THE OCCIPITAL BONE 



49 



is much narrower in front than behind. The ventral surface is rounded. The 

 cranial surface is concave and smooth; its posterior part supports the medulla, 

 and its anterior part has a shallow cavity on which the pons rests. The lateral 

 borders are thin and sharp, and form the inner margin of the foramen lacerum 

 (Foramen lacerum et jugulare). The anterior end has, in the young subject, a 



Fig. 28. — Ventral Htri ack op Skui.i. of Hor.se, Po.sterior Half Without Mandible. 

 The skull is inclined slightly. (Notation on key Fig. 27.) 



semicircular, flat, pitted surface which is attached to the body of the sphenoid bone 

 by a layer of cartilage; in the adult there is complete fusion. On the ventral aspect 

 of the junction are tubercles for the attachment of the ventral straight muscles of 

 the head. 



The squamous part (Squama occipitalis) is the somewhat quadrilateral mass 



