126 THE SKULL OF MARSUPIALS CHAP. 
the original statement of Owen was correct, at least in part. It 
is at most feebly developed (see Fig. 58, p. 118). 
As to skeletal characters, the Marsupial skull has on the 
whole a tendency towards a permanent separation of bones 
usually firmly ankylosed. Thus the orbitosphenoids remain 
distinct from the  pre- 
sphenoid. The palate is 
largely fenestrated, a return 
as 1t were—says Professor 
Parker—to the Schizogna- 
thous palate of the bird. 
The mandible is inflected ; 
this familar character of 
the Marsupials goes back 
to the earliest representa- 
tives of the order in Meso- 
zoic times (see p. 96); but 
it is not absolutely uni- 
versal, being absent from 
the much weakened skull 
of Tarsipes. On the other 
hand, the inflection is nearly 
as great in certain Insecti- 
vores, in Otocyon, etc. The 
malar always extends back 
4A to form part of the glenoid 
Pie 62: Saal of fisk, Wallaby (Petrsele cavity. The shoulder girdle 
bas.0c, basi-occipital ; bas.sph, basi-sphenoid ; has lost the large coracoid 
Rig ty teen Pea een basic) of Monotremes ; this bone 
premaxilla ; pr.sph, presphenoid ; pf, ptery- has the vestigial character 
goid ; sg, squamosal ; ¢y, tympanic. (From % 
PTA 
Parker and Haswell’s Zoology.) that -1t possesses 1n other 
Kutheria. The clavicle is 
present except in the Peramelidae. A third trochanter upon 
the femur seems to be never present. 
The Marsupials cannot be regarded as an intermediate stage 
in the origin of the Eutheria for a number of reasons. In the 
first place, the nature of their teeth shows them to be degenerate 
animals; one set, whether we regard it as the milk or permanent 
dentition, has become vestigial. The recent discovery of a true 
allantoic placenta in Perameles removes one reason for regarding 
