564 GEOLOGICAL SURVEY OF THE TEERITORIES. 



according to Marsh, but excavated on the margin only in Loxolopliodon. 

 It is neither in Elephas. There is a post-glenoid process much more 

 largely developed than in Elephantidce. Other differences of still less 

 importance are to be seen in the anterior position of the exterior uares, 

 and the presence of horns. 



The Batlimodontidce are represented by Bathmodon. With a structure 

 of the hinder limb nearly resemhWn g Uobasileiis, we have more pronounced 

 relationships to the Perissodactyles. The scapula has the massive 

 apical acumination of the Elephantidce, and there is no round ligament 

 of the femur in some of them. The astragalus has the same flattened 

 form seen in UintatJierium, and is even less like that of the Perissodac- 

 tyla. The tj^pe of molars and the long compressed canines are similar to 

 those of Loxolopliodon. On the other hand, the cervical vertebrae are 

 rather longer, and«there is a rudimental third trochanter of the femur. 



History, &g. I originally rei'erred the EobasileidcB to the Proboscidia, 

 on account of the structure of the limbs, and subsequently stated a num- 

 ber of reasons for this conclusion at a meeting of the Academy of Natural 

 Sciences of Philadelphia, held January 14th, 1873, (published January 

 10th.) In the present paper, numerous conlirmatory characters are 

 added. The Bathmodontidw I have heretofore referred to the Perisso- 

 dactyla. 



ProfessorMarsh, in describing a species of this group, Titanotlierium {?) 

 anceps, (July, 1871,) compares it with perissodactyle species, and in de- 

 scribing the tibia says that it, " at its proximal end, has the femoral sur- 

 faces contiguous, with no prominent elevation between them, resembling 

 in this respect some of the Proboscidia.''^ A few days before the publi- 

 cation of my conclusions, in a foot-note, (July 22d, 1872,) he altered the 

 name Titanotherium to Mastodon, indicating that he had reached the 

 same opinion. Shortly after, (American Journal of Science and Arts, 

 September 27th,) he altered his view, constructing a supposed new 

 order '■'•Dinocerata,'''' for their reception. 



As regards the name of the order here defined as including the four 

 families above mentioned, I have preferred using one already employed 

 to coining a new one. This is the Ibetter course also, if, as is not unlikely, 

 the distinctions on which it, as well as the other two orders, rex)Ose, shall 

 be broken down by new discoveries in i^aleoutology. 



EOBASILEID^. 



The genera of this group known to the writer are four, which differ 

 as follows : 



1. Nasal bones with i3at horizontal horn-cores overhanging their apex. 

 Cervical vetebrte short; malar bone much reduced in 



front Loxolopliodon. 



2. Nasal bones with small tuberosities. 



(Cervical vertebrae short Eobasileus. 



Cervical vertebrae longer; the malar bone reaching maxil- 

 lary face UintatJierium. 



3. Nasal bones without the anterior horn-cores. 



Cervicals (?) Megaceratops. 



The above is the closest approximation to nature which my present 

 material allows. It is not at all unlikely that the difference in develop- 

 ment of the anterior nasal tuberosities seen in Loxolopliodon cornutus 

 and Eobasileus pressicornis will turn out to be onlv specific. 



The dentition of this group requires special notice. Judging from the 



