THE EUROPEAN SEAS. 



145 



Medusa, of translucent gelatine, fringed with a 

 double row of cilia, which reflect lines of all deli- 

 cate tints of light as it moves through the waters. 



All these varied forms, as they are seen from a 

 vessel's side, drifting along on calm, sunny days, 

 suggest that they must be the sport of winds and 

 currents, and be so wafted into all zones or latitudes. 

 But such is not the case ; and whether it is that, 

 except on these calm and sunny days, they keep 

 below, and so are not affected by the agents that 

 bring southern forms of plants and animals into 

 our British seas, still it is the case that the 

 characteristic Lusitanian forms seldom reach us. 

 It will be sufficient to compare the series of forty- 

 five Naked-eyed Medusa, described by Ed. 

 Forbes as British, (a list which, for this purpose, 

 might be curtailed,) with about a like number from 

 the Mediterranean, to be satisfied how distinct are 

 the Medusae of these two regions. With respect to 

 the Arachnodermata generally, the laws of geogra- 

 phical distribution are not only rigidly observed, 

 but have also been somewhat closely drawn. 



The Mediterranean Bryozoa require a somewhat 

 detailed enumeration and notice. These are the 

 forms, some of which, though they will appear 

 under new names, have been long and familiarly 

 known to our sea-side collectors as Corallines, but 

 whose claim to take the higher rank of Molluscs 

 has become universally admitted. Like some of 

 the Polyps, these animals live associated in colonies, 



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