132 ODOXTORNITHES. 



together enclose the lateral foramen of the centrum. The posterior 

 prolongations of the pleurapophyses are broken off. 



The pre-zyg-apophyses look upward and backward at an angle of 

 nearly 45°, and a little inward. They are elongated, being fully twice as 

 long as broad, and are semi-oval in form. At the sides of the vertebra, 

 they are connected by a ridge with the bases of the post-zygapophyses. 

 AboA^e this riclge, on each side of the vertebra, is a deep foramen, appar- 

 ently pneumatic. The post-zygapophyses are similar in shape to the pre- 

 zvgapophyses, but look nearly directly downward, and a little outward. 

 They are each surmounted by a low tubercle, which does not project 

 beyond the zygapoph} T sis, but is placed nearly above the middle of it. 

 The upper surface of this vertebra is flattened, and destitute of a neural 

 spine. It presents a shallow oval depression at the middle of the anterior 

 margin, and, behind, shows a similar, but somewhat larger and deeper 

 median pit for ligamentary attachment. 



The principal dimensions of the tenth vertebra of Ichthyornis victor 

 are as follows : 



Measurements of Tenth Vertebra. (So. 1733.) 



Length of centrum, 6.0 mm 



Transverse diameter of anterior articulation of centrum, 3.0 



Vertical diameter of anterior articulation of centrum, 2.1 



Transverse diameter of posterior articulation of centrum, 2.8 



Vertical diameter of posterior articulation of centrum, 2.8 



Transverse diameter of neural canal, 2.7 



Vertical diameter of neural canal, 2.2 



Transverse diameters of vertebra, across pre-zygapophyses, 8.8-10.0 



Transverse diameter of vertebra, across post-zygapophyses, 8.5 



Transverse diameter of lateral foramen, 2.0 



Vertical diameter of lateral foramen, 1.8 



The Twelfth Vertebra. (Plate XXII, figure 1.) 



A vertebra here regarded as the twelfth of the series (number 1450) 



resembles the eleventh cervical of Sterna regia. The centrum is much 



reduced in thickness near the middle, and is pierced on each side by a 



pneumatic foramen. A strong hypapophysis arises from the anterior part 



