Cuap. X. TRANSMISSION OF MOTOR IMPULSE. 235 
the exterior tentacles to bend until half an hour or 
even several hours have elapsed. 
The motor impulse spreads gradually on all sides 
from one or more excited glands, so that the ten- 
tacles which stand nearest are always first affected. 
Hence, when the glands in the centre of the disc 
are excited, the extreme marginal tentacles are the 
last inflected. But the glands on different parts of 
the leaf transmit their motor power in a somewhat 
different manner. If a bit of meat be placed on 
the long-headed gland of a marginal tentacle, it 
quickly transmits an impulse to its own bending 
portion ; but never, as far as I have observed, to the 
adjoining tentacles; for these are not affected until 
the meat has been carried to the central glands, 
which then radiate forth their conjoint impulse on all 
sides. On four occasions leaves were prepared by 
removing some days previously all the glands from 
the centre, so that these could not be excited by 
the bits of meat brought to them by the inflection of 
the marginal tentacles; and now these marginal ten- 
tacles re-expanded after a time without any other 
tentacle being affected. Other leaves were similarly 
prepared, and bits of meat were placed on the 
glands of two tentacles in the third row from the out- 
side, and on the glands of two tentacles in the fifth 
row. In these four cases the impulse was sent 
in the first place laterally, that is, in the same 
concentric row of tentacles, and then towards the 
centre; but not centrifugally, or towards the ex- 
terior tentacles. In one of these cases only a single 
tentacle on each side of the one with meat was 
affected. In the three other cases, from half a dozen 
to a dozen tentacles, both laterally and towards the 
centre, were well inflected or sub-inflected. Lastly, in 
