9 
represent the structure of the mollusc which produces 
it, although moulded upon its surface, or formed from 
its secretions. It is wonderful, however, to see how 
near an approach to symmetry occurs in even inor¬ 
ganic matter when its form is determined by uncon¬ 
scious vital force. This is most especially conspicuous 
in the whole race of Corallines. 
14. Symmetry may be defined to be the general 
correspondence of one half of a given object with the 
other half, in structure, or other perceptible circum¬ 
stances ; or the general correspondence of one side of 
an object with the opposite side, in structure, or other 
perceptible circumstances. 
15. If understood in such a sense, all living objects 
whatever will be included under the denomination of 
symmetrical. That which we find universally in 
the animal kingdom, belongs to all parts of the living 
world, and must therefore occur equally in plants, 
however unlike animals they may be. The student’s 
attention cannot be directed too closely to this im¬ 
portant law, from which there is no real departure, 
except owing to accidents ; such as those which pro¬ 
duce monsters in objects with which we are most 
familiar. Indeed symmetry in plants arises out of 
their peculiar nature. It is dependent upon a highly 
complicated internal structure, which is in itself es¬ 
sentially symmetrical. The basis from which organs 
proceed being symmetrical, it seems to be an evident 
inference that the organs themselves should be sym¬ 
metrical also. A few illustrations will render this 
sufficiently obvious. 
16. Take a section of the stem of any palm tree; of 
the Sechelles Cocoa nut, for instance. It has a bark 
similar to what we are familiar with in other plants; 
a 5 
