NATIONAL ACADEMY OF SCIENCES. 



instruction, secured able assistants, and continued to supervise 

 and direct the work until his death, after twenty-five years of 

 service. 



In 1883 he took a prominent part in organizing the American 

 Society of Naturalists. He was chosen its first president, and 

 was afterwards made an honorary member in recognition of his 

 services. 



In 1888 he was offered the position of United States Commis- 

 sioner of Fish and Fisheries, but he declined it. 



In 1889 and years following he was in charge, as paleontologist 

 of the United States Geological Survey, of the Lower Mesozoic 

 of Texas and California. He also carried on from time to time 

 researches in paleontology in Labrador, Newfoundland, Canada, 

 New England, and New York, and zoological explorations of 

 the waters of the coast from Labrador to Connecticut. 



In 1895 he was elected to the American Philosophical Society, 

 and in 1897 he was made a corresponding member of the Geo- 

 logical Society of London. 



In 1898 Brown University conferred upon him the degree of 

 Doctor of Laws. 



The last years of Hyatt's life were almost completely devoted 

 to the study of the relation between the geographical distribu- 

 tion of the Achatinellidse of the Hawaiian Islands and the end- 

 less variety of color-patterns presented by these mollusks, as ho 

 believed that this study would throw important light upon the 

 general problem of the origin of species. He obtained great 

 numbers of the shells of these mollusks, and, making a plaster 

 model of Oahu, with each mountain range and valley in relief, 

 and representing the probable lines of migration by colored 

 threads, he devoted several years to the task of tracing out the 

 origin of new color-patterns. At the time of his death, in 

 January, 1902, he had perfected his plans for a visit to the 

 islands in the following March for the purpose of studying tho 

 subject in the field. 



The titles of some of his more important memoirs are these: 

 Observations on Polyzoa (1806-68) ; On the Parallelism between 

 the Different Stages of the Life of the Individual and those of 

 the Entire Group of the Molluscous Order Trtribranchiala 

 ( ISI',7 ) ; Fossil Cephalopoda of the Museum of Comparative 



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