364 



BUREAU OF AJVIERICAN ETHNOLOGY 



[Bull. 196 



Table 12. — Duration of marriages ' * 



» As of September 1, 1950. 



' Only those marriages are included whose dates are fixed with reasonable accuracy. Marriages broken 

 up temporarily but reunited are treated as a single marriage. Polygynous marriages are treated separately 

 for each woman involved. They often dissolved at different times. 



the arranged marriages fail to survive the first year or two because 

 of "incompatibihty" whether sexual or temperamental: The spouses 

 do not know each other or hardly know each other, and one or the 

 other has to live in, or in very close contact with, a group that is 

 unfamiliar and has somewhat different patterns of and for behavior. 



Inbreeding coefficients have been calculated for 316 matings which 

 produced 1,118 offspring during 7 generations (Spuhler, 1953). Of 

 the 316 sibships, 123 are inbred. The range of inbreeding coefficient 

 for individuals is 0.0010-0.0977, the mean for inbred siblings is 0.0175, 

 and the mean for the later generations 4 through 8 is 0.0080, and 

 the mean for the total population, generations 1 through 8 is 0.0066. 

 These values are minimum estimates for the population. 



Coefficients of the order observed for the Ramah Navaho, while 

 about two times those found for Japan and four times those reported 

 for Europe, are small compared to the estimate for the Dunker iso- 

 lates in the United States and compared to such regular systems of 

 inbreeding as full first cousin mating. 



RESIDENCE 



Even the most accurate picture of the distribution of a Navaho 

 group by locality on a given date can be misleading unless certain 

 facts are borne constantly in mind. The composition of some families 

 and their places of residence have shown remarkable continuity over 

 the past 20 years. The membership of these family groups has 

 changed, to be sure, with births, deaths, and marriages, but the basic 

 patterns have remained very stable. Residence has shifted at one or 

 more seasons of the year to other hogans, cabins, or camps, but the 

 moves have followed each year at approximately the same times to 

 places that varied only a little in location as dictated by grazing con- 

 ditions or the building of a new dwelling (after someone had died in 



