326 
. AETIODAOTYLA. 
In Procamelus Occidentalis, an extensive fossa is situated above the 
posterior premolar series of teeth, and greatly contracts the middle of the 
facial part of the skull. These fossae are represented by rudiments in the 
Auchenia lama. In addition, the cavities known as “larmiers” in the 
Cerviclcc are well developed in this g’enus, being many times as large as 
in the Llama, and quite equal to those possessed by some Deer. There 
are no lachrymal fossae. The supraorbital foramen communicates with the 
superciliary border by an open fissure ; the lachrymal bone is large. The 
cranium resembles that of the Llama in its moderate sagittal crest, elongate 
pairamastoid process, and otic bulla, and the downward production of the 
pterygoid bones. The incisive foramina are narrow and distinct. 
The ulna and radius are thoroughly coossified. The carpus displays 
the characters of the Camelidcc in the absence of trapezium and distinct¬ 
ness of trapezoides, and the subequality of the magnum and unciform facets 
of the lunar. There are but two metacarpals, which, in the specimen de¬ 
scribed, are only coossified in their proximal half. As the epiphyses of 
the vertebrae are not yet united, the present animal is not fully adult. In 
an older specimen, the cannon-bone is doubtless completed. In the tarsus, 
the cuboid and navicular bones are distinct, as in the existing Camel. 
I obtained a complete cast of the cranial chamber of the Procamelus 
occidentalism which bears a fair proportion to the general dimensions of the 
skull. As compared with a Llama of about the same size, the facial portion 
of the skull is longer, while the postorbital portion is as long, but narrower. 
This is indicated l^y the following measurements: 
ProcameJus Auchenia 
occidentalis. lama. 
M. M. 
Length of the skull anterior to tbe orbit. 0.180 0.153 
Length of the skull posterior to the orbit. 0.110 0.105 
Width of the skull at the anterior border of the orbit .. 0.080 0.090 
Width of the skull at the middle of tlie zygomatic fossa. 0.002 0.065 
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 heniispheres and rather small 
olfactory lobes. Tldie cerebellum is entirely uncovered by the hemispheres, 
but is in contact with them. The lateral lobes and vermis are well devel- 
