REMARKS ON THE FIGURES OF PLATE VII. 
VERTEBRA OF TRANSITION ARE COMPARED TO EACH OTHER. 
[fae several classes of Vertebre standing in series are linked together by vertebral forms which are of 
equivocal character, that is to say, of a caste which may be as well classed with one as with the other of 
those vertebree which they enchain together. The last cervical vertebra simulates the form of the first dorsal. 
The last dorsal vertebra partakes of the character of the first lumbar, and the last lumbar nearly represents 
the form of the first sacral vertebra. The spinal axis, viewed as a whole, gives example of an uninterrupted 
series of individual vertebree, and in it we also find that there exists a series of vertebral classes successionally 
arranged, such as the cervical, dorsal, lumbar, sacral, and terminal figures. Individual vertebrae are seen to 
stand in continuous order, from first to last, through series ; and so in like manner do we find that individual 
vertebral classes hold serial order with each other, hiatus appearing nowhere. Absolute variety, therefore, 
does nowhere exist amongst serial forms which are developed as one connected entity. And as this is the 
condition of a spinal axis, it must follow that uniformity is a positive condition of growth, attaching to this 
particular at least. Graduated modification of primitive uniformity is the characteristic of the vertebral line. 
Transitional vertebrae stand between those of the 
cervical and dorsal classes, between those of the dorsal 
and lumbar classes, and between those of the lumbar and 
sacral classes. Those vertebral forms which succeed the 
first sacral vertebra are graduatedly proportioned down to 
the quantity of the last caudal bone. 
Fig. A’ is the 6th cervical vertebra. Fig. A” is the 7th, 
and fig. A” is the 1st dorsal vertebra. In these three forms 
we mark a slight transitional modification, but whilst their 
elemental parts are the same, the modification can be no 
other than such as suits with the mechanical design of each. 
Fig. B’ is the 11th dorsal vertebra, fig. B” is the 12th, 
and fig. B’” is the 1st lumbar vertebra. In these we also 
discover transitional modification, yet the elemental parts 
are still the same in each, and identical also with those of 
the cervical class. 
In figs. C’C”C’”” we see the transitional variation from 
the 4th lumbar figure C’, through the 5th lumbar C”, to 
the first sacral C’”’, but still the elemental pieces persist 
the same in each, and also the same with those of the 
dorsal and cervical classes of vertebre. 
In fig. D’ we see the 5th sacral form to be a propor- 
tional of C’”’, the first sacral form, and also that D” is the 
proportional of D’, just in the same rule which renders D” 
the proportional of D’, or D’” the proportional of D”’. 
Between transitional vertebre the modification of form 
is almost imperceptible. The cervical units pass into the 
dorsal units in such slight shades of change that it is 
impossible to mark the difference anywhere between them. 
The same may be said of the transition of vertebrae of the 
dorsal class to those of the lumbar, and the same remark 
holds good of the passage from lumbar to sacral vertebral 
formation. 
But from sacral figures to caudal forms, the transition 
takes place from plus quantity to the minus. Some of the 
elemental structures of a first sacral vertebra are subtracted 
in order to fashion the last caudal bone; by which we 
mean that a caudal bone has been metamorphosed from a 
quantity originally equal to a first sacral figure: and this 
interpretation is equal to saying that all vertebree, from the 
occiput to the terminal caudal fractional, have been origi- 
nally equals; the rule of subtraction being that which 
renders them unequal whenever they happen to be so. 
It is by the addition of the costal piece to the dorsal 
vertebra that this quantity has been equated with the 
cervical or lumbar vertebra. It is by the subtraction of 
certain elemental parts from the vertebral type thus esta- 
blished in the cervical, dorsal, and lumbar spinal regions, 
that the small fractional of a caudal bone has been meta- 
morphosed to its own special condition of development. 
When we say that any form of lesser quantity has been 
metamorphosed from a plus quantity, we then are obliged 
to name the plus as archetype of the minus. The vertebra 
is archetype of the caudal fractional. 
Figs. A’B’ and C’ are equals or homologues. But figs. 
D’'D’D” D” are the proportionals of such homologues. 
