ELOPID.^. 
25 
from the occiput to the prefrontal region immediately in 
advance of the eye. A certain amount of crushing and 
distortion is at the same time obvious. The sclerotic (set,) 
is ossified and, unless appearances are deceptive, the eye 
is smaller than in the recent ih. cyprinoides. Remains of 
the delicate cheek-plates, with radiating markings, are pre¬ 
served both behind (s.o.) and in front (a.o.) of the eye. The 
relatively small premaxilla (pma?.) underlaps the front ex¬ 
tremity of the enormous maxilla {mx.), which exhibits a 
small knob (a\) for its anterior attachment to an inner 
element. The extent of the supramaxillaries is indicated 
only by the depression for their overlap of the maxilla. 
The whole length of the left mandibular ramus is displayed 
(cZ.), with its hollowed hinder articulation in contact 
with the condyle of the quadrate {qud ); and the latter 
element is directly apposed to the metapterygoid above, 
while apparently provided with a superiorly-pointed, 
slender, hinder process to grasp the small symplectic. 
The bases of clustered series of verj" minute teeth are 
shown on the margin of the jaws where preserved. The 
upper end of the hyomandibular (Jim.) is partly exposed, 
with its process for the support of the operculum [op .); 
and the latter element is well shown, with the pre¬ 
operculum {p.op.) in front, and the suboperculum {s.op.) 
and interoperculum (i.op.) below. The spaced series of 
branchiostegal rays (hr.) cannot have numbered less than 
20, although not so many are actually exhibited; and the 
gular plate (yi^^.) is nearly half as loug as the mandible. 
Purchased, 1861. 
P. 637. Hinder half of skull, labelled Hypsodon toliapicus by Agassiz, 
and intended to be the type specimen of that species. The 
cranial roof is shown from above of two thirds the natural 
size in PI. III. fig. 4, and the various elements can be 
readily distinguished as lettered. On the occipital face 
the exoccipital is shown to meet its fellow in the median 
line below the large, keeled supraoccipital; but the basi- 
occipital is broken and crushed to the left, with one short 
and deep vertebral centrum adhering to it. There is clear 
evidence of a basicranial canal. The otic region exhibits 
its characteristic conformation, and an elongated facette 
for the hyomandibular is shown on the pterotic. 
Egerton Coll. 
