AND AFFINITIES OF POTAMOGALE. a | 
narrow, forming by their union a very convex margin posteriorly, which is received 
between the parietals and a deep notch anteriorly, which receives the nasal bones. 
The frontals are entirely excluded from the orbits by the anterior extension of the 
_ parietals, which, passing between them and the lachrymals, are separated from the 
maxillaries by a very narrow extension of the lachrymals, which ascends to unite with 
the frontal. The frontal suture is obliterated posteriorly, but anteriorly it continues as 
an harmonia. The nasal bones are long and flat, forming a very convex edge posteriorly, 
where they are received between the frontals, while their anterior free edge presents a 
wide semicircular notch. The nasal suture, except for a short distance posteriorly, is 
entirely obliterated; the external edges of the single bone, thus formed, are nearly 
straight and parallel. 
The zygomatic process of the squamosal forms a small, horizontal, triangular plate, 
whose lower side affords a surface for the glenoid cavity. This cavity is bounded behind 
by a broad vertical process, which checks the retraction of the mandible; the axis of 
the cavity is inwards and slightly forwards. 
The facial plate of the maxillary is united internally with the premaxillary, the 
nasal, and the frontal, anteriorly with the premaxillary, and 
posteriorly with the lachrymal. The alveolar margin for the 
hindmost four teeth projects outwards and backwards, form- 
ing, by its coalescence with the rudimental malar, a com- 
pressed, sharp-edged process. There is no zygomatic arch. 
The antorbital foramen is very large. The orbits are very 
badly defined; they are marked by no postorbital process, 
and are continued without interruption into the wide tem- 
poral fossa. 
The palatine plates of the maxillary form the greater por- 
tion of the palate; the palatines form the posterior third, and 
the premaxillaries about a sixth. Two large incisive notches 
exist in the premaxillary, and are completed into foramina 
by the anterior edge of the palatine plate of the maxillary. 
The pterygoid ridges converge from before backwards, 
and enclose a deep, narrow interpterygoid fossa, whcse roof 
is continued without interruption into the inferior surface 
of the basisphenoid and basiocciptal. ; 
The horizontal ramus of the mandible is straight, with its upper and lower edge 
parallel; it forms with its fellow an acute angle, with a rather long and very oblique 
symphysis. The condyle is borne on a distinct neck; its axis is directed inwards and 
slightly downwards and forwards. ‘The posterior margin of the ascending ramus is thin, 
and runs from the neck of the condyle upwards and slightly forwards to the coronoid 
process, and downwards and backwards to the prominent hook-like angle. The anterior 
c2 
Lower jaw, twice the nat. size, 
