RECORDS OF IV. A. MUSEUM. 
[33 
portion of the crown is shorter than the succeeding molar, and has 
a broad working surface with complex transverse ridging between 
the inner and outer simple trenchant edges. A basal ridge is 
present on the inner, fore, and outer aspects ; that on the front of 
the tooth is plain, but the other two each give rise to three swellings 
or ribs that pass upwards to the crown. A vertical fold in the 
enamel is present at the intero-posterior angle ; the hind surface of 
the tooth is perfectly smooth and convex, both vertically and 
horizontally. 
The Molars (M1-M4). The lobes are thin and almost straight, 
though slightly convex backwards, crests slightly concave, angles 
sharp, particularly on the inner edge ; from the outer angle of the 
hind lobe, a marginal fold sweeps downwards and forwards, almost 
closing the mid-valley ; this fold from the fore lobe forms the edge 
of the anterior talon. Similar branching marginal folds are present 
on the anterior surface of the inner angle of the hind lobe. There 
are several vertical folds on the fore surface of each lobe. On the 
hind surface they are more numerous (about nine), but are almost 
rudimentary. A basal ridge is present on the hind surface of each 
molar, that on Mi being little more than a slight swelling. As a 
general rule the ornamentation on the posterior molars is less 
complicated than on the anterior ones. A longitudinal link connects 
the fore lobe with the hind one. 
The Ramus is strong and powerful, it is convex vertically and 
slightly so horizontally. The anterior vascular foramen is slightly 
in advance of the premolar and of fair size, as in S. atlas of Owen, 
but the second one is placed under Mi instead of beneath one of the 
posterior molars. The under surface of the ramus shows a distinct 
upward arch, the posterior portion passing up in an unbroken curve 
to form the under aspect of the coronoid. Of the coronoid suffi- 
cient is present to show that the anterior margin of the ascending 
ramus ran at right angles to the line of the teeth ; the condyle is 
absent. The “ fenestral vacuity” takes the shape of a pouch, 
having its opening slightly below the level of the teeth, it contains 
the posterior outlet of the dental canal and a fenestral foramen 
communicating with the inner pouch of the ramus. The symphysis 
is anchylosed and the diastema very short. 
