DORSIBRANCHIATA. TUBICOLA. 



in Europe. They are preserved for a long time by packing them 

 in moist earth or mud. On the approach of cold weather, they 

 bury themselves in mud at the bottom of ponds, and pass the win- 

 ter in a state of lethargy, and regain their activity in the spring. 



14. The ORDER OF DORSIBRANCHIATA or erratic Annelidans 

 are the most complicated in their organization of all, animals of 



this class. The head is almost always distinct from 

 the body, and is provided with a certain number of 

 antennae ; we see there also one or two pairs of eyes, 

 in form of black or variously coloured spots (Jig. 79). 

 The mouth is provided with a protractile trunk, the 

 length of which is sometimes very considerable, and 

 at -its extremity we often find two or more pairs of 

 horny jaws. Generally, on each side of the neck 

 there is a certain number of tentacular cirri, append- 

 ages analogous to antennaa, and each ring has 

 attached to it a pair of legs, varying in structure in 

 the different genera : they are often composed, each 

 of two tubercles, one placed on the dorsal, and the 

 other on the ventral arch of the ring, and studded on 

 top with a packet of setae. Nothing can exceed the 

 splendour of the colours which ornament some of 

 these fasciculi of hairs ; they yield, indeed, in no 

 respect to the most gorgeous tints of tropical birds or 

 the brilliant decorations of insects : green, yellow, 

 and orange, blue, purple, and scarlet, all the hues 

 of the rainbow play upon them with the changing 

 light, and shine with the metallic effulgence only 

 comparable to that which adorns the breast of the humming- 

 bird. 



15. These anne'lidans walk and swim very well, but neverthe- 

 less, commonly live under stones, among shells, or buried in the 

 sand ; a kind of mucus which exudes from them forms a tubular 

 sheath which they inhabit. They all live in the sea. 



The ARENICOLA, the APHRO'DITA, the EU'NICE, &c., are some 

 of the genera. 



16. The ORDER OP TUBICOLA comprises anne'lides which have 

 no distinct head, nor jaws, nor eyek, nor antennas, but the anterior 

 extremity of the body is furnished with a great number of ap- 

 pendages, some of which constitute bran'chiae, and others for the 

 prehension of food, or for locomotion. Their legs are but slightly 

 projecting, and only assist them in rising or descending in the 



Fig. 79. 



EUNICE. 



14. What are the characters of dorsibranch anne'lidans? 



15. What are the habits of dorsibranch anne'lidans ? 



16. How is the order of Tubicola characterized? 



