Figure 26. — Distribution and abundance of Eteone tonga in the New York Bight 



apex. 



row 1924). Rasmussen(1956, 1973) reported observing large num- 

 bers of young E. longa swimming in a warmer (12°C) backwater of 

 a creek in East Jutland (Denmark), while mature adults in an adja- 

 cent colder portion (10°C) remained in the mud, indicating a possi- 

 ble correlation between temperature and spawning. 



On the basis of living material, Rasmussen (1973) reported that 

 E. longa is mature at a length of 20 mm (males) or 30 mm (females) 

 in the Isefjord. 



Harmothoe (Lagisca) extenuata (Grube, 1840) 



DESCRIPTION: A crawling form, dorsal surface covered with 

 elytra (scales). Body depressed, length to 74 mm, width including 

 setae to 20 mm. segments 37-47. 



DISTRIBUTION: Widely distributed in the Arctic. Also Ice- 

 land. Faroes, Norway to Mediterranean and Adriatic. Hudson Bay 

 to Chesapeake Bay. North Carolina, Bering Sea to southern Cali- 

 fornia, north Japan Sea, South Africa (Pettibone 1963; Gardiner 

 1975). 



HABITAT: Harmothoe extenuata appears to have great powers 

 of dispersal and adaptation, occurring from the intertidal to 1,830 

 m; euryhaline. It is often associated with two other common north- 

 ern polynoids. Lepidonotus squamata and Harmothoe imbricata 

 (often confused with H. extenuata). Intertidally, it is found under 

 rocks, in tide pools with algae, sponges, etc.; on fronds of kelp; on 

 pilings among mussels, tunicates. sponges, hydroids, etc.; abun- 

 dant in beds of Mytilus edulis. Harmothoe extenuata is dredged on 



Figure 27.— Distribution and abundance of Harmothoe extenuata in the New 

 York Bight apex. 



all types of bottom (Pettibone 1963). Our New York Bight apex 

 data agree with these observations in that H. extenuata occurred, 

 usually in small numbers, in all sediment types ranging from coarse 

 sand to silt, with high to low organic levels (Fig. 27; Table 1). 



FEEDING ECOLOGY: H. extenuata possesses a large probos- 

 cis, armed distally with two pairs of amber-colored interlocking 

 jaws. They are slow-moving predators and, despite their strong 

 jaws, feed on small prey (Pettibone 1963; Day 1967). 



REPRODUCTION AND GROWTH: Reproductive strategies of 

 Harmothoe spp. are variable. 



In New Hampshire, female H. extenuata with coral-pink eggs 

 inside the body were found in April 1954; other females were 

 observed with eggs extruded and carried between the parapodia and 

 on the ventral surface (Pettibone 1963). 



Curtis (1977) observed that gametogenesis of H. imbricata (a 

 closely related species) occurred in Greenland throughout autumn 

 and winter with spawning activity confined to spring (March- 

 May). Ripe, large eggs (150-180 urn) were richly supplied with 

 yolk granules at spawning time. Maturity was reached at a length of 

 9-10 mm, with animals attaining a mean size of 6, 12, and 18 mm 

 after their first, second, and third years of life, respectively; most 

 individuals underwent reproductive development during their sec- 

 ond year. 



A population of H. imbricata at Arcachon, France, is described 

 as having a completely planktonic larval development (Cazaux 

 1 968 ) , and Blake ( 1 975 ) has also observed planktonic larvae on the 

 California coast, where the species broods eggs of 120-123 u,m 



19 



