26 
ACTINOPTERYGII. 
P. 356. Imperfect hinder portion of skull, longitudinally bisected in 
the median line to exhibit the extent of the supraoccipital 
bone. As shown in the section (PI. III. fig. 5), this 
element (s.occ.) is much thickened, and in its upper 
portion extends almost as far forwards as the investing 
parietals {pa.'). The exoccipitals {ex.occ.), as in the pre¬ 
ceding specimen, clearly form the upper border of the 
foramen magnum ; and there seems to be a persistent 
suture between the basioccipital (b.occ.) and basisphenoid 
(h.sp.). When viewed from behind (fig. 5 a), the basi¬ 
occipital exhibits the groove for the basicranial canal 
(b e.). Egerton Coll. 
P. 4153. Imperfect hinder portion of skull, smaller than the pre¬ 
ceding. The basicranial canal is indicated, and the 
remains of the otic region (PI. III. fig. 6) are interesting. 
The pro-otic {pr.o.), pierced as usual by the oval foramen 
for the fifth nerve, is in contact above with the sphe- 
notic or postfrontal (pt.f.) and the pterotic (pt.o.), these 
two latter bones meeting and forming the floor of a cavity 
which exists between the outer part of the otic mass and 
the squamosal {sq.). The upper end of the hyomandibular 
must have articulated with two distinct facettes (/.), the 
largest and deepest on the pterotic, the smallest at the 
point of contact of the sphenotic with its adjacent elements 
already mentioned. There are indications of the great 
triangular hollow in the otic mass immediately behind the 
pro-otic, and of the similar hollow on the occipital face 
between the outer edges of the epiotic and pterotic. 
Enniskillen Coll. 
P. 1698. Crushed fragment of hinder part of large cranium, showing 
suture between basioccipital and basisphenoid, and the 
parasphenoid forming the floor of the basicranial canal. 
Egerton Coll. 
Megalops oblongus, sp. nov. 
1841. Hypsodon ohlongus, L, Agassiz, Poiss. Foss. vol. v. pt. i. p. 101 
(name only). 
Type. Imperfect cranium ; British Museum. 
A species somewhat larger than the preceding, known only by the 
imperfect cranium. Length of cranial roof from occiput to post¬ 
frontal equalling its width at the position of the latter element. 
Form. Log. Lower Eocene (London Clay): Sheppey. 
