MAMMALIA OF THE SANTA CRUZ BEDS. 

 PART I. EDENTATA. 



/ 



BY 



WILLIAM B. SCOTT, 



PRINCETON UNIVERSITY. 



INTRODUCTION. 



FROM many points of view the fossil mammals of the Santa Cruz 

 formation are of remarkable interest. They present a number of 

 unusually instructive phylogenetic series and throw much welcome 

 light upon the manner in which the evolution of the Mammalia has been 

 accomplished. Further, they bring up questions of profound and far- 

 reaching importance, concerning their relationships to the animals of the 

 northern hemisphere, as well as to those of Africa and Australia. With 

 these questions are connected the problems of geographical distribution 

 and of the migrations of land animals, the former extent and connections 

 of the continents, in brief, the whole mystery of the southern hemisphere. 

 The able writings of Dr. F. Ameghino have directed the attention of 

 palaeontologists to these and kindred questions, but, unfortunately, this 

 wonderful Santa Cruz fauna has hitherto been but scantily represented in 

 the museums of Europe and North America, and, in consequence, stu- 

 dents of the Mammalia could gain only a very imperfect knowledge of 

 these animals from brief diagnoses and inadequate illustrations. In order, 

 therefore, to render the material useful to those who cannot examine the 

 originals, an otherwise unnecessarily minute prolixity of description and 

 fulness of illustration have seemed to be called for. This course is 

 further made advisable by the extraordinary variability of many of these 

 mammalian groups, which renders the usual systematic treatment so un- 

 satisfactory when applied to them. 



