Exploring Expeditions.
Of the important zoological expeditions the following may be selected as showing their influence on American Zoology:
The North Pacific Expedition, with William Stimpson as zoologist, returned in 1856 with much new information concerning the marine life of the coasts of Alaska and Japan and many new species of invertebrates.
In 1867–1869 the United States Coast Survey extended its explorations to include the deep sea marine life off the southeastern coasts and Gulf of Mexico under the leadership of Pourtales and Agassiz.
The Challenger explorations (1872–1876) added greatly to the knowledge of marine life off the American coast as well as in other parts of the world.
The explorations of the United States Fish Commission succeeded those of the Coast Survey in the collection of marine life off our coasts and in our fresh waters. These have continued since 1872 and have yielded most important results from both the scientific and economic standpoints.
Under the charge of Alexander Agassiz the Coast Survey Steamer “Blake,” in 1877 to 1880, was engaged in dredging operations in three cruises to various parts of the Atlantic. The U. S. Fish Commission Steamer “Albatross,” also in charge of Agassiz, made three expeditions in the tropical and other parts of the Pacific in the years from 1891 to 1905. The study of these collections has added greatly to our knowledge of systematic zoology and geographical distribution. The reports on some of the groups are still in course of preparation.
Period of Evolution, 1870–1890.
The time from 1870 to 1890 may be appropriately called the period of evolution, for although it commences eleven years after the publication of the Origin of Species, the importance of the natural selection theory was but slowly receiving general recognition. The hesitation in accepting this theory was due in no small degree to the opposition of Louis Agassiz. After the acceptance of evolution, although morphological and embryological studies continued as before, they were prosecuted with reference to their bearing on evolutionary problems.
Following closely the methods which had produced so much progress during the life of Agassiz, the field of zoology was now occupied by a new generation, among whom the pupils of Agassiz were the most prominent.