126 BRITISH FOSSIL REPTILES. 



larger, and the interorbital part of the frontal is narrower, concomitantly with the 

 larger proportional eyeballs and orbits of the young animal. The relatively larger 

 supratemporal apertures form another character of nonage ; but there is no ground for 

 deducing a specific distinction from any of the differences observable between this 

 part of the young crocodile's cranium and the corresponding part of that of the more 

 mature specimen (PI. \ J). 



Alligator Hantoniensis, JFood. Plate 1 C, fig. 2. 



London Journal of Palseontology and Geology. 



On reviewing the characters of the skull of the Crocodilus HastingslcE we perceive 

 that they combine to a certain extent those which have been attributed to the genus 

 Crocodilus and the genus Alligator ; in general form it resembles most the latter, but 

 agrees with the former in some of the particulars that have been regarded by Cuvier 

 and other palaeontologists as characteristic of the true Crocodiles. I allude more 

 particularly to the exposed position of the inferior canines when the mouth is shut. 

 Respecting which, however, I am disposed to ask, whether this be truly a distinctive 

 character of importance ? One sees that it needs but a slight extension of ossification from 

 the outer border of the groove to convert it into a pit ; yet the character has never been 

 found to fail as discriminative of the several species of existing Crocodiles and Alligators 

 hitherto determined. It constitutes, however, the only difference between the skulls of 

 the Crocodilus Hastmgsice in the collection of the Marchioness of Hastings and that fine 

 portion of skull now, by the kindness of Mr. Searles Wood, before me, on which he 

 has founded the species named at the head of the present section. So closely, in fact, 

 do those specimens from the same rich locality correspond, that any other comparative 

 view than that given in PI. 1 C appeared superfluous. In both the broad nasal bones 

 terminate at the same distance from the extei'nal nostril, which is accordingly formed 

 exclusively by the premaxillai'ies ; in both, the palate-bones present the same narrow, 

 truncate posterior ends, and the same equal breadth of their anterior portions included 

 between the maxillaries ; only these terminate rather more obliquely in Mr. Wood's 

 specimen, their anterior ends forming together a very obtuse angle directed forwards. 

 But this is comparatively an unimportant difference, and I regard as equally insignifi- 

 cant the slight interruption of the transverse line of the maxillo-premaxillary suture, 

 at the middle part, which will be seen by comparing fig. 2 with fig. 1, in PL 1 C. 

 The teeth are the same in number, arrangement, and proportion in the Alligator 

 Hantoniensis as in the Crocodilus Hastingsice, and the alveolar border of the jaws 

 describes the same sinuous course. 



Had the complete fossil skull first submitted to my inspection at the meeting of 

 the British Association at Oxford presented the same fossae for the reception of the 

 lower canines which exist in fig. 2, PI. I C, I should have referred it to the Alligators, 



