[207] 
A MEMOIR UPON THE GENUS PAL.EOSYOPS LEIDY, AND ITS ALEIES. 
By Charles Eaki.e. 
The following memoir is the result of my studies upon the collections of speci- 
mens belonging to the Palisosyops in the Museum of the Aciidemy of Natural 
Sciences of Philadelphia, in the E. M. Museum of Geology and Archmology of 
Pi-inceton College, in the collection of Professor E. D. Cope, and upon some of the 
specimens in the A" ale College Museum. 
The association of the renovYiied name of the late Dr. Joseph Leidy with this 
genus has made these investigations appear of especial interest at the present time. 
I am greatly indelited to the authorities of the Academy for their liberality in plac- 
ing in my hands the large and very valnahle collection of Palmosyops material which 
is deposited in the Museum of that historic institution. This collection is especially 
valualile as it contains many of the original type specimens of Palceosyops, from 
which Leidy first gave to the scientific world the knowledge of the existence of these 
animals, and which later, in 1873, he fully described in his “ Extmct Vertebrate 
Fauna of the West. ” 
Since Leidy in 1870 described the genus Palceosyops from a few scattered frag- 
ments of teeth which were found at Church Buttes, Wyoming, a great advance has 
been made in the palamntological history of this and allied genera. 
During the whole course of this investigation, 1 was fortunate enough to be sit- 
uated in Princeton, and through the kindness of Professors Scott and Osliom, 1 had 
access to the large collections of Pala^osyops material which had been made by their 
M'estern expeditions. Among the numerous exploring parties that have visited the 
Bridger Beds, none ^Yere more successful than those sent out by Princeton College, 
under the leadership of Professors Scott and Osliorn. Four parties in all have been 
sent out by Princeton to these beds, with the result that the collection in the 
Princeton Museum of material referalde to the genera Palcsosyops, Limnohyops and 
Telmatotherium is one of the most complete in this country. It is to this collection 
that I am chief!}- indebted. 
Like all palaamtological investigators, I have felt the want of more complete 
individual material to corroborate some of my identifications. In a fev- cases the 
parts were found Avidely scattered. In some cases I have placed parts of the skele- 
ton under a certain genus, Avhere the boiies Avere not associated Avith any teeth, and 
consequentlA' the reference Avas partly conjectural. This applies particularly to my 
36 JOURN. A. N. S. PHILA., VOI . IX. 
