720 ALPHEUS HYATT. 



For a number of years Dr. Hyatt was engaged in a study of the origin 

 and lines of evolution of the land shells peculiar to the Hawaiian Islands, 

 on which the Rev. John T. Gulick had already (1887-1890) made such 

 interesting and suggestive studies. Hyatt had presented several communi- 

 cations to scientific societies, showing the progress made in his work. His 

 beautiful model of the islands, and arrangement of the actual shells fas- 

 tened to the surface of the model, with cords of different colors showing 

 the lines of migration and corresponding segregations and consequent dif- 

 ferentiation of the specific forms, gave promise of the most valuable and 

 fruitful results. He was planning to make a journey to the Hawaiian 

 Islands in March of the present year, when death overtook him. But 

 the results of his long continued labors will, it is hoped, not be lost to 

 science, as arrangements were made previous to his death for their com- 

 pletion by a capable hand. 



The first paper of a general nature which young Hyatt published * 

 contained the germ of his chief life-work. It gave some of the results of 

 six years' study on fossil Cephalopods, and was on the parallelism existing 

 between the different stages of life in the individual and those of the 

 tetrabranchiate Cephalopods as a group. It was published in 1866, the 

 same year in which appeared Haeckel's " Generelle Morphologie," which, 

 he (Haeckel) says, constituted the first attempt to apply the general doc- 

 trine of development to the whole range of organic morphology (anatomy 

 and biogenesis). Although both of the Haeckelian principles of palingene- 

 sis and cenogenesis, with all their evolutional implications, were stated 

 with considerable fullness by Fritz MtiUer in his " Fiir Darwin," pub- 

 lished in 1864, Hyatt attempted to show that the life of the individual 

 displays, to use his own words, " during its rise and decline, phenomena 

 correlative with the rise and decline of the collective life of the group 

 to which it immediately belongs." In this memoir he carried out and 

 greatly amplified D'Orbigny's views, to which he gives the fullest credit, 

 as to the changes of the larger number of Ammonites from larval, or 

 to use his own term, nepionic, to adult, and from adult to senile stages. 

 Tlie theme, so often discussed by Agassiz before his students, that the 

 development of the individual is an epitome of that of the order or class 

 to which it belongs, with the later vital addition by F. Muller and by 

 Haeckel of the evolution by actual descent, the principle now being 



* " On tlie Parallelism between the Different Stages of Life in the Individual and 

 those in the Entire Group of the Molluscous Order Tetrabranchiata." Memoirs 

 Boston Soc. Nat. Hist, I. 1866. 



