450 MR. ST. GEORGE MIVART ON THE 
Looking mainly dorsad in the cervical region, they come to look mainly inwards in 
the dorsal region. 
Postzygapophyses. 
These may exist without prezygapophyses, as in the atlas. 
They undergo changes of form and direction corresponding with those of the prezy- 
gapophyses, but they never become quite so small as do the latter in the dorsal region. 
Metapophyses. 
These processes would escape notice were it not for their recognition through their 
more developed homologues in other animals. 
They are more or less to be distinguished outside and ventrad of the prezygapophyses 
from the fourth vertebra to about the eighteenth, after which they seem to merge in 
the wider diapophysial expansion. 
Hyperapophyses. 
These are only conspicuous in the axis and the third and fourth cervical vertebra, where 
they are situated above the postzygapophyses. Rudiments of them are to be found on 
the atlas, and on vertebri postaxial to the fourth, till perhaps the tenth vertebra. 
Paraxial Parts. 
By paraxial parts' 1 mean those portions of the skeleton which diverge from the 
centra and neural arches laterally, and tend to surround the visceral cavity. 
They include:—1, upper transverse processes or diapophyses; 2, lower transverse 
processes or parapophyses; 3, pleurapophysial parts, 7.¢. the ribs, with their capitular 
and tubercular portions, sternal ribs, and sternum, or parts representing the whole or 
portions of each pair of capitula and tubercula, with only a rudiment, or without any 
rudiment, of more distal pleurapophysial elements. 
These parts considered as one whole are, of course, as to size, most developed and 
most differentiated in the true dorsal vertebra. 
They are least differentiated in the true caudal region, where they stand out laterally 
as simple imperforate “‘ transverse processes.” 
Diapophyses. 
These are, with the neural spines, the most constant of all the processes, appearing 
even in the lumbar, dorsal, and caudal regions, where there are no zygapophyses. 
More or less antero-posteriorly extended in the cervical region, they are much so in 
the dorsal one. In the lumbar region they are long and slender, singularly remote 
from their respective parapophyses, and widely diverging from the latter. 
In the first four postsacral vertebre the diapophyses quite coincide with the para- 
’ See P. Z.S, 1870, p. 260, note; and see also Trans, of Linnean Society for April 21, 1870. 
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