FAUNA OF THE GOSATJ FORMATION. 643 



spine and transverse processes are broken away. The centrum has 

 the articular faces somewhat oblique ; but though this may be to 

 some extent natural, it is probably augmented by crushing, since the 

 form of the centrum has become in this way a good deal distorted. 

 Its length along the base is 2 T 2 7 inches, while the measurement along 

 the neural canal is about inch less. The posterior articular face, 

 as preserved, is subquadrate, lg inch deep, and about l T 7 y inch wide. 

 It is considerably excavated by a saucer-shaped depression. The an- 

 terior articulation was probably as deep, and Ifa inch wide ; but it 

 does not appear to have been so deeply excavated as the posterior 

 face. The base appears to have been flattened, and margined on 

 each side by an angular ridge. In the middle these ridges are about 

 y 8 -^ inch apart ; and they diverge towards both anterior and posterior 

 faces. The sides of the centrum are distinctly defined from the 

 neural arch by the deeply marked horizontal suture, below which 

 in front is the oblong articular face for the rib, which is about 

 y 7 -^ inch long and ^ inch deep. It is about y 4 ^ inch behind the 

 articular face. It rises as a slight pedicle ; and the transverse mea- 

 surement over these parapophyses is 2-^ inches. The centrum is 

 compressed from side to side below these processes, so that a median 

 cavity divides the side into a highly convex upper portion and a 

 comparatively flat lower portion. The articular margin of the cen- 

 trum is moderately sharp, thickened, and rounded. The neural 

 arch has an aspect of leaning forward obliquely, which is more 

 marked than that of the centrum, and may probably be taken as 

 evidence that the neck of the animal was carried in a somewhat 

 raised position. The pedicles lean forward at an angle of nearly 

 45°, have their anterior margins concave, and are compressed from 

 side to side, but especially pinched in the middle. The greatest 

 width of the arch in front at its union with the centrum is 1 T 6 7) inch, 

 while behind and above the middle of the centrum its width is 

 reduced to inch, again to become expanded to 1^ inch near 

 the posterior articulation. This median depression extends up to 

 the side of the neural arch, being margined above and behind by a 

 sharp buttress, which widens laterally and extends outward so as 

 to underprop the transverse process, and form with it the upper 

 head for the rib. Where fractured this process is 1 inch above the 

 capitular articulation, and has a triangular outline pointed in front 

 and about y 4 ^ inch deep. There is a triangular area which is concave ly 

 excavated behind these transverse processes and in front of the poste- 

 rior zygapophyses. The posterior zygapophyses are divided from each 

 other throughout their length of an inch by a notch y-^ inch wide 

 behind and rather wider in front, where it terminates in the vertical 

 wall of the neural spine, which in the middle has a slight sharp 

 ridge. These processes have their inner sides subparallel, are placed 

 obliquely, and are convex superiorly from below outward. The 

 articular facets are large, subovate, flat, and look downward and out- 

 ward so as to make with each other an angle which is more than a 

 right angle. The anterior zygapophyses extend entirely in front of the 

 articular face of the centrum . They are similarly divided anteriorly 



2 it 2 



