320 THE AQUARIAN NATURALIST. 



quarters of an inch in length, by half an inch wide 

 towards the middle ; it is beset by several rows of 

 short, spinous papillae, placed towards the extremity, 

 which is terminated by a circle of them. The largest 

 row is composed of at least thirty of these dental 

 structures. The proboscis reflects light, as though it 

 were composed of a hard substance, which it is not 

 it is protruded when the animal is in a state of ex- 

 treme weakness, and at length becomes incapable of 

 being withdrawn. 



The colour of this Nereis is nearly white, with a 

 line down the middle of the back ; but no figure can 

 do justice to its beauty. It is quite possible, indeed, 

 for a person to study these elegant creatures in 

 engravings, and thus imagine that he has acquired a 

 tolerably exact idea of their structure, without having 

 the slightest conception of the interest which attaches 

 to an inspection of their living forms and active evo- 

 lutions. 



The Nereis margaritacea swims by a serpentine 

 motion, in a horizontal direction, with great violence 

 and rapidity. When at rest, it lies among the sand 

 close at the bottom of the vessel, with its head par- 

 tially protruded. It is extremely timid, and, if near 

 the top of the tank, retreats downwards upon the 

 slightest alarm. If its site is about to become dry, 

 the body twists, as if preparing to leap. 



This animal frequents the sands of the sea-shore 

 somewhat lower than the point of half- tide. 



PHYLLODOCE LAMINOSA. " Laminated Nereis." 

 But the most magnificent Nereis inhabiting our 



