290 SUPPLEMENT 
with the swiftness and elegance of the sepia and the calamary ; 
they perform this movement rather by whirling in an irregular 
manner enough, the head usually downwards, and by rowing 
with the assistance of their long tentacular appendages. On 
the other hand, they can walk, or to speak more correctly, 
draw themselves along over a resisting ground at the bottom 
of the water, or even on the shores, in the anfractuosities of 
the rocks. For this purpose they attach one of their arms, 
previously considerably extended, to a solid body, and then 
make use of it to draw towards this point the rest of their 
body. It has also been supposed that these animals can walk 
with the head downwards, and by means of their eight ten- 
tacula; but this is less probable. Aristotle, nevertheless, 
declares positively enough that this is the only molluscous 
animal which makes use of its arms for walking. According 
to this notion hé admits, as do Pliny and all the ancient 
writers, that this animal issues from the water, and that it 
sometimes visits the land, avoiding however all the smooth 
places. lian and Atheneus add that it can also mount on 
trees, which is much more doubtful ; for, in truth, what should 
it go in search of there? They suppose that it must be fruits! 
Most generally the long arms of the octopi serve the pur- 
pose of enlacing their prey, and of attaching themselves to it 
by means of the numerous suckers with which they are 
armed, and the action of which it is easy to conceive. In 
fact, beside the trifling adherence which may be owing to the 
viscosity produced by these organs, each nipple acts abso- 
lutely like a cupping-glass, its edge being fixed, and a capa- 
bility given of producing a vacuum by the contraction of the 
longitudinal fibres of its bottom. Now, as the number of 
these cuppers, or suckers, may amount to several hundreds, 
we may easily conceive that the adherence of the octopi to a 
body is so strong that it is almost impossible to tear them 
from it otherwise than by cutting off the arms, and that they 
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