The teeth of both jaws are rooted, but tend to be hypsodont. The elongated incisors of the upper series are characterized by the presence of a longitudinal furrow in the top of each tooth, which, with wear, becomes a pit, and, as it is shallow, disappears in old individuals. This is the only suggestion of a horse character in the genus, but the pit in a horse’s incisor is a late development, and here it is also probably a specialization due to eating grass. Incisor 1 is the largest and they decrease in size toward either side. The canine is small, and is also marked by having a furrow in the crown, but in this case it is transverse to the long axis of the jaw. The premolars are peculiar in having on the anterior internal corner a highly developed cingulum, which so builds out the tooth that it is usually wide and is rectangular in outline. As this cingulum rises, it incloses a bay on the ant. int. corner of the tooth, which, with wear, becomes first a bay, then a pit, and lastly may disappear entirely in old age. On each premolar the anterior and posterior lobes are developed, inclosing between them an elongated basin, which with wear becomes a long narrow pit. On the molars, the cingulum on the ant. int. corner is wanting entirely. The external anterior corner of the tooth, however, is prolonged, so that the crown has a rhomboidal outline. The crown is made up in the typical manner of the wall, the anterior, and the posterior lobes, which inclose between them an elongated basin, which, as in the premolars, becomes, on wear, a pit extending obliquely across the tooth. The lower incisors have no furrows in the crowns, but in this genus there is a small cingulum on the inner side just above the base of the enamel. The lower canine is incisiform, and also has the basal cingulum. Each of the premolars has, on the external side, a median vertical groove, beginning at the base of the enamel, and widening toward the top. This is progressive if less marked from pm. 1 to pm. 4. The premolars and molars consist essentially of two crescents, the shorter anterior, and the posterior which is about twice as long as the anterior. The details are as described on page 96, and seen in figure 55.