Alpheus Hyatt II, naturalist, paleontologist, and educator, was born in Washington, D. C. an April 5, 1838, the son of Alpheus and Harriet Randolph (King) Hyatt. He attended various private schools, including the Maryland Military Academy, and then entered the class of 1856 at Yale. After completing his freshman year, however, he dropped out for a year of travel in Europe with his mother, upon his return he entered Lawrence Scientific School of Harvard University. As an outstanding pupil of Louis Agassiz, he graduated with highest honors in 1862. He then enlisted as a private in the Massachusetts Volunteer Infantry for the Civil War, emerging with the rank of captain.

At the end of his service, Hyatt decided to pursue his scientific studies, working for a time at the Essex Institute at Salem, Mass. where he and other naturalist friends founded and for a number of years edited the "American Naturalist". In 1867 he was appointed one of the curators of the Essex Institute, working with his friends A. S. Packard, A. E. Verrill, E. S. Morse, and Alexander Agassiz. He took an active part in the foundation of the Peabody Academy of Science. In 1867 he married Audella Beebe and soon became the father of Alpheus Hyatt III, Harriet Randolph Hyatt and Anna Vaughn Hyatt. A second son died in infancy. In 1871 Hyatt was elected custodian of the Boston Society of Natural History, becoming its curator in 1881 and remaining 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 fossil cephalopods of the Museum of Comparative Zoology which were his first scientific love. In 1879 he established a summer laboratory for the study of marine zoology at his country home at Annisquam, Mass. He kept a 60 foot schooner with which he made scientific cruises along the New England coast to study fossils and the general geology of these regions. But the location was found unfavorable for the site of a general marine laboratory, so after a few years the station was moved to Woods Hole, Mass., and Hyatt became the first president of its board of trustees.

As an educator, Hyatt served as professor of zoology and paleontology at M.I.T., a chair he held for eighteen years. He also was professor of biology and zoology at Boston University from 1877 until his death. His scientific studies revolved around the lower forms of animal life and was one of the first to combine the study of both living and fossil forms. In 1875 he was elected a fellow of the National Academy of Sciences and in 1898 received the honorary degree of L1. D. from Brown University. His studies took him ton y parts of the world. He died at his home at Cambridge in 1902.