Haast.—On the Extinct Genus Harpagornis. 73 
formed by the iliac plates of Harpagornis being consequently considerably 
steeper. 
The surfaces for the head of the two free sacral ribs are strongly developed, 
the iliac roof extending, however, a little beyond them. 
The under surface of the first sacral centrum in its anterior portion is 
slightly carinate, whilst the centres of the two succeeding ones are rounded, 
the edges of their articular surfaces being well raised, the posterior one of the 
third centre the least ; after which they flatten and expand to the beginning 
of the interacetabular region, contracting again to its termination, and 
possessing a transversely concave, shallow, inferior surface, being broadest 
near the anterior articular surface of the seventh vertebra. 
From the eleventh to the fourteenth they still diminish in breadth, and 
now exhibit a low but well marked inferior ridge, running out before the last 
sacral vertebra is reached. 
The parapophyses of the third to the sixth sacral vertebra are anchylosed 
to the lower border of the ilia, forming four interapophysial vacuities on both 
sides ; of these the last parapophysis is the strongest and thickest, standing at 
right angles to the direction of the axis of the vertebral column. 
There is a short parapophysial process starting from the seventh vertebra 
(the first of the four next vertebra forming the interacetabular region), which 
has a downward direction, and is still attached on the left side of the pelvis to 
the inner edge of the head of the pubic bone (A). 
In the pelvis of Zarpagornis assimilis this process does not exist, and it 
resembles in this respect the recent species previously used for comparison. Of 
the parapophyses of the last four vertebrz, forming the postacetabular region, 
the first one belonging to the eleventh sacral centrum is a filamentary bone 
(m) joining the second round and strongest parapophysis, which abuts against 
the innominate, and with which the posterior ones are also connected by 
their distal ends. 
Of the interapophysial vacuities the first, second, and fourth are elongate, 
whilst the third and largest is more circular. In the smaller pelvis of 
Harpagornis assimilis these vacuities are not relatively, but actually, larger 
than in that of Z. moorei. 
The coalesced distal portion of these parapophyses runs in an oblique angle 
from the inner region of the ilia to the abutment of the twelfth sacral centrum, 
the space between this distal line and the upper side of the ischiadic foramen, 
below the pelvic disk, being spanned over by a thin deck of bone (d), 
perforated by a large oval opening 0-48 inch in its largest diameter, which 
runs parallel to the main axis of the pelvis, and is situated on each side behind 
the upper and anterior wall of the ischiadic foramen. 
The last sacral vertebra of H. moorei is not yet quite anchylosed to the 
K 
