1875.] MR. A. H. GARROD ON HALMATURUS LUCTUOSUS. 5S 
spicuous in the undisturbed tooth, even projecting slightly beyond 
the osseous alveolar margin. In D. luctuosa this septum is scarcely 
visible. 
The most important characters of the skull of Dorcopsis, as a 
genus, which distinguishes it from Dendrolagus, are the following :— 
In Dendrolagus the head is proportionally much shorter, the effect 
of which on the lower jaw is that, as the dental series is not cor- 
respondingly reduced, the ramus and the body of each lateral moiety 
meet at a right instead of an obtuse angle; there are no palatine 
foramina; the zygoma is considerably deeper ; the exoccipital pro- 
cesses are longer, though not much so; the lower incisors are con- 
siderably broader, at the same time that the upper lateral incisors 
are larger and more cylindrical, with superficial grooves which can 
searcely be termed inflections; the premolars are not so broad, and 
their outer posterior tubercles are more distinctly developed. 
The molar teeth of Dorcopsis and Dendrolagus are almost iden- 
tical (vide Plate IX.). 
The cranial characters which distinguish Dorcopsis, as a genus, 
from Macropus are not very significant. Looking at the base of 
the skull the arrangement of the teeth deserves attention. In 
Dorcopsis the premolar with the molars on both sides form straight 
lines which are exactly parailel one to the other; whilst in Maero- 
pus the molar-premolar series form slight curves, convex outwards, 
converging behind as well as in front. 
In Dorcopsis the zygomata are not so powerful or deep from 
above downwards as in the similar-sized species of MJacropus. A 
peculiarity also presents itself in the lateral occipital region, the 
exoccipitals descending considerably below the free extremities of 
the paramastoids in Macropus, whilst in Dorcopsis they reach down- 
wards scarcely any further distance. 
Respecting the teeth, Dorcopsis differs from Macropus in the 
much diminished size of the superior lateral incisors. The central 
incisors are not so broad, but nearly as long. The second incisor is 
very much smaller; and though presenting a slight inflection in 
D. luctuosa, as mentioned above, this inflection is not, as in Macro- 
pus, posterior and internal, at the line of contact with the anterior 
margin of its more lateral neighbour. The third incisor is also very 
much smaller. The inflection on its labial or outer surface presents 
the same differences in the two species of Dorcopsis that are found 
in the various species of Macropus: in D. luctuosa, as in M. brunii 
and M. thetidis, it is very near its posterior border; whilst in 
D. muelleri, as in M. major and most of the other species, it is far 
forward. 
The inferior incisors in Dorcopsis are proportionally narrower 
than in Macropus, in which peculiarity Dendrolagus resembles the 
latter genus; they, however, wear down in a similar manner, namely 
at the anterior end of the supero-lateral margin, differently from 
that in the Hypsiprymniform Macropodide, in which they wear in a 
rodent-like fashion. 
The presence of the superior canines in Dorcopsis distinguishes it 
