xxvi 



the animals thus obtained to the fossil casts. This essay was followed 

 by his ' Etudes critiques sur les Mollusques fossiles.' 



At about the same period his attention was attracted to the study of 

 the Radiata and of Embryology. Under his direction experiments were 

 conducted through several seasons on artificially fecundated eggs of the 

 Swiss White-Eish, Coregonus pcdcea^ by Karl Vogt ; and in 1842 the 

 account was published as a part of the ' Poissons d'eau douce.' It is 

 worth noting that the GrOA^ernment of jNTeuf chatel in that same year issued 

 directions to fishermen for the impregnation of fish eggs. 



Agassiz had turned his attention to Echinoderms almost as early as to 

 Eishes. In 1834 he had published a paper, " Ueber die aussere Organisa- 

 tion der Echinodermen," in the 'Isis;' and in 1839 he published an admi- 

 rable anatomical essay on Astropliyton. He prosecuted these investigations 

 with extraordinary zeal, and was aided by Desor. Between the years 1838 

 and 1842 appeared his " Monographies d'Echinodermes vivans et fossiles." 

 Erom the beginning of his studies he felt the need of having a systematic 

 record of what specialists in palaeontology and zoology were doing. He 

 commenced an index, arranged alphabetically and zoologically, of all the 

 generic names introduced into science from the time of Linnaeus ; this was 

 accompanied by the proper bibliographical references, and formed the com- 

 mencement of the reform in zoological nomenclature, which was becoming 

 entirely unmanageable. The work was revised and enlarged by 22 of his 

 colleagues, each of whom took a group. The whole was completed in 

 1846, under the name of " Komenclator Zoologicus." The bibliographical 

 part was subsequently published by the Eay Society ; it was edited by 

 the late Mr. Strickland. 



In 1845, on the suggestion of Lyell, Agassiz had been invited by Mr. 

 John A. Lowell to come to Boston and deliver lectures before the Lowell 

 Institute. About the same time, the King of Prussia had been persuaded 

 by Humboldt to present him with a sum of money in aid of a Scientific 

 Mission to America. Agassiz was thus induced to cross the Atlantic 

 Ocean in 1846; and when in 1847 Mr. Abbot Lawrence olfered to found 

 for him a professorship of Zoology and Oeology in the Scientific School 

 at Harvard College, he obtained his release from his engagements in 

 Europe and accepted the position. 



In 1848 he explored Lake Superior, and his account of the observations 

 made there was edited by Mr. J. Elliot Cabot. At the request of Prof. Bache, 

 of the Coast Survey, he passed the ^dnter of 1850 among the Elorida 

 Beefs, where he determined the law of growth by which that peninsula 

 has gradually extended southwards by the successive formation of reefs, 

 keys, and mudflats. 



In 1852 he was appointed Professor of Comparative Anatomy at the 

 Medical College of Charleston. This appointment did not interfere with 

 his duties at Cambridge, his lectures at Charleston being delivered during 

 the winter vacations of Harvard College. He remained there for only 



