345 
strongly produced ridge overhanging the vertical postacetabular plate (P]. LXX XIX. 
fig. 1, 62, 7) of the ilium, which coalesces with the similarly vertical expanding plate of 
the ischium (ib. 63). The foramen (ib. m) between the ilium and beginning of the 
ischium is a full ellipse or oval. The ischium developes downward a ridge, behind the 
obturator notch (q); but this does not meet the ridge reciprocally directed upward from 
the pubis (ib, 6t): there are impressions of the attachment of a strong fibrous sheet 
which closed the obturator groove behind; and this sheet becomes a thin plate of bone 
in old individuals of some existing Rallines (Zribonyx ventralis, Ocydromus australis). 
The proportions and form of so much of the pubis (64) as is preserved adhere to the 
ralline type of that bone; but the tubercle, prominent below the fore part of the bone 
in most existing Rallines, is not developed in Aptornis. 
I have restored, in outline (Pl. XCIV.), the parts of the ischium and pubis broken 
away from the otherwise complete and truly singular and interesting form of pelvis in 
Aptornis defossor. It may aid in future comparisons of this most complex of bones to 
subjoin a list of the parts of the pelvis, conveniently indicated by names, with the 
symbols used to indicate them in Pls. LX XXVIII. and LXXXIX, 
The specimens of Aptornis defossor above described are from a cavernous fissure at 
Timaru, Canterbury Settlement, South Island of New Zealand. I am indebted to 
Dr. D. 8. Price, of the Crystal Palace, Sydenham, for the much valued opportunity 
of describing, comparing, and figuring them. 
Parts of the Pelvis of Aptornis defossor, Ow. 
a. Acetabulum (the letter marks, in Pl. LXX XIX. fig. 1, the inner aperture). 
6. Postacetabular facet. 
c, Centrum (marking, in Pl. LXXXVIIL. fig. 2, the ridged underparts of the first and 
second sacral vertebrz). 
¢. Centrum (marking the unridged underparts of succeeding centrums). 
d. Diapophysis (marking, in Pl. LXXXIX. fig. 1, the diapophysial articular surface). 
e. Subacetabular fossa. 
f, f. Antacetabular part of ilium (Pl, LXXXVIIL. fig. 1). 
g. Gluteal ridge. h. Gluteal process (Pl. LXX XIX, fig. 1). 
i. Ilium (marking, in Pl. LX XXVIII. fig. 2, the part anchylosed with and overhanging 
the foremost diapophysis). 
id. Interdiapophysial vacuities (marking the six anterior ones). 
1, Postiliac tuberosity. m. Ischiadic foramen. 
n. Neurapophysis; w' in Pl. LXX XVIII. fig. 1, is the fore part, n* the hind part, of 
the neurapophysial crest. 0. llio-neural orifices. 
p. Parapophyses, ) both combine to separate, below, the interdiapophysial vacuities : 
pl. as in Pl. LXXXIX. fig. 1, pl marks the articular surface for the 
head of the first sacral rib. 
