1940 Fitzhugh Township, Pontotoc County, Oklahoma Census
Henry W ... Head ... 51 Arkansas
Ola ... Wife ... 37 Arkansas
Melvin B ... Son ... 21 Arkansas
Morris ... Son ... 17 Arkansas
Cecil ... Son ... 14 Arkansas
Ruby ... Dau ... F 9 Texas
Billy R ... Son ... 6 Arkansas
"United States Census, 1940," index and images, FamilySearch (https://familysearch.org/ark:/61903/1:1:VBKF-D2Q : accessed 21 April 2015), Henry W Garrett, Fitzhugh Township, Pontotoc, Oklahoma, United States; citing enumeration district (ED) 62-21, sheet 6B, family 112, NARA digital publication T627 (Washington, D.C.: National Archives and Records Administration, 2012), roll 3326.
It may be possible to confirm family relationships with Morris by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree: