254 Mr. R. I. Pocock on 
of the inferior edge of the pinna. The notch between the 
antitragus and the small flap-like tragus is deep. The supra- 
tragus is a small ridge continuous posteriorly with the upper 
curved edge of the cavity of the pinna and overlapped in 
front by a flap of the pinna continuous with the overfolded 
supero-anterior edge. Below the supratragus this flap 
terminates near the middle of the anterior portion of the 
cavity of the pinna. 
The ear is capable of being folded by the forward move- 
ment of its posterior half up against its anterior half, so that 
the central cavity is obliterated and the external auditory 
meatus closed by the antitragus coming into contact with the 
tragus. 
T am unable to find any differences of importance between 
the ears of Hapale jacchus and those of Leontocebus rosalia, 
unless it be that in Leontocebus the depression on the lower 
portion of the lamina extends a little further forwards on to 
the antitragus. This character may be inconstant. The ears 
fold in the same way as in Hapale. 
In Gdipomidas wdipus, however, the ears are very different. 
They are relatively much smaller and quadrate in shape, 
both the upper and the posterior borders being markedly 
angled. The edge in front of the upper angle is folded ; 
elsewhere the edge is simple. ‘The flap-like area of the pinna 
above the central cavity is wide and deep, as in Hapale; but 
below the posterior angular point the flap rapidly narrows, 
and disappears entirely behind the antitragus, there being no 
broad laminate flap completing the pinna below and standing 
away from the cartilaginous basal portion of the ear. The 
antitragus forms a large fleshy valvular flap, but the tragus 
itself is very smal]. ‘The ear folds as in the other species, 
the posterior angular point turning backwards. The only 
member of the Hapalide which resembles Gdipomidas 
edipus in the size and structure of the ear is its near ally 
CE. geoffroyi. In all the other species that I have examined 
the ear is of the type described in Hapale and Leontocebus in 
the sense that the free lamina of the pinna arises inferiorly 
beneath the antitragus and close behind the notch between 
the tragus and antitragus, and extends right round the carti- 
laginous capsule of the pinna, standing every where well away 
from the head. 
Since, however, I have been dependent mostly upon dried 
skins, 1 cannot speak positively of the exact shape of the ears 
in all cases. Such species as J/ystaw midas and M. mystaa, 
for example, appear to have the posterior edge of the ear 
