AND CLASSIFICATION OF THE FOSSIL REPTILIA. 
197 
the forms of the articular ends of the centrum are imperfectly seen, but the condition 
displayed by the third vertebra of the series (Plate 14, 4) appears to show that the 
intercentral articulation in that vertebra, at least, was opistliocoelous. 
The first vertebra, which is very imperfectly preserved, has the centrum l - 9 c.m. 
long. The second is of the same length. The third vertebra is the longest, and 
measures 2'5 centims. The fourth is about a rnillim. shorter. The fifth measures 2 
centims.; and the sixth, which is badly preserved, is about 1'8 centim. long. 
In relative elongation as compared with dorsal vertebrae, these cervical vertebrae 
show a character which is most closely paralleled among Ornithosaurs, but is also met 
with in various existing Birds and Mammals. Some Chelonians have the cervical 
vertebrae of a similarly long form; and in the fossil the zygapophyses have a develop¬ 
ment which is scarcely equalled among Chelonians. The strong, broad, elevated neural 
spine is distinctive. 
The external layer of bony tissue in these vertebrae appears to be as thin as in an 
Ornithosaur, or a Dinosaur like Coelurus, as though the centrum were occupied by an 
air-cell. But, although there is a small foramen in the middle of the side, in a position 
which might coincide with the junction of the centrum and the neural arch, it is scarcely 
larger than the ordinary nutritive foramen, common in such a position, and gives no 
indication of a pneumatic function. The forms of the articular surfaces make the 
inferences probable that the neck was carried or capable of being carried in a vertical 
position, as in the Galapagos Tortoises. Only the side of the vertebrae is exposed. 
In the third vertebra (Plate 14, 4) the centrum is marked with three narrow, sharp, 
sub-parallel ridges which extend in curves between the anterior and posterior articu¬ 
lations ; they are but little elevated, and give a channelled aspect to the side of the 
centrum. The anterior articular ball of the centrum appears to be well ossified ; it is 
about 6 millims. deep, and hangs obliquely forward. There is a less obliquity in the 
posterior cup, which is somewhat deeper, and is defined by a sharp margin. The neural 
arch extends along the centrum. The anterior and posterior borders of the neurapo- 
physial lamina which margins the intervertebral neural foramina are concave from 
above downward, convex from within outward. The antero-posterior distance between 
them is 2 centims., and the arch, as usual, ascends from the centrum close to its 
anterior end, just over the anterior articulation. From the upper side of the neural 
canal the prezygapophysis extends forward and upward. It is 8 millims. long and 
2 millims. wide, and its upper surface is 1 centim. above the base of the centrum. 
Immediately behind it is a strong ridge or slight transverse process which connects 
with the posterior zygapophysial process. Its transverse extension outward is broken 
away. The extreme measurement between the extremities of the zygapophyses is 
3T centims. The neural spine is sub-quadrate, compressed from side to side, rising 
about 9 millims. above the interzygapophysial ridge. The upper border is truncate, 
slightly rounded from the post-zygapophysis behind, as it extends forward and upward. 
The front border of the neural spine leans a little forward. In the fourth vertebra the 
