FORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 265 



As an indication of the variation of the whole species as thus known, 

 data for P4, a rather variable and characteristic tooth best represented 

 in the combined collections, are here presented (table 62). Individual 

 measurements of the many specimens studied, and many other data, 

 are on hand and will be permanently filed. 



The uniformity of these results with those based on Torrejon 

 specimens only is striking. Despite the great increase (one and a 

 half times) in the size of the sample by the addition of specimens of 

 widely different provenience, the two means are increased by only 

 0.08 and 0.04, respectively, the first figure only 0.01 more than the 

 corresponding standard error for the smaller sample and the second 

 less than the corresponding standard error. The standard de\dations 

 are altered by amounts considerably less than their standard errors in 

 the smaller sample and the same is true of one coefficient of variation, 

 while the other is not changed at all. 



The interest of the coefficients of variation for the Torrejon sample 

 should also be pointed out. One of them, for WP3 is unusually high, 

 but this is largely caused by the single aberrant or abnormal specimen 

 previously mentioned. ^^ If we accept P3 as abnormally variable or as 

 represented by some extraneous material, the other eight coefficients 

 of variation range from 3.8 to 5.7 and average 4.8.'^ The accumula- 

 tion of such figures is of great importance in view of our almost com- 

 plete lack of any exact knowledge of the variability of fossil species 

 in samples collected under the usual field conditions. 



The preceding discussion is based on lower teeth. The upper 

 dentitions have also all been examined and compared, but they merely 

 substantiate the evidence of the lower dentitions, and the samples 

 are less satisfactory in all respects. 



Order PANTODONTA Cope, 1873 (as suborder), new usage 



The order Dinocerata (emended from Dinocerea) was proposed for 

 the uintatheres by Marsh in 1872, In 1873 Cope proposed to reduce 

 this to subordinal rank and with the new suborder Pantodonta, for 

 the coryphodonts, placed it in the order Proboscidea. In 1875 the 

 two suborders were transferred by Cope to a new order Amblypoda. 

 In 1883 he added to this order the suborder Taligrada, based solely 

 on Pantolambda, and in 1897, as stated on an earfier page, added the 

 periptychids to the Tahgrada. Marsh in 1884 proposed "Ambly- 

 dactyla" and "Coryphodontia" as strict synonyms of Cope's names 

 (which Marsh claimed to be essentially preoccupied) Amblypoda and 



« Omission of this specimen would reduce V from 12.3 to 7.5±2.0. 



'« This is within twice the standard error (that is, within the range of probable true values) for all the 

 ■single coefficients and is within less than the standard error for all but two. If the aberrant individual be 

 omitted, it is also well within the range of probable true values for P3. 



