Vi PREFACE. 



A small but interesting collection of Mazon Creek Amphibia is that of the Pea- 

 body Museum of Yale University. Through the courtesy of the officers of this 

 museum the writer was permitted to study these specimens and was given a grant 

 for their illustration. The results of that study are contained in a previous paper 

 (478) and in the present memoir. Dr. Schuchert has offered suggestions as to the 

 environmental conditions of the ancient Amphibia. 



A few specimens of Coal Measures Amphibia are at the Walker Museum, Uni- 

 versity of Chicago. This collection includes the type of Micrerpeton caudatum 

 Moodie, the first branchiosaur discovered in the western hemisphere, and a few 

 specimens from Linton, Ohio. 



A single specimen of Amphibamus grandiceps Cope, very beautifully preserved, 

 is in the possession of Mr. L. E. Daniels, of Rolling Prairie, Indiana. This specimen 

 has been studied and described by Hay (316) and by the writer (462, 469, 478). 



The works of Cope and Dawson, published between 1860 and 1897, on the 

 Amphibia from the Coal Measures, have been indispensable in the present study. 

 It has been necessary to rely on the published descriptions and photographs of the 

 interesting fauna from Nova Scotia, since it has not been possible for me to visit 

 and examine the types preserved in the Peter Redpath Museum of McGill Uni- 

 versity and in the British Museum of Natural History. It has been possible to 

 check Dawson's work, to a certain extent, by a study of a series of excellent photo- 

 graphs of the types of Coal Measures Amphibia collected by Dawson and Lyell 

 and described by Dawson and Owen. The descriptions of these authors have been 

 drawn on for the discussion of the Canadian forms. 



The descriptions given below have been made full and complete in the belief 

 that in this way our knowledge of these interesting vertebrates may be advanced. 

 Many of the species have been described elsewhere in scattered papers by various 

 authors. These descriptions have been revised and verified and are collected here 

 in monographic form. The work is a morphologic and taxonomic revision of the 

 Amphibia from the Coal Measures of North America. Especial attention has been 

 paid to the factors which have been most active in the evolution of the group, so 

 far as these factors may be interpreted. It is the author's hope that this review may 

 open up the field for many more workers, since we are just beginning to learn about 

 the evolution of this group of vertebrates. 



The trustees of the Elizabeth Thompson Science Fund allotted a grant for the 

 present investigation. This aid has enabled the writer to present his work in much 

 better form than would have been possible otherwise. Dr. S. W. Williston has 

 offered many suggestions and criticisms which have been gratefully adopted. It 

 is with the greatest sense of pleasure that the author dedicates this memoir to his 

 teacher and friend. After the manuscript was completed the author enjoyed a visit 

 from Mr. D. M. S. Watson, of King's College, London, whose knowledge of the 

 European and African forms enabled him to offer several very valuble suggestions. 



It is fitting also to express my indebtedness to the Carnegie Institution of 

 Washington for the privilege of publishing my work in the series of monographs 

 contributed by Dr. E. C. Case, dealing with the anatomy and relationships of the 

 early land vertebrates of North America. 



ROY LEE MOODIE. 



