REMARKS ON THE FIGURES OF PLATE XXX. 
MAMMALIAN PROPORTIONAL SERIES VARY AS TO THEIR NUMERICAL LENGTH. 
LE which persist in full quantity, and archetypes which have undergone metamorphosis, 
. and now present as proportional quantities, are those figures which constitute the mammalian-serial 
axes. The mammal series is a design by the loss of quantity, and this quantity is proper to the plus 
costo-vertebral series. It is the law of proportioning or metamorphosis which has degraded the plus serial 
originals, and which are now presented to us in proportional variety, from being once absolute archetype 
uniformity. The numerical proportional length of the mammal serial axis mainly depends upon the 
numerical situation of that archetype unit of series, which having undergone the greatest amount of 
subtraction, exists as it were on the extreme verge of entity, and next to the state of nihil. The ultimate 
caudal nodule is the vanishing point of series, but the numerical position of this point is by no means 
fixed and invariable for even one species, much less for two or more species. The caudal prolongation 
is that region of the serial proportional axis which varies most as to numerical length, and it is impos- 
sible to determine its precise limits in any animal. When it is described as commencing immediately 
after the last sacral vertebra, and as terminating at the last caudal bone, this account does not pretend 
to assign to it a fixed numerical length: moreover, it is not the less true that any other region of series 
is fluctuating in the like inconstancy of number, and therefore it is that uncertainty attends all particular 
descriptions of the mammalian serial axis, because it is a series of proportional quantities which give 
instance of the infinitude of minus variation, and cannot be encompassed by any other mode of description 
save that of generalisation. 
In the serial spinal axis we discover that the units suffer | terminated below, at caudex, then we would have it to be 
modification from plus quantity to minus quantity. Thus | understood that this last caudal unit marked 38, fig. A, is a 
a lumbar vertebra is minus compared to a plus costo-ver-.| proportional of its own archetype quantity, which may be 
tebral archetype, and so is a terminal caudal ossicle minus | said to equal the unit marked 15 a, of the thoracic series, 
compared with the lumbar:vertebra. For which reason | and in this reading we endeavour to account for the fact 
the caudal quantity must also be interpreted as minus the | that the same numerical unit of separate axes is seen to 
thoracic quantity, and hence we interpret that each region | present the like modifications from plus to minus quantity. 
of spinal series terminates and commences at those units The opposite figures represent various species of the 
which happen to be subjected to that degree of modifica- | monkey tribe, and we have marked by digital numbers 
tion which each spinal region instances ; hence, also, each | all the units of each serial axis, counting from the first 
spinal series may be interpreted as terminating at that | unit succeeding the occiput to the terminal caudal ossicle 
unit which is an example of the lowest degree of quantity, | below. Every unit bearing the same mark, in each 
such as we find in a terminal caudle ossicle. Now from | skeleton axis, is seen to present no other difference than 
this it is clear that any unit whatever of series, such as | that consequent upon the law of proportioning. 
thoracic quantity, would, if subjected to the same degree In fig. A we say that the unit marked 20, is a propor- 
- of metamorphosis, which at one place fashions the cervical | tional of such a unit as that marked 19, above it. If this 
vertebra, at another the lumbar vertebra, and at another | be true, then we say that fig. A, such as it appears in 
the caudal vertebra, furnish the like form of quantity, | creation, is as a special modification planned from a series 
such as we find in the cervix, loins, or caudex. of thoracic archetypes, holding a serial order from occiput 
For example, when we say that fig. A is a serial axis | to the other extreme of the same series. It is true that 
