ALPHEUS HYATT. 



Zoology; Embryology (1867) ; Eevision of the North American 

 Porifera (1875-77) ; The Genesis of the Tertiary Species of 

 Planorbis at Steinheim (1880); Genera of Fossil Cephalopoda 

 (1883-84); Larval Theory of the Origin of Cellular Tissue. 

 (1884-85) ; Genesis of the Arietidae (1889) ; Bioplastology and 

 the Related Branches of Biological Eesearch (1893) ; Phytogeny 

 of an Acquired Character (1894) ; Cephalopoda (1900). 



Most of the memoirs are beautifully illustrated by the author, 

 whose artistic and accurate pencil adds greatly to their value. 



Hyatt's researches on the Polyzoa of fresh water, on the 

 sponges of North America, and upon the Mollusca of fresh 

 water and of the land are worthy of notice, but his most im- 

 portant works are those that treat of the fossil cephalopods. 

 These organisms held the foremost place in his mind throughout 

 the whole period of his scientific activity, and they afforded the 

 material for most of his published memoirs. These memoirs 

 won for him distinction among zoologists and paleontologists, 

 and upon them his fame must rest. It is estimated that there 

 are some twenty-five hundred species of Nautiloids and some 

 five thousand species of Ammonoids, and Hyatt became familiar 

 with most of those that are contained in the museums of Europe 

 and North America. He discarded much of the established 

 classification and established many new genera, which were 

 more accurately defined than had been customary. This reforma- 

 tion excited opposition, but he lived to see it prevail. The brill- 

 iant work of a younger generation of paleontologists who ac- 

 knowledge him as one of their great masters and leaders is the 

 best proof of his success. 



If this catalogue of his works conveys the impression that 

 they lack unity, and that they were not inspired by any broad 

 central principle, I regret this exceedingly. Few naturalists who 

 have carried on researches in many fields for many years have 

 been actuated, as Hyatt was from beginning to end, by a single 

 motive, which has inspired and directed all they have undertaken 

 and has never been absent from their minds for an instant of 

 their working hours. H^yatt was accustomed to speak of his 

 own guiding motive as the "old-age theory." No account of his 

 life is complete without a statement regarding this doctrine, 

 which exercised a great influence over all his work; yet I must 

 admit that I do not understand it. 



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LIBRARY 



