1905.] OSTEOLOGY OF THE EURTL^MIDiE. 43 



The quadrato-jugal is long, extending to beyond the middle of 

 the orbit. 



The vomer is not yet ossified. 



The ixdathies difler from those of the adult in that the trans- 

 palatine elements (?) are as yet membranous. 



The j^terygoid 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 pteiygoid shaft retains its primitive 

 integiity, but that the hemipteiygoid element has been lost, 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 

 Euryl?emida3, is suppoi-ted entirely by the palatines, as in all other 

 cases where the hemipteiygoid 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 Yeetebral Column. 



All the presynsaci-al vertebrae are hetei'oco^lous and free. 



The cervical vertebrae are characterised by the deeply incised 

 neural plates of the 6th- 10th vertebrae, where the posterior 

 zygapophyses are bome 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 thiixl have large quadrangular 

 neiu^al plates, the hinder angles of which in the third vertebi'a are 

 produced upwards into strong hyperapophyses. The outer borders 

 of these plates are pierced, on each side, by a small foramen. The 

 hyperapophyses of the 5th to 8th vertebi'se ai-e placed about 

 midway between the neural spine and the posterior zygapophysis. 

 From the 5th to 11th vertebrae 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 vertebrae ; 

 the 7th to 10th bear catapophyses, feebly developed ; hypapo- 



