would much more evenlj^ divide the space between the cauiue and pre- 

 molar 2 than In p. transmontanus, where premolar 1 is only about a 

 third the distance from the canine. If the posterior tooth be talien as 

 the permanent one, then the conditions would be reversed and premolar 

 1 would be a little more than a third the distance from premolar 2 to 

 the canine. 



Incisor 3 is a long (high) robust tooth, much larger than the canine, 

 but much like it in shape, being pointed, slightly curved forward, and 

 subround in section. The first premolar is smaller than the canine 

 antero-posteriorly, is not so high and is more flattened on the inner 

 Bide. Only the top is coated with enamel. 



Premolar 2 has nearly the form of a half cone.There are two slight 

 concavities on the inner side, one anterior and one posterior to tli ■ 

 median line. On the outside of premolar 3 is a small anterior ridge, 

 posterior to this a broad convexity on the protocone, and back of this 

 a smaller one and a well developed posterior ridge. 



The molars are so much like those of Gomphotherium cameloid< s 

 figured by Wortman (Extinct Camelidae of North America,*) that if 

 only the molars had been found they would have been taken for tt'Oth 

 of that species. The length of the last three premolars and the molars 

 is about one-fifth greater iu Protolobis Montanus. 



The last two molars differ from the corresponding ones of P. Trans 

 montanus in being less quadrate, the posterior portion being narrower 

 than the anterior. 



Dug from a clay cliff. Miocene lake beds, loAver Madison valley, 

 Montana. 



Portions of the posterior part of the lower jaw were found, iii~ 

 eluding a mutilated third molar. 



MEASUREMENTS. 



M. 



Length of dental series from front of base of first incisor 19.5 



Diastema between incisor 3 and canine, length 012 



Length of incisor 3, anteroposterior 0095 



Width of incisor 3, transverse 009 



Diastema between canine and premolar 1 015 or .021 



Diastema between premolar 1 and premolar 2 019 or .014 



Length of three contiguous premolars 038 



Length of Premolar 2 009 



Length of Premolar 3 016 



Length of Premolar 4 0148 



Width of premolar 3, greatest 009 



•=Am. Mus. Nat. Hist.; Vol. X. Art. VII, p. 118. 



