by the epiotiCj, opisthotiCj, prootiCj, and basioccipital„ and is 

 also slightly in contact with the pterotic and the supraoccipitalo 



The opisthotic forms the posterior portion of the brain 

 chamber o It is visible both from the ventral and from the dorsal 

 sides, and is external to the exoccipitalo Its anterior portion 

 and outer sides are in contact with the prootic and pterotic boneso 



The basioccipital is a bone directly under the floor of the 

 foramen magnumo It has a concave occipital condyle on its poste- 

 rior portionc, It joins dorsally with the exoccipitalj anteriorly 

 with the prootic p and vent rally with the parasphenoido 



The nasal is a somewhat elongated bones flat in formo Its 

 posterior portion is fixed to the anterior edge of the frontal, 

 and posteriorly it rests on the palatine,, 



The preorbital is an elongated flat bone beneath the eyeo 

 It has an articulating surface for articulating with the process 

 on the ventrolateral side of the prefrontal. The dorsal edge of 

 this bone is rather thick^ but the ventral edge is extraordinarily 

 thino It protects the lower surface of the eyeo 



The suborbitals are thin flat bones arranged in a circle 

 posterior to the eye. They are inconspicuous bones which are not 

 greatly differentiated from the scales of the cheeko 



The premaxillary is a long curved bone with a greatly 

 thickened anterior endo The posterior portion, however^ is 

 flattened and narrow and is without any marked peculiarities 

 such as grooves and so fortho 



The maxillary is also a long narrow curved boneo Its 

 anterior tip is thick and has a concavityo It rests on the pre- 

 maxillaryo 



The palatines are on the outer sides of the vomer and are 

 fused to the anterior end of the maxillary,, Palatine teeth are 

 developed on themo The pterygoid is a T-shaped bone which is 

 joined by its small horizontal axis to the palatine.. The poste- 

 rior end broadens and joins to the inner surface of the metaptery- 

 goid and the quadrate. The mesopterygoid is a flat thin bone 

 which is joined to the palatine and the pterygoido Its inner 

 edge rests on the parasphenoido There is a band of villiform 

 teeth on this boneo 



The hyomandibular is a strong boner Its upper portion is 

 broad and its lower part is somewhat rod-shapedo The anterior 

 and superior parts have two articulating processes which articu" 

 late with the palatine /?/o Posteriorly there is another process 

 which articulates with the opercieo 



6 



