Bates (1) has Devlin, but the company E descriptive roll (2) has Derlin.
He was born in 1831/32 (2 [32 in 1863?, 6 [29 in 1861]). He was born in Philadelphia, Pennsylvania (2, 6).
When he enlisted, he was a teamster, and was living in Philadelphia (2, 6).
When he enlisted, he was 5 feet 6-1/2 inches tall, had a dark complexion, brown eyes, and dark hair (2, 6 [5'7", dark complexion, brown eyes, black hair).
He enlisted and was mustered into service as a private in company E on 21 August 1861, at Philadelphia, Pennsylvania (1, 6). He was a private, in company E (8, 9).
On 10 April 1863, he was detailed as a stretcher bearer (4).
He re-enlisted for three years, as a veteran volunteer on 24 December 1863, at Bealton, Virginia (2, 6 [26 Dec]). He was enlisted by Lieutenant Carpenter, and mustered into service by Lieutenant Swann (this could be about his initial enlistment) (1, 2).
On 12 November 1864, he went on a furlough, which ended on 23 November 1864 (5).
On 26 January 1865, company E published resolutions mourning the death of sixteen comrades, and sympathizing with their families (7). He was on the committee (7).
On 5 June 1865, he was detailed for duty in the quartermaster department, 5th Army Corps (3).
He mustered out on 10 July 1865 with his company (1, 2, 6). He was a private, in company E (8, 9).
1 Bates, Samuel Penniman. History of Pennsylvania volunteers, 1861-5. Harrisburg: B. Singerly, state printer, 1869-71. 5 volumes. 'Ninety-first regiment', volume 3, pages 186-233. (In the roster)
2 descriptive roll, company E, entry 32 (James Derlin)
3 special order 124, headquarters, 5th Army Corps, 5 June 1865
4 consolidated morning report, 91st PA, 10 April 1863 (James Devlin)
5 enlisted men's furloughs (Privt James Devlin)
6 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 6 May 2004 (James Devlin)
7 'Headquarters company E', Philadelphia Inquirer 26 January 1865 page 5 (James Devlin)
8 index to compiled service records of volunteer Union soldiers who served in organizations from the state of Pennsylvania (Develin, James)
9 index to compiled service records of volunteer Union soldiers who served in organizations from the state of Pennsylvania (James Devlin)