them in a drop of seawater, immobilizing them 

 with gentle pressure on a cover slip, and blot- 

 ting off the excess water. Larger individuals 

 are immobilized by mounting them in a drop 

 of gelatine solution, which is just ready to set, 

 and placing a cover slip over the mountant using 

 gentle pressure. Details of the alimentary canal, 

 pharyngeal glands, and peptonephridia of the 

 Enchytraeidae can be seen more readily in living 

 animals. 



Because most marine oligochaetes are poorly 

 known and because many have been described 



only within the last 6 years, the known distribu- 

 tion of many species merely reflects the distribu- 

 tion and collecting activities of a few specialists. 

 Therefore, the scope of this work is expanded 

 somewhat to include species which are known 

 from the entire east coast of North America. 

 It is hoped that this introduction to the marine 

 Oligochaeta will stimulate further interest in this 

 important class and be instrumental in amassing 

 more information on their ecology and distribu- 

 tion. 



KEY TO THE MARINE OLIGOCHAETA OF THE EAST COAST OF 



NORTH AMERICA 



The first five couplets of the key, which strictly apply only to those species included in this 

 key, are designed so that immature Oligochaeta may be identified to their family; immature Naididae 

 and Enchytraeidae can usually be identified to species but immature Tubificidae usually cannot. 



1 Hair setae present 2 



1 Hair setae absent 3 



2 (1) Dorsal setae absent on segments II to V. 

 Eyes usually present. Male and sperma- 

 thecal pores situated on segments VI and 

 V respectively NAIDIDAE (in part).' . . 9 



Figure 3. — Generalized naidid; lateral view, anterior segments, 



2 (1) Dorsal setae present from seg- 

 ment II onwards. Eyes always 

 absent. Male and spermathecal 

 pores situated on segments XI 

 and X respectively TUBI- 

 FICIDAE (in part) 12 



Figure 4. — Generalized tubificid; lateral view, anterior segments. 



3 (1) Setae with bifid ends, at least in some parts of the body. Body wall generally thin, 

 imparting fragile appearance to worm. Genital pores on segments V and VI, or X 

 and XI 4 



3 (^) All setae with simple-pointed or rounded ends. Body wall generally thick, robust, im- 

 parting rigid appearance to worm. Male pores on segment XII or XVIII 5 



"In part" indicates that only part of a taxon will key out at that point. 



6 



