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BULLETIN 169, UNITED STATES NATIONAL MUSEUM 



are closer to those from Loc. 25. This impression of slight heterogene- 

 ity cannot now be considered dependable or formally recognized. 

 The differences could hardly be of more than subspecific scope in any 

 event and perhaps are merely those of separate strains within one 

 subspecies, and the data are too few to establish them as real. 



The best data for material from one locality, dimensions of P4 and 

 Ml from the Gidley Quarry, may be compared with the Torrejon 

 sample by Fisher's t-test, previously mentioned, with the following 

 results: 



Thus these two teeth are probably significantly longer, but not 

 wider, than those of the Torrejon sample as a whole. Since the latter 

 is heterogeneous in origin and perhaps as to race, it does not neces- 

 sarily follow that the Gidley Quarry race does not occur in the Torre- 

 jon, but it probably does not. Comparison of the whole Fort Union 

 sample, however, shows no significant difference, as the following 

 figures for the only variates probably significant in the Gidley Quarry 

 sample show: 



In short, the evidence now is that the Fort Union sample may 

 include more than one local or temporal genetic group of minor 

 scope and the same may be true of the Torrejon material. At least 

 one of these minor groups in the Fort Union is distinct from the 

 Torrejon sample as a whole and probably from any group included in 

 the latter. But the definitive separation of these minor groups can- 

 not be accomplished from the data now available, and there is no 

 significant dift'erence between the Fort Union Anisonchus as a whole 

 and that of the Torrejon as a whole. All are referable to a single 

 species, A. sectorius. 



Table 62. — Numerical data on P4 of Anisonchus sectorius 



