259 



acters, which, taken by themselves, are of absolute value 

 as distinctions between these two classes, yet when the 

 combinations of characters, which exist in any given 

 instance, are considered, there can be but little room for 

 doubt as to the true zoological atHnities. 



There exist no known forms of recent or fossil reptiles or fishes, 

 which, where all their osteological details are known, cannot be 

 referred unequivocally to one or the other of these classes. A 

 comparison of the Ichthyoid Reptiles and Sauroid Fishes shows, 

 that although it is through them that the two classes approach 

 nearest to each other, yet there are no forms so completely 

 intermediate, as to bridge over the space which separates them. 



He made comparisons between the form and structure of the 

 feet of reptiles and the fins of fishes, showing, that although 

 they resemble each other as regards their functions, yet morpho- 

 logically they are always distinct. There is no known fish, 

 recent or fossil, the pectoral or ventral fins of which could pro- 

 duce a series of tracks like those discovered in the coal strata of 

 Pennsylvania, by Mr. Lea and Prof. Rogers. Although among 

 Lophioid fishes, the pectoral fins are used for locomotion on the 

 shores, yet they, in every instance, conform to the fish type — 

 are fins and not feet. An analogous condition of things is found 

 among Cetaceans and marine Saurians, where the limbs serve the 

 purpose of paddles, and may be compared to fins, yet, morpho- 

 logically, they can be referred only to the Mammalian or Rep- 

 tilian types. 



Prof. Wyman therefore thought, that, in the present state of 

 knowledge, there was no ground for denying that the quadrupe- 

 dal tracks found in the coal formations were made by Reptiles. 



It was voted, that Prof. Wyman be requested to furnish 

 a copy of his memoir for insertion in the Journal. 



Dr. T. M. Brewer presented, in the name of J. W. Butler, 

 Esq., Treasurer of the American Verd-Anlique Marble 

 Company, specimens of that marble, and of several min- 



