PROFESSOR OWEN ON THE MEGATHERIUM. 
737 
mence as distinct and well-marked tuberosities above the diapophyses of the second 
dorsal ; subside at the eighth, and are rudimental to the thirteenth ; they recom- 
mence as distinct processes at the fourteenth dorsal, where they project forwards on 
the outer side of, but quite distinct from, the prozygapophyses ; ascend upon those 
processes in the first lumbar, and so continue throughout the lumbar series. There 
are no anapophyses. 
In the Camel [Camelus Bactrianus), with d 12, / 7, the metapophysial tubercle is 
developed from the diapophysis in the eleven anterior vertebrae, and passes upon the 
prozygapophysis in the twelfth, continuing in that position throughout the lumbar 
series. There are no anapophyses. 
In the Vicugna {Auchenia Vicugna) the metapophysis is between the diapophysis 
and prozygapophysis, from the fourth to the tenth dorsal, and passes upon the pro- 
zygapophysis at the eleventh dorsal. There are no anapophyses. 
Tribe Non-Rumlnantia. 
In an Indian Wild Boar {Sus scrofa), with d 13, /6, the metapophysis commences 
as a tuberosity upon the diapophysis of the middle dorsal vertebra, projects forwards 
midway between the dia- and prozyg-apophysis in the tenth, passes upon the pro- 
zygapophysis of the eleventh dorsal, and is continued in that position throughout the 
lumbar series. There are no anapophyses. 
In the Peccari {Dicotyles lahiatus), with dlA, Z 6, the metapophysis begins to be 
developed at the third dorsal, and increases in length to the eleventh, beyond which 
it is transferred from the dia- to the prozyg-apophysis. 
In the Hippopotamus {Hippopotamus amphihius), with d ^b, I A, d metapophysial 
ridge is developed above the diapophysis of the eighth dorsal, changes its position 
and shape in the succeeding vertebrae, and in the eleventh has passed, as a tuberosity, 
upon the prozygapophysis. It retains these characters throughout the rest of the 
dorsal and the lumbar series. There are no anapophyses. 
Suborder Perissodactyla. 
In the Horse {Equus cahallus), with c? 19, / 3, the metapophysis, commencing as a 
tuberosity above the diapophysis, passes gradually from that part to the outer side of 
the prozygapophysis, which it finally attains in the seventeenth dorsal vertebra, and 
continues in the same place throughout the lumbar series. There are no anapo- 
physes. 
In the Sumatran Rhinoceros {Rhinoceros Sumatranus), with d 19, / 3, the metapo- 
physis begins, as a tuberosity, above the diapophysis of the fourth dorsal, projects 
distinctly forward from the eighth, and continues so projecting, and slightly in- 
creasing in length, to the seventeenth ; in the eighteenth it begins to approach the 
zygapophysis, and gets outside of it in the nineteenth ; and so continues, reduced to 
