The Elephants proper, ELEPHANTIDAE, differ from the Dinotheriidae in, and are characterised by, a number of anatomical features. They possess long tusks (incisors) either in both jaws, or, if only in one jaw, in the upper. The molar teeth are very large--so large that only a few of them are simultaneously in use. There are but three definable genera of Elephantidae, of which {218} _Elephas_ alone survives. This genus also includes many extinct forms, both American and European, as well as Asiatic and African. The entirely extinct genera are _Stegodon_ and _Mastodon_. The group is clearly one dwindling towards extermination. From the Middle Miocene downwards these great "pachyderms" have existed; and from the Miocene up to Pleistocene times they were almost world-wide in range and numerous in species. The genus _Elephas_ comprises usually large, but occasionally (the pygmy Elephant of Malta) quite small forms. The external features of the genus differ slightly in different species, and will therefore be described in relation to those species which we shall notice here. The vertebral formula is C 7, D 19-20, L 3-5, Sa 4-5, Ca 24-30, or even more. The bodies of the vertebrae are remarkable for their shortness and for the very flattened articular surfaces. [Illustration] FIG. 116.--A section of the cranium of a full-grown African Elephant, taken to the left of the middle line, and including the vomer (_Vo_) and the mesethmoid (_ME_); _an_, anterior, and _pn_, posterior narial aperture. x 1/12. (From Flower's _Osteology_.)