Cope.] ^V [Dec. 21, 



caudals of this one. The sides of the centrum are strongly concave, and 

 the borders of the cup flaring. The neural arch is everywhere excavated, 

 so as to reduce the bulk, and produce lightness so far as consistent with 

 strength. The diapophysis rises from a point above the neural canal. It 

 sends a narrow ridge clown to the sides of the latter, on each side of which 

 its shaft and base are deeply excavated. The posterior of these fossae is 

 overlooked by the wide zygapophysis ; and the roof of the anterior one 

 supports the anterior zygapophysis. The former are separated by another 

 and vertical septum, which bifurcates below, forming two prominent bor- 

 ders of the neural canal. At each side of the base of the neural canal there 

 are two trilateral fossse, of which the anterior is much the larger and ex- 

 tends higher upon the lateral edge of the spine, They are separated by a 

 lamina. The diapophysis is not very long and is subtriangular in section 

 near the extremity. The neural spine is thickened at the extremity as 

 though for the attachment of a huge ligament, At the summit of its pos- 

 terior basal fossa, at the middle of its height, is an outwardly curved pro- 

 cess with a smooth extero-superior face. 



Measurements. M. 

 Length of centrum 275 



Total elevation of vertebra 830 



Elevation to posterior zygapophyses 550 



" of superior edge of diapophysis above centrum .350 

 " " neural spine above posterior zygapophyses. . .295 



Length of diapophysis behind 215 



Depth of extremity of do. (restored) 075 



Transverse extent of summit of neural spine 215 



" " neural spine at middle 330 



In a dorsal vertebra from a more posterior position, the centrum is larger. 

 The capitular costal articulation occupies a lower position, its inferior edge 

 being in line with summit of the neural canal. The lamina which supports 

 it is separated from the anterior lamina which is at the base of the diapo- 

 physis, by a deep cavernous sinus. The posterior zygapophyses send up- 

 wards to the broad neural spine a median buttress each, which enclose a 

 fossa with the marginal buttress of the same. The hyposphen is repre- 

 sented by a vertical lamina only. 



M. 



Total elevation of vertebra , .900 



Elevation of neural spine 300 



" distally 280 



Diameter posterior articular face of centrum 360 



A lumbar vertebra displays a greater expanse of the posterior articular 

 extremity, which is expanded like a dish. The neural arch and transverse 

 processes have a small fore and aft diameter, and the lateral caverns at the 

 base of the diapophysis are obsolete. The pneumatic foramina are slight- 

 ly higher than long. Posterior zygopophyses are wanting. 



