Sent off.
--Two Yankee Captains, for some time confined at the Libby prison, were yesterday paroled and sent off to City Point, to go North via flag of truce boat. Their names are Capt. A. W. Metcalf, Co. K, 14th N. Y. cavalry, and Capt. H. H. Gregg, Co. A, 13th Pennsylvania cavalry. The first was captured at Fort Donelson, on the 25th of September last , and the second was taken at Warrenton on the 14th of October, 1863.