REMARKS ON THE FIGURES OF PLATE XIV. 
THE DUPLICATION OF VERTEBRAL SERIES GIVES THE FORM AN ANTERO-POSTERIOR SYMMETRY. 
A SERIES of equal quantities which constitute a uniform line will still retain fvougti metamorphosis 
the character of uniformity, provided the modification which may affect any one quantity in. any 
one manner shall operate in the same way on all the others.. When vertebral forms are plus throughout 
the serial line, we shall see that such plus series is uniform to itself, When from each of these plus 
Tune equal quantities shall be subtracted, these forms of proportioning will still be uniform with one 
another. When, again, from plus vertebree unequal quantities shall be subtracted in several parts of series, 
then series is struck difform to itself, but the difformity is relative not absolute, for it has resulted by process 
of subtraction. Lastly, we find that whatever be the condition of the serial line, whether it be equal or - 
unequal throughout. its extent, still the duplication of the series yields a figure of symmetry both as to 
lateral and antero-posterior faces. The equality of serial forms is-synonymous with the homology of those 
forms. The multiplication of equal forms in series implies the condition of uniformity. When we compare 
with this state of formation another state, wherein we find that forms are multiplied in series, at the same 
time that the process of subtraction is rendering those forms unequal to one another, then all we can 
truthfully understand of the series thus produced is, that if subtraction had not occurred, plus equals would 
have persisted through uniform series ; but subtraction having occurred, and serial inequality being the result, 
we then attribute the effect to the cause, and know the secondary state of modification by comparing it to 
the primitive uniform state. Now the symmetry of serial sides is, like series, dependent upon the repetition 
of form ; and as series may be modified from plus to minus quantities, so may symmetry become exceptional 
by the very same law of proportioning. We seldom find that bilateral symmetry is interrupted, whatever 
be the degree of modification carried out upon series. But more frequently we find that antero-posterior 
symmetry does not endure, and the sole cause of this may be dependent upon the metamorphosis of dorsal 
structures. For we see that the ventral face is plus compared with the dorsal face of the mammal spinal 
axis, and also that the repetition of the dorsal structures at the ventral region gives the entire form a dorso- 
ventral symmetry. 
Symmetry is the repetition of form. Any figure, which 
considered, per se, instances the most awry character, 
will, when doubled or repeated, and placed opposite to its 
The law of 
symmetry, therefore, is, in essence, dependent upon no 
counterpart, produce the form of symmetry. 
other fact than that of Nature repeating her prime crea- 
tion. The side is homologue of the other side, because 
Nature has repeated the side. 
We have seen that all vertebre of series are cleavable 
through the median line passing from the spinous process 
behind through the centre of the body before; and we 
have also seen, that when a vertebra was divided through 
its transverse diameter,.the resultant pieces were dis- 
similar; but we have further seen that when two vertebre 
were placed body to body, then an entirety of form was 
constructed, which was capable of being divided into 
symmetrical sides, both by transverse and perpendicular 
cleavage. ‘The same remarks apply to the spinal series, 
when viewed as a whole. 
The mammalian spime of human form is capable of 
