Cope. ; 50 [May 4, 
dibular branch is quite distinct from the others. The optic nerves are 
large. The olfactory lobes are separated by a deep fissure below the ex- 
tremity of the hemispheres ; they project freely beyond the latter, being 
separated by a deep fissure. Their free portions are short, truncate and 
compressed. The anterior pyramids are not preserved on the inferior face 
of the cast of the medulla oblongata. The hippocampal lobes are subround 
and protuberant. 
From the detailed description following, it may be derived, that while 
the arrangement of the convolutions of the anterior lobes of the hemi- 
spheres is more simple than in any recent Ruminant, that of the middle 
and posterior lobes is essentially similar to that characteristic of the latter 
order of Mammalia.* 
The brain displays the characters of the older types of Ruminantia, 
although not materially smaller than that of the llama, an animal which it 
equaled in general proportions. The hemispheres are, however, not pro- 
duced so far posteriorly in the Procamelus as in the Auchenia, reaching 
only to the line of the meatus auditorius externus in the former. 
The vermis of the cerebellum rises abruptly from the medulla, having a 
nearly vertical direction to a point a little lower than the superior plane of 
the hemispheres. The lateral lobes extend on each side of it, each one 
having a rather greater width that the vermis. Their posterior faces are 
sub-vertical, and are directed slightly forwards. Each projects laterally 
into an apex at the middle of its elevation, and then contracts downwards 
into the angular line which marks the posterior border of the petrous 
bone. From a point between each apex and the vermis a ridge rises ob- 
liquely inwards to the superior plane of the cerebellum, where each one 
enlarges and joins the median transverse line. The angle above described 
as descending from the lateral apex of the cerebellum curves forwards, 
forming a lateral angular border of the pons varolii on each side. The 
flat space enclosed between this line and the posterior border of the hemi- 
sphere is interrupted by two prominent tuberosities. The superior is 
small, sub-oval, and is near to the posterior border of the hemisphere. 
The other is a short prominent ridge directed downwards and forwards, 
just behind the lobus hippocampi. Its inferior end corresponds with the 
origin of the mandibular branch of the trigeminus, and perhaps the facial 
nerve. 
The medulla oblongata is contracted at the foramen magnum, and has a 
sub-round section slightly flattened below. Its inferior face is then 
rounded, then flattened, and then concave between the anterior part of the 
lateral ridges. The bases of the maxillary branches of the trigeminus 
nerves are stout, and directly in line with the origins of the mandibulars. 
Between them the base of the brain is concave, and the optic nerves issue 
but a little distance in front of them. The lobi hippocampi are sub-round 
and rather prominent ; they are terminated in front at the foramen spheno- 
orbitale by the contraction of the cranial walls. Their surface displays 
* See Paul Gervais’ Journal de Zoblogie, I, 1872, p. 459. 
