STAR-FISH AND SEA-URCHINS. 281 
five rows of feet would act in antagonism to one 
another ; for there seems nothing more to determine 
either the action or the inaction of one row rather 
than another. Indeed, if there were any moral 
philosophers among the Echinoderms, they might 
point with triumph to the fact of their being able 
to right themselves as an irrefutable argument in 
favour of the freedom of the Echinoderm will. “We 
are in form,” they might say, “ perfectly geometrical, 
and our feet-rows are all arranged with perfect 
symmetry ; therefore there is no reason, apart from 
the sovereign freedom of our choice, why we should 
ever use one set of feet rather than another in exe- 
cuting this important movement.” And indeed, I 
do not see how these Echinoderm philosophers could 
be answered by any of the human philosophers, who, 
with less mathematical data and with less physio- 
logical reason, employ analogous arguments to prove 
the freedom of the human will. Physiologists, 
however, would give these Echinoderm philosophers 
the same answer that they are in the habit of giving 
to the human philosophers, viz. that although the 
physiological conditions are very nicely balanced, 
they are never so nicely balanced as to leave 
positively nothing to determine which rows of feet 
—that is to say, which sets of nerves—shall be 
used. And in this connection I may observe that 
on making a number of trials it becomes apparent 
in the case of certain individual specimens that 
they manifested a marked tendency to rotate 
always in the same direction, or to use the same set 
of foot-rows for the purpose of righting themselves. 
