Propalaeotherium hassiacum (Cuvier 1824, Gervais 1840, Haupt 1925, Ypresian, Eocene, 55–60cm at the shoulder) is a short-necked, short-legged, pre-rhino with four fingers and three toes. It is not closely related to Palaeotherium. It is basal to Mesohippus, too. The jaw joint is close to the occipitlal. The canine is large.

Hyrachyus eximius (Leidy 1871; 1.5m long; Eocene, 40 mya) is considered a perissodactyl with teeth resembling those of a rhinoceros. Here it nests at the base of the rhinos (see below) and titanotheres lik Embolotherium. The nasals extend a wee bit further out than the premaxilla, the cervicals are robust with tall neural spines. Hyrachyhus is derived from Hyracotherium and Heptodon, coeval taxa which it closely resembled.

Ceratotherium simum (Gray 1868; extant; up to 4m in length, shoulder height 1.8m) currently nests as a sister to Embolotherium, though both have smaller hornless ancestors. Both sisters have distinct teeth.

The nasal was anteriorly elevated to support a keratinous horn and the frontal had a smaller keratinous horn. The premaxillary teeth and canines are absent. The legs are short, the neural spines over the shoulder are high.