1885.] Recent Literature. 373 
extinct to the living groups, their genealogy, and finally the origin 
of the class itself from the lower vertebrates. 
The points of special value to paleontology and bearing on the 
doctrine of evolution, worked out by Professor Cope in this vol- 
ume, are quoted from Professor Hayden's letter of transmission 
to the Secretary of the Interior: i 
“1, The discovery of the fauna of the Puerco group, of thirty 
genera and sixty-three species, This includes many important 
ramie saurian genus Champsosaurus in the Puerco group. — 
“2, The new classification of the Ungulata rendered possible 
sources together. 
“3, The new classification of the lower clawed mammals, based 
on the analyses of fifteen new genera and forty-seven new species of 
flesh-eaters and six new genera and sixteen new species of allied 
forms, all discovered since the publication of the author’s volume 
in connection with the Wheeler survey. 
“4. The restoration of Hyracotherium, the four-toed horse of 
the Wasatch group. ; 
“o. The restoration of the genera Triplopus and Hyrachyus of 
the Bridger fauna. 
“6. The determination of the systematic relation of the Dino- 
cerata as seen in the genera Loxolophodon and Bathyopsis. 
“The whole number of genera described in this volume is 125 
and of species 349, of which 317 species were determined by 
Professor Cope. : . 
“ The explorations that furnished the materials for these vol- 
umes began in 1872 and are still being continued. It will there- 
fore be readily seen that the amount of new matter towards the 
origin and history of the Mammalian group, brought together by 
the author in these two volumes, is most extraordinary, and wil 
probably never be surpassed.” 
The eoaid: for the fossils here described were made by 
the author largely at his own expense, and full acknowledgment 
is made of the services of those who made the collections when 
the author was not in the field, and of the preparator in the labo- 
ratory. : ; 
The volume lay for a year in the bindery, so that while printed 
in 1883 it was not bound until 1884, and was not distributed until 
February of the present year. 
