4 
permits of the interior of the chamber being seen. ‘The articulation 
of the squamous portion with the great ala of the sphenoid, is oblique 
from the inferior margin of the zygomatic process in the anterior cen- 
tral portion of the bone of the auditory chamber. The lower part 
of the squamous element and this outer portion of the pterygoid are 
on the same plane, and though bulbous, they dg not form a second 
auditory chamber, as in some marsupials, but merely an inflated por- 
tion of the cranial cavity. The glenoid cavity for the articulation of 
the lower jaw is indistinct. This jaw resembles in general form that 
of Myrmecophaga jubata, and it moreover bears a considerable ana- 
logy to that of the Monotremata. It is subiinear, slender, almost 
without a trace of coronoid process, and there being no angular pro- 
cess, it does not present the peculiar conformation of this part of the 
lower jaw which characterizes all the known marsupials ;° and the 
condyle, instead of being transverse as in these animals, is situated at 
the apex of a little curvature formed by the entire masseteric portion 
of the maxillary, approaches to a circular form, and is somewhat 
oblique in its direction, as in the Myrmecophaga jubata and in the 
Monotremata. In the Myrmecobius an approach to this disposition 
of the condyle is observable. The masseteric depression is in the 
form of a longitudinal cleft, which is much longer than the cleft found 
in certain species of Macropodide, and very much resembles that which 
we observe in the lower jaw of some birds. The two inferior maxillary 
are joined at the symphysis by a ligament only, but their junction ap- 
pears to be more perfect than in the Edentata in general: these 
bones are as remarkable for their compact structure as for their trans- 
parency. 
Of the remaining portion but few parts are known, viz. the radius 
and the inferior portion of the cubitus; these are separated in their 
whole length; the tibia and the fibula, which are also separated as 
far as their articulation with the tarsus; the fibula is much com- 
pressed at its upper extremity. 
The dental system of the Tarsipes is most anomalous: the lower 
jaw presents in front a pair of cultriform teeth which have the same 
horizontal direction as the jaw ; the basal portion of these teeth is 
narrower than the other portion, and the root is very deeply inserted 
into the jaw; the apical portion is unfortunately broken. ‘These 
teeth are applied one against the other by their internal surface. 
Near the posterior third of the dental portion of the same jaw isa 
small transparent gemmiform tooth, which has the appearance of a 
little process recurved angularly outwards. 
On the anterior third of the left side of the upper jaw are three 
small teeth ; the first, which appears to be im the incisive bones, and 
which is in a line with the incisive openings, is in the form of a 
minute simple tubercle ; the third, which is situated at the hinder 
extremity of the anterior third of the dental portion of the jaw, is 
also gemmiform, rather slender, longer than the first, and somewhat 
inclined forwards. Between this and the foremost tooth is another 
tooth, which is smaller than either, and situated nearer to the third 
than the second tooth. All these teeth are transparent and have but 
