13 



2, and premolar 4 still larj^er than premolar 3. The last premolar is 

 luucli like that of Frocainelus occidentalis Leidy, and of P. lacastris 

 to be described later. The ramus is rather slim. The incisors were 

 nearly procumbent. 



P^ound by myself in a clay cliff in bluffs on the east side of the 

 Madison valley. Gallatin Co., Mont. 



MEASUREMENTS. 



M. 



Length of diastema between canine and first premolar 015 



I-ength of diastema between first and second premolars 017 



lyength from front of jaw to second premolar 056 



Length of premolars 2, 3 and 4 029 



Length of first premolar 0065 



Length of second premolar 008 



licngth of third premolar 0105 



Length of fourth premolar 0112 



rvpth of ramus beneath premolar 2 021 



Depth of ramus beneath molar 1 025 



I,ength of symphysis 040 



PROTOLABIS MONTANUS, N. SP. 



Plate III. 



Represented by the entire superior dentition of the right side, with 

 the exception of the first incisor, which has fallen out of the alveolus. 



All the incisors were large, well developed teeth. The first, judging 

 from its alveolus, was as large as the second. 



The species was larger than P. transmontanus Cope* from Cotton> 

 wood Creek, Oregon. I will give the main points of difference be- 

 tween this and Cope's specimen. 



In the present species the distance between the third incisor and 

 the canine is twice as great. The height of the crown of incisor 3 is 

 greater. In P. transmontanus molar 2 is as wide as long. In the pres- 

 ent species the anteroposterior diameter is greater than the transverse. 

 This is also true of molar 3. Premolar 2 is two-rooted but is small as 

 compared with premolar 3, which is a trifle longer than premolar 4. 



In the present specimen there are two first premolars of almost 

 the same shape and size. They are closely crowded. The anterior 

 one is slightly larger than the other, and perhaps should be taken for 

 the permanent tooth. This, measuring from the roots of the teeth. 



♦Bulletin U. S. CkK)l. Surv. of Territories. Vol. V.. No. 1, p. 67. 



