But its general characters at once prove the close affinity of C. Journei with the other true Crocodiles, from which it differs only in its elongated and gradually tapering skull, and in the more backward extension of the mandibular symphysis[4], which attains the level of the posterior margin of the sixth tooth.
In this character, and in the extreme slenderness of the snout, there is doubtless an approximation to Mecistops; but Crocodilus Journei is sharply separated from that genus by the characters of its teeth, and by those of its dermal armour.
5. Crocodilus bombifrons (palustris?).
All the species of Crocodilus which I have hitherto mentioned have, in common, the backward curvature of the premaxillo-maxillary suture to the level of the seventh tooth. But there is a species of Crocodile, about whose proper specific name I am by no means clear, in which this suture passes straight across the palate, or may even be a little convex forwards.
And not only do the skulls of this species exhibit this approximation to those of the Alligatoridæ, but they resemble them still further in their rounded snouts, their great width immediately behind the canine groove, and in the fact that, in young specimens, one or the other canine may be received into a pit instead of into a groove[5].
In the Hunterian Collection there are seven skulls, varying in length from 51/4 inches up to 16 inches, in none of which does the crown of the premaxillo-maxillary suture extend beyond a line joining the sixth pair of teeth. In all there are two short ridges (convergent in young specimens, nearly parallel in old ones) upon the lachrymal bones, which end before reaching the anterior limits of those bones. They all have an oblique ridge on the upper jaw above the tenth tooth; and the snout attains the width which it has opposite this tooth immediately behind the canine groove. In the British Museum there are five middle-sized skulls with the same characters; but two of these have a pit on one side of the upper jaw, and a groove on the other, and one has something between a pit and a groove on each side.
Dr. Gray, has in his 'Catalogue[6],' mentioned the peculiar transverse disposition of the premaxillo-maxillary suture in his Crocodilus bombifrons; and on examining the two crania thus named in the British Museum collection, one of which is 20 and the other 21 inches long, I can discover no distinguishing character between them and those already described. There can be no doubt then, I think, that these constant and well-marked characters, exhibited by fourteen skulls which vary in length from 51/4 to 21 inches, prove the existence of a distinct species of Crocodile, which I would provisionally term bombifrons.
I believe that this species has been constantly confounded with biporcatus, from which it may be at once distinguished by the direction of the premaxillo-maxillary suture, and by the shape of the snout behind the canine groove. I have found these distinctions to hold good at all ages; but the last-mentioned difference is far more marked in middle-aged than in either young or old specimens.
All the skulls named Crocodilus palustris which I have seen are referable either to C. biporcatus or to C. bombifrons. With respect to the C. palustris of Lesson and Duméril and Bibron, the latter authors consider it to be only a variety of C. vulgaris. Their description would, however, apply very well to C. bombifrons, as I have defined it above; and they expressly state ('Erp. Générale,' t. iii. p. 113) that all their specimens (twelve in number and varying in length from 30 centimetres to more than 3 metres) came from the East Indies or the Seychelle Islands. Now, Duméril and Bibron enumerate only three Asiatic Crocodiles—C. biporcatus, C. palustris, and C. galeatus, the last of which was only known to them by description; so that all the numerous Asiatic crocodiles which passed through their hands belonged either to C. biporcatus or C. palustris. On the other hand, all the skulls of crocodiles from Asia which I have met with (amounting to at least twenty) are either those of C. biporcatus or of the species which I have called bombifrons; so that I suspect the latter title will turn out to be a synonym of palustris.