34 ODOXTORXITHES. 



Measurements of Eleventh Vertebra. (Xo. 1207.) 



Length of centrum, 29.0" 



Least diameter of centrum, at base, -- 9.0 



Transverse diameters of anterior articulation of centrum, - 14.0-1 7.0 



Vertical diameter of anterior articulation of centrum, - 8.0 



Transverse diameters of posterior articulation of centrum, 11.0-14.0 



Vertical diameters of posterior articulation of centrum, 7.5-12.0 



Transverse diameter -of vertebra, across pre-zygapophyses, - 39.0 



Transverse diameter of vertebra, across post-zygapophyses, 32.0 



Greatest diameter of pre-zygapophyses, 13.0 



Least diameter of pre-zygapophyses, . 8.0 



Greatest diameter of post-zygapophyses,.. 13.0 



Least diameter of post-zygapophyses, - 9.5 



Length of floor of neural -canal, .. 27.5 



Length of roof of neural canal, 21.0 



Transverse diameter of neural oanal, at anterior opening, 9.0 



Vertical diameter of neural canal, at anterior opening,.. 5.5 



Transverse diameter of neural -canal, at posterior opening, 10.0 



Total length of pleurapophysis, _ 30.0 



Length of free portion of pleurapophysis, 24.0 



Diameter of pleurapophysis, at base, 7.2 



Transverse diameter of lateral foramen, 7.0 



Vertical diameter of lateral foramen 8.0 



The Twelfth Vertebra. (Plate IV, figure 3.) 



The twelfth, vertebra is shorter than the eleventh, and the zyga- 

 pophyses are more approximated. The post-zygapophyses are tubercular 

 above, and the neural spine is rudimentary. The diapophysis is more 

 projecting, but a little less elongated, than in the eleventh vertebra. 

 The lateral foramen for the vertebral artery is larger, and the descending 

 processes stronger. The pleurapophyses are somewhat shorter than in the 

 preceding vertebra. 



The dimensions of a nearly perfect twelfth vertebra of Hesperomis 

 regalis are given in the table which follows : 



Measurements of Tioelfth Vertebra. (No. 1207.) 



Length of centrum, 24.0 mm 



Least diameter of centrum, at base, 7.0 



Transverse diameters of anterior articulation of centrum, 12.0-14.2 



Vertical diameters of anterior articulation of centrum, 7.5- 9.0 



Transverse diameter of vertebra, across pre-zygapophyses, 46.5 



