NO. 1 HARTMAN : POLYCHAETOUS ANNELIDS 177 



Genus DRILONEREIS Claparede 

 Type D. filum (Claparede) 



Drilonereis is nearly related to Arabella Grube but differs most nota- 

 bly in its proboscidial parts and parapodial structures. The mandibles are 

 typically more reduced, or even absent {D. nuda Moore) ; the maxillary 

 carriers are proportionately smaller, the unpaired piece sometimes very 

 short ; maxilla I is usually falcate, but sometimes also dentate at its base ; 

 the other maxillary pieces, especially II, may be toothed, and III and IV 

 are often reduced to sharp fangs ; maxilla V is usually reduced or absent. 

 Parapodia are uniramous, provided with only simple, bilimbate setae, 

 and a stout, projecting aciculum. The dorsal cirrus is very tiny or absent, 

 and ventral cirri are absent. The prostomium is usually greatly depressed, 

 spatulate, rarely provided with eyespots. 



The form of the body is often very long, slender, attenuate, rarely 

 much larger. Crossland (1924, p. 57) records a length of 430 mm and 

 width of 3.5 mm for D. major, from the Red Sea; typically species are 

 much smaller. 



More species have been attributed to this genus from the Western 

 Hemisphere than from all the rest of the world taken together. It is 

 difficult or even impossible to distinguish some of them from their de- 

 scriptions, and their affinities to one another are obscure. A revision of 

 the genus is needed. These include the following species, 



1. D. attenuata (Treadwell) (1911, p. 5) from Florida. (This was 

 originally described as Aracoda, later referred to Drilonereis 

 [Treadwell, 1921, p. 107] ; but, since it is said to lack heavy pro- 

 jecting acicula and the prostomium is oval, with eyespots, its allo- 

 cation to this genus is still in doubt.) 



2. D. brunnea Treadwell (1921, p. Ill) from the West Indies. 



3. D. canadensis Mcintosh (1903, p. 161) from the Gulf of St. 

 Lawrence, Canada. 



4. D. debilis (Ehlers) (1887, p. 113) from Florida. 



5. D. falcata Moore, p. 179. 



6. D. filum (Claparede), p. 180. 



7. D. heterognatha Grube (1878, p. 101) from Desterro [Florian- 

 opolis], Brazil. 



8. D. intermedia Grube (1878, p. 100) from Desterro, Brazil. 



9. D. longa Webster (1879, p. 240) from Virginia, p. 178. 



10. D. magna Webster and Benedict (1887, p. 725) from Maine, 

 p. 178. 



11. D. nw^a Moore, p. 178. 



