THE ANIMAL ANCESTRY OF MAN 89 



known anthropoids which are unquestionably nearer to 

 man than any others are the three African forms, the chim- 

 panzee, the gorilla and the extinct Australopithecus. Also 

 the European fossil species Dryopithecus rhenanus and 

 Dryopithecus Jontani in the detailed patterns of their molar 

 teeth appear to be especially related to the African group 

 and therefore, according to the evidence of blood tests, 

 etc., to man. 



CONCLUSIONS 



In conclusion, the theory of man's derivation from lower 

 vertebrates according to the general sequence of stages 

 outhned in this article may claim to be distinctly more than 

 a trial hypothesis, since it rests upon many converging lines 

 of evidence. It is in fact an outgrowth of the general advances 

 of the past half-century in vertebrate palaeontology, verte- 

 brate zoology and taxonomy, human and comparative 

 anatomy, anthropology, embryology, physiology and related 

 sciences. The theory of the brachiating ancestry of man 

 rests in the first place upon the general subject of the classi- 

 fication and evolution of the vertebrates as a whole. A host 

 of zoologists and palaeontologists have estabhshed the fact 

 of man's place in nature: he is a member of the anthropoid- 

 human division of the higher Primates, which may be 

 traced to the stem of the order of Primates; these in turn 

 derive from primitive placental mammals related to the 

 existing tree-shrews; thence we pass downward through the 

 imperfect records of the Age of Reptiles to the progressive 

 mammal-hke reptiles of the Triassic; downward again by 

 plainly recognizable morphological stages to the theromorph 

 stem forms in the Permian; still downward to, or near to, the 

 captorhinomorph division of the cotylosaurs; and thence to 

 the horizon of the varied eotetrapods of the Coal Measures; 

 in the Devonian we see the crossopterygian and dipnoan 

 forerunners of the Tetrapoda and below that a long gap to 

 the varied ostracoderms of the Silurian, which show us the 

 early chordate stem in various guises. Below that the rest is 

 darkness, except that comparative morphology throws 

 considerable hght on the origin of the basic chordate loco- 

 motor apparatus which all the later forms inherited in part. 



