AXIAL SKELETON OF THE OSTRICH. 425 
Compared with the thirty-fifth vertebra, its neural arch is more antero-posteriorly 
extended, and shows a less defect of ossification dorsally (fig. 61,8). Ventrally the 
neural lamina extends postaxially over the preaxial half of the root of the capitulum of 
the next vertebra, and thence ascends so as completely to enclose the postvertebral per- 
foration, so that the neural arch may be said to be rather perforated than postaxially 
notched. The postvertebral interspace or perforation is considerably larger than in the 
three preceding instances. 
The diapophysis (figs. 59, 60, & 61, d°) is remote from the parapophysis, is stouter 
than that of the preceding vertebra, and extends more outwards and less preaxially. 
The parapophysis is a scarcely noticeable prominence from the side of the preaxial 
part of the ventral side of the centrum; and this concurs with a process from the post- 
axial part of the thirty-fifth' vertebra (fig. 60,7&8) to form a surface for the capi- 
tulum. This capitulum arises thence by an expanded base with a somewhat hexagonal 
outline, rapidly contracts, then rapidly expands, ascending dorsally and postaxially to 
anchylose with the similar expansion of the capitulum next behind, and contributing to 
form the dorsally and postaxially extended surface (fig. 59, p*®") which abuts against 
the postacetabular part of the ilium. 
Tue THIRTY-SEVENTH VERTEBRA. 
This vertebra (figs. 59, 60, & 61, 9) has a lower neural spine, which, in the young, is 
free both pre- and postaxially. 
Its centrum, but not its neural arch, is more extended antero-posteriorly than in the 
last vertebra. 
DORSAL ASPECT OF LUMBAR AND SACRAL VERTEBRA OF AN IMMATURE SPECIMEN 
(F natural size). 
Fig. 6]. 
1-12. Neural arches of vertebre from the twenty-ninth to the fortieth inclusive; d'-d"", diapophyses of these 
vertebree to the thirty-eighth inclusive; dp", conjoined di- and parapophysis of the thirty-ninth vertebra ; 
p*°’™, conjoined capitula of sacral vertebre; s', neural spine of twenty-ninth vertebra. In the neural 
arches of the vertebra from the thirty-third to the thirty-sixth, considerable defects of ossification are to 
be seen. 
VOL. VIII.—PART vil. March, 1874. 3 
20 
