56 



GREGORY: NOTHARCTUS, AN AMERICAN EOCENE PRIMATE 



The next year, 1870, Leidy described another fragmentary fossil from the Bridger formation, consist- 

 ing of the right ramus of a lower jaw, which he named Nothardus tenehrosus, the name indicating that 

 the describer recognized that the animal was not a carnivore, in spite of its subcarnivorous appearance. 

 He regarded it as a small extinct "pachyderm." It was the first to be discovered of the subfamily 

 which is the subject of the present work. 



The year following, 1871, Professor Marsh described another jaw fragment from the same formation, 

 under the name Limnotherium. tyranmis. He at first thought it was a small "pachyderm" distantly 

 allied to a certain problematical fossil, the Hijopsodus paulus of Leidy, which Leidy had supposed to be 

 related to the suilline family. 



In 1872 Marsh described some other fragmentary remains, consisting of lower jaws and upper and 

 lower teeth, basing upon them the genus and species Thinolestes anceps. Of this material he speaks as 

 follows : 



The collections made by tlie Yale party include the remains of a number of small carni\ orous mammals, which are 

 apparently very unlike any hitherto known. In dentition, they somewhat resemble several extinct species, supposed 

 to be of suilline affinities, but their carnivorous characters appear unmistakable. All apparently had the angle of the lower 

 jaws inflected, and present other marsupial characters, although in general structure they are very different from any 

 known form of that group. The teeth in the present genus are similar to those of Limnotherium, and the two genera are 

 evidently nearly related. . . (p. 205). 



Although he did not understand the relationships of these forms, he saw that they probably repre- 

 sented a distinct family and he accordingly proposed for their reception the family " Limnotheridse," 

 without formal definition. 



In a brief paper dated August 7th, 1872, Professor Cope described a more complete lower jaw, like- 

 wise from the Bridger formation, containing most of the teeth of an animal which he named Tomitherium 

 rostratwm, but which was later referred to Nothardus. This jaw was associated with a humerus, a femur, 

 the upper part of the forearm and other fragments. In this first description of Tomitherium Cope did 

 not discuss its affinities. 



In October, 1872, additional material, including portions of the limb bones, enabled Marsh to place 

 correctly in the order Quadrumana (Primates) the puzzling animals for which he had erected the genera 

 Limnotherium and Thinolestes. "Although these remains differ widely from all known forms of that 

 group, their more important characters show that they should be placed with them. The genera Limno- 

 therium, Thinolestes, and Telmatolestes, especially, have the principal parts of the skeleton much as in 

 some of the Lemurs, the correspondence in many of the larger bones being very close. The anterior 

 part of the lower jaw is similar to that of the Marmosets, but the angle is more produced downward, and 

 much inflected. The teeth are more numerous than in any known Quadrumana. Some of the species 

 have apparently forty teeth, arranged as follows: Incisors !, canines t, premolars and molars 7. • • • " 

 (p. 406). 



In the same month, October 1872, Cope described a minute jaw from the Bridger Eocene under the 

 name Anaptomorphus ocmulus; he compared its dental and other characters with those of Sitnia and Homo. 



In 1873 (pp. 86-90) Leidy i^ublished a very full and accurate description of his type lower jaw of 

 Nothardus tenehrosus. He speaks of it as a "small extinct pachyderm" and then says: "I at first viewed 

 it as pertaining to a carnivorous animal, and thus referred it, but the anatomical relations of the specimen 

 with those of remains of other animals which have been found in association with it have led me to view 

 the jaw as having belonged to a pachyderm." 



At the end of his description of the specimen we find this very noteworthy passage: 



