179 



CHAPTEE IX. 



SEA-WORMS. 



GENERAL DESCRIPTION. — CLASSIFICATION. — OUT-DOOR STUDIES. — SERPULA 

 CONTORTUPLICATA. — AJIPHITRITE /EGEANA. — SABELLA TUBULARIA. — SA- 

 BELLA ALVEOLATA. — TEREBELLA CONCHILEGA. — NEREIS BILINEATA. — 

 APHRODITE ACULEATA. 



Marine Annelids, or Sea-TFormSj belong to the same 

 class as Earth- Worms and Leeches, many of whose cha- 

 racteristics they possess in common. All are curious in 

 their structure and habits, while some are extremely beau- 

 tiful. They are all more or less elongate and cylindrical 

 in form, and their bodies are capable of contraction and 

 elongation. They derive their class appellation from the 

 fact that the body is composed of annular joints, or rings, 

 united by a flexible skin. The first joint being variously 

 modified as a head, and the last as a tail ; the intermediate 

 ones are generally very much alike. The heads of some 



