40 FOSSIL REPTILIA OF THE LONDON CLAY. 



the facial part of the prefrontal (14) and lachrymal (73) is greater in the Croc. Hastingsia 

 than in any existing species of true Crocodile. Another characteristic of the present 

 fossil presented by the upper surface of the skull, is the shortness as well as breadth of the 

 nasal bones, and their almost truncate anterior termination at nearly one inch from the 

 external nostril. In all the Alligators' skulls that I have examined or seen figured, 

 the nasal bones are broadest at their posterior third part, and converge to a point 

 anteriorly, where in the Alligator lucius, e. g., they extend across the nasal aperture. 



The interorbital space is slightly concave in the Crocodilus Hastwgsia ; two broad 

 and slightly elevated longitudinal tracts are continued forwards upon the face from the 

 fore part of the orbits ; but they are not developed into ridges, as in the Croc, biporcatus. 

 The maxillaries swell out a little in advance of the middle of the nasals, and then 

 contract to the crocodilian constriction at the suture with the premaxillaries, where the 

 tips of the lower canines appear in the upper view (fig. 1, T. VI), and their whole 

 crown is exposed in the side view (fig. 1, T. VII). The conjoined parts of the 

 premaxillaries send a short pointed projection into the back part of the external nostril. 



On the under or palatal surface of the skull (T. VII, fig. 2) the maxillo-premaxillary 

 suture runs almost transversely across, as in the Crocodilus rhombifer, figured by Cuvier 

 in pi. iii. fig. 2, of the volume above cited. There is no appearance of the vomer 

 upon the palate. The palatal bones (20), though somewhat broader anteriorly, and more 

 abruptly truncate than in any existing Crocodile that I have seen, are more like those 

 bones in the true Crocodiles than in the Alligators. The portion between the post- 

 palatal vacuities is longer and narrower ; the posterior end of the palatines is nar- 

 rower, and the part of the bone anterior to the notch receiving the posterior angle of 

 the palatal plate of the maxillary does not expand in advancing forwards, as it does in 

 the Alligators : in the Alligator niger this expansion is greater than in the All. lucius, 

 and the posterior ends of the palatines are also remarkably expanded, and applied to 

 the anterior borders of the pterygoids almost as far as their articulation with the 

 ectopterygoids, the postpalatal vacuities not at all encroaching on the pterygoids, as they 

 are seen to do at 24, T. VII, fig. 2, and also in the figure of the Crocodilus rhombifer above 

 cited, and in other true Crocodiles. The form of the pterygoids (24, T. VII, fig. 2) is 

 peculiar in the Crocodilus Ilaslingsics : they are contracted anteriorly, and send forwards 

 a short truncated process to meet the narrow posterior ends of the palatines (20) ; and 

 the same character being repeated in another skull of the same species, from Hordle, 

 also in the collection of Lady Hastings, m which this part of the bony palate (T. VI, 

 fig. 3) is more perfect than in the subject of T. VII, fig. 2, it may be regarded with 

 some confidence as specific. In the Crocodilus chamjjsoides of Sheppy it will be seen, 

 by fig. 2, T. II, that the pterygoids (24, 24) arc not produced where they join the 

 palatines (20). In the Alligators, the posterior border of the conjoined pterygoids is 

 deeply notched behind the posterior nostrils, the angles of the notch being slightly 

 extended backwards : in most Crocodiles, the sides of the notch are so developed that 



