Haast. — On the Extinct Genus Hai-pagoi'nis. 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 develojDed, 

 the iliac roof extending, however, a little beyond them. 



The iinder 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 biit 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 vertebrae foi-ming 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 (7i). 



In the pelvis of Harpagornis 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 vertebrge, forming the postace tabular region, 

 the first one belonging to the eleventh sacral centrum is a filamentary bone 

 {m) joining the second round and strongest parapoj)hysis, 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 cii-cular. In the smaller pelvis of 

 Harpagornis assimilis these vacuities are not relatively, but actually, larger 

 than in that of H. 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 //. moorei is not yet quite anchylosed to the 



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