PROFESSOR OWEN ON THE MEGATHERIUM. 
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short but strong diapophysis developes from its lower edge the anapophysis ; on the 
thirteenth the diapophysis has disappeared, but both metapophysis and anapophysis 
remain, the anapophysis being developed as a long pointed process. In the lumbar 
vertebrae the diapophyses reappear, but both the metapophyses and anapophyses are 
present, although they gradually diminish in size and distinctness to the sixth, and 
the anapophysis disappears on the last lumbar vertebra. 
In the Brown Monkey {Macacus nemestrinus), with d \2,17, metapophysial and 
anapophysial tubercles are developed on the second and succeeding dorsal vertebra, 
increasing in distinctness and size to the tenth (Plate XLV. fig. 3, lo, m, a). In the 
eleventh they suddenly become separate processes, and the metapophysis {m) deve- 
lopes a facet for the accessory articular surface of the posterior zygapophysis in the 
tenth dorsal. This additional interlocking is continued to the antepenultimate lum- 
bar vertebra, the joint being further strengthened by the imderlapping of the long- 
pointed anapophysis : this ‘processus acutus’ of Vesalius disappears on the last lum- 
bar. The diapophysis is a rudimental ridge in the last dorsal {d 12), but becomes a 
distinct depressed sharp plate in the first lumbar and progressively increases in size, 
with an antroverted direction in the succeeding lumbar vertebrae. 
In a Mandril (Paplo Mormon), with d 12, I 6, an anapophysial tubercle is deve- 
loped from the diapophysis of each dorsal vertebra, progressively increasing in length 
and distinctness to the lumbar vertebrae, in which it gradually diminishes, and is re- 
duced in the last to a mere ridge on the upper part of the base of the diapophysis : 
a corresponding ridge may be recognized on the first sacral vertebra. The met- 
apophysis is suddenly developed from the tenth dorsal, and presents an articular sur- 
face to a second articular facet on the outer side of the posterior zygapophysis. 
In another Mandril the accessory joint between the zygapophysis and the par- 
apophysis begins between the tenth and eleventh vertebrae. 
In the Papio porcarius a rudimental metapophysis and anapophysis may be re- 
cognized in all the dorsal vertebrae after the second : they gradually increase in size 
to the ninth, and more suddenly in the tenth, where the metapophysis articulates with 
the accessory facet of the posterior zygapophysis of the ninth. The metapophysis, an- 
apophysis and diapophysis are quite distinct processes in the last dorsal ; in the lumbar 
vertebrae the pointed anapophyses progressively decrease, and they disappear in the 
last of this series. 
In a Spider-Monkey {Ateles paniscus), with 14, / 3, the metapophyses begin to 
curve inwards from the second dorsal, assume the form of a distinct plate in the 
tenth and eleventh, and separate themselves from the anapophyses in the thirteenth 
and fourteenth dorsal vertebrae : the latter processes are suppressed in the last lumbar. 
In the Marimonda {Ateles Beelzehuth), with d 14, 1 4, the tuberous rudiment of the 
accessory processes above the diapophysis of the middle dorsals beeomes a ridge, 
which is produced forwards into an angular metapophysis in the eleventh dorsal. In 
the thirteenth it is produced to the same extent backwards into an anapophysis : in 
5 A 2 
