detected far back in its socket, is still very rudimentary and much less developed.
than in the more adult skull of the previous specimen.
In the British Museum example of M. brunneus the only permanent teeth in the
upper jaw are the first molar and the first incisors, which are only partially exposed;
the second pair of permanent incisors are only appearing behind and internal to the
milk p a ir; the two milk-molars have not been shed. The second permanent molar
is seen deep in its alveolus, but only imperfectly developed. In the type of M.
brunneus the only permanent tooth is the first molar.
In the lower jaw of the Liverpool monkey the permanent teeth are through
the jaws, but the canines and the last molar are only partially so. The type of
M. melanotus has all its permanent teeth in the lower jaw except its canines and the
last m olar; the former are only on a level with the jaw, and it appears as if the
milk-incisors had been shed, or, it may be, lost in the preparation of the skull.
The last molar is only very imperfectly developed and far back in its socket. In
the lower jaw of the British Museum specimen of M. brunneus the milk-canines
and two molars are still in the jaw ; the second permanent molar is not above the
surface and is only a sh e ll; there is no trace of the last tooth. The lower jaw of
the type of M. brunneus has all its milk-teeth and its first molar.
The dentition of M. melanotus, Ogilby, thus proves it to be an older specimen
than the British Museum example of M. brunneus, which in its turn is older than
the type in India. The skull characters of the last mentioned have been elsewhere
described,1 and the second example agrees with it except in a few trifling details which
do not merit enumeration. The skull of M. melanotus also is in no wise separable
from these two skulls—a statement which is borne out by the tabulated measurements
which I here give, any little differences that do exist being legitimately
referable to individual peculiarities:—
brunneus,
type sp.
Occipital to premaxill® . . . • •
Anterior margin of ocdpital foramen to premaxill® .
Anterior margin of ocdpital foramen to palate .
Pronto-nasal process to premaxill® . . . .
Auditory process to auditory process _ . . .
Auditory process to tip of premaxill®, in straight line
Greatest breadth of skull behind root of zygoma
Breadth across orbito-malar suture . . . .
Least breadth in temporal fossa
Breadth across zygomatic arch, at middle .
Breadth of muzzle at base below maxillo-malar suture
Breadth o f muzzle at middle, anterior end opposite nasals
Height of orbit . . ■ ~ •
Length o f orbit •. . • . • •
Length of lower jaw in line with alveolar margin
Macaeus arctoides, Is. Geoff. St.-Hil.
brunneus,
B. M. sp.
2-65
1-15
1-77
2-14
2-50
265
2*45
1-90
2-73
4 4 0
2-90
1*15
1-60
2-52
2-75
2-80
2-52
1-87
310
1-66
1-40
arctoides.
B. Iff. sp.
In.
4 4 6
2-99
1-27
1-81
2-40
2-90
2-68
2-50
1-87
3-70
1-52
2-05
1-80
2-25
1-65
1-25
•71
The skull of the adult specimen in the British Museum, agreeing with Blain-
ville’s figure of the skull of M. arctoides, is distinguished from the others by the
great development of its orbital ridges and the depth of its temporal fossa; the
former are of great thickness and are thrown forwards, so that the orbits are considerably
broader than high. The skull is longer from the frontal to the occipital
than in M. melanotus and M. brunneus. The facial portion is more developed than
in these latter in proportion to the more advanced state of its dentition. The base
of the skull is also broader and the basicranial axis more anteriorly projected than
in M. melanotus or M. brunneus. The zygomatic arch is also of great strength as
compared with these skulls. In all these characters it only evinces its greater
maturity, and there are no others that present themselves that would indicate any
specific distinction between it and these two supposed species; and these remarks
seem to be verified by the table of measurements, when due allowance is made
for its greater age.
The bones of the skull of the adult M. arctoides are unnaturally thick, as
are also those of M. brunneus; and this condition is in all likelihood attributable
to confinement; whereas the skull of M. melanotus has no more than the thickness
generally characteristic of healthy animals, although it was also a specimen kept
in confinement.
A comparison of the bones of M. brunneus and of M. arctoides in the British
Museum, while it dpes not reveal any difference in their forms, yet shows them
to be notably smaller in the specimen of M. brunneus. But a consideration of the
relative ages of the bones as revealed by the conditions of their epiphyses fully
accounts for their difference of size.
The following table gives the relative measurements of their bones:—
Total length of scapola along c r e s t ....................................... .........
Length or scapola along inferior margin of articolar sorface
Greatest b r e a d t h .....................................................................
Length of hnmerns . - .................................................
Length of r a d i o s ...........................................................
Length o f o l n a ...............................................................................
Length of os innominatom . . . . . . .
Anterior angle o f symphysis pohis to soperior angle of callosities
Breadth across ilinm at middle . . . .' - .
Length of femur . . . . ... , .
Length o f t i b i a ....................................... ..........
Macacas arctoides, Is. Geoff. St.-Hil.
M. brunneus,
type sp., 3.
M. brunneus, M. arctoides,
B. M. sp., 3 .
In. In. 1 In.'
2 49 2-80 3-60
2-10 2-40 3-20
d-70 1-72 2-83
413 4-55 5-88
3"95 4'55 5-80
4 37 5-08 6-20*
3-96 4-70 5-70
1-70 2-20 2-87
101 1-39 1-70
4-20 4-96 6-40
3-90 4-56 5-88
The credit is due to Dr. Sclater of being the first to point out that M. melanotus,*
Ogilby, and the monkey from the Kakhyen hills and Cachar,3 are not different
from M. arctoides, Is. Geoff.; and Dr. Murie4 shortly afterwards adopted a similar
1 Epiphyses lost.
5 Proc. Zool. Soc. 1872, p. i
1 Proc. Zool. Soc. 1860, p. 420.
♦ Ibid, pp. 770,771.