THE COASTS OF SICILY. 221 



leaf, covered by Polypes crowded together like 

 the different blades of a tuft of grass. Yet it 

 would actually appear, from the discoveries of 

 MM. Siebold*, Sarsf, Loven, Dujardin, Van 



* Carl von Siebold, Professor at the University of Munich, has 

 contributed more perhaps than any other naturalist in Germany to 

 diffuse amongst his countrymen a taste for the study of the In\er- 

 tebrata. He has not only published a series of excellent reports on 

 the progress of our knowledge of the lower animals, but has also 

 largely contributed numerous observations to this department of 

 science. He was the first who seems to have recognised the singular 

 metamorphoses of the Medusas, and the phenomena which accom- 

 pany the formation of the embryo in the Planarias. In the 

 admirable chapter on the development of intestinal worms which 

 he contributed to Burdach's great work on Physiology, he opened 

 a path of inquiry which has since been followed by many successive 

 investigators, and which has finally led to the solution of a problem 

 which had almost been regarded as insoluble. But of all his works 

 the most useful, and at the same time the one most generally 

 known, is the Manual of Comparative Anatomy, which he published 

 conjointly with Stannius, and in which he has incorporated all the 

 facts at present known in relation to the Invertebrata. It would be 

 impossible to condense a larger number of facts, and more valuable 

 data in a smaller number of pages, and hence this manual has been 

 regarded as a standard work from its first appearance. It has been 

 translated both into French and English. 



f Sars, a clergyman at Bergen in Norway, has availed himself of 

 the advantages afforded by his vicinity to the sea for studying the 

 lower marine animals, to whose mode of development he has 

 devoted the most persevering attention, together with a remarkable 

 amount of learning and ingenuity. We owe to him some of the 

 most curious and unexpected discoveries by which this branch of 

 science has been enriched. Amongst these, we may mention the 

 facts which he has ascertained in reference to the metamorphoses of 

 the Nudibranchiate Gasteropods, and with regard to the early condi- 

 tion and subsequent metamorphoses of several of the Echinoderms 

 a subject which has been subsequently investigated with special care 

 and ingenuity by the physiologist Miiller. Sars shares with 

 Siebold the honour of having discovered the remarkable mode of 

 propagation in the Medusae, which he followed through all its phases. 



