1897.] On the Affinities of Tarsius : 575 
human placenta is diffuse to start with, yet has nothing in 
common with the Ungulates, though it may be compared, ap- 
parently, directly with that of the Lemurs.” 
I am not, at present, in a position to discuss the whole organ- 
ization of the Lemurs, and will merely refer to the brain and 
female reproductive organs. In regard to the structure of the 
brain in the Lemuroidea, it may be said that the genus Lemur 
has a lower type of encephalon than is found in the Indrisine. 
As compared with the Jnsectivora, the brain of the Lemurs is 
in a much higher stage of development, and approaches 
nearer that of the Cebide than any other group. In Lemur 
the frontal lobes of the cerebrum are narrow, and the olfactory 
lobes are plainly visible in front; however, in Propithecus, the 
frontal portion of the cerebrum is quite highly developed, 
being as broad as in the American Monkeys, and contains 
secondary convolutions not seen in the lower forms of Lemurs. 
Again it is to be noted that in the Lemurs as in the Apes, the 
sylvian fissure is largely developed and extends a good ways 
superiorly on the hemispheres, and this character is particu- 
larly noticeable in the Indrisine. The antero-temporal sulcus 
is also well-marked in the Lemur’s brain, and resembles this 
fissure in the Anthropoids. The posterior lobes of the cere- 
brum remain in a primitive condition, and the cerebullum is 
exposed as in the lower Mammalia. Prof. Flower calls par- 
ticular attention to the presence in the brain of the Lemurs of 
the calcarine fissure which is so characteristic of the higher 
Primates, and speaking in general of the sulci of the inner 
part of the cerebrum of the Lemur’s brain, Prof. Flower re- 
marks that they follow also those of the Anthropoidea. The 
general configuration of the frontal lobes in Nyctipithecus 
among American monkeys is like that of Propithecus, but in 
the former the surface of the hemispheres is smoother and 
lacks the smaller convolutions seen in the Indrisinæ. Again, 
in Nyctipithecus the olfactory lobes project considerably beyond 
the cerebrum. In conclusion it follows from the above that 
the brain of the Lemurs is much more primitive than that of 
the Apes, but may represent a stage in the evolution of the 
brain which leads to the higher differentiated encephalon of 
the Anthropoids. 
(To be continued.) 
