American naval officer and conchologist. Couthouy was conchologist on the Wilkes Expedition of 1838-1842 and also collected plants in Ecuador in 1855. Of French extraction, Couthouy was born in Boston and acquired a taste for seafaring as a young man by sailing with his father. He entered into a career as a merchant seaman, but was also a keen naturalist and joined the Boston Society of Natural History in 1836.

In 1838 he applied for a scientific position on the U.S. Exploring Expedition (1838-1842), but was at first rejected as all such roles had been filled. Desperate to join the voyage he implored the U.S. president, Andrew Jackson, to appoint him to the expedition. Successfully gaining a place as conchologist, he set off in August that year with the expedition under the command of Lt. Charles Wilkes. Ports of call were to include Madeira, Cape Verde, Brazil, Tierra del Fuego, Peru, New South Wales, New Zealand, Antarctica, the Sandwich Islands, Oregon, California, the Philippines, Sumatra and Cape Town. Couthouy, however, was sent home halfway through the expedition for disobeying Wilkes' orders to hand over his notes and drawings to the commander, who wanted to consult them for his account of the trip.

After returning home from Honolulu in 1840, more misfortune befell Couthouy; a great part of his mollusc collections from the trip were lost when the ship carrying them, the Peacock, ran aground in the mouth of the Columbia River and went down. Those that made it back to the Smithsonian Institution in Washington were rendered all but scientifically useless as the official tasked with unpacking them removed their identification tags, which Couthouy had meticulously correlated with notes. These events, coupled with a pay cut, left him extremely disappointed in his lot and, with a wife and two children to support, he returned to work as a merchant seaman. He travelled to South America and the Pacific in this guise, where he continued to collect specimens, including some plants in Ecuador. In 1854 he led an expedition to the Bay of Cumana, spending three unsuccessful years in search of the wreck of a Spanish treasure ship, the San Pedro. Volunteering in the navy in 1861, he commanded several ships in the American Civil War, at one point being taken prisoner. He was killed in 1864, shot during an ambush off the coast of Louisiana.

Sources:
W.H. Dall, 1888, "Some American conchologists", Proceedings of the Biological Society of Washington, 4: 108-111.