Genus 5. Mecistops.
The cranium is elongated, and the snout slender and Gavial-like. There are eighteen slender and subequal teeth above, and fifteen below, on each side. The mandibular symphysis extends back to the level of the seventh tooth. The cervical scutes are arranged in two transverse rows, each of which contains two scutes; and there is no space left between the posterior row and the tergal series.
This excellent genus, as established by Dr. Gray, includes Cuvier's Crocodilus cataphractus (which Dr. Gray considers to be the young of a species whose full-grown form was discovered by Mr. Bennett in West Africa), Crocodilus Journei and Crocodilus Schlegelii. As I have endeavoured to show, however, C. Journei is a true crocodile; and, as I shall point out below, Müller and Schlegel have satisfactorily proved C. Schlegelii to be a Gavial. Consequently Mecistops is at present represented by only one species, which must be called M. cataphractus if M. Bennettii of Gray is really the adult of the form which Cuvier described.
III. In the family of the Gavialidæ, the snout is always very long and slender; the teeth are for the most part slender, sharp-edged, and subequal. The two anterior mandibular teeth pass into grooves, one of which lies on each side of a beak-like prominence of the premaxillæ, which carries the two anterior upper teeth. The canines are received into grooves. The mandibular symphysis extends back to at least the fourteenth tooth, and is partly formed by the junction of the splenial bones. The premaxillo-maxillary suture is always strongly convex backwards. The posterior nares are situated more forward than in the Crocodili. The temporal fossæ are large. The feet are strongly webbed. The dorsal scutes are not articulated; and there are no ventral scutes.
I distinguish two genera in this family, Rhynchosuchus and Gavialis.