2S SIU, OR SEVER EVANG CHAP. 
Hlephas 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 Hephas 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? * Whesvertebral stormulasis (C.7) D 9-207 a3 =a, 
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. 
The skull is large and massive. Its large and heavy character 
is, as has been stated in the definition of the sub-order, due to the 
Fic. 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 (J/#) ; an, 
anterior, and pn, posterior narial aperture. x 4/5. (From Flower’s Osteology.) 
immense development of air cavities in the diploe; the diameter 
of the wall of the skull is actually greater than that of the 
cranial cavity. These cavities are not obvious in the young 
animal. They are most conspicuous in the roofing bones of 
the skull, but are seen elsewhere, and thicken the basis crani, 
