This great field of the morphology of nonvertebrates could be properly worked only with access to the marine fauna, and at that date there were few facilities for seaside study in America. A true disciple of Louis Agassiz, Professor Brooks saw the need of a marine laboratory, and devoted himself, as Dohrn did at Naples, to the accomplishment of an end so necessary for the advance of natural science. Encouraged by the aid of a few citizens of Baltimore, in 1878 there was started an experiment--"The Chesapeake Zoölogical Laboratory," at Fort Wool, Va., with Professor Brooks as director. With the absolute devotion of its director to research as example, and with the liberal aid of the trustees of the Johns Hopkins University, this laboratory became a most important adjunct to the university and a virile center of zoölogical study. So great was its success as a factor in the advance of zoölogical knowledge that the trustees bravely continued to support it whenever financial disaster did not rob them of the last penny. For eight years in the Chesapeake, or in the remoter waters of North Carolina, the station flourished; then, in 1886, we find the director, with a few enthusiastic students, venturing in a small schooner to the but little known Bahama Island, Green Turtle Cay, there to enlarge their experiences with such delightful realization of naturalists' dreams of the tropics as Haeckel experienced in his Journey to Ceylon. Subsequent annual expeditions to Nassau, the Bemini Islands, and to various parts of Jamaica served as marked eras in the lives of many young naturalists who will not soon forget the contact with life thus obtained. From these sources and from his connection with the United States Fish Commission, as director of the Marine Station at Woods Holl, Mass., in 1888, Professor Brooks drew inspiration and fact for the work and thought by which he is so well known to the working naturalist. There are few great divisions of the animal kingdom that have not excited his special interest and claimed his long-sustained labor upon the problems they express. Like McCrady, deeply fascinated by the _Hydromedusæ_ and their wonderful changes, many smaller papers, as well as the Memoir of the Boston Society of Natural History, entitled The Life History of the _Hydromedusæ_ and the Origin of Alternation of Generations, testify to his success in unraveling plots that thickened with new discoveries.