246] 
RECORDS OF W.A. MUSEUM. 
origin of the vertical member of the episternum. The inferior and 
the postero-superior angles are more rounded and constant in 
position. 
The imperfect pelvic girdle comprises two fused sacral verte- 
brae and part of the right innominate bone with the complete, 
perforated articular cavity and the adjacent portions of the ilium 
and ischium. The sacral vertebrae, the second and third of the 
series, have marked intervertebral cavities and their neural spines 
fused together at their tips, the neural arches also send out bony 
processes forwards and backwards to completely cover the neural 
canal. There are the usual lateral openings for the passage of the 
nerves. The anterior vertebra is attached to the ilium by the 
usual lateral growths from centrum and neinal arch and the 
posterior one by the pleurapophysial ossification only. The 
vertebrarterial passage on the right side is larger than the neural 
canal. 
The ilium is trihedral its fusion with the other components 
of the innominate bone complete, its acetabular border short and 
concave, with the prominence for the attachment of the rectus 
(extensor) muscle of the leg forming a prominent compressed sub- 
limate area close to the rim of the acetabulum — in the Australian 
Tachyglossus this surface is markedly triangular. The acetabulum 
is large, more ovate than in Tachyglossus, somewhat flattened on the 
dorsal surface, incompletely ossified but with an entire margin ; 
its dimensions are 40 mm x 34 mm. The pubis has a well- 
marked pectineal process which is comparatively more developed in 
Tachyglossus. Very little of the broad flat ischium is preserved. 
Both femora are present in the collection. The complete 
right one (plate XXXVI, fig. i) is short and broad, flattened from 
before backwards with a well defined head that rises but little above 
the great trochanter on a short and indistinct neck; in this it differs 
from the femur of T. a. ineptiis (plate XXXVI, fig. 2), and from the 
fossil Z. [Echidna) oweni specimen F13580 of the Australian 
Museum, represented in this collection by a cast, whose heads rise 
considerably above the trochanter. The great trochanter is much 
more massive than in the living form and gives rise to a strong, 
rough, projecting ridge that extends along two-thirds of the shaft, 
where it ends abruptly. The lesser trochanter on the inner side of 
