174 ELEMENTS OF ORNITHOLOGY, 
each of which is called an ilium—one of them abutting against 
its whole length on either side. 
Looked at on the ventral surface, there is a continuous 
median bone—made up of the centra of the anchylosed vertebre 
—which is narrowest towards the anterior and more posterior 
parts of the sacrum, and is somewhat broad and flattened towards 
its middle from before backwards. ‘Transverse processes pro- 
ject outwards conspicuously both in front of and behind this 
median part, on either side of which no such prominences are 
conspicuous, so that a depression or hollow appears between 
that median part and the ilia beside it. This hollow receives 
and shelters a portion of the kidney. 
The most anterior lwmbo-sacral vertebree show well developed 
diapophysial (higher) transverse processes, which become gra- 
dually augmented, from before backwards, by parapophysial 
(lower) transverse processes joined with them, and all these abut 
against the ilium. There may be from two to five or more of 
these vertebre. (Fig. 149, 1-7.) 
The true sacral vertebree are those without conspicuous para- 
pophysial transverse processes, though they may be represented 
by very short blunt processes, whereof one projects from the 
front and another from the hinder part of the side of each 
centrum. 
The “ diapophyses” are in the form of lateral plates which 
pass outwards, one from either side of the neural arch, to an- 
chylose with the ilium against which they abut. There may 
be from two to five of these vertebra. 
The wro-caudal vertebre are plainly distinguishable by their 
conspicuous slender lateral processes, which are directed out- 
wards, backwards, and upwards, and the first three or four of 
them are for a time united by suture * with their centra, so as 
to seem more or less distinct in nature. They recall to mind 
the pleurapophysial processes of the cervical vertebrae, which 
are, for a time, distinct and separate bones. As the latter are 
termed cervical ribs, these sacral annexed lateral parts may 
be called sacral ribs. Besides these, the uro-caudals give out 
plate-like diapophysial processes. The whole series of lateral 
processes, whereof those just described are the most anterior, 
* A suture is a line indicating the junction of two bones by a more or 
less extended apposition of their edges instead of by any other kind of 
joimt 
