1918] Merriam: New Mammalia from the Idaho Formation 525 



of California, in /. osborni of the Ricardo Pliocene, and in Machae- 

 rodus palaeindicus of the upper Siwalik beds of India. 



The Idaho specimen possesses three mental foramina in contrast 

 to the one large foramen seen in Smilodon calif or nicus. 



The tooth crowns in no. 22343 are unfortunately all broken away 

 with the exception of a considerable part of the lower canine and about 

 one-half of the crown of P3. Sufficient portions of the roots remain 

 to give an estimate of the relative dimensions of the teeth. These 

 measurements indicate that P 5 is relatively smaller and M T larger 

 than in S. calif or nicus. As these measurements are based upon the 

 upper portions of the roots or upon the neck of the teeth they are not 

 exactly comparable with the measurements from perfectly preserved 

 crowns of S. calif 'or nicus, as the lower region of the crowns has a some- 

 what longer anteroposterior diameter than the upper portion of the 

 root or the neck. 



The incisors of the Idaho form appear somewhat thicker trans- 

 versely than in the typical species of Smilodon from Ranch o La Brea. 



With the fragmentary material available it is impossible to draw 

 very satisfactory conclusions as to the systematic position and age 

 of the Idaho sabre-tooth. The presence of a well developed P3 taken 

 with the unusual anteroposterior diameter of the flange and the rela- 



Figs. 2a to 2c. Neotragocerus lindgreni, n. sp. Horn-core. Type specimen, 

 no. 3941, U. 8. Nat. Mus. X %. Fig. 2a, median view; fig. 2b, cross-section at 

 middle height; fig. 2c, posterior view. From beds referred to the Idaho forma- 

 tion three miles east of Boise, Idaho. 



2a 



2c 



