288 NOVEMBER. 



its breathing organs scarcely available, if these were 

 placed, as in most Annelida, in pairs on the body- 

 segments. They are therefore much modified, and that 

 not only in position but in form. They consist of most 

 elegant comb-like filaments, richly coloured, arranged 

 in two rows around the front extremity, one row on 

 each side of the mouth. They are graduated in length, 

 and are so affixed, that, where the rows meet behind, 

 they can be thrown-in, so that a vertical view of the 

 circular coronet shows a great sinus in it. These bril- 

 liant gill-tufts form the most attractive feature in these 

 elegant Worms, and are individually most exquisite 

 examples of mechanical contrivance. Examined under 

 a low microscopic power, they present a most charming 

 spectacle. Each filament consists of a pellucid cartila- 

 ginous stem, from one side of which springs a double 

 row of secondary filaments like the teeth of a comb. 

 Within both stem and filaments the red blood may be 

 seen, with beautiful distinctness, driven along the artery, 

 and back by the vein (which are placed close side by 

 side) in ceaseless course, constituting a very striking 

 spectacle. 



The exterior of these organs is set with strong cilia, 

 so arranged that the water- current is vigorously driven 

 upward along one side of the filament, and downward 

 along the other. Yet the combined result of all the 



