704 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



according to Boas and PauUi (1908.1), is merely 

 the front part of the buccinator, which also extended 

 backward alongside the grinding teeth and between 

 the molars and the malar. 



To the corner of the mouth was doubtless attached 

 the zygomaticus muscle, which arose from the front 

 part of the zygomatic arch, beneath the orbit. 



To the surface of the upper lips at the sides was 

 attached the wide nasolabialis, which passed obliquely 



side, as in the horse and tapir. It very probably 

 ran above the huge nasal cartilage and beneath the 

 lower rim of the nasal bone back to its origin in the 

 wide depression in front of the orbit, which was 

 bounded above by the nasals and behind by the 

 raised anterior rim of the orbit. 



The anterior end of the upper hp and the side of 

 the nose were very probably retracted^by the inferior 

 branch of the maxillolabialis, which ran back along 



Figure 641. — Facial musculature and nasal cartilage of an Eocene titanothere 



Superficial layer of muscles; A2, relations of nasal chamber and surrounding muscles to skull, 

 natural size. 



upward and backward, overlying both branches of the 

 maxillolabialis (levator labii superioris alaeque nasi), 

 to its origin on the curved rim of the nasal and 

 maxillary, beneath the horn swelling and in front of 

 the orbit. 



The anterior tip of the lip was raised by the superior 

 branch of the maxillolabialis. This was perhaps 

 joined by ligament with its fellow of the opposite 



the side of the face to its tendinous origin beneath 

 the orbital portion of the zygomatic arch. The 

 very massive nostrils were doubtless compressed by 

 the action of the dilator naris and lateralis nasi 

 muscles, which surrounded the back part of the 

 nasal chamber and its diverticulum, which together 

 filled the space below the nasals and above the 

 maxilla. 



