G. GENERAL NATURAL HISTORY AND ZOOLOGY. 319 



tute not an order, but a sub-class of mammals ; and of such 

 a sub-class the tardigrades (including the sloths and the 

 megatheriums) would form an order. 



RECENT EXPLORATIONS OF PROFESSOR COPE. 



Professor E. D. Cope has recently returned to Philadelphia, 

 after completing an extended examination into the vertebrate 

 paleontology of certain tertiary strata in Colorado and Wyo- 

 ming. A rough estimate places the number of species ob- 

 tained by him during the season at one hundred and fifty, 

 2)rincipally Mamrtialia and i?e^9^^7^, of which from seventy- 

 five to one hundred are new to science. About one hundred 

 species w^ere obtained from the miocene in Colorado. This 

 fauna possesses many points in common with that of the 

 "White River, in Dakota, but includes many species, and'some 

 higher groups, not known to occur in the latter region. Thus 

 five new species of serpents and seven of lizards are the first 

 of either order discovered in the American miocene. Amons: 

 3Iam.inalia^ several new genera and species of Inseetivora, 

 mostly of small size, are added, while the discoveries of new 

 Rodentia are quite as numerous ; two new genera are called 

 Heliscomys and Fricimn. Several new feline and canine 

 genera and species were procured, noteworthy among which 

 are some sabre-toothed tigers. Of hoofed animals, the most 

 striking are the six new species of the new genus Symhorodon, 

 which is an ally of Titanotlieriuin. They are described as re- 

 sembling the rhinoceros in many respects, the points Avhere- 

 in they differ constituting resemblances to the EohasilidcB. 

 Thus they were more elevated than the rhinoceros, and had 

 shorter feet. They bore a pair of horns on the front or snout, 

 above or in front of the eyes, as indicated by solid cones, in 

 some of the species reaching a foot in length. The largest 

 species, S, bucco (Cope), was as large as the African elephant, 

 the smallest, S. acer (Cope), equaled the Indian rhinoceros. 

 Portions of over fifty of these animals were obtained, twenty- 

 five of which embraced crania. Some of the artiodactyls 

 are remarkable for their small size, one species not exceeding 

 a squirrel in bulk. 



The earliest appearance of serpents in geologic time is, so 

 far as known at present, in the eocene period. Professor 

 Owen was the first to determine the existence of these ani- 



