diameter, releasing them into seawater after the trochophore larvae 

 have developed. 



The size of mature oocytes in the study by Curtis (1977) in 

 Greenland was similar to that found for H. imbricata in the Ise- 

 fjord, Denmark, where they measured 150 /xm (Rasmussen 1956). 

 In the Isefjord. the species spawns in winter and produces typical 

 trochophore larvae with a pelagic phase after intial brooding under 

 the female elytra. However, egg size for H. imbricata is variable 

 and Rasmussen cited other observations ranging from 50 to 76 fim. 

 It is postulated that such small ova probably give rise directly to 

 pelagic planktotrophic larvae without any early protection of the 

 embryos. 



Daly (1972, 1974) stated that H. imbricata is capable of complet- 

 ing its life cycle in a single year in British waters, where all survi- 

 vors of a new year class apparently spawned at the end of their first 

 year. The smallest specimens in the population at the time had 

 reached a size of 9 mm, which closely coincides with the minimum 

 size reported for the Greenland population (Curtis 1977). Each 

 female underwent two successive spawnings, about 1 mo apart, 

 releasing large oocytes (140-160 ^m) to be brooded beneath the 

 elytra. 



Sthenelais limicola (Ehlers, 1864) 



DESCRIPTION: A burrowing form, with dorsal surface covered 

 with translucent elytra (scales). Length to 100 mm, width including 

 setae to 4 mm, segments to 200 or more (Pettibone 1963). 



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Figure 28.— Distribution and abundance of Sthenelais limicola in the Ne« York 

 Bight apex. 



DISTRIBUTION: Gulf of St. Lawrence to North Carolina, Nor- 

 way to Mediterranean. Adriatic, South and West Africa (Pettibone 

 1963). 



HABITAT: Collected on sandy or muddy bottoms from the inter- 

 tidal to 770 m (Pettibone 1963; Gardiner 1975). Kinner (1978) 

 found Sthenelais limicola to be one of the dominant species in sand 

 on the inner and mid-shelf from Georges Bank to Cape Hatteras. In 

 the New York Bight apex, 5. limicola was collected in all sediment 

 types, usually in low numbers. It was most abundant in medium to 

 fine, low organic sands (Fig. 28; Table 1). 



FEEDING ECOLOGY: Members of this family (Sigalionidae) 

 are. in general, burrowing predators (Day 1967). They are eaten by 

 cod, flounder (Mcintosh 1900), and haddock (Wigley 1956). 



REPRODUCTION AND GROWTH: No information specific 

 to the genus Sthenelais is available. Brooding among the Siga- 

 lionidae has not been reported as it has been for other scale worms 

 of the family Polynoidae (Schroederand Hermans 1975). 



Glycera dibranchiata Ehlers, 1868 



DESCRIPTION: Commonly known as the "bloodworm," a 

 commercially valuable bait worm. Active burrowers; length to 510 

 mm (Klawe and Dickie 1957). 



DISTRIBUTION: Gulf of St. Lawrence to West Indies, Gulf of 

 Mexico, central California to the Pacific coast of Mexico (Petti- 

 bone 1963; Hartman 1969; Gardiner 1975). 



HABITAT: Intertidal to 400 m. Found at low water and collected 

 in deeper water on bottoms of sand, mud, mud mixed with gravel, 

 rocks, and particularly, mud rich in detritus. Found on more 

 exposed beaches than Glycera americana, especially where cur- 

 rents flow swiftly; found in brackish waters and tidal estuaries (Pet- 

 tibone 1963; Gardiner 1975). From Cape Cod to Cape Hatteras, 

 Kinner (1978) found Glycera dibranchiata to be a dominant mid- 

 shelf sand species. Kinner and Maurer (1978) regularly collected 

 G. dibranchiata in Delaware Bay. with increasing numbers associ- 

 ated with sediments containing increasing amounts of silt-clay; 

 Pearce. Caracciolo. Halsey, and Rogers (1977a) also found it to be 

 abundant in New York-New Jersey outer continental shelf samples. 



In the New York Bight apex, G. dibranchiata was found in 

 depths ranging from 9.6 to 33.1 m. It was present in all grades of 

 sand (none was found in silt), but was most abundant in fine sand. 

 Glycera dibranchiata was absent or occurred in low numbers ( 10/ 

 m : ) in sediments having the highest organic content; it was most 

 abundant in low organic sediments (Fig. 29: Table 1). 



FEEDING ECOLOGY: Glycera spp. possess a strong, muscular, 

 clavate proboscis, armed distally with four equally spaced large 

 jaws. The proboscis serves glycerids as an organ of special sense, 

 with a remarkably well-developed nervous system (Gravier 1898). 

 Both Day (1967) and Fauchald (1977) agreed that glycerids appear 

 to be mainly carnivorous, for very little sand is ever found in the 

 gut: however, Sanders et al. (1962) believed glycerids to be omni- 

 vores. Klawe and Dickie (1957) classified them as detritus feeders 

 and Adams and Angelovic (1970), in a feeding experiment using a 

 radioactive tracer, carbon-14, also found detritus to be an important 

 food source. Studies on Glycera alba showed them to be preda- 

 ceous (Ockelman and Vahl 1970). possesing both proteolytic and 



20 



