1897.] On the Affinities of Tarsius : 685 
Forbes pointed out the important fact that the structure of 
the orbit in the Old and New World Apes differs; in most of 
the Cebide there is a large articulation between the malar and 
parietal, the broad plate-like alisphenoid is limited to the infe- 
rior portion. In the Cercopithecide the alisphenoid is narrow 
and prolonged above to the frontal, so as to separate the malar- 
parietal contact. In the structure of its orbis Tarsius more re- 
sembles the Old World Apes, for the alisphenoid articulates 
with both malar and frontal as in the Cercopithecide. The 
structure of the skull of Tarsius is of importance as showing 
how the closure of the orbit of the Apes is brought about. It 
is evident that the relations of the orbital bones found in the 
Cebide is the primitive one, the broad and inferiorly placed 
alisphenoid is characteristic of the lower orders of Mammals, 
as the Rodents and Carniverous Marsupials. Coincident with 
the increase in breadth of the frontal lobes of the cerebrum of 
Tarsius as compared to other Lemurs, has taken place a reduc- 
tion of the facial portion of the skull, and with it the near ap- 
proach of the lachrymal foramen to the orbital border. Nesopi- 
thecus represents another step in the evolution of the skull of the 
Apes from that of the Lemurs, as in this form the facial axis is 
still more reduced, and at the same time the lachrymal foramen 
has been taken within the orbit. In Nesopithecus the orbits are 
directed forwards asin the Apes, and Forsyth Major concludes 
from the broken condition of the posterior orbital wall, that 
this genus had a completely closed orbit. The skull of Tarsius 
represents a stage in the evolution of the Primate cranium ex- 
actly intermediate between that of the Apes and Lemurs. 
Among the typical Lemurs the general form of the cranium 
in the Indrisine is closely similar to that of Tarsius. 
Although the structure of the molars in Tarsius is very 
primitive, and may represent the ancestral pattern from which 
that of the Lemurs and Apes has been derived, this cannot be 
claimed for the anterior part of the dentition. The reduction 
in size of the canines in Tarsius and the enlarged upper me- 
dian incisors is certainly a case of specialization. We see this 
same change in the Insectivora, and Flower concludes: “The 
strongly marked distinction of the canines from the incisors 
