fossils constitute a great group of the animal kingdom probably equivalent to a suborder. In 1867 he named 26 genera and 126 species of ammonites.
He also made a detailed and very careful study of the anatomy of the so-called "moss-animals," or fresh-water Polyzoa, the structural details of the species being tabulated in order to facilitate comparisons. This work was published in the Proceedings of the Essex Institute, in 1866-67, and also in the American Naturalist, and is illustrated by careful and accurate outline figures drawn from life by Hyatt and beautifully engraved on wood by that matchless draughtsman E. S. Morse. In this and all of his subsequent papers Hyatt furnishes a model that systematic zoologists will do well to follow in the accurate and detailed description of species.
While at Salem he also began that study of sponges which was to make him the leading authority among systematic zoologists of America upon these animals. His principal papers upon sponges were not published, however, until 1875-78 in the Proceedings and Memoirs of Boston Society of Natural History. He agrees with MacAllister that sponges constitute a subkingdom or branch of the animal kingdom equivalent to one of the larger divisions. He describes 36 new species, and gives an excellent account of the methods of the commercial sponge fisheries of Florida, and discourses upon the embryology, anatomy, physiology and relationships of sponges, deciding, in common with Barrois, that in sponges there is no gastrula stage.
But Salem was too small to provide careers for so many young, active and well-trained students of natural history. Of the four friends, Morse remained in Salem; Packard went to Brown University; Putnam became an anthropologist and curator of the Peabody Museum in Cambridge and also in other institutions; and on May 4, 1870, Hyatt was elected custodian of the Boston Society of Natural History. In 1881 he became its curator and remained the scientific head of the society until his death in 1902.
After 1873 he made his home in Cambridge, where he could be near the great collection of cephalopods of the Museum of Comparative Zoology, and in 1879, under the auspices of the Woman's Educational Association of Boston, he established a summer laboratory for the study of marine zoology upon his country place at Annisquam, Mass. At this time also he owned a 60-foot schooner yacht, the Arethusa, with which he made scientific cruises along the New England coast, going as far north during the summer of 1885 as the west coast of Newfoundland and lower Labrador, to study the fossils and the general geology of these regions. His companions upon this cruise were five young men, among whom were Professor George Barton and the late Dr. E. A. Gardiner.
The situation of Annisquam was found to be unfavorable for the site