The doctrine of descent and Darwinism . un-known ; on the other hand, partly from the directcomparison of these genera with the present Ungulata,partly from numerous intermediate links found in theMiocene, Pliocene, and Diluvium, it appears that, in thelapse of time, the separation which characterizes thepresent age was initiated, and the seeming Isolation wasproduced by the extinction of the intermediate links. Itwas this isolation which induced the older systematizersto institute three orders of Ungulata. The special pedigree emanating from the Palaeotheridaeincludes, among the present Ungul
The doctrine of descent and Darwinism . un-known ; on the other hand, partly from the directcomparison of these genera with the present Ungulata,partly from numerous intermediate links found in theMiocene, Pliocene, and Diluvium, it appears that, in thelapse of time, the separation which characterizes thepresent age was initiated, and the seeming Isolation wasproduced by the extinction of the intermediate links. Itwas this isolation which induced the older systematizersto institute three orders of Ungulata. The special pedigree emanating from the Palaeotheridaeincludes, among the present Ungulata, the horse, tapir,r^ and rhinoceros. The transi-\ j tion from the Palaeotherium/ to the horse may be directlytraced, and this, moreover,in the two most importantcharacters, the dentition andthe feet. In the Anchithe-rium and Hipparion, thetransformation from the tri-dactyle to the unidactyleUngulate is accomplished ;_ and Riitimeyers brilliant re-searches have shown how, inthe milk dentition of each genus, the definitive dentition. Fig. 26. Skeleton of the foot,rium. (H) Hipparion. (E) Horse PEDIGREE OF MAMMALS. 275 of the aboriginal genus is repeated, and Philogenesis isunequivocally expressed in Ontogenesis. The Anchi-therium is a three-toed horse, in which, however, themiddle toe has already undertaken the chief task. Butin the Hipparion the two side toes are entirely raisedfrom the ground, and by disuse are brought to the con-dition of arrest which is completed in the horse. In the constitution of the molar teeth the tapirs haveremained most faithful to the ancestral type. The cir-cumstance that the tapir has four toes in front, whereasthe Palaeotheridae known to us, have three shows, how-ever, that the genus Palseotherium cannot have beenthe ancestral stock of the tapirs. For the suppositionthat the tapir acquired the fourth toe is contrary to allexperience respecting the formation of the are also four-toed in front, and their closekindred with
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Keywords: ., bookauthorschmidtd, bookcentury1800, bookdecade1880, bookyear1882
