ANNELIDS. 



65 



bearing the name of Serpula (Fig. 40). " If, while the con- 

 tained animals are alive, they be placed in a vessel of sea- 

 water, few spectacles are more pleasing than that which they 

 exhibit. The mouth of the tube ~ 



is first seen to open by the raising 

 of an exquisitely constructed door, 

 and then the creature cautiously 

 protrudes the anterior part of its 

 body, spreading out, at the same 

 time, two gorgeous fan-like ex- 

 pansions of a rich scarlet or purple 

 colour, which float elegantly in the 

 surrounding water, and serve as 

 branchial or breathing organs."* 



The minute convoluted shells 

 (spirorbis), which are seen like 

 whitish specks upon almost every 

 piece of sea- weed, exhibit an instance 

 no less striking of the same exquisite 

 design, the same admirable adapta- 

 tion of means to the required end. 



The fourth tribe present, in their Fig. 40. GROUP OF SERPULJE. 

 habits, a complete contrast to the last. They are formed for 

 locomotion, and some among them can swim with considerable 

 swiftness (Fig. 41). The roving life they lead has induced 



Fig. 41.- NEREIS. 



Milne Edwards, the eminent naturalist, whose classification we 

 have followed, to bestow on them the characteristic appellation 

 of Errantes.^ 



* Jones's Natural History of Animals, page. 313. 

 f Recherches pour Servir a 1'Histoire Naturelle du Littoral de la 

 France. Paris, 1834. 



