168

144

will be obvious in comparing fig. 1 with fig. 7, both of the natural size ; but the
difference in relative vertical extent of ilium and ischium, and relative size of the
foramen (m) is to be noted. The parapophyses of the six anterior sacral vertebrae abut
against the ilia near the lower border of those bones. Below this abutment the first
and second vertebrae develop the cups for the tubercles of the last two pairs of movable
ribs ; the cups for the heads of these ribs are on the centrum, below the origins of the
parapophyses. These processes in the four following sacrals have coalesced with the
ilia. Of the interapophysial vacuities (ib. fig. 2, d) the first and second are the largest,
the other three smaller ones are subequal.

Four interacetabular sacrals, in which the parapophyses are suppressed to give
space to the praerenal lobes, are followed by four postacetabular sacrals, in which the
parapophyses are resumed. Of these the first pair are slender, the second and third
suddenly expanded, the latter (ib. ib. u) apparently bifurcate ; the fourth pair are
short , and inclined backward ; on each side of the sacrum these parapophyses coalesce
with each other and with the ilia at their outer ends. The last sacral vertebra (ib.
ib. 15) has not coalesced with the preceding, but appears to have been closely joined
therewith, as the ends of its short and thick parapophyses combine with those of the
fourteenth sacral to abut against the inflected parts of the ilio-ischial deck-like process
(ib. ib. v). In the number of sacral vertebrae (fifteen) Harpagornis agrees with Falco
and Circus, and differs from Aquila ; in the species of which I have examined the pelvis
there are but fourteen sacral vertebrae. The ischiadic foramen (m) extends relatively
further beyond the postacetabular facet in Harpagornis than in Aquila ; the foramen is
relatively less than in Circus.

The praerenal or interacetabular fossae (Pl. CV. fig. 2,t) are relatively narrower in
Harpagornis than in Aquila or Circus, and more resemble those in Buteo. The pubic
portion of the acetabulum does not extend so far outward as in Aquila. Buteo vulgaris
and Falco communis, as well as Circus gouldi and Circus cyaneus, resemble Harpagornis
in the vertically oval figure of the anterior orifice of the neural canal (ib. fig. 3, n) ; in
the smaller species figured (Circus pygargus, the Ring-tail or Montagu's Harrier) this
outlet is circular (ib. fig. 8), as in most species of Aquila. the iliac roofs (ib. fig. 3, f,f)
of the long acetabular division of the pelvis are steeper in their slope than in Circus
(ib. fig. 8) and most Eagles ; the ilio-neural openings (ib. ib. o') have consequently, as
Dr. Haast has remarked, " a greater vertical than lateral extent." The parts of the
pelvis in Pl. CV. are indicated by the same symbols as in that of Aptornis 1. The
gluteal processes (ib. fig. 1. h) appear to have been broken off in the fossil ; they are
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bird in Gould's 'Birds of Great Britain,' folio, part xii. 1867. In no animal does the size become so reduces,
in the skeleton, as in the feathered class ; with the above plate showing our native 'Harrier' clothed in its
plumage, some conception may be formed of the size of the extinct Hawk of New Zealand, magnified according
to the proportions of figs. 1, 2, and 6, 7 in Pl. CV.
1. P. 125; Pls. LXXXIII. & LXXXIV.