GRECiORY: NOTHARCTUS, AN AMERICAN EOCENE PRIMATE 



55 



Stage 5. Permian. Therapsida. 



Stage 6. Triassic. Prototheria. 



Stage 7. Jurassic. Pre-placentals. 



Stage 8. Cretaceous. Pre-lemuroids. 



Stage 9. Eocene. Pre-anthropoids. 



Stage 10. Miocene. Pre-hominids. 



Stage 11. Pliocene. Primitive Hominidaj. 



Stage 12. Pleistocene. Modernized races of man. 



From this point of view Notharctus and its allies represent the comparatively little-changed sur- 

 vivors of the primitive lemuroid stock which gave rise to all the higher lines of primates. In the other 

 direction these Eocene lemuroids tend to connect the primates with the long series of stages leading back 

 to the beginning of the gnathostome vertebrates. 



PREVIOUS DISCOVERIES AND INVESTIGATIONS! 



The history of the discovery of Eocene primates in Europe is given by Stehlin (1912, p. 11G5), who 

 states that as far back as 1822 G. Cuvier (op. cit., p. 265) described a certain small and imperfect fossil 

 skull from the Paris Basin; he regarded it as a small pachyderm related perhaps to Anoplotherium, with 

 which he compared it, and so gave it the name Adapts "nom employe quelquefois pour le Daman." 



In 1873 Delfortrie described a similar skull from the French Phosphorites, under the generic name 

 Palceolemur. Gaudry (in an appendix to Delforties's paper) confirmed the lemurine affinities of this 

 genus and showed that it was very probably the same animal as Cuvier 's Adapts; but the idea that Adapts 

 was related to the " Pachyderms " long persisted in France. 



Subsequent contributions to knowledge of the structure and relations of Adapts and allied forms 

 were made by Gervais, Filhol, Gaudry, Flower, Lydekker, Schlosser, Zittel, Winge, Leche, Forsyth 

 Major, and Grandidier. In 1883 (pp. 43-47) Filhol confirmed the generic distinction of Adapts from 

 Notharctus and other North American "lemuriens." He demonstrated the resemblances to and the 

 differences from the existing lemurs, and refers to an earlier work in which he had proposed the name 

 Pachylemuriens to distinguish the Adapts group from recent lemurs. 



Forsyth Major (1901, p. 135) concluded that "since Adapts parisiensis agrees in several important 

 features with recent, and most of all with the Malagasy, Lemurs, it may be fairly taken to be in their 

 ancestral line." In 1912 Dr. H. G. Stehlin added to his series of monographs on the mammals of the 

 Swiss Eocene the section on Adapts, in which the morphology of the skull and dentition, and the sys- 

 tematic status of the subgenera, species and varieties of the genus, were treated in the most thorough and 

 comprehensive manner, and the relations of the Adapidse to other groups of primates, including the 

 Notharctidfe, were fully discussed. 



In America, the first discovered fossil primate, from the Eocene formation near Fort Bridger, Wyo- 

 ming, was described by Leidy in 1869 under the name Omomys carteri. Leidy gave an excellent descrip- 

 tion of the lower teeth, but did not recognize the real affinities of the animal, stating that the specimen 

 indicated an insectivorous mammal, probably belonging to the family of the hedgehogs (Leidy, 1869, 

 p. 65). 



1 The references cited are listed in the bibUography, pages 242, 243, below. 



