In 1839-1840, the ichthyologist Richard Parnell left London for a collecting expedition to Jamaica and a tour of museum collections in the United States. An authority on both fishes and grasses, Parnell published two noted works as a young man, his Prize Essay on the Natural and Economical History of the Fishes Marine, Fluviatile, and Lacustrine, of the River District of the Firth of Forth (Edinburgh: Neill and Co., 1838) and The Grasses of Britain, 2 vols. (Edinburgh: Blackwood, 1842-1845). He appears, however, to have abandoned publication in 1845, although he continued collecting for many years. The notebook kept by Richard Parnell during his voyage to the West Indies and United States in 1839-1840 contains little narrative, but dozens of pencil and watercolor sketches of the marine life that absorbed his interest, primarily fishes. Most sketches are accompanied by brief notes on the anatomy of the fish, sometimes with close-ups of fin structures, air bladders, or the digestive tract and stomach. Although collecting localities are seldom recorded, the majority of specimens seem to have been collected in Jamaica, with at least a few observed in vitro at the New York Museum.