PROFESSOR OWEN, ON THE RHYNCHOSAURUS. 361 



The lachrymal bone presents the same relative size and position as 

 in the Thorictes, Lacerta, and most Lizards; a tubercle rises from 

 about the middle of its external surface. 



The superior maxillary is a broad vertical triangular plate of bone, 

 with a smooth external surface : the alveolar border projects externally 

 like a ridge, above which the bone is slightly concave : this ridge 

 appears to be slightly dentated, and overlaps the corresponding alveolar 

 border of the lower jaw. The posterior superior margin of the max- 

 illary bone is slightly concave, and joins the malar and lachrymal bones, 

 and a small part of the prefrontal : the anterior superior margin joins 

 the upper half of the elongated intermaxillary bone, which divides it from 

 the nasal bone and the external nostril: the lower side or base of 

 the triangle, which forms the alveolar border, is convex. 



The most singular character of the cranium of the present fossil 

 Reptile is afforded by the intermaxillary bones. These, in their length 

 and regular downward curvature, give to the fore-part of the skull 

 the physiognomy of that of an accipitrine bird; but they differ es- 

 sentially from both those of the bird and lizard, in being on each 

 side distinct throughout their whole length, and in gradually diminish- 

 ing to their inferior or rostral extremity, which is not expanded or 

 continued laterally to form any part of the alveolar border of the 

 upper jaw. Each intermaxillary bone is a slender subcompressed elon- 

 gated bone, bent so as to describe a quarter of a circle ; the upper 

 half is thinner, but rather broader, than the lower one, and is wedged 

 in between the superior maxillary, frontal, and nasal bones: the lower 

 half, which is somewhat narrower, but thicker and subcylindrical, pro- 

 jects freely downwards beyond the superior maxillary hone ; and the deep 

 anterior extremity of the lower jaw is applied to the posterior surface 

 of these produced extremities of the two intermaxillaries when the 

 mouth is closed. The two intermaxillaries converge towards each other 

 from their posterior origins, and are in close contact with each other 

 where they form the singular curved and prominent beak. 



The external nostril I presume to be situated between the upper 

 diverging ends of the intermaxillaries, but a fracture of the fossil at 



