262 THE POPULAR SCIENCE MONTHLY. 



and in connection with the Boston Society is manager of the Teachers' 

 School of Science, which was founded in 1870-'71, for the purpose of 

 giving lectures to teachers in Boston and vicinity. 



The Society of Naturalists of Eastern United States, founded in 

 1883, really arose from an idea of Professor Hyatt's that there should 

 be a society representing the practical side of natural history. He 

 communicated his ideas to Professor Clark, of Williams College, who 

 realized the value of the plan ; and it was mainly through the execu- 

 tive ability and energy of Professor Clark that the first meeting was 

 called at Springfield. Professor Hyatt was elected first president of 

 the society for a term of two years. In 1869 he was elected Fellow 

 of the American Academy of Arts and Sciences, and in 1875 he be- 

 came Fellow of the National Academy. 



In his scientific researches Professor Hyatt has been exceedingly 

 active. He first published an article upon *' Beatrecia," a large and 

 curious fossil first described as a tree, and then successively placed by 

 different authors in all the several classes of Invertebrata, till at last, 

 by another paper of Professor Hyatt's, it has been again shifted to 

 the Protozoa. In 1866 appeared his " Observations on Polyzoa," an 

 article of importance at that time, upon the structure of this curious 

 and beautiful group of fresh-water animals. This was followed, in 

 1867, by an article upon "Parallelism between Different Stages of 

 Life in Tetrabranchiata," and in 1872 by an important paper upon 

 the " Fossil Cephalopods of the Museum of Comparative Zoology." 

 In these and other subsequent pamphlets upon the fossil cephaloi^ods 

 he has steadily endeavored to elaborate a practical demonstration of 

 the theory of evolution, and to illustrate the laws by which this has 

 taken place among the cephalopods. One of his best works is " Re- 

 vision of North American Poriferae," the only work on North Ameri- 

 can commercial sponges, and one which is recognized throughout the 

 world as one of the finest monographs of Porifera ever published. 

 The field was entirely unexplored, and the group one of the hardest 

 in the animal kingdom — so hard, in fact, that few naturalists have ever 

 touched it. In his " Effects of Gravity uj^on Forms of the Shells of 

 Planorbis," Professor Hyatt shows how important the action of 

 gravity has been in modifying the shape of the shells of Ammonites 

 and other animals, pointing out many cases where it has undoubtedly 

 fundamentally affected the forms of shells and the growth of the parts 

 and organs of the animals, and produced specific and generic modifica- 

 tions. Some of Professor Hyatt's most important theories have been 

 set forth in an extensive paper, entitled " Genesis of Tertiary Species 

 of Planorbis at Steinheim." It covers one hundi-ed pages, quarto, and 

 has nine plates. Professor Hyatt went to Steinheim with the intention 

 of making additional observations and proving Ililgendorf's theory of 

 the evolution of Planorbis, which was then recognized by paleontologists 

 in Europe as the only positive demonstration of the theory of evolution. 



