HIPPARION HIPPO 739 ie enamel of the molar teeth was in more )mplex folds than in the present horse. Fos- horse-like animals have heen found in the later tertiary and quaternary of North and }uth America, Europe, and northern Asia, id especially in the western regions of the Inited States. This genus has been obtained the later tertiary of Europe, Asia, and Forth America. Of the species described by [ayden, H. venustum, half the size of the ass, i been found in South Carolina ; H. occiden- 'osum, and qffine, from the pliocene of )akota and Texas, about the size of an ass, are 11 nearly allied, if not the same species. Pro- ihippus, hippidion, and merychippus are al- 3d genera. This series of horse-like animals interesting from the point of view of the re- ition of past to present species, and of the srivation of the latter from the former ; most ituralists of the present day, rejecting the rinciple of direct or miraculous creation, and lizing a natural law or secondary cause, 'the servant of predetermining intelligent 1. Palseotherinm. 2. Hipparion. 3. Horse Will," as Prof. Owen has it, as operating^in the production of species in orderly succession and progression. As proofs of the hypothesis that the existing are modifications of extinct species, changing by small degrees, it became ' nportant to collect a series of such inter- lediate forms from the fossil world. Prof. >wen, in his "Anatomy of Vertebrates, "^ de- votes a chapter to this subject, and especially mentions the series of anoplotherium, palseo- therium, and hipparion, as supplying the links required by Cuvier to connect the pachyderms with the horse of the present day. In the ac- companying illustration, p and m signify premo- lar and molar teeth, and 2, 3, 4 are the digits or toes. The palasotherium had three nearly equal toes, each with a hoof; the hipparion was also in one sense three-toed, but the lateral hoofs were spurious, not touching the ground ; and it is interesting to note that these three-toed horses are found only in deposits of that ter- tiary period intervening between the older >alseotherium and the newer strata in which the modern horse first appears to have lost its lateral hooflets, and to have walked upon the end of the single second toe or digit, the two lateral splint bones being entirely internal and hoofless. He makes the series, from the hoofs and molar teeth, palceotherium,paloplotherium, ancitherium, hipparion, and equus (horse). To admit this does not require either the hypothe- sis of appetency or volition of Lamarck, the fit- ness of the surrounding medium of Geoffrey Saint-Hilaire, or the natural selection of Dar- win ; but simply the continuous operation of natural law or secondary cause, successively and progressively, " from the first embodiment of the vertebrate idea under its old ichthyic vestment, until it became arrayed in the glori- ous garb of the human form." (See HORSE.) HIPPEAU, Celestin, a French author, born in Niort, May 11, 1803. He studied in his native town, and in 1855 was sent on an educational mission to England, and in 1867 to the United States to report on American education. His principal works are : Eistoire de la philosophic ancienne et moderne (1863) ; Histoire du gou- vernement de la Normandie (9 vols., 1863-'73) ; and Dictionnaire de la langue francaise au douzieme et treizieme siecle (1873). HIPPIAS AND HIPPARCHUS, the rtms and suc- cessors of Pisistratus, tyrant of Athens. Ac- cording to an early popular opinion, Hippar- chus was the elder brother ; according to He- rodotus and Thucydides, Hippias. While they ruled jointly the government was conducted on the same principles as that of their father, and that period was subsequently regarded by the Athenians as a kind of golden age ; but from the murder of Hipparchus by Harmodius and Aristogiton (514 B. C.) the character of the government of Hippias became arbitrary, ex- acting, and oppressive. His despotism was, however, at length overthrown. The Delphic oracle was bribed to favor the cause of liber- ty, and the pythoness repeatedly enjoined the Lacedemonians to free Athens from the des- potism of the Pisistratidse. A Spartan force under Cleomenes, having defeated Hippias in the field, and captured his children, compelled him to surrender the Acropolis, and to evacu- ate Attica with all his relatives (510). No sooner had they departed than a decree was passed condemning the tyrant and his family to perpetual banishment, and a monument was erected in the Acropolis commemorative of their crimes and oppressions. Hippias ulti- mately retired to the court of Darius, and there instigated the invasion of Greece. Ac- cording to some, he fell at Marathon (490). HIPPO, or Hippo Begins, an ancient city of Nu- midia, the ruins of which are still to be seen near Bona in Algeria. It was one of the resi- dences of the Numidian kings, and afterward celebrated as the episcopal see of St. Augus- tine. It was taken and destroyed by the Van- dals in 480. Its surname served to distinguish it from another town of the same name on the Carthaginian coast, W. of Utica.
