CLELAND ON RIBS AND TRANSVERSE PROCESSES. 
117 
scientific anatomy, that it sliould be solved. If we cannot understand 
the laws of variation of the most constant elements of the skeleton, 
how shall we expect to comprehend those of the most changeable ? Yet 
it is the fact that, though the bones and processes proceeding from the 
vertebral column have long been a subject of study to anatomists, 
and the varieties which they present have been carefully observed, 
and many of them minutely recorded, no one can point, amid the 
variety and uncertainty of opinion that still prevails, to any largely 
admitted demonstration of the relations of the transverse processes, 
ribs, and inferior spines of fishes to parts in the higher vertebrata. 
Having had my attention recently drawn by circumstances very 
particularly to the processes of the vertebral column, and being con¬ 
firmed in a conviction that the difficulties which have been encoun¬ 
tered in the study of their correspondences have arisen in great part 
from the skeleton being looked on too often as a structure arranged 
round the chorda dorsalis as its sole axis, I venture, at the risk of 
being thought over-speculative, to tread upon this oft-trodden ground, 
endeavouring, however, to use not speculation, but analysis, as the 
instrument of inquiry. 
Before passing to the more general part of the subject, we shall 
find that some useful lessons may be drawn from the simpler study 
of the varieties of mammalian vertebrae. 
The processes passing out laterally from the vertebral column in 
mammals, viz. the transverse, the mammillary and the accessory, are 
well understood in their relations among themselves; and especially 
the varieties wffiich they present in different families have been made 
the subject of elaborate investigation by Prof. Betzius. # 
The learned Professor has very satisfactorily shown that the mam¬ 
millary, accessory and transverse processes of the lumbar region in 
the human subject are all of them represented by the transverse pro¬ 
cesses of the dorsal region. That this is the case one may easily 
convince one’s-self by observing on a well marked specimen the three 
tubercles upon the transverse process of the 12th dorsal vertebra. 
These tubercles are manifestly serial with the three processes in the 
lumbar region; while it is equally obvious that the whole process 
corresponds to the transverse processes of the vertebrae above it. 
These correspondences are ably illustrated by Mr. Humphry in 
his “ Treatise on the Human Skeleton” (p. 141). They become yet 
more fully appreciable on examination of the muscular attachments. 
We trace the transverso-spinales muscles passing upwards and inwards 
from the mammillary processes and from the superior and inner angles 
of the extremities of the dorsal transverse processes; while the inner 
row of attachments of the longissimus dorsi are inserted into the 
accessory processes, and into the inferior angles of the extremities of 
* Ueber die richtige Deutung der Seitenfortsatze an den Riicken und Lenden- 
wirbeln beim Menschen und bei den Saiigethieren. Translated from the Swedish 
Muller’s Archiv. 1849, p. 593. 
