160 U.S. NATIONAL MUSEUM BULLETIN 227 



ing only as bisexual heteronereids, spawning at the surface and 

 producing planktogenic larvae; the latter reproducing as protandric 

 hermaphroditic atokous individuals, spawning within the tube and 

 producing nonpelagic nereidogenic larvae. 



Rarely has viviparity been reported, perhaps as an accidental 

 consequence of the unusually long survival of sperm in the body cavity 

 of "hermaphroditic females," and of self-fertilization taking place. 



Material examined. — Numerous specimens from Massachusetts 

 (Buzzards Bay, Vineyard Sound on gulf-weed; Martha's Vineyard, 

 Gay Head, Lagoon Pond; Woods Hole region. Eel Pond, Fisheries 

 Dock and Steamship Wharf, Nobska, Stony Beach, North Falmouth; 

 Ehzabeth Islands; Cape Cod Canal; Wellfleet, Cape Cod), Rhode 

 Island (off Newport), Long Island Sound, Maryland (lower half 

 Chesapeake Bay, southwest Ocean City, Foxhill Levels, Assateague 

 Island, Chincoteague Bay), Georgia, North Carolina (Beaufort), 

 Puerto Rico (Caballo Blanco and Mona Island Reef, Parguera, 

 heteronereids, M. J. Allen), Barbados (Pelican Island). 



Distribution. — A cosmopolitan form with wide geographic 

 distribution in warm seas. Massachusetts (Cape Cod), south of 

 Newfoundland (surface) to Florida, Gulf of Mexico, West Indies, 

 Brazil, Iceland, Faroes, Scandinavia to France, Mediterranean, 

 Iranian Gulf, Red Sea, Indian Ocean, central Pacific (Bikini), West 

 and South Africa. In low water to 71 fathoms; young and sexual 

 epitokes in surface waters; all stages in floating seaweed (Sargassum). 



Genus Nereis Linnc, 1758 



Type (designated by Hartman, 1949): Nereis pelagica Linne, 1758. 



Subgenus Neanthes Kinberg, 1866; enaend. Hartman, 1940 



Type (designated by Hartman, 1959a): Neanthes vaalii Kinberg, 

 1866. 



Subgenus Hediste Malnigren, 1867 



Type (monotypy): Hediste diversicolor (O.F. Miiller, 1776). 



In Neanthes Kinberg, as originally defined and followed by Fauvel 

 and others, all the areas of the proboscis are equipped with hard and 

 discrete paragnaths, while in Nereis Linne, sensu stricto, 1 or several 

 groups of paragnaths are lacking. The distinction may fail when 

 considering the variability within a single species, as has been shown 

 for Nereis virens by Tiu-nbull (1876) and Berkeley and Berkeley 

 (1954). Based on the types, the definitions of the genera have been 

 revised by Hartman (1940, pp. 219-220). It seems advisable to 

 denote the close relationship of the North Atlantic A^. diversicolor 

 O.F. MiiUer, A^". limnicola Johnson from the North American Pacific 



