274 University Geological Survey of Kansas. 



Ceratohyal : Greatest length 238 mm. 



Width across anterior end 86 " 



Width across posterior end 97 " 



The palato-quadrate arch is made up of six bones — the pala- 

 tine, pterygoid, metapterygoid, mesopterygoid, symplectic, and 

 quadrate. The first and last of these mentioned form the ex- 

 tremities of the arch, the other four intervening. The palatine 

 presents a prominent malleolar portion, which has an articular 

 face above and below for the prefronto-palatine articulation for 

 binding the maxilla to the cranium, so characteristic of the 

 Saurodontidse and Ichthyodectidse. The lower of these faces is 

 the larger and is slightly concave, while the upper is somewhat 

 convex. The external surface presents no markings other than 

 a prominent tuberosity on the posterior side. Just back and 

 above this portion there are two prominent tubercles of bone, 

 one of which may give attachment for a nasal bone. 



The pterygoid and mesopterygoid are joined to the palatine 

 posteriorly. The first of these is a long, thin bar of bone, 

 which extends backward and downward nearly to the condyle 

 of the quadrate and forms most of the lower border of the arch. 

 The mesopterygoid is a somewhat triangular-shaped bone oc- 

 curring just above the pterygoid. It is evidently united to the 

 metapterygoid by means of a very broad squamose suture, as 

 the bone appears to be rather small when seen externally, while 

 the internal side, as figured by Professor Hay 32 seems to be 

 nearly as large as the metapterygoid. I have been unable to 

 discover any teeth on the external side of this and the ptery- 

 goid, and none on the internal side of the pterygoid, as far as 

 can be examined, which seems to be beyond the point where 

 Professor Hay has shown them to be in his specimen. A sec- 

 ond specimen shows that in this region there was a great deal 

 of ossified cartilage covered with denticles, some of which is 

 adhering to the matrix on the internal side of the mesoptery- 

 goid, and I am inclined to think that it was some of this carti- 

 lage that Professor Hay mistook for teeth on the bone. The 



32. Zool. Bull., vol. II, p. 39. 



