On his return from the voyage of "Chevrette", Dumont was sent to the naval archive where he encountered Lieutenant Louis Isidore Duperrey, an acquaintance from the past. The two began to plan an expedition of exploration in the Pacific, an area out of which France had been forced during the Napoleonic Wars. France considered it might be able to regain some of its losses by taking over part of New South Wales. On 11 August 1822, the ship "Coquille" sailed from Toulon with the objective of collecting as much scientific and strategic information as possible on the area to which it was dispatched. Duperrey was named Commander of the expedition because he was four years older than Dumont. Dumont discovered the Adélie penguin, which is named after his wife. René-Primevère Lesson also travelled on "Coquille" as a naval doctor and naturalist. On the return to France in March 1825, Lesson and Dumont brought back to France an imposing collection of animals and plants collected on the Falkland Islands, on the coasts of Chile and Peru, in the archipelagos of the Pacific and New Zealand, New Guinea and Australia. Dumont was now 35 and in poor health. On board "Coquille", he had behaved as a competent official, but disinclined to military discipline and subordination. On the return to France, Duperrey and Dumont were promoted to commander. On "Coquille", Dumont tried to reconcile his responsibilities as second in command with his need to carry out scientific work. He was in charge of carrying out research in the fields of botany and entomology. "La Coquille" brought back to France specimens of more than 3,000 species of plants, 400 of which were previously unknown, enriching moreover the Muséum national d'histoire naturelle in Paris with more than 1,200 specimens of insects, covering 1,100 insect species (including 300 previously unknown species). The scientists Georges Cuvier and François Arago analysed the results of his searches and praised Dumont. As a botanist and cartographer, Dumont d'Urville left his mark on New Zealand. He gave his name to the genus of seaweeds "Durvillaea", which includes southern bull-kelp; the seaweed "Grateloupia urvilleana"; the species of grass tree "Dracophyllum urvilleanum"; the shrub "Hebe urvilleana" and the buttercup "Ranunculus urvilleanus".