20 ME. ST. GEOEGE MIVAllT ON THE 



par- and diapophysial processes are more distant from one another than in the pre- 

 ceding vertebra. The neural spine is higher, but not shorter axially. The postaxial 

 excavations of the neural spine are much as in the twenty-second vertebra. The pre- 

 axial fossse of that spine are deep. 



The twenty-fourth vertebra has no trace of a hypapophysis, even in front ; otherwise 

 it differs from the twenty-fourth vertebra of Struthio as does the twenty-first vertebra 

 (first lumbar) of Bhea, except that the neural spine is more slender, the transverse 

 process more extended axially, and the parapophysial surface larger. The preaxial 

 fossae of the neural spine are deep ; and it is more excavated postaxially than in Struthio. 



THE DOESO-LUMBAE VEETEBE^. 



The twenty-Jifth vertebra is sometimes (as shown in fig. 12) a dorsal vertebra. It 

 may have its neural spine higher than the corresponding vertebra of Ehea ; but it is 

 never so high as is that of Struthio. The neural spine's postaxial excavation is not 

 divided by a vertical ridge. There is no sharply defined concavity beneath the prae- 

 zygapophyses, and no excavation beneath the transverse process ; otherwise this vertebra 

 is like the twenty-second vertebra of Ehea. 



The twenty -sixth vertebra resembles the twenty-third of Ehea, except that the pre- 

 axial articular surface is higher dorso-ventrally and more concave. There is no deep 

 fossa ventrad and external to the praezygapophysis. 



THE LUMBAE VEETEBE^. 



The twenty-seventh vertebra apparently answers to the twenty-fourth of Ehea and to 

 the twenty-eighth of Struthio. It may be a dorso-lumbar vertebra. It has no con- 

 spicuous rib, and is the first trunk-vertebra so distinguished. It becomes ankylosed to 

 the sacral mass, as does its predecessor also. It differs from the twenty-fourth vertebra 

 of Ehea in that its ventral surface is less concave. In the young the transverse pro- 

 cess is directed less preaxiad than in the adult ; and there is a rudimentary rib (as in 

 No. 1358 a) beneath it, directed outwards and postaxiad and greatly expanded at its 

 distal end, where it unites with the inside of the ilium (fig. 16, xxvii, 2>l)- 



The twenty-eighth vertebra has its neural spine fused with that of the two preceding 

 and the four succeeding vertebrae into one great mass of cellular diploe. Its trans- 

 verse process is smaller than is that of the twenty-seventh vertebra; and there is no 

 rudimentary rib even in the young. 



The twenty-ninth and thirtieth vertebrae can only be distinguished as differing from 

 the twenty-sixth and twenty-seventh of Ehea in that they have smaller transverse pro- 

 cesses, and that the thirtieth sends no process to the praeacetabulum. 



The thirty-first vertebra is quite like its preaxial predecessor, thus differing from 

 both the twenty-eighth of Ehea and the thirty-second of Struthio (fig. 16). 



