REMARKS ON THE FIGURE OF PLATE XLIX. 
THE LAWS OF SYMMETRY AND SERIAL HOMOLOGY PRESIDE OVER THE GENESIS OF FORMATION. 
oe is not created equally for all forms which are produced of the same order or cast. Skeleton 
. quantity is not equal for all animal fabrics. Not only is this the fact with regard to the skeleton forms 
of the four animal classes of mammals, birds, reptiles, and osseous fishes ; but even mammal forms themselves 
present unequal skeleton quantities, and the same inequality of osseous quantity is manifested amongst birds 
as a class, amongst reptiles as a class, and also amongst osseous fishes. Equality or absolute uniformity is 
not in Nature. Inequality may be seen to characterise even two or more human skeletons at the adult age. 
And as, through all the phases of development or formation, inequality is the word, so is there no other 
condition of formation presented to the contemplation of the comparative anatomist, except that of minus 
quantity standing in the presence of plus quantity. The law of serial proportionals is, therefore, the only 
existing theme; and serial progressions and proportions is the subject, whether we rise with the growth of 
the individual framework from infancy to manhood, or pass, with the operation of this transcendent law, 
from one extreme to the other of an animal kingdom. What the giant is to the dwarf, the adult is to 
the foetus, viz., a plus fabric in presence of a minus quantity. Where then is uniformity? If absolute 
equality or uniformity cannot be found either in the individual at various stages of its being, or even between 
two beings of one species at the same stages of formation, or even between any two beings of an animal 
kingdom at various or the same phases of development ; if an ever-moving metamorphosis be the law of 
‘Nature, which, by the creation of inequality everywhere, leaves equality or uniformity persistent nowhere ; 
what then is to be the goal and object of comparison? This object resides in the differentials of serial 
proportionals ; and we believe that the exact knowledge of the quantity which differences proportionals to 
one another, can never be attained without having some fixed standard of comparison, to which, as being 
uniformity or the whole quantity, those infinite proportionals may be referred. Therefore, uniformity is 
the rational object of the comparative method, and equation is the means by which we are to develope 
the ideas of it. 
The endo-skeleton increases from minus to plus quan- 
tity in the individual animal body. In the embryonic 
state of the mammal body the-skeleton fabric is minus. 
In the adult state of the mammal, the skeleton has become 
plus, and hence the adult state must be regarded arche- 
type of the embryonic state. The process of growth is the 
process of perfectioning. ’Tis true that the foetal condi- 
tion of a skeleton quantity is as perfect. and fitting for 
that stage of the being as the adult full skeleton quan- 
tity is for the adult being; so, therefore, what we here 
mean by the term “process of perfectioning,” is the 
process of increase from minus to plus quantity, the 
addition of quantity to the fraction, until the integer be 
created. Every stage of development for the individual 
skeleton which has added an elementary part to the quan- 
tity existing at a former stage, may be regarded as arche- 
type of all former stages of the growing ens, and every 
arrest of development at any one stage of the individual’s 
growth, may be regarded in the light of subtraction 
compared with adult quantity, forasmuch as the form is 
similarly affected whether it be arrest of development or 
subtraction of parts. If the 12th costa be never produced, 
