ABSTRACT
The evolutionary development of the Primates has resulted from the sum of the processes of cladogenesis and anagenesis. In the order Primates, cladogenesis is exemplified by the prosimian phytogenies, and anagenesis is exemplified by hominine phylogeny. The living primate fauna can be arranged according to grades of morphological organization into a remarkable sequence which goes from the tree shrew to man and simulates the successive anagenetic stages of the history of the Primates. There are a number of questions concerning the phylogenetic relationships of various living Primates. Chicken, monkey, and rabbit antisera to purified human serum proteins were used to develop cross reactions with heterologous antigens from a number of different Primates. Evidence that the chimpanzee has more recent common ancestry with man and gorilla than with orangutan or gibbon is furnished by the cross reactions of antisera to chimpanzee serum.
