He was apparently dropped from the rolls after Vicksburg as his name does not appear on the companies muster rolls for the following periods:

Stationed at parole camp near Enterprise, November-December 1863.
Since last muster a portion of the company (three commis-
sioned officers and twelve privates) have been declared exchanged
and ordered to duty.

Stationed at [illegible], January-February 1864.

Stationed at Atlanta, Georgia, July August 1864

Missing from the records for Company G is this roll, which is recorded for all the other companies of the regiment:

Stationed near Enterprise, Mississippi, April 30-October 31, 1863

It is this roll in which James Martin's name would have been dropped with reason given therein. Unfortunately, it didn't survive to be incorporated in the records.