744 
PROFESSOR OWEN ON THE MEGATHERIUM. 
physes are developed from behind the diapophyses of the first three dorsals ; they de- 
crease in size in the succeeding" dorsals, but again increase in the posterior dorsals 
and in the lumbar vertebrae, where they present an articular surface to the metapo- 
physis of the succeeding vertebrae. The metapophyses commence as ridges on the 
upper surface of the diapophyses of the second and third dorsals ; they form promi- 
nent tubercles on the seventh and eighth dorsals, and rapidly elongate in the suc- 
ceeding vertebrae, where they surpass in length and equal in thickness the neural 
spines. They are much diminished in length in the first sacral vertebra. Each of 
these elongated metapophyses presents a distinct articular surface to an accessory 
posterior zygapophysis ; and on its opposite side an articular surface to the subjacent 
anapophyses of the preceding vertebra, producing two additional pairs of joints to the 
normal ones formed by the anterior and posterior zygapophyses. 
The parapophyses of the lumbar vertebra do not materially increase in length, but 
chiefly in antero-posterior extent, overlapping each other, the back part of the ana- 
pophysis of the last dorsal resting on the fore-part of the parapophysis of the first 
lumbar vertebra, and the parapophyses of the last lumbar vertebrae similarly arti- 
culating with a prominence of the iliac bone ; an additional pair of articulations being 
thus formed externally to those between the anapophyses and metapophyses. 
The long sacrum has coalesced with both the iliac and ischial bones. The pubic 
bones complete a wide arch by their confluence at their slender symphysis. The 
ischiatic notches are converted into foramina, which are inferior in size to the fora- 
mina obturatoria. The spines of most of the sacral vertebree form by their conflu- 
ence a continuous ridge. The strong tuberosity of the ischium is bifid. The zyg- 
apophyses are developed and coarticulated in the first five caudal vertebree. The an- 
terior ones support short and thick metapophyses, and these are continued in the 
succeeding caudal vertebrae, after the anterior zygapophyses have disappeared. 
In the Pangolin {Manis pentadactyla), with d 13, I 4, the metapophyses commence 
as tubercles on the first dorsal vertebra and rapidly increase in size. Anapophyses 
are not developed. The metapophyses continue to be developed from the sacral 
series. The transverse processes of the last sacral suddenly expand both in length 
and breadth, and articulate with the tuberosities of the ischium. Well-developed 
haemal arches are articulated to the inferior interspaces of the caudal vertebra 
as far the penultimate one. The anterior zygapophyses cease upon the fourteenth 
vertebra of the tail, but the metapophyses are continued as far as the penultimate 
caudal. 
In the Tamandua {Mynnecophagn Tamandua) , with d 17, / 2, all the cervical ver- 
tebrae have spinous processes except the atlas ; that of the dentata is produced for- 
wards, not backwards, and those of the sixth and seventh cervicals are as long as the 
spine of the first dorsal, which exceeds in length that of any of the other vertebrae. 
Tlie pleurapophysial part of the transverse process of the dentata is broad, and pro- 
duced downwards and outwards : it increases in length and breadth in the four sue- 
