clxxiv GENERAL SUMMARY OF SCIENTIFIC AND 



ment of reptile life, and representatives of that class were the mon- 

 archs of the time. 



The Cretaceous epoch in this countrj^, as in Europe, was distin- 

 guished by the great development of certain peculiar reptiles. 

 Among these the most characteristic and strange in many respects 

 were the Pterodactyles^ or Flying Lizards. Not long ago these were 

 supposed by some not to have lived in America, but now quite a 

 number of forms have been discovered in this country. Among 

 these were some distinguished from the forms previously known 

 from Europe by the absence of teeth, and with this condition were 

 co-ordinated other characters : these animals have, therefore, been 

 distinguished under the name Pteranodon^ and even presented as 

 the rejDresentatives of a suborder {Pteranodontia) distinct from other 

 pterosaurians, which, as tooth-bearing animals, must then be con- 

 trasted under the name " Pterodontia." 



From certain strata of the Territory of Montana, whose age has 

 been disputed. Professor Cope, in a recent expedition to that region, 

 has obtained numerous species of reptiles, especially of the order of 

 Dinosaurians. Some of these were of large size, and among them 

 were apparently carnivorous as well as herbivorous species. 



In a still earlier age of the secondary epoch, in widely separated 

 parts of the world, a remarkable group of reptiles existed, which 

 were characterized, according to Owen, by teeth resembling those 

 of typical mammals, in that they had " incisors defined by position, 

 and divided from the molars by a large laniariform canine on each 

 side of both upper and lower jaws, and the lower canine crossing in 

 front of the upper, as in mammalia." The earliest described remains 

 of any representatives of the grou^D were made known, but without 

 appreciation of their systematic relations, by Russian naturalists, and 

 were found in certain deposits in Russia that have been referred to 

 the Permian age. In 1876 Professor Owen further elucidated the af- 

 finities of the group, and described a considerable number of species 

 from rocks of South Africa which have been assigned to the Triassic 

 epoch. These have been grouped into two sections or families 

 Binarialia, characterized by the external nostrils being divided by a 

 narrow partition, and Mononarialia, distinguished by the external 

 nostrils being single and undivided. To this group of Theriodontia 

 has also been referred a form, described by Professor Leidy, from 

 Prince Edward's Island. 



