Length of first premolar 007 



Width of first premolar 004 



Length of first molar 031 



Width of first molar 015 



Height of first molar (greatest) 020 



I/ength of second molar 035 



T>epth of ramus behind third incisor, about 033 



Depth of ramus behind premolar 1 0294 



Depth of ramus beneath premolar 2 031 



Depth of ramus beneath molar 1 03G7 



Depth of ramus under molar 2, posterior part 041 



Found in clay cliff, lower Madison valley, Montana. 



The second jaw fragment contains premolars 3 and 4 and molars 

 1 and 2, and a fragment of the mandible. The teeth are large but 

 the ramus is even more slender than the corresponding part of the one 

 previously described. Premolars 3 and 4 ai'e about the same size. 

 The latter has a posterior valley. This tooth does not fill the pos- 

 terior part of its alveolus. The lower border of the ramus is nearly 

 straight. There is a small alveolus under molar 1. 



MEASUREMENTS. 



Premolars. Premolar 4. Molar 1. Molar 2. 



M M. M. M. 



Length.. .0185 .020 .028 .0347 



Breadth .0085 .009 .018 .020 



Height.. .013 .013 greatest .022 greatest .026 



Length of last two premolars and first two molars 0965 



Depth of ramus beneath premolar 3, anterior 028 



Depth of ramus beneath Molar 1, anterior 028 



Depth of ramus beneath molar 2, anterior 029 



Depth beneath molar 2, posterior 032 



Found in lower Madison valley, Montana. 



PROCAMELUS LACUSTRIS, N. SP. 



Plate I, Figure 2. 



The type specimen of this species is the left mandibular ramus with 

 all the teeth except the incisors. The dentition with the exception of 

 the canine is nearly like that of P. occidentaUs Leidy. The principal 

 differences so far as I can determine are in the smaller and more 

 compressed canine and the depth of the ramus, which Is much slimmer 

 than in P. occidentaUs. Premolar 2 is also more robust than in the 

 specimen figured by Leidy. There are some minor differences in the 

 teeth which approach nearer to P. angustidens Cope, especially in the 



