In February 1834, a young Whalebone Whale was taken near the Queensferry, in the Frith of Forth. After being exhibited for a short time by the proprietors, it was dissected by the author as carefully as time and circumstances would permit. The term Rorqual is employed throughout this memoir in the sense employed by M. Cuvier, as designating “Whalebone Whales, with longitudinal folds under the throat and chest.” He thinks the present specimen quite distinct, specifically from the “Great Rorqual” (the Balæna boops, jubarte, musculus, &c), and not as M. Cuvier seems to think it, a mere variety. Among other distinctions, the Great Rorqual has 13 dorsal, and 43 lumbar, sacral, and caudal vertebræ; while the individual now under consideration has only 11 of the former, and 36 of the latter. There are, therefore, at least two species of Rorquals inhabiting the North Seas, viz. the Great Rorqual, and the one now under consideration, a specimen of which was described by Fabricius (Balæna rostrata); another dissected by Hunter, and a third casually observed by James Watson, Esq., who sent a drawing of the same to Dr Traill, by whom it was communicated to Mr Scoresby.