There are twenty-seven or twenty-eight teeth in the upper, and twenty-five or twenty-six in the lower jaw. The mandibular symphysis extends to the twenty-third or twenty-fourth tooth. The lateral teeth of both jaws are, all but the very hindmost, directed obliquely downwards (or upwards), forwards or outwards, and are not received into interdental pits. The anterior margins of the orbits are raised. The premaxillæ and the end of the mandible are greatly expanded. The premaxillo-maxillary suture reaches the level of the fourth tooth behind the canine notch. The only true _Gavialis_ is the well-known _G. Gangeticus_ from the East Indies. In this 'Gavial,' or 'Garrhial,' the vomers are slender bones which do not extend further forwards than the level of the twenty-second or twenty-first tooth, and have but a very short and slender representative of the anterior flattened division of the bone in _Jacare_; posteriorly they extend back to the level of the descending processes of the prefrontals. In a skull 25 inches long the vomers have a length of about 4 inches, extending as they do a little further forward than the palato-maxillary suture. The median nares are opposite the twenty-fifth tooth. * * * * * All the _Crocodilia_ which I have enumerated are provided with two perfectly distinct kinds of dermal armour,--the one consisting of plates of horn, produced by a modification of the superficial layer of the epidermis; the other composed of discs of bone marked by a peculiar pitted sculpture on their outer surfaces, and developed within the substance of the dermis. To the former I shall apply the term "scales;" the latter are what I have denominated "scutes." All recent _Crocodilia_ have both scales and scutes in the dorsal region of the body, the scutes underlying, and having the same general form as the scales. In all, the ventral region of the body is also covered with scales which have a very definite shape; but in no recent Crocodilian which I have examined, save those species which are included in the genera _Caiman_ and _Jacare_, are there any scutes in the ventral region. Again, in the genera _Alligator_, _Crocodilus_, _Mecistops_, Rhynchosuchus, and _Gavialis_, the edges of the scutes, except those of the two median longitudinal rows, are hardly ever united by sutures, nor do the posterior margins of those in each transverse row overlap the anterior margins of the succeeding row. At any rate, there is no flat, bevelled, articular facet on the outer surface of the anterior margin of a scute, for articulation with the inner surface of the posterior margin of its predecessor. In the genera _Caiman_ and _Jacare_, however, the lateral edges of all the scutes of the dorsal and ventral shields are united by serrated sutures; and the anterior end of the outer face of each is provided with a well-marked smooth facet, which is overlapped by the smooth under-surface of the scute in front of it.