332 
AKTIODACTYLA. 
to the line of the extremities of the last molars. In the Llama, it is deep, 
reaching the line of the middle of the penultimate molars. Second, the 
basioccipital is flat in the Llama, and the sphenoid only rounded; in the 
P. occidentalism both are angnlate or keeled. Third, the foramen magnum 
has a V-shaped superior border in the Llama; in the P. occidentalism it is 
slightly notched at the middle of the superior border. Fourth, the ptery- 
' goids are only angulate in the extinct animal, not produced into processes 
as in the Llama. Fifth, the palatal foramina in the Llama have a more 
anterior position, issuing in front of the third (first) premolar. The glenoid 
and condylar foramina are much larger in the Llama. 
The teeth of the specimen described are in good preservation. The 
external incisors and canines are alike, their crowns being slightly-com¬ 
pressed cones. The space between them is about equal to that separating 
the canine and first premolar, while the space between the first and second 
premolars is greater. The second premolar is small, half as large as the 
third, is compressed, and has a slight anterior cusp. The third consists of 
a small anterior cusp and a long posterior blade. A strong basal cingulum 
represents the interior crescent. The fourth premolar is little longer than 
the third, but differs from it in the possession of an inner crescent; its 
external angles are prominent, separating a concave face. The true molars 
are rather narrow. The anterior horn of each crescent is prominent, repre¬ 
senting the section of a prominent ridge; between the ridges, the external 
face of the lobes is flat or concave. There is no enamel on the outer wall 
of the inner crescents in the last two molars. The enamel is smooth, and 
is wdthout cingula. As compared with Auchenia larnUm the molar teeth are 
larger and longer, and lack the prominent ridges on the external faces of 
the external crescents. The incisors and canine teeth have not the com- 
})ressed trenchant form of those of the Llama. 
Total length of the skull below.. 0.303 
Length (axial) to the'external incisor... 0.023 
Length (axial) to the canine. . 0. 041 
Length (axial) to the first premolar. . 0.061 
Length (axial) to the second premolar... 0.093 
Length (axial) to the first true molar.. . 0.126 
