146 
Records of the Geological Survey of India. 
[vOL. IX. 
bones, viz., the frontal, nasal, maxilla, and jugal As far as I can make out from the skull of 
Hippopotamus with which I have compared this specimen, in the latter genus the lachrymal 
articulates with the same four hones, but not quite in the same proportions ; in Sns, on the 
other hand, we have a very different relationship of these bones; owing to the shortness of 
the lachrymal and nasals, those bones do not articulate with each other; hut between the 
two a process of the frontal extends downwards to articulate with the maxilla,—a union 
which does not occur in either Hippopotamus or Merycopotarms. The lachrymal foramen 
is single, and pierces the orbital portion of the lachrymal close to the angle separating the 
former from the facial portion, a condition intermediate between Sns and Hippopotamus; 
the fossils do not, of course, show whether the lachrymal formed a thin capsule within the 
orbit as in the latter genus. 
Frontals. —These bones are depressed, and are united by a straight sagittal suture,— 
simple interiorly, but with interlocking processes superiorly; the distal extremity of the 
frontals forms a slight re-entering angle for the articulation of the nasals ; the naso-frontal 
suture is deeply indented ; a small process is given off from the frontals, which is wedged in 
between the lachrymal and the nasals ; in front of the orbits the frontals seem to have been 
somewhat expanded laterally, but do not form the “telescopic” orbits of Hippopotamus; 
their form was probably more like that of Sus. The venous foramina on the surface of the 
frontals are situated above the centre of the orbits, and pierce the houe at right angles, 
somewhat as in Hippopotamus; in Sus these foramina perforate the bone obliquely, and 
have long sulci below them. 
Parietals. —The fro0to parietal suture is not shown in any of the known skulls; the 
two bones at their union form a hold sagittal crest which divides at its lower third, and 
runs to the superior angles of the orbits; the surfaces of the temporal fosse are somewhat 
convex. The hinder portion of the parietals is very greatly longer iu proportion to the size 
of the skull in Merycopotamus than in Hippopotamus; the sagittal crest in the former is 
a long straight ridge for a considerable distance, whereas in the latter it bifurcates to join 
the orbits after a very short distance. This greater length of the cranial portion of the 
skull quite, does away with the relative excessive length of the nasals, which forms such a 
remarkable feature in the skull of Hippopotamus. 
In Merycopotamus the cranial and facial portions of the skull are approximately equal, 
(see plate 67, fig. 5- “ Fauna Autiqua Sivalensis”), and from the long sagittal crest the 
whole cranium has much more the appearance of the cranium of a Carnivore than of 
Hippopotamus. In Merycopotamus the lateral boundaries of the temporal fossae are in the 
same autero-posterior line with the lateral borders of the orbits, whereas iu Hippopotamus 
the latter reach outwards to the zygomatic arches. 
Occiput. —The form of the occipital surface approaches nearer to that of Sus than 
Hippopotamus ; the occipital crest forms a bold ridge, angulatcd in the centre, and some¬ 
what overhanging the general surface of the supra-oceipital. The breadth of the supra- 
oocipital is less in proportion to its height than in Hippopotamus, and thereby approaches 
to Sus: further, the occipital surfaces of the squamosals are placed considerably more in 
advance of the plane of the supra-oceipital than in Hippopotamus, thereby giving the latter 
bone a more prominent and isolated character, similar to that of Sas. The bony ridge con¬ 
necting the extremity of the occipital crest with the zygomatic process of the squamosal is 
placed somewhat higher up on the occipital surface, and is larger and stouter than in Sus: 
the prominence of the zygomatic process of the squamosal which overhangs the meatus 
auditorius externus is wanting in Merycopotamus. The supra-occipital is an oblong bone, 
with its superior extremity produced into a median angle; the ex-occipitals and paramastoid 
