CERVICAL VERTEBRAE OF HESPERORNIS. 39 



In addition to the figures of this vertebra given in Plate IV. the 

 accompanying cut shows the posterior aspect of the same specimen. 



Figcre 10. — Fifteenth vertebra of Sesperorriis regalis, Marsh; (No. 1207), posterior view; natural size. d. 

 diapophysis; p. parapophysis ; h. hypapophysis ; nc. neural canal ; s. neural spine ; z. pre-zygapophysis ; 

 z". post-zygapophysis. 



The measmements given below are from three vertebrae, in different 

 individuals of Sesperomis regalis. 



Measurements of Fifteenth Vertebra. (No. 1207.) 



Length of centrum,. - 22.0 11 



Transverse diameters of anterior articulation of centrum, 14.0-22.0 



Vertical diameters of anterior articulation of centrum, 6.5- 7.5 



Transverse diameters of posterior articulation of centrum, 14.0-19.0 



Vertical diameter of posterior articulation of centrum, 13.0 



Transverse diameter of vertebra, across pre-zygapophyses, 36.0 



Transverse diameter of vertebra, across post-zygapopbyses, 33.0 



Diameters of pre-zygapophyses, 12.5-12.0 



Diameters of post-zygapopbyses, 13.0-11.0 



Length of floor of neural canal, - 22.0 



Length of roof of neural canal, 19.0 



Transverse diameter of neural canal, at anterior opening, 9.0 



Vertical diameter of neural canal, at anterior opening, 7.5 



Transverse diameter of neural canal, at posterior opening, 8.0 



Vertical diameter of neural canal, at posterior opening, 9.0 



Length of hypapophysis, - 20.0 



Length of bifid portion of hypapophysis, - - 5.0 



Diameters of articulation for head of rib, 5.2- 3.5 



