244 PROFESSOR OWEN ON THE GENUS DINORNIS. 
Breadth (across fore end) . . 
» (across hind end) 
Depth, or vertical diameter, anteriorly 
»5 posteriorly, including ischium and pubis . 
, of ischium, distal end . 
Vertical diameter of acetabulum . ie ales lke 
Horizontal diameter, including trochanterian surface . 2 
ee eS) 
Hoowon~zatk 
The pelvis includes, as in other birds, the parts corresponding to sacrum, ilia, ischia, 
and pubes in mammals, but all coalesced into one mass or bone. 
The sacrum includes eighteen vertebra. 
The ribs of the first or foremost (s 1) have not coalesced with the centrum and neural 
arch; the articular surfaces for these elements are distinct on each side. The ribs of 
the second sacral (Pl. LIV. fig. 1, pl. 2) are confluent by both head and tubercle; and 
the body of the rib arches outward and downward for an extent of 2 inches 9 lines from 
the tubercular confluence. 
The ankylosed ribs (ib. pl. 3) of the third sacral vertebra project freely for about 
5 lines from their coalesced tubercle. The pleurapophyses of the fourth, fifth, and 
sixth sacrals consist of the ‘head’ and ‘neck’ only, the fourth terminating in a slightly 
prominent ridge, the others expanding at both ends, one confluent with its parapo- 
physis, the other with the ilium. The pleurapophyses of the sixth and seventh sacrals 
haye coalesced into one short and thick process, slightly expanded at the distal end, 
which blends with the confluent acetabular or proximal ends of the ischium and pubis. 
In the eighth, ninth, and tenth sacrals the parapophyses and costal elements are 
absent; they abruptly reappear in the eleventh and twelfth sacrals, and coalesce with 
each other at their respective distal extremities; the proximal ones are coextensive 
with the two centrums, the distal ends expand into a thick mass abutting against and 
confluent with the inner or central surface of the posterior or trochanterian tract of 
the acetabulum. 
A plate of bone extends from the hind border of the thirteenth pleurapophysis, and 
expands as it extends outward and backward to coalesce with the mesial and under 
margin of the ilium. The pleurapophyses of the fourteenth to sixteenth sacrals 
have a similar course, outward, backward, and slightly upward, with similar expanded 
abutments against the ilium, increasing in thickness and decreasing in length as they 
recede in position. ‘The corresponding coalesced processes of the two last (seventeenth 
and eighteenth) sacral vertebrae are the shortest and thickest ; and their distal, sutural, 
iliac connexions are not wholly obliterated. 
The breadth of the first sacral centrum (Pl. LIV. fig. 1, s1) midway between its 
articular ends is 1 inch; this dimension gradually increases to 1 inch 5 lines in the 
fifth sacral (ib. 5); it suddenly diminishes to 11 lines in the eighth vertebra (ib. 8), 
