732 
PROFESSOR OWEN ON THE MEGATHERIUM. 
with a slight posterior projection to the antepenultimate lumbar; it is rudimental on 
the penultimate one, and disappears on the last lumbar. The last dorsal and the 
three first lumbars are remarkable for their long hypapophysis. 
In the Lagotis Ciwieri, with d 12, 1 7 , the common potential base of the dia-, ana- 
and met-apophyses divides more equably than usual into the three processes ; and 
perhaps no better example can be had of their real distinctness from one another 
and from the zygapophyses, than that which the ninth dorsal (Plate XLVI. 
fig. 10, 9, «, wi, f/, 2 , 2 :') affords ; the neural arch seems studded with processes, the 
nature of which is perfectly comprehended by the comparisons which are given in 
the present Memoir. In the tenth dorsal the anapophysis (a) and metapophysis (m) 
increase in size, especially the latter, which is now closer to the prozygapophysis. 
The anapophyses are remarkable for their length and slenderness in the lumbar ver- 
tebree {ib. 2 and 3, a a). The long and slender anapophyses are equally remarkable in 
the Lagostomus, to judge from the figure of the skeleton in the Linneean Transac- 
tions for 1828, vol. xvi. pi. 9, but as those processes had not at the time been de- 
fined in the Rodentia no notice is taken of them in the text. 
The Capybara {Hydrochcerus capyhara), with d\A,lQ, gives one of the best illus- 
trations of the distinction of the metapophyses {Apophyses antohliques of Straus- 
Durckheim) from the true anterior oblique processes. The metapophysis may be 
distinguished as a tubercle above the diapophysis from the third to the eighth dorsal 
vertebrse inclusive : at the eighth and ninth it (Plate XLVII. fig. 1 1, a and 9, m) begins 
to project forwards ; in the tenth (fig. 11, 10 , m,) it is longer than the diapophysis {d) 
that supports it ; in the eleventh the metapophysis {ih. n, m) begins to shift its posi- 
tion and rises half-way between the diapophysis and the prozygapophysis (z) ; in the 
twelfth dorsal it rises behind the prozygapophysis ; in the fourteenth dorsal it has got 
above that process and the articular surface begins to ascend upon the inner side of 
its base: the change of place and aspect of that surface is completed in the lumbar 
series. The anapophysis separates itself from the metapophysis in the eleventh dorsal 
{ib. 11, a), and progressively increases to the penultimate dorsal, beyond which it 
decreases, and it disappears on the fifth lumbar. The diapophysis is suppressed in 
the last four dorsal vertebrae. 
Order Insectivora. 
In the Hedgehog {Erinaceus europoeus) the metapophysis commences as a slight 
tuberosity above the diapopbysis of the second dorsal, becomes a distinct process in 
the third, projects outwards and forwards freely above the diapophysis in the fourth 
and fifth dorsals, ascends to the outside of the base of the prozygapophysis in the 
sixth, and continues there, inclining a little more upwards, and with increased breadth 
in the remaining dorsals, and in the lumbar vertebree : also along the caudal verte- 
brse as far as the tenth, where the zygapophyses disappear and the metapophyses 
alone are present. There are no anapophyses. 
