HABITAT: Intertidal to 3,445 m. Found at low water on bottoms 

 of mud, muddy sand, gravelly mud, and shifting sand. Collected on 

 bottoms of sticky and soft mud, silty clay, various combinations of 

 mud, sand, gravel, pebbles, stones, worm tubes, shells, and detri- 

 tus (Pettibone 1963). In Kinner's (1978) study from Cape Cod to 

 Cape Hatteras, Lumbrineris fragilis was a dominant species in sand 

 on the inner and mid-shelf, and in silt-clay on the mid-outer shelf 

 and slope. Greatest numbers occurred in medium, well-sorted 

 sands. Steimle and Stone (1973) found L. fragilis to be a dominant 

 species in medium-coarse grain sand off southwest Long Island. 

 Similarly, in the New York Bight apex, L. fragilis, although present 

 in all grades of sand, was most concentrated in medium-coarse sand 

 with an organic content of <4%. It was absent from most stations 

 with high organic contents or was present in very low numbers 

 (10-20/m : ) (Fig. 45; Table 1). 



Within the Lumbrineris population at Disko Fjord, Greenland, 

 Curtis ( 1977) observed that large oocytes (200-250 jtm) of L. fragi- 

 lis were present at all times of the sampling interval (1959-60) indi- 

 cating that the species produces larvae having a direct 

 development. Yet, although most specimens were large and pre- 

 sumably mature, only about 20% of those sampled were involved 

 in gametogenesis. This suggests that a large segment of this popula- 

 tion did not reproduce. Thorson (1946) also considered that L. fra- 

 gilis has a direct larval development as did Pettibone (1954), who 

 collected nonpelagic larval lumbrinerids. tentatively identified as 

 L. fragilis, at Point Barrow, Alaska, during September. These lar- 

 vae were found in mucus masses, sometimes attached to the tuni- 

 cate, Bohenia echinata. 



Lumbrineris tenuis Verrill, 1873 



FEEDING ECOLOGY: L. fragilis, as other lumbrinerids, is con- 

 sidered a carnivore. Blegvad (1914) listed the gut content for L. fra- 

 gilis as polychaetes. ophiuroids, nemerteans, small crustaceans, 

 and bivalves. 



Lumbrineris fragilis has been found as a prey item in the stom- 

 achs of cod and haddock (Pettibone 1963). 



Tyler (1973) found no seasonal trend in caloric value for Cana- 

 dian specimens; the annual mean was 4,565 g cal/g dry weight. 



REPRODUCTION AND GROWTH: L. fragilis has been 

 observed containing large eggs in August in the Woods Hole. 

 Mass., area (Pettibone 1963). 



DESCRIPTION: Body threadlike, length to 150 mm, width to 1 

 mm, segments to 200 (Pettibone 1963). 



DISTRIBUTION: 

 (Gardiner 1975). 



Maine to North Carolina, Gulf of Mexico 



HABITAT: Intertidal to abyssal depths. Found at low water bur- 

 rowing in mud and sand beneath stones, in compact sand mixed 

 with mud, and in sandy mud flats close to the low water mark. Col- 

 lected on bottoms of gravel with shells, mud, compact mixtures of 

 mud and sand, various combinations of mud, sand, gravel, with 

 sponges, shells, and amphipod and worm tubes. Common among 



Figure 45.— Distribution and abundance of Lumbrineris fragilis in the New 

 York Bight apex. 



Figure 46. —Distribution and abundance of Lumbrineris tenuis in the New York 

 Bight apex. 



32 



