Osteological Studies of the Sub-Family Ardeince. 
19 
postzygapopliyses face directly downwards, and the entire bone is 
much compressed from side to side. From the third to the 
sixth, the vertebrae are much elongated ; their general pattern 
being seen on side view in Fig. 27. Along the median line of 
their neural arches above, these bones are thin and sharp. Their 
several articular facets are so arranged that they only permit the 
head to be bent forward and back again. 
The neural canal in them is small and 
circular on section. The ‘ vertebral canal’ is 
present in all, being longest in the third verte¬ 
brae and shortest in the sixth ; owing to the 
manner in which the parapophyses assert them¬ 
selves. This is done by a foramen, which ex¬ 
ists opposite the middle of the canal in its lat¬ 
eral wall ; this elongates in the vertebrae from 
third to sixth, in a backward direction until it 
cuts through the hinder and outer margin of 
the vertebral canal of the sixth vertebra. Then 
a long pair of parapophyses is the result, they 
being very short and blunt in the third, fourth 
and fifth vertebrae, and only become sizable in 
the sixth when overtaken and developed by the 
advance and breaking through of the foramen 
in the manner indicated. 
A large covered “ carotid canal” is seen 
in the seventh to the thirteenth cervical verte¬ 
brae, inclusive ; a slight deficiency taking place 
in the wall of the last, in the median line be¬ 
neath. (A. he rodias.) It is the most anterior 
part of each of these segments, and they are 
further characterized by being shorter and 
stouter than the last four described. The pneu¬ 
matic foramina of these vertebrae are chiefly 
within the neural canal, piercing its upper 
wall posteriorly. From the fourteenth to the 
bv the author. 
seventeenth inclusive, these vertebrae are gradually changing in 
form and character to resemble finally those of the dorsal re¬ 
gion. The fifteenth is the first to show a high neural crest, with 
spreading diapophyses at the fore part of the vertebra, while the 
vertebra terial canal increases in calibre. 
