132 DISOOGLOSSID^. 



Skeleton. — Ethmoid short, not extending poste- 

 riorly beyond the anterior third or two-fifths of the 

 parasphenoid, embracing above a large fontanelle 

 which extends to the line of the anterior borders of 

 the orbits, and which remains exposed between the 

 diverging anterior borders of the fronto-parietals ex- 

 cept in very old specimens ; its upper lamina obtusely 

 pointed and partly covered by the nasals, which are 

 large and form a long suture in the median line. 

 Fronto-parietals large, in contact along their posterior 

 two-thirds or more. Zygomatic branch of the squa- 

 mosal joining by suture an ascending process of the 

 maxillary. Vomers large, their posterior toothed 

 border nearly straight, and covering the feeble pala- 

 tines, narrowly separated from each other in the 

 median line ; pterygoids regularly trifurcate, with a 

 small round outer wmg-like expansion at the meeting- 

 point of the three branches, joining a corresponding 

 process of the angular bone of the mandible; the 

 inner branch of the pterygoid in contact with the 

 parasphenoid, which is ±-shaped, obtuse or truncated, 

 or indentated anteriorly, and not quite reaching the 

 vomers. Mento-Meckelians quite indistinct. 



Hyoid a large, broad cartilaginous plate with 

 rounded lateral wings, small postero-lateral processes, 

 and proximally slender, mesially broad and lamellar 

 ceratohyal cornua without forward pi'ocesses ; in addi- 

 tion to the rather large thyrohyals, which meet with 

 their inner angles, there is a V-shaped, slender, ventral 

 ossification, which is in contact with the latter at its 

 apex, and reaches forward to the anterior notch of the 

 cartilaginous plate ; this ossification often paired, the 

 two branches being disconnected at the apex. 



Vertebral column twice to twice and one-third as 

 long as the skull. Vertebra imbricate and completely 

 covering the spinal cord above, with a long postero- 

 median neural process. Second, third, and fourth 

 vertebrte with short diapophyses, to which short ribs 

 are attached. The first rib is the shortest, horizontal 



