PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
799 
nostril. The fore or free edge of this plate is thick, rounded, and slopes backward as it 
rises in a greater degree than the subnasal coalesced plate. 
Of the right side-plate but an inch and a half is preserved; the left one (ib. ib. 22) 
is continued to its junction with the maxillary (21') ; and this extends backward to near 
the orbit, 7| inches from the incisive alveoli. The upper border of this plate is, at first, 
thinner than the anterior or ascending border, but gains in thickness as it approaches the 
orbit (Plate LXXXIII. fig. 1, 21'); it may have been broken and the fractured margin 
worn smooth and obtuse; as it is, it shows no trace of the junction with the nasal bone. 
xAs much of the plate as remains is nearly vertical, neither swelling outward, as in Macro- 
pus major and Osphranter, nor bending inward at its upper part to join the nasal, as in all 
recent Kangaroos. The external nostril must have been relatively narrower, and seems 
to have been longer and more upward in aspect than in other known Macropodidce. 
The floor of the nostril is continued backward by the coalesced premaxillaries 2 inches 
behind the lower border of the aperture (Plate LXXXIII. fig. 1, n) ; it is here half an 
inch in breadth, concave and pitted along the line of the interpremaxillary suture. 
Then, seemingly, it has been broken off, the thinner vertical plates rising from the par- 
tition of the confluent prepalatine openings (ib. a), which are seen at a lower level. 
Behind these the bony base of the “ septum narium ” rises for about half an inch before 
its fracture ; and it can be traced back three inches (as at n) before it suddenly sinks 
down to the lower level of the upper surface of the bony palate (ib. b b). This sub- 
sidence is more abrupt than in living Kangaroos (ib. fig. 2, b b), and each lateral division 
of the superpalatal part of the floor of the nasal chamber forms, anteriorly, in Palor- 
chestes a blind fossa (ib. fig. 1 , b b) below the level of the floor of the antorbital part 
(ib. n') of that chamber. 
• Some traces are, discernible of the suture between the premaxillary and maxillary 
upon the palate (Plate LXXXII. fig. 1, 21') and upon the side of the facial part of the 
skull. Behind the third incisive alveolus, on the right side, a narrow oblique cavity like 
an alveolus (Plate LXXXI. fig. 1, c) is exposed by fracture or attrition of the outer palate 
of the premaxillary, into the base of which cavity opens a small vascular or nervo- 
vascular canal ; this may have contained the germ or aborted rudiment of a canine. 
The bony palate (Plate LXXXII. fig. 1) loses a little breadth behind the incisive 
foramen (a), then expands with an outward curve to the sockets of the premolars (p 3 ). 
A mid tract of the breadth of the incisive foramen is continued backward as a very 
shallow channel to opposite the third grinder ( m 1), where the uniform level of the bony 
palate is gained. A similar but rather deeper channel is continued forward from the 
fore part of the incisive foramen, and slightly expands to its termination at the outlets of 
the mid incisors ( i 1). The intermolar tract of the bony palate is less concave longitudi- 
nally than in Macropus and Osphranter, and less so transversely than in Maropus 
major. Osphranter more resembles Palorchestes in this direction. 
There is no trace in Palorchestes of the pair of small oblong holes where the palato- 
maxillary suture (ib. ib. 20) begins to bend backward near the socket of the last molar. 
mdccclxxiv. 5 p 
