230 Mr. O. Thomas on 
appears to be fractured near its termination, where it indi- 
cates a pulp-cavity, though the inner and outer walls are 
compressed close together. The roots are about 1 millim. 
wide. Notwithstanding a certain resemblance in form of the 
interspace between the roots to the form of the crown, I do 
not see any ground for affirming that it has been produced 
by absorption. It is, however, certain that the character is 
an abnormal one, since it is absent from the other isolated 
teeth, and its chief interest consists in showing that it is 
possible for a reptile to develop roots to a tooth of the 
mammalian molar type; so that if this abnormal condition, 
seen in Nuthetes, were normal and general in a fossil jaw, it 
would constitute an important deviation from the reptilian 
dentition. 
The figure is ten times natural size. 
XXXVUI.— Descriptions of Two new North-Bornean 
Mammals. By OLDFIELD THOMAS. 
[Plate VIL.] 
Semnopithecus sabanus, sp.n. (Pl. VII.) 
Body, arms and legs, and tail grey; hands and feet black, 
as in the group to which S. Hose?, S. Hvereti’, and S. Thomast 
belong. 
Forehead with a high median black crest, commencing 
immediately behind the centre of the brow-ridges; the hairs 
of the crest stand up vertically and are about an inch and a 
half in length. Eyebrow-bristles long, black, projected 
forwards over the eyes; behind them, on each side of the 
central crest, the forehead-hairs lie back flat against the head 
and are whitish in colour over the whole crown. Outside 
these whitish patches, again, the sides of the face, from the 
orbits to the ears, are quite black, and the hairs of the occiput 
are also decidedly darker, especially terminally, than are 
those of the pale frontal patches. It results from this arrange- 
ment of the colours that on looking down vertically on the 
crown one sees a pale frontal area, bisected mesially by the 
blackish crest and surrounded on all sides by black, in front 
by the black eyebrows, laterally by the black temples, and 
posteriorly by the black-tipped occipital hairs. These crown 
