ON RADUTES IN GENERAL. 3 



Pacific, and giving an account of the Coral islands, the many 

 memoirs of Milne Edwards and Haime, and the great works of 

 Quoy and Gaimard, and of Dana, are the chief authorities upon 

 Polyps. In tlie study of the European Acalephs we have a long 

 list of names high in the annals of science. Eschscholtz, P(*ron 

 and Lesueur, Quoy and Gaimard, Lesson, Mertens, and Huxley, 

 have all added largely to our information respecting these ani- 

 mals, their various voyages having enabled them to extend their 

 investigations over a wide field. No less valuable have been the 

 memoirs of Kolliker, Leuckart, Gegenbaur, Vogt, and Haeckel, 

 who in their frequent excursions to the coasts of Italy and France 

 have made a special study of the Acalephs, and whose descrip- 

 tions have all the vividness and freshness which nothhig but 

 familiarity with the living specimens can give. Besides these, 

 we have the admirable works of Von Siebold, of Ehrenberg, 

 the great interpreter of the microscopic world, of Steenstrup, 

 Dujardin, Dalyell, Forbes, Alhnan, and Sars. Of these, the four 

 latter were fortunate in having their home on the sea-shore with- 

 in reach of the objects of their study, so that they could watch 

 them in their living condition, and follow all their changes. The 

 charming books of Forbes, who knew so well how to popularize 

 his instructions, and present scientific results under the most at- 

 tractive form, are well known to English readers. But a word on 

 the investigations of Sars may not be superfluous. 



Born near the coast of Norway, and in early life associated 

 with the Church, his passion for Natural History led him to em- 

 ploy all Ms spare time in the study of the marine animals im- 

 mediately about him, and his first papers on this subject attracted 

 so much attention, that he was offered the place of Professor at 

 Christiania, and henceforth devoted himself exclusively to scien- 

 tific pursuits, and especially to the investigation of the Acalephs. 

 He gave us the key to the almost fabulous transformations of 

 these animals, and opened a new path in science by showing the 

 singular phenomenon of the so-called " alternate generations," 

 in which the difierent phases of the same life may be so distinct 

 and seemingly so disconnected that, until we find the relation 

 between them, we seem to have several animals where we have 

 but one. 



