200 PEOF. D. M. S. WATSON AND MR. E. L. GILL ON THE 
f rentals ; these bones articulate with the " tabular " behind, and seem just 
to reach the free anterior edge of the shield. 
The lateral edge of the " tabular "' and " frontal'' is attached to a series of' 
bones, the posterior two ? of which are narrow and form that margin of the 
skull to which the operculum is attached; they are imperfectly shown from 
the dorsal surface on the right, and are absent on the left side. Immedi- 
ately in advance of these is a very large element forming an outstanding 
wing behind the orbit. This extends forward and just touches a much 
smaller bone, which forms the anterior and upper quadrant of the orbital 
margin. 
The dorsal shield is completed by a pair of bones which articulate with the 
front margins of the frontals and interfrontal. 
There are no traces of other circumorl)itals or of premaxillse. 
The palate presents an interesting modification of the Dipnoan ijpe. The 
parasphenoid has a long, slender dorsally channelled stem, which expands 
into a broad, shovel-sha])ed, flat bony plate extending forward as far as the 
symphysis of the lower jaw. This region of the parasphenoid is covered with 
teeth, small and very closely packed anteriorly, somewhat larger and moie 
scattered posteriorly. These teeth are quite irregular in arrangement, but 
little grouf)s of two or three of them are often supported on a common raised ■ 
base ; anteriorly where the teeth become inconspicuous the bases may persist 
as short curved ridges. 
The pterygoid on the left side seems to retain its natural position, standing 
up nearly at right-angles to the jjalate. 
The bone is very narrow anteriorly, forming a border to the great para- 
sphenoid and having irregularly arranged small teeth. Posteriorly the bone 
becomes converted into a deep thin flange, which was formerly applied to 
the quadrate and stands nearly at right-angles to the palate. 
The operculum has long been known- as a concavo-convex bone with an 
umbo at its antero-dorsal corner. This specimen shows a small bone on the 
right side which seems to be a sub-operculumj because of its resemblance to 
that bone in Dipterus and Sagenodus. 
The structure of the lower jaw is not satisfactorily shown. There is a 
powerful symphysis formed by bones of the outer surface homologous with 
the "dentaries'" of Sagenodus, but possibly including true dentaries in 
addition. 
There is a large angular of whose structure nothing can be said. Although 
this lower jaw lies in its natural position and the mouth is closed, no trace of 
the bones usually called spleniai can be seen in it. There is, however, a 
strange tooth-bearing bone with a concave visceral surface lying displaced in 
contact with the right ramus, which apparently can only be this element. It 
differs from the corresponding bone in all other Dipnoi in lacking a posterior 
flange passing back to the articular and an anterior symphj'sis. The two 
