162 Transactions. — Zoology. 



breadth, and the height of the post-axial face of the centrum 

 is equal to the breadth ; the posterior margin of the neural 

 platform is straight or slightly concave. The neural spine is 

 not divided in Nos. 3, 4, or 5. Hyperapophyses are well 

 developed on No. 4, slightly so on No. 5. The faces of the 

 post-zygapophyses in Nos. 4 and 5 are directed more post- 

 axially than in other genera. Middle cervicals, 7 to 17 : The 

 post-axial surface of the centrum is broad, the greatest 

 breadth at the ventral margin being more than twice the least 

 vertical (dorsi-ventrad) height ; and the ventral breadth less 

 than twice the dorsal breadth. There is generally a pneu- 

 matic foramen behind the diapophysis. The neural ridges are 

 more elevated than in any other genus, and converge only 

 slightly pre-axiad ; the transverse bar is high, with well- 

 marked pre- and post-axial rough ligamentous areas. The 

 faces of the post-zygapophyses are directed more outwards 

 than usual ; and usually there is a deep conical pit on each 

 side at the pre-axial end of the neural ridges. The posterior 

 cervicals — 18 to 21 — have the same characters, but the centra 

 shorten in length considerably, and there are no pits at the 

 pre-axial bases of the neural spines. The neural spine is occa- 

 sionally single on 19 and 20, and the haemapophyses become 

 single on 20. 



Thoracic Vertebra. 



The centra have broad post-axial surfaces. The anterior 

 pneumatic foramen is very large, and in Nos. 24 to 28 descends 

 below the rib-facet (in very old birds this foramen becomes 

 obliterated) ; the posterior pneumatic foramen is large in all. 

 The haemal ridge (hypapophysis) is not continued to the pos- 

 terior end of the centrum in 22. In 23, 24, and 25 it extends 

 all along the centrum, but is deeper pre-axiad, and often pro- 

 jects forwards as a hook. The transverse processes are short 

 and thick, as also are the neural spines, which in Nos. 22 and 

 23 are nearly square in section, and have both pre- and post- 

 axial surfaces remarkably rough. The post-zygapophyses are 

 short, with broadly-oval faces ; the channels between them 

 and the buttresses of the neural spine are shallow. The pre- 

 zygapophyses are short, and not expanded at the extremity. 



Pelvis. 



The pre-acetabular portion of the ilium is moderately deep, 

 the anterior margin projecting much forwards, and the dorsal 

 margin nearly straight axially. The anterior margin of the 

 acetabulum is in the centre of the ilium. The posterior por- 

 tions of the ilia begin to diverge at the anterior margins of the 

 acetabula, but soon become more nearly parallel than in any 

 other genus. The post-acetabular portion is short, and does 



