To Geoffroy was assigned the four classes of vertebrates, but in reality he only occupied himself with the mammals and birds. Afterwards Lacépède[33] took charge of the reptiles and fishes. On the other hand, Lamarck's field comprised more than nine-tenths of the animal kingdom. Already the collections of insects, crustacea, worms, molluscs, echinoderms, corals, etc., at the Museum were enormous. At this time France began to send out those exploring expeditions to all parts of the globe which were so numerous and fruitful during the first third of the nineteenth century. The task of arranging and classifying single-handed this enormous mass of material was enough to make a young man quail, and it is a proof of the vigor, innate ability, and breadth of view of the man that in this pioneer work he not only reduced to some order this vast horde of forms, but showed such insight and brought about such radical reforms in zoölogical classification, especially in the foundation and limitation of certain classes, an insight no one before him had evinced. To him and to Latreille much of the value of the _Règne Animal_ of Cuvier, as regards invertebrate classes, is due. The exact title of the chair held by Lamarck is given in the _État_ of persons attached to the National Museum of Natural History at the date of the 1er messidor, an II. of the Republic (1794), where he is mentioned as follows: "LAMARCK--fifty years old; married for the second time; wife _enceinte_; six children; professor of zoölogy, of insects, of worms, and microscopic animals." His salary, like that of the other professors, was put at 2,868 livres, 6 sous, 8 deniers.[34] Étienne Geoffroy St. Hilaire[35] has related how the professorship was given to Lamarck. "The law of 1793 had prescribed that all parts of the natural sciences should be equally taught. The insects, shells, and an infinity of organisms--a portion of creation still almost unknown--remained to be treated in such a course. A desire to comply with the wishes of his colleagues, members of the administration, and without doubt, also, the consciousness of his powers as an investigator, determined M. de Lamarck: this task, so great, and which would tend to lead him into numberless researches; this friendless, unthankful task he accepted--courageous resolution, which has resulted in giving us immense undertakings and great and important works, among which posterity will distinguish and honor forever the work which, entirely finished and collected into seven volumes, is known under the name of _Animaux sans Vertèbres_." Before his appointment to this chair Lamarck had devoted considerable attention to the study of conchology, and already possessed a rather large collection of shells. His last botanical paper appeared in 1800, but practically his botanical studies were over by 1793.