244 ^^^ American Geologist. '^p'"'- ^'-^^^ 
derof the crown including the greater part of the proto- 
loph is very much damaged. 
Tlie crown of the molar obtained last summer is prac- 
tically perfect and has been subjected to little wear during 
the life of the animal. It is probably the second molar 
and is shown in the accompanying figures. This tooth is 
brachyodont, with well-developed low cross crests (proto- 
loph and metaloph). The crown, seen from below, is subob- 
long in outline, transversely broader in front than behind,, 
and relatively narrow in an antero—posterior direction. 
The outer border (ectoloph) rises higher than the cross 
crests. The latter are unequal in length, the protoloph be- 
ing longer, and better developed, than the metaloph. The 
intermediate cusps (protoconule and metaconule) are both 
well-defined although the protoconule is larger than the 
metaconule and more distinctly separated from the proto- 
cone than is the metaconule from the hypocone. The pro- 
tocone is slightly larger at its base than the hypocone, but 
both have about the same hight. There is no hypostyle. 
The parast}le is large and adds considerably to the crown's 
anterior trar.sverse diameter. The mesostyle and meta- 
style are distinct, and the ribs are distinguishable, the an- 
terior one being the better defined of the two. The cingu- 
lum is well-developed and passes from the metastyle entire- 
ly round the inner side of the crown to the parastyle with- 
out interruption except for a short distance on the front 
inner slope of the protocone ; it connects in front with the 
parastyle with which the outer end of the protoloph shows 
a marked tendency to unite. Outwardly the cingulum rises 
on to the parastyle but does not cross it ; it also merges 
with the mesostyle and metastvle. 
Af. wesioni approaches closely in tooth-structure to 
M. latidens * Douglass (Oligocene of Montana ) from whicli 
its upper molars are distinguished principally by the pres- 
ence of the internal cingulum. by the less pronounced para- 
st3de and a proportionately greater antero-posterior diame- 
ter with the protoloph more nearly equal in length to the 
* Annals of the Carnegje Xfuseuvi. vol. II, No. 2. 1903. New Verte- 
brates from the Montana Territory by Earl Douglass, p. 161, fig. 7. 
