28 



with tlic iKuiies of PaliPosyops luul Liiiuiohyiis. From tlic iiotico it would 

 appear he has overlooked the description of Palaeosyops in the report last 

 mentioned. He intimates the reference of the genus to the Perissodactyls as 

 if previously nnknown, and suggests the reference of specime'ris to it in which 

 "the last upper molar has two inner cones," though it is distinctly stated in 

 the al)ove report that " the last upper molar of Palaeosyops has but a single 

 lobe to the inner part of the crown." Upon this character he founds the pro- 

 posed genus Limnohyus, which,' under the circumstances, appears untenable ; 

 but if a pair of lobes to the inner part of the crown of the last molar be con- 

 sidered a distinctive generic character, the name might be transferred to the 

 geiuis possessing it. 



The skull of Palseosyops, and the same may be said of other parts of 

 the skeleton so far as they are known to us, approximates in form and 

 constitution those of its probably- contemporaneous ally, the Palseotherium 

 of the Eocene period of Euroi>e. In both genera the skull presents a 

 broad, triangular forehead. In Palaeosyops it is more prolonged posteriorly, 

 and is more abruptly curved forward to the root of the muzzle. In both the 

 temporal fossae are very capacious, indicating masticatory muscles approaching 

 in power those of the great carnivores. In Pateosyops they are separated by 

 a much shorter crest than in Pateotherium. In the former the muzzle is rather 

 abruptly prolonged forward from the l)ase of the forehead ; in the latter the con- 

 vexity of the forehead is continued in the muzzle to tlie end of the nose. In 

 both genera the muzzle is broad, but in Palaeosyops the nasals are longer and 

 project forward as much as the jaws. The lateral nasal notch is nearly alike in 

 both, but is longer in Palaeosyops. In both, the orl)its are open behind, and are 

 defined from the temporal fossffi by long, angular post-orbital processes. The 

 jaws nearly repeat one another in the two genera. The number of teeth, 

 their kind, relation, and general construction, are likewise the same. In 

 Palaeosyops they form more unbroken series in the two jaws, as tlu; hiatus 

 back of the canines, which is comparatively .large in Paleeotherium, is very 

 trilling in extent in Palaeosyops. 



Pal/eosyops paludosus. 



The species Valceosxjops paludosus was first indicated under this name in the 

 Proceedings of (he Academy of Natural Sciences of Philadelphia in 1870, and 

 was founded on a number of isolated teeth and fragments of others oI)tained by 

 Professor Ilayden at Church Buites, Wyoming. Of the specimens, a last 



