THE COASTS OF SICILY. 213 



Medusidoe, there is only a single opening, which is 

 alternately employed for both purposes. 



One of the most important results of M. Edwards's 

 researches on the Beroid^e has been the recognition 

 of their nervous system. The existence or absence 

 of this apparatus in the lower animals has always 

 been a much-disputed question. Some of the most 

 illustrious naturalists have wholly denied its pre- 

 sence ; and Cuvier, although he did not go quite so 

 far, undoubtedly inclined towards these views, as he 

 suffered them to influence him in the establishment 

 of his fourth division of the animal kingdom — that of 

 the Radiata. The admirable discoveries of Ehren- 

 berg have led, in our own day, to the correction of 

 these somewhat premature views ; and very probably 

 observers may sometimes have been led from a 

 natural reaction to admit rather more in theory than 

 the reality warranted them in concluding. The 

 importance of the question and the authority of the 

 illustrious men who profess such widely different 

 opinions in reference to this question, combine to 

 impart the highest value to every well-established 

 fact that bears upon the subject. Let us not omit 

 to mention, then, that M. Edwards has discovered 

 in the Beroidse a central nervous system, or a kind 

 of brain, from whence issue threads, which are 

 distributed over the Avhole body. These facts in 

 some respects confirm the less completely elaborated 

 results which Ehrenberg obtained from his observa- 

 tions on the Medusae. It would thus appear that 

 the Beroidas, and very probably also the Medusae, 

 actually possess that important organic system which 



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