specimens to genus. However, juveniles of Heteropodarke and Gyptis have 

 been reported to have less than the normal generic complement of tentac- 

 ular cirri (Dorsey, 1978), so this character should be used with some 

 caution, particularly with small specimens. Other features of generic 

 importance include characteristics of the palps (simple or biarticu- 

 late), parapodia (biramous or subbiramous), and margin of the pharynx 

 (smooth, papillose or fimbriated); presence or absence of the median 

 antenna, jaws, and notosetae; and morphology of the notosetae. 



Species of hesionids are often separated on the basis of setal 

 morphology, both of the notosetae and neurosetae. Notosetae, if pres- 

 ent, may be acicular, capillary, pectinate, or furcate, with various 

 modifications such as spikes (Figure 28-30e) or serrations (Figure 28- 

 30d). The setiger on which notosetae first appear is species-specific 

 in some genera such as Gyptis. Neurosetae are normally composite, long- 

 bladed falcigers, but may include highly modified falcigers (Figure 28- 

 12c-e) and composite spinigers (Figure 28-12g) as in Heteropodarke ; 

 falcigers with spurred blades (Figure 28-20d) as in Nereimyra ; superior 

 and inferior simple setae, particularly on the posterior parapodia of 

 some species; or acicular setae (Figure 28-24e) as in Hesiospina. Other 

 characters such as the presence of a median antenna, eyes, and pigmenta- 

 tion patterns; placement of the median antenna, if present; and relative 

 length of the dorsal cirri, may be used to distinguish species in vari- 

 ous genera. 



Neurosetal blade-length ratios given herein compare the lengths of 

 the longest to shortest blades within a fascicle, usually in the midbody 

 region. All illustrations of the anterior end are from a dorsal or 

 dorsolateral view. All parapodia illustrated are from the midbody 

 region except as noted. 



BIOLOGICAL NOTES 



Hesionids are active, non-tubicolous worms common in shallow water 

 and on hard substrates (Fauchald, 1977a:73), but also found in soft 

 sediments and in deep water. Some of the larger forms such as Hesione 

 and Leocrates are common on coral reefs. The minute members of the 

 Microphthalminae are mostly interstitial. Some hesionids may be commen- 

 sal with terebellids, echinoderms, crustaceans, and sipunculids 

 (Pettibone, 1963:101; Westheide, 1982b:192). 



The larger hesionids are carnivorous, feeding on polychaetes and 

 other small invertebrates; some may be surface deposit-feeders, ingest- 

 ing detritus (Day, 1967:221; Fauchald and Jumars, 1979:217). The inter- 

 stitial species feed on diatoms, bacteria-rich detritus, copepods and 

 f orarainif erans. 



Reproduction has been investigated in few species of hesionids. 

 Swarming occurs in Podarke obscura, with egg-laying and fertilization 

 apparently accomplished at the surface during the evening hours in 

 summer months. Microphthalmus sczelkowii lays eggs in sticky mucus 

 masses early in the year. Nereimyra punctata has large, yolky eggs 

 which develop into yolky, planktonic larvae. The larvae settle to the 

 bottom when they have grown to 7-8 segments; a transitory median antenna 

 and transitory setae on the second and third tentacular segments may 

 appear until the young have reached 18 segments (Pettibone, 1963:103- 

 108). Small interstitial hesionids have reproductive strategies that 

 include copulation. In some species, such as Hesionides arenaria , sexes 



2 8-2 



