260 G. T. BEXTANY ON THE OENUS MERYCOCHXERTTS. 



Professor Hughes having kindly permitted me to examine these 

 remains, I now present an account of Merycochcerus, so far as I am 

 at present able to give one, together with a description of two new 

 species, which are remarkable additions to the Tertiary vertebrate 

 fauna — hoping at some future time to furnish a more complete 

 account of the family and its relations to extinct and existing 

 Ungulates. 



The progress of our knowledge of the Oreodontidse has been com- 

 paratively slow, extending now over nearly 30 years. Fossils 

 belonging to this family were first obtained from the Mauvaises 

 Torres, Nebraska ; and a jaw of a large species, supposed to be a 

 JPalceotheriwn, was described in 1846 and 1847 by Dr. Prout, in the 

 ' American Journal of Science and Art.' Gradually other specimens 

 came to light, and were described by Prof. Leidy, who gives the 

 following account of their mode of occurrence. " The deposits of 

 the Mauvaises Terres are remarkable for the great quantity of fossil 

 remains of mammals and turtles they have yielded without further 

 exploration than picking them up from the surface of the country. 

 Detached from the neighbouring soft and readily disintegrating 

 rocks, the fossils lie strewn about, and have often attracted the 

 attention of the least curious of those who have traversed the 

 district. Many of the loose fossils have gradually been collected by 

 travellers and others. Of those collected, by far the greater part 

 have been submitted to my investigation ; and these have amounted 

 to the enormous quantity of between three and four tons in weight." 

 Prof. Leidy collected and completed his earlier descriptions in 1852, 

 when he published, in the Smithsonian Contributions, " The Ancient 

 Fauna of Nebraska," consisting of 126 pages, with 24 splendid 

 plates. In succeeding years the Mauvaises Torres were further 

 explored by Drs. David Dale Owen, John Evans, and F. Y. Hayden, 

 who brought to Philadelphia large collections of fossils. Altogether 

 Prof. Leidy supposed, some years ago, that he had seen entire skulls 

 or portions of skulls of about 500 individual Oreodonts, a very 

 large proportion of them belonging to one species, Oreodon Culbert- 

 soni. In 1869 the results of his twenty years' labour were pub- 

 lished, forming the seventh volume of the second series of the 

 1 Journal of the Academy of Natural Sciences of Philadelphia/ and 

 entitled "The Extinct Mammalian Fauna of Dakota and Nebraska." 

 This work contains 472 pages and 29 plates, and gives a synopsis of 

 the entire mammalian remains of North America, with the most 

 complete references and the author's valuable critical opinions. A 

 considerable portion of this work is devoted to the Oreodontidse. 

 Still more recently, Prof. Leidy 's ' Contributions to the Extinct 

 Vertebrate Fauna of the Western Territories,' published in 1873, 

 records further progress in reference to the Oreodontidae, especially 

 Merycochoerus, which, however, is still described only from incomplete 

 upper and lower jaws. In a letter to myself, dated Oct. 26, 1875, 

 Prof. Leidy says, " In answer to your question about Merycochcerus, 

 I have seen no other remains than those described in my two 

 works " (those already referred to). 



