Tlte Jhdd of DuiichtlnjH.—Claijpole. 205 
front. Its pre-orbital process is slenderer than the post-orbital 
and meets the front end of the sub-orbital at or near its junc- 
tion with the premaxillary, thus completing the enclosure of the 
orbit. The pre-orbital overlaps the post-orbital, the ethmoid and 
the nasal. Its front edge runs from the nasal to the point of the 
pre-orbital process. It is strengthened on its inner face by a 
sharp, low ridge beginning at the point of the process and thick- 
ening inwardly as it rises for about one inch, after which it again 
sinks, until at length it merges in. the low, flat end of the temporo- 
masseter and capsular ridge already described. This re-enforce- 
ment of the pre-orbital plate is connected with the insertion of 
the premaxillary tooth which was carried in part at least on its 
front edge, the remainder being borne by another plate to lie men- 
tioned later. 
The nasal openings, or what were apparently such, were situated 
on the fi'ont edge of the nasal plate and extended in part on the 
inner front edge of the adjoining pre-orbital. In the specimen 
described they are on the very margin, but this is owing to the 
loss of the plate to be mentioned below. (No. 12.) 
(9.) The Ethmoid plate is missing from this specimen, but it 
is so well known from other examples, and its size and relations 
are so clearly marked on the adjoining plates, that no difficnltv is 
found in tracing it. It overlaps the hinder end of the nasal and 
a large area of the inner edge of the frontal, and underlaps the 
pre-orbital along its inner face. It resembles a spear-head in 
form with the point liehind. On its inner face is seen the deep 
fontanelle, regarded as a place of lodgment for the extension of 
the pineal gland to a probable pineal eye. The fontanelle usually 
and perhaps normally, reaches the outer surface by a ver}' small 
aperture, but was apparentl}' in some specimens altogether closed. 
(10.) The Niisal plate is trapezoidal in outline and completes 
the front of the head on the median line. It underlaps the pre- 
orbital and the ethmoid and overlaps to a very small extent, at 
its outer edge, the premaxillary plate, to be mentioned immedi- 
ately. (No. 12.) 
(11.) The Suh-orhlt<il plate is a thin blade of bone four inches 
long, with thickened front and lower margins, passing at its lower 
front angle into a narrow but thicker projecting arm two and a 
half inches in length and extending forward. On the lower edge 
of this arm is n long, thin, crescentic plate which serves as a but- 
