184 



pusteriorly near the middle of the skidl, aiul are well developed. Thcv are 

 hounded in front by the prefrontals and ethmoid. The ])rcfrontals are stout 

 hones, directed ol)liquely downward, and terminate in a large truncate articu- 

 lar face for a facet of the palatine. The ethmoid is generally wide, and ter- 

 minates in an apex. It presents a large fiicet downward and laterally I'or 

 the anterior articular surface of the maxillary, opposing a corrcspondintr facet 

 of tlie vomer. Anterior and exterior to this point it exhil)its a lateral excava- 

 tion for the superior condyle; of the premaxillary. 



^ 



Fig. 8. — Craiiimii of I'orthvns molossus, Cope, oiic-foiulU iialiii:il sizu (linear) ; », snpraoceipital 

 bone; b, cxoceipital ; e, basioceipital ; d, parietal; c, pterotic; /, epiotie ; y, postfrontal ; It, iVoiital ; 

 i, lirefrontal ; A, etbmoiil; ?, Iiyo-niaiiJibuUir ; ni, metapteryf;oid ; «, quadrate ; o, cctoiiterygoid ; j), pala- 

 tine ;'/, sclerotic; ?', suborbital ; s, parasphenoid ; ?, jireniaxillary ; », maxillary ; r, accessory maxillary ; 

 u; deutary ; x, articiilo-angnlar. The opercular bones are ■wanting. 



Viewing the cranium on the inferior aspect, the parasphenoid and vojner 

 are seen to form a stout axis, the former running well posteriorly, and fissured 

 Iji'hind for the muscular tnlie. Neither supports teeth in any known s[)ecies. 

 Just Ijehind the line of the orljits, the parasphenoid gives off a latcial process, 



