FORT UKIOX OF CRAZY MOUXTAIX FIELD, MONT. 



153 



posteroexternal base of which also meets a small ridge descending the 

 inner face of the paracone. This protoconule is very small, and the 

 metaconule is still smaller and indistinct. The posterior crest from 

 the protocone apex forms a sharp loop around the expanded posteroin- 

 ternal corner of the crown, thus maldng the teeth distinctly quadrate 

 although no hypocone is present. 



^P is shorter than M^~^, with the whole posterior half, most notice- 

 ably the metacone and posterointernal loop, much reduced. The 

 internal base has only one lobe. On one specimen (9542) there is no 

 groove, and on the other (9540) it is very slight and does not reach the 

 base. 



Table 30. — Numerical data on lower teeth of Paromomys maturus 



Table 31. — Measurements of individual specimens of Paromomys maturus 



Type Lower Jaw i 



Characteristic Upper Dentitions 



1 These measurements have been taken, and ratios calculated, on 30 difierent specimens, but these are most 

 usefully summed up by the statistical data derived from them and wherever possible in this memoir I do not 

 publish the long tables of raw measurements. Data for M1-3 have not been calculated. Althouirh at first 

 sight this would appear to be the best single size measurement, in fact it depends to so great a degree on 

 crushing and other extraneous factors as to be highly inaccurate and hence of little value. 



