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individuals form a continuous progression of stages of development. 
If we survey the whole progression, we can observe that the 
difference, existing between the most primitive stage and the highest, 
is greater than the differences in the composition of the vertebral 
columns not only in some species, but even in several genera of 
Primates. 
Consequently it is not an unimportant part of the history of the 
human vertebral column that the formulas allow us to survey. 
Three dorsal vertebrae have successively become proximal lumbal 
vertebrae, three distal lumbal vertebrae have the one after the other 
been lodged in the proximal part of the sacrum, and from the distal 
extremity of it gradually tree vertebrae have passed into the caudal 
region, which has lost three vertebrae at the extremity. 
The diminution of the number of praesacral vertebrae does, 
however, not. necessarily involve a shortening of the trunk; by 
measurements we can come to the conclusion, that in the higher 
stages the bodies of the vertebrae become higher and this occasions 
a compensation. 
In the sternum and the arcus costarum, too, analogous modifications 
take place. 
All these observations justify the notion, that in the region of the 
trunk an important transformation is working; the processes in the 
vertebral column can certainly not take place, if the parts of the 
body, surrounding this extensive organ, do not participate in the 
transformation. 
The knowledge of these processes must consequently exercise an 
influence on the descriptions which systematical and topographical 
anatomy give of the composition of the trunk. Both branches of 
science pay too little attention to the transformation of the organism. 
I cannot enter into further details on this subject now ; in con- 
clusion I wish only to point out in a few words the importance of 
the series of formulas with regard to anthropology. 
This becomes apparent when we consider, how the vertebral columns 
are arranged by the series of the stages. 
The result appears from a graphical representation *). 
On horizontal lines, answering to the stages, the specimens belonging 
to each stage are indicated by dots. 
At the end of each line the accessory forms are indicated by marks, 
placed either a little lower or a little higher, further is denoted, what 
characterizes each accessory form. 
The rows of the representatives of each stage have been placed 
'!) This will be published in another communication. 
