PHYLOGENY OF THE PALZOGNATHA AND NEOGNATH. 211 
Casuarius in having a bony bar running from the diapophysis backwards to the 
hyperapophysis. 
The thoracic vertebre call for no special remark here. ‘They have already been 
minutely and carefully described by Mivart. 
The vertebra known as the cervico-thoracic should probably be regarded as true 
thoracic vertebra, the ribs of which have lost their sternal segments through the 
backward shifting of the sternum. ‘This view has already been promulgated by the 
late T. J. Parker. Writing of Apteryx, he says: “The occasional absence of 
the cervico-thoracic uncinates, taken in connection with the vestigial condition of the 
ribs in one case and with the fact that in the same skeleton the first thoracic rib 
of the right side terminates ventrad in a blunt free end and has no sternal portion, 
seems to point to an inclusion of anterior thoracic vertebre in the cervical region by 
atrophy of their ribs.” 
b. The Synsacral Vertebre. (PI). XLV. fig. 5.) 
In Casuarius there are 8 (eight) pre- and 8 (eight) post-sacral vertebre, with the 
two true sacrals numbering eighteen synsacrals. 
Of these, two are thoracic. The Ist lumbar has large parapophysial processes; the 
2nd to 3rd of this series are much smaller; the 4th and 5th become larger and 
abut, the 4th against the pectineal process and the 5th against the ischium. Behind 
these follow two lumbo-sacral. The true sacrals are closely crowded and have slender 
parapophysial processes, which abut against the ilium and ischium immediately behind 
the acetabulum. Behind these in C. bicarunculatus lie two pseudo-sacrals with large 
parapophysial processes abutting against the ilium. But for the sacral plexus they 
might readily be mistaken for true sacrals. They are really the first two caudals, behind 
which follow six fused caudals with diminishing and backwardly directed transverse 
processes. In other Cassowaries there is but one pseudo-sacral. The sacral vertebre 
do not bear diapophyses. 
In Dromeus the number of synsacral vertebre is the same as in Casuarius. The 
6th lumbar, however, does not send out a parapophysis to abut against the pectineal 
process. 
The neural spines of the synsacral vertebra are all highly pneumatic, and made up 
of loose cancellated tissue. ‘They remain separate for some time after hatching, but 
in the adult are fused into one mass, all traces of separate vertebre being lost. In the 
young bird the pre-sacral vertebre are just distinguishable between the closely 
approximated pre-acetabular regions of the ilium. The post-sacral have the neural 
spines laterally expanded so as to keep the post-acetabular ilium moderately widely 
separated, so that between each vertebra is a deep loculus (Pl. XLIV. fig. 5). 
In the adult the whole becomes roofed over by a thin bony plate extending across 
from the post-acetabular ilium of one side to that of the other. 
