1905. ] OSTEOLOGY OF THE EURYLEMID&. A3 
The quadrato-jugal is long, extending to beyond the middle of 
the orbit. 
The vomer is not yet ossified. 
The palatines difter from those of the adult in that the trans- 
palatine elements (?) are as yet membranous. 
The pterygoid is rod-shaped, bent at its posterior extremity at 
an obtuse angle, so as to fit closely to the parasphenoidal rostrum. 
The free end of this rod is pointed, and bears a small pointed 
piece of cartilage. Whether this represents the hemipterygoid, 
or, as seems more likely, the unossified extremity of the shaft, is 
a point which can only be determined by the examination of 
somewhat older skulls. 
The palatine extends backwards beneath these bent limbs of the 
pterygoid. 
The apparent absence of the hemipterygoid is a point of con- 
siderable interest. The interpretation to be placed upon this fact 
is, I think, not that the pterygoid shaft retains its primitive 
integrity, but that the hemipterygoid element has been Jost, just 
as it has in many other groups of birds. My reason for this view 
is that the vomer, which shows various grades of reduction in the 
Eurylemide, is supported entirely by the palatines, as in all other 
cases where the hemipterygoid has been greatly reduced or is 
wanting. 
There is nothing remarkable in the absence of this element, 
because, as has been shown, the skull in this group is highly 
specialised in many ways. 
The elements of the mandible are as yet distinct. 
iv. THE VERTEBRAL CoLUMN. 
All the presynsacral vertebree are heteroccelous and free. 
The cervical vertebre are characterised by the deeply incised 
neural plates of the 6th—10th vertebrae, where the posterior 
zygapophyses are borne upon the under surface of the free ends 
of long beams. 
The atlas has the odontoid ligament perforated. 
The axis bears a large tooth-like neural spine and a large pair 
of hyperapophyses. The second and third have large quadrangular 
neural plates, the hinder angles of which in the third vertebra are 
produced upwards into strong hyperapophyses. The outer borders 
of these plates are pierced, on each side, bya smallforamen. The 
hyperapophyses of the 5th to 8th vertebre are placed about 
midway between the neural spine and the posterior zygapophysis. 
From the 5th to 11th vertebra the neural plates are deeply incised 
both before and behind the neural spine. The neural spines 
gradually decrease in size from before backwards, so that from the 
9th to the 12th they are represented only by the merest tubercle. 
Hypapophyses are borne by the 2nd, 3rd, 4th, and 5th vertebre ; 
the 7th to 10th bear catapophyses, feebly developed ; hypapo- 
