Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/522

 They are found in the 'Annales du Museum d'Histoire Naturelle,' t. xii. article iv. pp. 88-101 (Paris, 1808), and in the ' Ossemens Fossiles,' t. v. partie ii. article iv. p. 143 (5th ed., Paris, 1826).

In a collection of fossil bones from the neighbourhood of Honfleur, made by the Abbe Bachelet, and afterwards transferred to the Museum of Natural History, Paris, Cuvier recognized parts of the upper and lower jaws of two species of Gavials, differing from all recent and extinct ones then known, and also vertebrae of two kinds. The least-mutilated lower jaw comprised the entire dentary portion, with the greater part of both rami. The composite character of the jaw, its teeth, and the manner of their implantation and of their succession demonstrated the crocodilian nature of the fossil. In its long symphysis and in the restriction of the teeth to this part of the dentary bone, Cuvier saw resemblances to the Gavial ; but he also perceived that the Honfleur Gavial differed from the Gangetic in the relatively greater length of the ramus, in the smaller angle included by the rami at the symphysis, in the more regularly tapering form of the head, and in the absence of the oval hole present in the outer surface of all known living crocodiles. Cuvier does not give a very detailed account of the teeth ; but he mentions that they are conical and striated, and have "deux aretes tranchantes." (Figs. 1 & 2, pl. viii. Oss. Foss., are upper and side views of this lower jaw.)

To this lower jaw Cuvier confidently allotted the fragment of an upper jaw comprising the symphysis with part of both intermaxillaries containing three alveoli and forming the front of the external nostril. (Figs. 6 & 7, pl. viii., are upper and under views of this fossil.)

Cuvier's lower jaw wants the posterior extremities of the rami, while from the Kimmeridge jaw the middle of the dentary piece is absent. A comparison of its measurements with those of the Honfleur jaw given by Cuvier is therefore not possible; but in all the points in which a comparison can be instituted, the resemblance between the Kimmeridge and the Honfleur jaw is very close.

The Kimmeridge lower jaw, like the Honfleur (tete a museau plus court), has also a very long non-tooth-bearing ramus, which includes a larger angle with the straight tooth-bearing symphysis than does the living Gavial's ; and this makes a sharper mandibular arch, indicative of a more uniformly tapering head, than the Gavial's. It also has not the oval hole in the outer surface which we find in all living crocodiles, and in all those, I think, of the Tertiary period. Its teeth, too, are conical, (very finely) striated, and they have " deux aretes tranchantes."

Next, the likeness of Cuvier's upper view of the fragment of the maxilla of the " tete a museau plus court " (fig. 6, pl. viii. ' Ossemen's Foss.') to the corresponding view of the same part of the upper jaw of this Kimmeridge crocodilian is so striking that it is impossible not to recognize it.

This Honfleur fragment is very remarkable from the absence of bulging, and from the lateral compression of its terminal nostril.