http://mscgr.homestead.com/MSCGRaz.html
I believe the man below is who you are lokking for...
Avera, Raston L.
Company E, 37th Mississippi Infantry
Roll dated MAR 8 to APR 30, 1862: Present
Enlisted May 8, 1862 at Columbus, MS. for "three years or the war" by (?L.L. Houge?)
Roll dated MAY & JUN, 1862: Present
Roll dated JUN 30 to AUG, 1862: Present
Roll dated AUG 30 to OCT 30, 1862: Present. Last paid AUG 31, 1862 by Major Landry
Roll dated NOV and DEC 1862: Present. Last paid OCT 31, 1862 by Captain Davis
Roll dated JAN and FEB 1863: Present. Last paid by Captain Davis OCT 31, 1862. Enlisted MAR 8, 1862 at Shubuta, MS by R. McClain
Roll dated APR 30 to OCT 31, 1863: Last paid by Captain Davis APR 28, 1863. Died in hospital Vicksburg JUN 28, 1863
Maybe someone else can explain the different enlisting officer info?