E. H. Barbour — New Longirostral Mastodon. 525 



symphysis becomes broader than thick, unlike other forms in 

 the Nebraska State Museum. The elongated, mental foramen 

 is close upon the inferior border. The inner alveolar border 

 extends as a ridge well to the condyle. 



The jaw is that of an adult, but not an aged individual. 

 Molars five and six are present and are fairly well worn. The 

 fifth molar has three, while the sixth has four, transverse crests 

 and a large heel. This heel, which is as well developed as the 

 fifth ridge in Mastodon amerioanus, would have developed into 

 a fifth crest by continued wear. Along the middle line of the 

 tooth rise the accessory cones, regularly and mostly singly. 

 Accordingly, the tooth is made up of alternating major and 

 minor ridges. Excepting these alternating cones, the tooth is 

 not unlike the sixth molar of Mastodon americanus. The 

 cingulum is strong and broad. The sixth molar is 7-J inches 

 (190 mm ) long, 3 inches (76 mm ) wide through the cingulum, and 

 has a grinding surface of 2 inches. Where the teeth are 

 broken, the dentine shows distinct decussation. The pattern 

 of the worn crown is not distinctly trefoiled as are many of 

 our Tetrabelodons. The teeth slant backward and inward. 

 The low stature of the creature, 7 feet, and the long jaw, 5 

 feet, made it easy to reach the ground with the lower tusks. 

 The inferior tusks are long and strong. They are imbedded 

 the length of the symphysis and are about as long as the supe- 

 rior tusks, and protrude, at most, about 10 inches out of the 

 jaw. They are \\ inches (38 ram ) thick and 2 inches (51 mm ) 

 broad, and are produced into a dull edge laterally. 



The jaw and its tusks protruded more than 2 feet (610 mm ) 

 beyond the skull. It was a grotesque head on a grotesque 

 body. The skull, still in plaster " cinches," is relatively short, 

 about two-thirds that of the mandible, and the upper tusks 

 very short and stout. 



Fortunately, both of the upper tusks are perfect and in 

 place in the skull. They curve downward and outward and 

 are produced to a distinct point and are somewhat flattened on 

 the inner side. They are about 4 inches (102 mm ) in diameter 

 and very short, for scarcely more than 16 or 18 inches (407 to 

 457 mm ) protrude beyond the incisive sheath, and still less beyond 

 the flesh in life. 



In association with this specimen were teeth of three other 

 individuals of unlike species, and the bones and teeth of horse 

 {Protohippus and Hipparioii), rhinoceros, camel, and rodent 

 (Dipoides tortus). 



The articulated forelimb indicates an animal little more than 

 7 feet in height, half that of a large mammoth, The vertebrae 

 seem large out of all proportion, being equal in size to those of 

 the mammoth. This Tetrabelodon was short- legged, broad- 



