124 PROFESSOR OWEN ON THE GENUS DINORNIS. 
On a first view of the pelvic viscera, as exposed by removal of the intestines, the kidneys 
appear to be chiefly developed anteriorly, the broad lobes there extending beyond the 
ilia with a convex border covering, or lying in contact with, part of the iliac origins of 
the abdominal muscles. The length of these anterior renal lobes equals that of the 
antacetabular part of the pelvis in Aptornis defossor; the second lobes, commencing 
mesiad of the anterior ones, acquire their greatest breadth where those terminate, but 
are here much narrower than the anterior lobes. Thence the middle lobes contract 
transversely to a point, underlapping the narrow posterior lobes, which seem to end 
where the ischia join the sacrum, and to blend with each other; but it is merely 
close contact, they are distinct’. 
On each side of the hind part of the kidney is the belly of the “ obturator internus” or 
postrenal muscle, which underlies the inferior opening of the ilio-ischial excavation. 
This muscle being removed, the renal substance is found to pass “ neurad,” expanding 
to a breadth equal or superior to that of the anterior lobes, with much greater depth 
or thickness in the neuro-hemal or dorso-ventral direction; and this the true posterior 
renal lobe is shown, by a vertical longitudinal section of the side of the pelvis, to fill the 
whole of the great posterior ilio-ischial cavity, extending from the partition bounding 
posteriorly the interacetabular cavity backward to above and beyond the ischio-iliac 
deck-like plates (Pl. XV. fig. 2, v’). 
The vertebree numbered 19, 20in Pl. XV. fig. 2 are homologous with the first two free 
caudals in Rallus aquaticus and Ocydromus australis. 'The parapophyses of the seven- 
teenth and eighteenth sacrals expand, coalesce (a small foramen intervening), and unite 
with the “deck” (v'), of which they form the inner beginning. The parapophyses of 
the first caudal in Rallus abut against the ilia, leaving a small intervening foramen 
between them and the antecedent parapophyses. The homologous foramina are seen 
on each side of the vertebra 19 in fig. 2. Pl. XV. 
From these foramina each ilium extends backward 2 inches. ‘The free terminal ends 
bend slightly toward each other, leaving an interval of 9 lines; they are obtusely 
rounded. Externally each is strengthened by a vertical ridge (Pl. XIV. fig. 1, /). 
The entire length of the ilium, following the upper curve, of Aptornis defossor is 
124 inches, equalling that of the same part of the pelvis in Casuarius bennettiit. This 
length is pretty equally divided by the mesial beginnings of the “gluteal ridges” 
(Pl. XV. fig. 1, 9). 
The fore half of the ilium repeats very closely the characters of that part in Aptornis 
otidiformis®. ‘The upper curve is greater in Aptornis defossor; the gluteal ridge is 
stronger, runs more outward, and ends by an obtuse process (Pl. XIV. fig. 1,4). The 
‘In my ‘Anatomy of Vertebrates,’ the statement (vol. ii. p. 227) that ‘“‘the kidneys are more or less 
blended together at their lower extremities in the Coots (Fulica)”’ will probably bear the above explanation. 
I am indebted to our excellent Secretary, Mr. Sclater, for the subject of the above dissection. 
2 Trans. Zool. Soc. vol. vii. p. 366, pl. 42. fig. 1, pl. 43. fig. 1. 
