1892.] 241 [Cope. 



Survey of the country for determination and description. I express here 

 my thanks to the honorable Director of the Survey, Dr. A. R. C. Selwyn, 

 for the opportunity of examining these important specimens. 



The first specimen consists of the skull, from the orbits to the muzzle 

 inclusive, with the two dentary bones with teeth adhei'ing to the inferior 

 surface. The second specimen includes most of the parts absent from the 

 first. The muzzle and orbital region are wanting, but the parietal and 

 occipital regions are present, with the basis cranii and palate ; parts of the 

 quadrate bones and both mandibular rami nearly complete with teeth. 



Tiie bones of the skull are dense and light, and some of them are pneu- 

 matic. The sutures separating the premaxillary, maxillary and nasal 

 bones are not distinguishable in the specimen, and both are considerably 

 injured. There is a large subround preorbital foramen whose centre is a 

 little nearer the superior plane of the skull than the alveolar border. It 

 is separated from the orbit by a narrow isthmus. The frontal bone is 

 very narrow between the orbits. The prefrontal forms a vertical convex 

 crest on eacli side, as represented by Marsh to exist in the Megalosaurus 

 nasicornis. The orbits are longitudinally widely parallelogrammic, and 

 are of enormous size, equaling in long diameter the length of the muzzle 

 in front of them. The postfrontal and postorbital elements appear to be 

 fused, and form an L-shaped bone, whose horizontal limb is supraorbital, 

 extending forwards over the orbit anterior to its middle, and terminating 

 in an acute apex. The other limb is vertical and postorbital, extending to 

 the jugal bone. A small piece on the inner side of the postfrontoorbital 

 at its posterior angle on the superior face of the skull is of ttncertain deter- 

 mination. The maxillary diminishes rapidly in depth below the orbit and 

 terminates a little posterior to it. The jngal overlaps it above, and prob- 

 ably terminated at about the posterior third of the orbit, but the suture is 

 not clear at this point. The frontal is supported below by two vertical 

 elements posterior to the middle of the orbit. These closely resemble the 

 corresponding pieces in Sphenodon, and are the postoptic* and epiptery- 

 goid respectively. They are preceded by a vertical compressed element 

 which corresponds with the orbitosphenoid of Sphenodon, but it is not 

 perforate, and the optic foramen is posterior to it. It is elongate autero- 

 posteriorly, and its anterior extremity is concealed anterior to the orbit. 

 The postoptic is strongly concave at its anterior margin, and the inferior 

 part of this border is produced anteriorly. The epipterygoid, on the 

 other hand, is openly concave posteriorly, its inferior portion being di- 

 rected posteriorly and enclosing a large foramen with the postoptic. The 

 external face of the maxillary bones is rugose with fine ridges, and rather 

 numerous foramina. The jugal extends well posteriorly, and increases in 

 depth, but its posterior extremity is broken from the specimen. 



The mandibular rami are compressed, and the symphysis is oblique and 

 ligamentous. The dentary bone is followed posteriorly above by a deep 

 surangular, with rounded superior border, whose superior outline, though 



*ror the definition of this element, see Proc. Amer. Philos. Soc, 1892. 



