CROCODILIA. 43 



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

 view than that given in T. VIII appeared superfluous. In both the broad nasal bones 

 terminate at the same distance from the external nostril, which is accordingly formed 

 exclusively by the premaxillaries ; in both, the palate-bones present the same narrow, 

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

 between the mamillaries ; 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 T. VIII. 

 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, T. VIII, I should have referred it to the Alligators, 

 notwithstanding the crocodilian characters of the small orbits, the long facial plates of 

 the prefrontal and lachrymal, the wide supratemporal apertures, the non-expansion of 

 the fore part of the palatines, and the non-appearance of the vomer on the palate, with 

 other minor marks of the like affinity. For all these characters arise out of secondary 

 modifications, and are presented in different degrees in the different species of 

 Crocodile, and are rather of a specific than a generic value. They determine the 

 judgment by the extent of their concurrence rather than by their individual intrinsic 

 worth, and for that reason, therefore, the exposed position of the lower canine in the 

 lateral groove of the upper jaw inclined the balance in favour of a reference of the 

 previously-described fossil to the true Crocodiles. One cannot, indeed, attach any real 

 generic importance to the modification of the upper jaw in relation to the lower canines. 

 In three examples, however, in the collection of the Marchioness of Hastings, the 

 crocodilian modification of this character is repeated, as it is shown in T. VII, fig. 1 ; 

 and we have to choose, therefore, between the conclusion that Mr. Wood's specimen 

 (T. VIII, fig. 2) presents an accidental variety in this respect, or to view the fossae in 

 the upper jaw as indicative of not only a different species but a distinct genus from the 

 Crocodilus Hastingsioz. I should be glad to have more evidence on this point, and 

 especially the opportunity of comparing the posterior nostrils, the orbits, the supra- 

 temporal apertures, and the occipital part of the skull of a specimen from Hordwell, 

 repeating the alligatorial character of the fossae in the upper jaw for the lower canines. 

 I am disposed to regard this character, notwithstanding its constancy in the living 

 species of Alligator, as a mere variety in the Hordwell fossil ; but pending the acquisition 

 of further evidence, it seems best to record this fossil under the title proposed for it by 

 the able geologist by whom it was discovered. 



