1896.] SKULLS OF A LEMUR AND ORANG. 997 
they were not uncommon in the genus Lemur, especially in young 
individuals, although their existence had apparently not been 
recorded. The bones in the specimen examined by me are tri- 
angular in form and, as will be realized from the sketch (fig.1), occupy 
Fig. 1. 
Skull of Lemur, from above. 
Fr. Frontals. x. Supernumerary bones. L. Lachrymals. N. Nazsals. 
M. Maxille. 
a position corresponding with the prefrontals in a Lizard or Croco- 
dile. The suture which marks their limits is very clearly defined. 
It is interesting to note ‘that corresponding bones have been 
recognized in the genus Hippopotamus. In a memoir! contributed 
to tome xvi., 1894, of the ‘Annales des Sciences Naturelles’ by 
MM. Grandidier and Filhol, for a reference to which I am indebted 
to Sir W. Flower and Dr. Forsyth Major, these bones are described 
and figured both in the case of an extinct species, H. lemerlei, 
from Madagascar and of young individuals of existing Hippo- 
potami from Senegal. On examination of our only specimen of 
the skull of a Hippopotamus in the Museum of Queen’s College, 
Belfast, I find the same bones (regarded by MM. Grandidier and 
Filhol as representing prefrontals) distinctly indicated, though the 
suture separating them posteriorly from the frontals is to a con- 
siderable extent obliterated. 
In Sir W. Flower’s admirable ‘ Introduction to the Osteology of 
the Mammalia’ (8rd edition), the following statement occurs 
(p. 162) with respect to the squamosal in Monkeys : “The squamosal 
in the higher forms is developed much as in Man, but in the lower 
forms it is more reduced and takes a smaller share in the formation 
of the side-wall of the cranium. It generally comes in contact at 
1 “Ossements d’Hippopotames.” 
