the maxillae, and so forth. This state of affairs, together with the presence of the huge tusks, has, as it were, pushed back the nasal orifices to near the top of the skull in a very Whale-like fashion. As in the Cetacea, the nasal bones are limited in size, and the premaxillae send up processes to join the frontals and the nasals. There is a straight and somewhat slender zygomatic arch, but the orbit is not separated from the temporal fossa. The malar bone is small, and, as in Rodents, forms the middle part of the zygoma. This is not the case with most Ungulata. The symphysis of the mandibles forms a spout-like rim. The scapula has a narrow prescapular, but a very wide postscapular region. The spine has a strong process projecting backwards from near its middle; this is a point of likeness to certain Rodents. No Elephant has a clavicle. The most remarkable feature about the fore-limb is the separation and crossing of the radius and ulna. The arms of these animals are permanently fixed in the position of pronation. The foot is short, and the bones of the carpus are serially arranged. There are, however, traces of a commencing interlocking of these bones in many forms. The hind-feet are somewhat smaller than the fore-feet, and the tibia and fibula are both developed.
As to the teeth, this genus is to be distinguished from allied forms by the presence of tusks in the upper jaw only. These tusks have no bands of enamel such as characterise those of Mastodon. They are incisors. There is, however, a trace of the former enamelling in the shape of a patch at the tip, which soon wears away. The molar teeth of Elephas are so large that the jaws cannot accommodate more than at the most two and a part of a third at a time. These are gradually replaced by others to the number of three, the replacement of teeth suggesting that of the Manatee. Each molar is deeply ridged, the interstices between the ridges being filled up with cement. As the tooth wears away, therefore, the surface continues to be flat. Each ridge consists of a core of dentine surrounded by a coat of enamel. The number of these ridges varies greatly from species to species. The Indian Elephant is one of those which have the greatest number of plates in a single tooth, as many as twenty-seven.[1] Of the six molars which eventu-
- ↑ It must be borne in mind that the teeth increase in complexity, those first pushed up having the fewest plates. The first has only four transverse plates.
