246 haeckel's anthroeogenie. 



second), all belong to the placentalia, "wMcli were developed either 

 in tlie end of the mesozoic br in the beginning of the tertiary period. 

 The fact that the placentalia must have been entirely developed during 

 this proportionately very short time (not more than three per cent, 

 of the whole length of the earth's history) accords fully with the 

 phylogenetic hypothesis. The chief anatomical peculiarities of the 

 placentalia, as distinguished from their ancestors, are to be found in 

 the mode of nutrition of the foetus and the extent of development of 

 the brain. The lower placentalia have no decidua, the higher have ;. 

 and thus we distinguish the indeciduata from the deciduata. To the 

 indeciduata belong the ungulata, the sirenia, the cetacea and the ant- 

 eaters ; to the deciduata, the carnivora, insectivora, rodentia, ele- 

 phants, bats, lemurs and primates. These two groups diverged from 

 each other, and consequently it is only with the deciduata that we 

 have now to do. According to the shape of the placenta, the deci- 

 duata may be divided into zonoplacentalia and discoplacentalia, 

 among which latter group man stands. 



The limited distribution and the wide diversity of character of 

 the prosimise, point to their being very old forms, and it is easy 

 to trace resemblances in the different discoplacentalia to different 

 groups of that order; so that we may conclude that among living 

 forms the prosimise are those which stand nearest to the common 

 ancestral form of discoplacentalia. The eighteenth ancestral stage is 

 thus to be found in the primordial prosimise, and has probably its 

 nearest living representatives in the lemxxrs. 



The true apes form the nineteenth stage of evolution, and the 

 question of their relations to man has been finally disposed of by 

 Huxley. The fact of this relationship was recognized by Linnseus 

 when he established his order primates, which, from a misconception 

 of the nature of hand and foot, was afterwards split up into quadru- 

 mana and "bimana. The primates are naturally divided into two 

 groups, the catarhinse and the platyrhinse, the former characteristic of 

 the Old, the latter of the New World. To the former group man 

 belongs, and this is shown by his participation in the anatomical 

 peculiarities of the catarhine group, and notably the form of the nose 

 and the dentition. These two groups must be regarded as divergent 

 descendants of the primordial apes, and consequently the relationship 

 of man to the New World apes is only a very distant one. On the 

 contrary, his relation to the highest catarhines is a very much nearer 



