248 MEMOmS OF THE QUEENSLAND MUSEUM. 



In the temporal region the anterior horn of the squamosal extends to the- 

 middle of the large oval fossae, articulating with the postorbital. The fossae are- 

 fairly symmetrical, approximately 120 mm. in length, with a breadth of 75 mm. 



On the right-hand side the orbit is well preserved, except for its posterior 

 border. The cavity has been largely set free from the cement-like matrix, which here 

 contained molluscan fragments. It was carefully excavated in the hope that the 

 characteristic sclerotic plates, possibly driven inwards, might be exposed, but 

 these have entirely disappeared. It is evident that the orbit was the characteristic 

 oval. Its vertical diameter at the periphery is 110 mm. Beneath the orbit, portions 

 of the jugal can be seen, but the full extent of the zygomatic arch with its sutures 

 cannot be outlined. The jugal appears first as a raised process near the midline of 

 the anterior border of the orbit and then curves down to form its lower edge. 



A large supratemporal bone is present on the left-hand side, and its superior 

 margin junctions with the lateral border of the squamoso-postorbital arcade. Mueh 

 controversy has taken place over the "' additional temporal bone," as S. W. Willistott 

 called it in the Ichthyosaurs, and the author has followed the nomenclature of 

 Lydekker,* Sollas (loc. cit.), Gilmore, and Andrews in calling it supratemporal. 

 Williston considered the inner bone of this " Diapsid " group the tabular and the 

 outer the squamosal, ^ but in view of Watson's demonstrations*^ it is surely better 

 to reserve the name " squamosal " for the more constant element. Perhaps the latero- 

 temporal or " sclerodermal plate," as Owen called it, is really a separated division 

 of the quadratojugal. 



The quadratojugal is present, and its posterior portion is visible in the 

 occipital region, where it forms the inferolateral border of the vacuity presented by 

 the curved shaft of the quadrate. Its sutures with the supratemporal are obscure. 



Basi- Occipital. — The stout symmetrically convex condyle extends back- 

 wards beyond the pterygoids for a distance of 33 mm. ; the tranverse diameter is. 

 74 mm., vertical diameter 64. 



Ba.sis Cranii. — The suture between the basioccipital and the basisphenoid 

 can be traced, giving a length of 60 mm. to the former bone. The basisphenoid 

 is about 75 mm. in length, and forms with the posterior element a rectangular 

 rostrum for the support of the pterygoids. The basisphenoid has a visible width 

 of about 60, whilst the basioccipital is about 40 mm. Near the posterior margin 

 of the basisphenoid the opening of the single canal for the carotic arteries can be 

 clearly seen ; this foramen is circular and has a diameter of 10 mm. In the median 

 line of the interpterygoid vacuities the splint-like parasphenoid may be' seen, but this 

 has been only partially freed from the matrix, compared with which it is very friable. 

 This bone evidently increases in thickness towards its upper surface and is trian- 

 gular in section. It can be traced anteriorly for a distance of 220 mm., where it is 



«R. Lydekker, Catal. Fos-s. Kept. Brit. Mus., Part 11, 1889, p. 3. 



5 S. W. Williston, Phylogeny and Classification of Reptiles (Journ. Geo XXV), 1917, 

 p. 416. 



« D. M. S. Watson, Ann. Mag. Nat. Hist. (8) XIV, 1914, pp. 84-93. 



