tirely anterior, and is narrowed below, in accordance with the narrowing 



of the premaxillaries. 



M. 



Length of interior dental series to bases of symphyseal 



tooth , 0.170 



Depth ramus at last molar 050 



Length symphysis 060 



" muzzle from canine 017 



• " symphyseal tooth projected 010 



Diameter " " " 026 



" canine " " 023 



If the body of this animal were of usual proportions as relates to the 



skull, it was about the size of the black bear ( Ursus americanus). The 



worn condition of the teeth indicates an old animal, and one that had 



lived on hard food. 



EOBASILETJS CORNUTUS. Cope. 



Gen. et sp. nov. 



Established on remains of five individuals of the average size of the 

 Mastodon ohioticus. These indicate clearly a form of proboscidian not 

 before recognized. The structure of the tibia and astragalus, clearly 

 indicate that the species is not artiodactyle, while the perfectly simple 

 femur is not perissodactyle. The posterior part of the cranium, and the 

 short stout phalanges are proboscidian. The existence of horns on the 

 frontal bones separates it at once from Dinotherium, Mastodon, Stegodon, 

 or Elephas, and indicates a remarkable combination of structure not 

 before known to naturalists. The gigantic size of the typical species 

 adds to its interest, and shows it to have been the monarch of the remark- 

 able fauna disclosed by recent researches in Wyoming. 



The distal extremities of both humerus and femur are flat, the former 

 •with oblique trochlear face and shallow olecranar fossa. The great tro- 

 chanter of the femur is flat and not recurved ; little trochanter wanting. 

 Spine of tibia very obtuse; distal extremity little excavated. Distal 

 extremity of phalanges not divided by trochlear ridge. 



Articular extremities of vertebrae plane ; the cervicals very short. 



Cranium with vertical occiput with broad convex superior outline. 

 Temporal fosste lateral, posteriorly small. Horn-cores obtuse, com- 

 pressed, most at base ; direction divergent. 



Number 1. M. 



Length of horn-cores (6 inches) 0.152 



Elevation occiput from the foramen magnum .180 



Width across supra-occipital crest 315 



" of condyles with foramen .206 



" " paramastoid process 087 



Number 2. 

 ' Transverse diameter condyles humerus 185 



