DESCRIPTION OF A NEW SPECIES OF MASTODON, 

 GOMPHOTHERIUM ELEGANS, FROM THE PLEISTO- 

 CENE OF KANSAS. 



By Oliver P. Hay, 



Research As.iu.iiitc of the Carnegie In-stituti'in of Wn-:]iingto)i. 



The specimen here described was found about 1908 near McPher- 

 son, Kansas, by Mr. Frank Dillon, of the town named. It was met 

 with in a sand pit, at a depth of about 35 feet, in section 34, town- 

 ship 19 north, range 3 west. The tooth was presented to the United 

 States National Museum by Mr. Dillon. 



Type-speHmen. — A lower left hindermost molar, No. 8255, of the 

 United States National Museum. 



Type-locality. — McPherson, McPherson County, Kansas. 



Type- formation. — Sheridan beds. 



Diagnosis. — The lower hinder molar furnished with six cross- 

 crests, or five cross-crests and a large talon, a deep longitudinal 

 median cleft and principal cones and accessory conules. Outer ends 

 of valleys closed by buttresses and forming trefoils on wear. Inner 

 ends of valleys partially closed by accessory conules. 



Judging from the narrowness of the tooth and the fact that the 

 crests run across the crown somewhat obliquely, the writer concludes 

 that it is the lower left hindermost molar. It had not yet been cut 

 and is therefore wholly unworn. The pulp cavity is large and the 

 roots had not j^^et been developed. Unfortunately, in the process of 

 exhumation, the tooth was injured somewhat; but nevertheless it is 

 in good condition. 



The length of the tooth is 217 mm.; its width at the first cross- 

 crest, 83 mm.; at the fourth, 85 mm. It will be seen from the 

 measurements and the figures (pi. 26, figs. 1, 2) that the tooth is a 

 long and relatively narroAv one. There are present six cross-crests, 

 the hindermost one being something more than a talon. The inner 

 and the outer halves of each crest are separated by a narrow but 

 very deep cleft. Each half of each crest may be regarded as com- 

 posed of two cones, the principal one and another nearer the mesial 

 cleft. The latter does not rise quite as high as the principal cone 

 and is separated from the latter by a cleft. 



To these four cones of each crest may be added accessory conules. 

 It is probable that at a later time the median cleft and those sepa- 



Proceedings U. S. National Museum. Vol. 53— No. 2198. 



219 



