1877.) 49 
{Cope. 
On the Brain of Procamelus Occidentalis. 
By E. D. Cops. 
(Read before the American Philosophical Society, May 4, 1877.) 
I obtained a complete cast of the cranial chamber of the Procamelus 
occidentalis, which bears a fair proportion to the general dimensions of the 
skull. As compared with a llama of about the same size, the facial por- 
tion of the skull is longer, while the postorbital portion is as long, but 
narrower. This is indicated by the following measurements : 
Procamelus Auchenia 
occidentalis. lama, 
Length of skull anterior to orbit ....... teses 1180 158 
ee *« posterior Of Gasehad ved . .110 105 
Width ‘« at anterior border of orbit.... .080 .090 
ef ee middle of zygomatic fossa.. .062 065 
The olfactory lobes of the brain have nearly the same position in the 
two species, extending anteriorly to opposite the middle of the orbits. 
The brain exhibits large cerebellum and hemispheres, and rather small 
olfactory lobes. The cerebellum is entirely uncovered by the hemispheres 
but is in contact with them. The lateral lobes and vermis are well devel- 
oped. The hemispheres are well convoluted, the longitudinal posterior con- 
volutions giving way anteriorly to lobulate ones. The sylvian fissure is 
well marked. The sides of the medulla oblongata are compressed and 
vertical at the pons, in correspondence with the vertical position of the 
petrous bones. The origins of the ophthalmic and maxillary branches of 
the trigeminus nerve are not divided by a septum, while that of the man- 
PROC. AMER, PHILOS. soc. xvit. 100. G 
