208 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
relatively further from the orbit in Macropus Titan than in Macr. major ; and in this 
character Macr. rufus more resembles the large fossil Kangaroo. The front pier of the 
zygoma springs from the side of the skull more posteriorly in Macropus Titan than in 
either of the large existing Kangaroos. 
The bony palate (Plate 26) is extended further back, and the production of the 
alveolar border of the maxillary behind the last molar is more convex transversely 
than in Macr. major or Macr. rufus. The bony palate is entire in the fossil as in Macr. 
major , but is relatively wider than in that species ; it has not the reticularly disposed 
small perforations shown by the specimen of Macropus rufus described in the ‘ Zoolo- 
gical Transactions’*. The interspace between the right and left ultimate molars in 
Macr. Titan is twice and two thirds of the fore-and-aft diameter of that tooth ; in Macr. 
major that interspace equals two diameters and one fifth of the last molar. 
The lower area or outlet of the zygomatic arch (Plate 26. fig. 1 ,z) is relatively larger 
in Macr. Titan than in Macr. major ; it exceeds the length of the molar series of four 
teeth ( d 4 , m i, m 2, m 3) by the length of m 3 in Macr. Titan , while in Macr. major the 
outlet does not equal in length the same series of teeth by one half of the anterior 
molar (^ 4 ). 
The diastemal border is less obtusely rounded in Macr. Titan than in Macr. major ; 
it resembles more that border in Macr. rufus f and in some of the smaller existing 
Kangaroos ( Phascolagus erubescens, e. g.). The extent of the diastemal interval in the 
upper jaw of the fractured fossil has been approximately estimated on the grounds 
above defined. 
Subjoined are admeasurements of the fossil skull above described, and of that of a 
male at the same phase of dentition of a large existing Kangaroo. 
Macropus major. 
Length of skull from superoccipital ridge to fore part in. lines. 
of d 4 ... 49 
Breadth of skull at widest span of zygomata .... 4 3 
Breadth of cranium at postorbital constriction ... 1 0 
Breadth of cranium at the mastoids 2 11 
Breadth of foramen magnum 010 
Length of cranium from superoccipital ridge to post- 
orbital constriction 2 7 
Length of cranium from superoccipital ridge to fore 
border of orbit 4 3 
Length of orbito-temporal vacuity, lower opening 1 9 
Breadth of orbito-temporal vacuity, lower opening ..14 
Prom hind border of palate to fore border of d 4 . . . 2 4 
Breadth of palate between the right and left molars (m 2 ) 1 4 
Prom alveolus of m 3 to hind border of palate .... 0 6 
* Yol. ix. plate lxxiv. fig. 3. 
Macropus Titan. 
in. lines. 
6 6 
5 9 
1 6 
3 8 
0 11 
3 2 
5 8 
2 6 
1 8 
3 0 
1 10 
1 1 
Tom. cit. plate lxxiy. fig. 3. 
