of Vertebra from Cape Colony. 339 



inch behind the anterior intercentral facet. Hence the sides 

 of the centrum are concave in length, so that the lateral 

 compression is greatest immediately under the attachment of 

 the rib (fig-. 2, R), where the pneumatic excavation seen from 

 below occupies the anterior half of the length of the centrum. 



The pneumatic impression or excavation is apparently 

 situate between the centrum and the neural arch, though the 

 neuro-central suture is obliterated. Seen from beneath (fig. 1) 

 it is a pear-shaped or triangular cavity, wide in front and 

 narrow behind, situate between the flattened compressed side 

 of tlie centrum and tlie overhanging neural arch. On the 

 underside of this anterior part of the arch, beneath the small 

 broken process for the rib, is an oval hole (P), not unlike the 

 pneumatic foramen seen in the wide cervical vertebrae of Creta- 

 ceous Ornithosaurs. In Ornithosaurs the foramen is below the 

 ridge which extends between the anterior and posterior zyga- 

 pophyses, but the ridge which forms the upper boundary of 

 this foramen extends forward on the side of the centrum from 

 the middle of its posterior articular face, with a concave 

 lateral contour, which widens transversely to the position 

 above the foramen, and then narrows towards the anterior 

 articular face (fig. 2). The ridge is compressed and rounded 

 from above downward. Above it in the middle of the side is 

 a pit or depression, which separates this ridge on the centrum 

 from the less conspicuous zygapophysial ridge above it, 

 upon the neural arch, which is badly preserved. In morpho- 

 logical position this foramen makes an approximation to 

 that seen laterally on the anterior part of cervical vertebrae 

 of Saurischian reptiles, and especially to some of the Cetio- 

 sauria. But it differs from American types in the excavation 

 being undivided vertically and in the foramen itself looking 

 downward (fig. 1, P), so as to be invisible from the side 

 (fig. 2). 



The small transverse process above the foramen arches, 

 somewhat in a penthouse form. Its fractured base is less 

 than half an inch long. It was probably very short and may 

 have been co-ossified with the cervical rib as in Saurischian 

 types like CoeluruSj and in Ornithosaurs. There is neces- 

 sarily no evidence as to its articulation with the intercentrum ; 

 but such a relation is found in the early vertebras of Cyno- 

 gnathus, in which the intercentral ossifications are of larger 

 size. The imperfect evidence suggests a condition for the 

 cervical ribs intermediate between the Theriodontia and the 

 pneumatic Megalosauria. 



The neural canal is of moderate size and appears to ba 



