474 Reviews — Prof. Edward D. Cope — 



head distinct from the trochlear and distal articular facets. The 

 cusps of the upper and lower molars develope into Vs. All the 

 vertebras have flat articulations. There is no inter-trochlear ridge 

 to the humerus ; and the femur has a third trochanter. Excluding 

 the characters of the astragalus, there are resemblances to the 

 Condylarthra in the narrow ilium, and in the molar teeth having but 

 one internal lobe ; but the dentition is especially like that of the 

 Ainblypoda, and there are resemblances to the Pantodonta in the 

 premaxillary teeth, the short flat cervical vertebras, and the third 

 trochanter to the femur ; but the characters of the astragalus are 

 rather like those of the Periptychidas and the Proboscidea. In 

 Pantolambda the brain indicates small nearly smooth hemispheres, 

 extending with little contraction into a rather large cerebellum, 

 while the olfactory lobes are produced anteriorly at the extremity of 

 a rather long isthmus. The dentition would indicate Pantolambda 

 to be the ancestor of the Coryphodonts. The superior molars are all 

 triangular from having a single internal cusp. This type of tooth 

 at the present day is found among Insectivorous and Carnivorous 

 Marsupials, in the Insectivora, and in the tubercular crowns of some 

 Carnivora ; and among Ungulates it is found in the molars of the 

 Coryphodonts, and in the last upper molar of the Dinocerata. The 

 only species is Pantolambda bathmodon, in which the hinder part of 

 the skull is Opossum-like, and the nasal bones give an obtusely roof- 

 shaped form to the muzzle. 



The Perissodactyla are well represented in the North American 

 Tertiaries. The group may be described as intermediate in dentition 

 between the Proboscidea and the lowest Selenodont Artiodactyla. 

 On dental characters Professor Cope recognizes ten families arranged 

 into four divisions. First, animals with the anterior crescent of the 

 upper molars shortened, and not distinguished from the posterior 

 crescent by an external ridge, with cross-crests to the inferior molars, 

 and with premolars distinct from the molars. This comprises the 

 Lophiodontidas, in which the toes are 4-3 ; and the Triplopodida?, 

 in which the toes are 3-3. Secondly, a division in which, while 

 the exterior crescents of the upper molars, and the cross-crests of 

 the lower molars, remain as in the first division, while the upper 

 molars and premolars are alike, and furnished with cross-crests. 

 Under this type are comprised the Hyracodontidas, in which the 

 mastoid bone enters into the external wall of the skull ; and the 

 Ehinoceridae, in which the mastoid bone is excluded from the wall 

 of the skull, by contact of the squamosal bone with the occipital 

 bone. The third division has the exterior crescentic crests of the 

 upper molars subequal and distinct, with cross-crests to the inferior 

 molars. This type comprises the Tapiridae, in which the upper 

 molars and premolars are alike furnished with cross-crests, and with 

 the toes 4-3. The last division has the nearly equal external 

 crescentic crests of the upper molars separated by an external 

 ridge, while the inferior molars are furnished with crescents. First 

 in this group are placed the families with superior premolars 

 different from the molars, and with only one internal cusp. The 



