174 Professor Marsh’s Monograph of the Dinocerata. 
The volume ends with a Bibliography of all the important 
literature on the Déinocerata, and thus the librarian, also, has at 
hand material ready for a catalogue. In most volumes on 
paleontology, as well as on Seley hamid of natural science, 
these four divisions are mixed together, so that each different 
class of readers must seek out what it needs with much labor. 
The author’s general plan of publication was given in the 
introduction to his previous memoir, and this is supplemented 
in the preface of the present volume, from which we quote the 
following : 
“The present memoir is the second of a series of Mono- 
graphs designed to make known to science the Extinct Verte- 
brate Life of North America. In the first volume, on the 
Odontornithes, or Birds with Teeth, the author gave the result 
of his investigations of that remarkable group, which he dis- 
covered in the Cretaceous deposits on the Eastern slope of the 
Hoek Mountains. 
“This second Monograph contains the full record of a 
peculiar order of Mammals, which the author also brought to 
light in the early Tertiary strata of the great central plateau 
of the continent. 
“Tn preparing the present volume, it has been the aim of 
the author to do full justice to the ample material at his com- 
mand, and, where possible, to make the illustrations tell the 
main story to anatomists. The text of such a memoir may 
horizon in which they are found, beginning as follows : 
“ Among the many extinct animals discovered in the Ter 
tiary deposits of the Rocky Mountain region, none, perhap 
ma 
size, roamed in great numbers about the borders of the ancient 
