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 exoecipitals (ex.occ.), as in the pre- 
ceding specimen, clearly form the upper border of the 
foramen magnum ; and there seems to bo a persistent 
suture between the basioccipital (b.occ.) and basisphenoid 
(b.sp.). When viewed from behind (fig. 5 a), the basi- 
occipital exhibits the groove for the basicranial canal 
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 (IT. III. fig. 6) are interesting. 
The pro-otic (pr.o.), pierced as usual by the oval foramen 
for the fifth nerve, is in coutact 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 betwoon tho outer part of the otic mass aud 
the squamosal (sq.). The upper end of the hyomandibular 
must have articulated with two distinct facettes (/.), the 
largest and deepest on the pterotic, the smullest at the 
point of contact of the splienotic 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 tho basicranial canal. 
Egerton Coll- 
Megalops oblongus, sp. nov. 
184 4. Hypsodon oblongus, L. Agassiz, Poiss. Foss. vol. v. pt i. P- 1 
(name only). r 
Type. Imperfect cranium ; British Museum. 
■ } ° leS somc " hat larger than the preceding, known only by t 
mporfect cranium. Length of cranial roof from occiput to P<» 
rental equalling its width at the position of the latter element. 
M ' 4- Loc. Lower Eocene (London Clay) : Sheppey. 
