442 Annals of the Carnegie Museum. 



the llama, is separated from the lacerum medium only by a long thin 

 bridge. The carotid canal is separated from the posterior lacerated 

 foramen as in the llama and differs in this respect from that of the 

 recent camel where the two canals have a common exit. The con- 

 dylar foramen is located well back under the anterior edge of the ac- 

 cessory facet and is not visible from a direct palatine view of the 

 skull. The postglenoid foramen is situated posterior to the glenoid 

 process and is in appearance very similar to that of the recent camel. 

 On the superior wall, at the base of the zygomatic process of the 

 Squamosal there is a perforation somewhat smaller than the corre- 

 sponding foramen in the llama, and, as in the recent camel, it is situ- 

 ated in advance of the postglenoid foramen. There is a deep depres- 

 ion and a foramen superior to the exoccipitals similar to the foramens 

 found in this region in recent forms. In a direct back view the fora- 

 men magnum appears somewhat triangular. Its superior border is 

 slightly emarginated, the lateral borders being almost vertical, while 

 the inferior border is V-shaped and terminates in the groove which 

 separates the accessory facets. 



Tlie Mandible. — {V\. IV, Fig. i.) The mandible is long and 

 slender. The symphysis is long and the rami firmly united, display- 

 ing little or no trace of the suture, which is also true of the recent 

 forms. The region anterior to the continuous molar-premolar series 

 is comparatively heavier than that of the recent genera, owing to the 

 presence of all the premolars. In this region there are also two slight 

 constrictions, one in front and one back of pm. y, which are not 

 present in the recent forms. The ascending ramus compares well 

 with the recent forms, especially the llama. The coronoid process is 

 high, thin, and projects slightly backward at its extremity. The con- 

 dyles have a comparatively greater transverse extension than in the re- 

 cent forms. There is a strong hook-like process on the angle below 

 the condyle, similar to that in the recent camel. In the llama this 

 process is less pronounced. The masseteric fossa is much deeper than 

 in the recent camel. In size, depth, and location it is more nearly 

 like that of the llama. 



The Foramina. — The inferior dental foramen is large and occupies 

 a position similar to that of the recent forms. The mental foramen 

 is placed low down on the jaw directly under the first premolar. 



Cranial and Denial ]'ariaiions in Lama linanaco. — In connection 

 with the dental characters and some osteological features of the 



