project between 
them, then they withdraw and the mantle lips close. Seen from 
above the cirri appear at the rounded side of the lips (ventrad), 
push along the slit dorsad, draw back and dis-appear. This rhythmical 
movement which is very much like that in the barnacles and goose 
barnacles is repeated from about 50 to 54 times a minute but often 
with short irregular pauses. The latter last about as long as one 
movement would be. I counted such pauses for instance after the 
7th, 37th, 43d and 52d protrusion and noticed that each time the 
lips contracted and withdrew a little from the slit. 
To a light touch the animal usually, but by no means always, 
responds by ceasing the rhythmical movements and often contracting 
the mantle lips besides. A stronger stimulus causes cessation of 
the movements and contracting and withdrawal of the lips for a 
longer time. Sometimes the lips are retracted and extended 
repeatedly and are pushed a little to the right and to the left. 
The rhythmical movements, of course, produce an ingoing and 
outgoing current of water. Fine particles are seen under the 
microscope to be drawn in and others pushed out often to a con- 
siderable distance, particles loosely attached near the slit are 
rhythmically attracted and repulsed. In this way the animal pro- 
cures its food and water for respiration. 
On carefully breaking the shell so as to leave the disk attached 
and uninjured but expose the rest of the body, the animal will often 
perform wave-like proceeding violent contractions of the mantle and 
extrude mature eggs or nauplii through the mantle lips. 
After the animal has become quiet again, it shows irregular 
slow contractions of the mantle proceeding wave-like from the lips 
towards the disk as other animals show from the beginning. These 
movements have been described and as Berxpr thinks, they aid 
in boring by pressing the armature of the mantle against the wall 
of the cavity. 
The boring movements and the movements of the head and 
cirri have been discussed by AukiviLLıus and BERNDT. I have at 
present nothing to add. 
The rhythmical movements in animals freed from the shell 
as described go on for a long time and the observations on such 
animals confirm those made on specimens in situ. Contrary to 
