PROFESSOR OWEN ON THE MEGATHERIUM. 
761 
Fig. 18. The eleven dorsal vertebrae and four of the lumbar vertebrae of the long- 
tailed Armadillo {Dasypus longicaudus), from the dorsal aspect, showing 
the abrupt commencement and great development of the metapophyses, m. 
Fig. 19. The twelve dorsal vertebrae and three lumbar vertebrae of the Three- banded 
Armadillo (Dasypus tricinctus) ; a side view, showing the successive super- 
addition to the diapophyses (d), of metapophyses (m), anapophyses (a) and 
parapophyses (p) ; and the progressive development of the anapophyses and 
metapophyses. 
Fig. 20. The last five dorsal and first three lumbar vertebrae of the Great Ant-eater 
(Myrmecophaga jubata), showing the progressive development of the met- 
apophyses (m) and anapophyses (a a'), together with the diapophyses (d) and 
parapophyses (p). The pleurapophyses (pi) are left in outline. A side view. 
PLATE L. 
Fig. 21. Front and back views of the eleventh dorsal vertebra of the same Ant-eater, 
showing — 
p. The parapophysis ; p a, its articular surface. 
d. The diapophysis ; d, pi, its articular surface for the pleurapophysis. 
m. The metapophysis ; ma, its articular surface for the anapophysis. 
a. The anapophysis ; ap, its articular surface for the parapophysis ; am, 
its articular surface for the metapophysis. 
The anterior zygapophyses, with articular surfaces looking upwards. 
z’ . The posterior zygapophyses, with articular surfaces looking down- 
wards. 
pi. Head and tubercle of pleurapophysis. 
Fig. 22. Front and back views of the last (15th) dorsal vertebrae; which in addition 
to the parts specified above, shows — 
mz. The articular surface of the metapophysis for the modified or newly 
developed posterior zygapophysis (^'). 
zm. The articular surface of the posterior zygapophysis for the inetapo- 
physis. 
The ordinary zygapophyses are almost suppressed. 
Fig. 23. Front and back views of the third lumbar vertebra, which besides the parts 
specified above, shows — 
da. The articular surface on the diapophysis for the anapophysis. 
ad. The articular surface on the anapophysis for the diapophysis. 
PLATE LI. 
Fig. 24. Side view of a middle trunk-vertebra of the Python Seba\ 
Fig. 25. Front view of ditto. 
