214 
NATURAL HISTORY. 
m. 
EYE OF LEMUROID, 
SHOWING CONTRAC- 
TION AND DILATA- 
TION OF PUPIL. 
( Original , "fter Murie.) 
even to a point, the iris moving so as to shut out the superfluous and injurious illumination. The 
nocturnal kinds require a very dilatable pupil, for they move often in comparative darkness, and when 
the least ray of light is of benefit to them. Besides this structure, there is another which has to 
do with husbanding, and making the most of faint light. If the eyes of a 
Lemur are examined a little carefully, they will be found to glare with a very 
metallic lustre in certain lights, just as those of a Dog and Cat. It appears 
that in certain animals, and in the Lemuroids, there is a peculiar layer within 
the eye which looks coloured, but really it is only very finely marked by 
fibres, which decompose the common white light into its primitive colours, in 
the same manner as the extremely delicate markings invisible to the naked 
eye on mother-of-pearl produce the well-known beautifully iridescent tints. 
This layer is behind the sensitive layer of the eye, and it acts as a concave 
reflector, collecting the slightest glimmers, and making them of use. The 
membrane is called the tapetum. It has been noticed that there is a difference 
in the expression of the eyes of the Lemuroids and Monke} r s, and certainly these 
last have the advantage of showing their impudence, malice, and fear in their 
beautiful organs of sight. 
The ears of some Lemuroida are small, but in the majority not only 
are they large, but they possess singular powers of movement, and in some can 
be folded up. The sense of hearing is undoubtedly acute in the nocturnal 
kinds, and their capacious ears are of immense importance to them, for they 
have to discover them prey by their sense of smell and sight, and also to be on 
the alert against their natural enemies. 
There is a singular want of sameness in the teeth of the Lemuroida, and several kinds, which 
apparently lead the same kinds of lives, and eat the same food, have different arrangements of the 
cutting and grinding teeth. Sometimes the front teeth fall out when the second set is cut, and are not 
replaced, and in the Aye-Aye they act as perfect chisels. As a rule, in all kinds, the lower front teeth 
project horizontally forwards from the jaw, and somewhat resemble 
in their direction those of the Marmosets, but the upper ones are 
straight. As the Lemuroida live easily and perform movements of 
very much the same character year after year, their brains are not 
much called upon. They are not as tractable or as intelligent as 
Monkeys, and although their muscles act with vigour and ease, still 
they are not required to perform the actions which are regulated by 
the superior intelligence of the Apes. Hence it is not to be expected 
that the brain of the Lemuroida will be as well developed as that of 
the Ape or Monkey. It is, in reality, not so bulky, and not so 
convoluted. The brain is low in height, longer than broad, and 
does not cover the cerebellum. Finally, the young Lemuroida are 
nourished within their parent through a placenta, which is diffuse, 
and more or less disc-shaped, and therefore unlike that of the animals 
already described, and of man. 
They have a pecidiarity about the under part of the tongue, 
namely, beneath its tip there is a fringe of scaly flesh, the free ends of 
which, when the mouth is shut, fit in between the front teeth. Its use 
is unknown, but some have said that it is to keep the back of the teeth and the spaces bet ween them clean. 
It is their general shape, and the possession of what may be called a toe-thumb, which makes the 
Lemuroids resemble Monkeys, but the likeness is not with those of the Old W orld, but with the furry 
Marmosets, with long canine and projecting front teeth, of the New World. But although there are 
these points of resemblance, the intelligence of the Monkey is far in advance of that of the Lemur, and 
this can be well estimated when their eyes are compared. In the Monkey the eye is very movable, full 
of varying expression, and often has the aspect of supreme cunning and mischief j but this is never the 
case in the others, whose fixed, staring eyes have no speculation in them. 
UPPER SURFACE BRAIN OF LEMUR 
CATTA OF NATURAL SIZE. 
( Original , after Marie.) 
