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U.S. NATIONAL IMUSEUM BULLETIN 227 



Female stolon (fig. 39) with 6 prenatatory, 19-24 natatory, and 

 38-48 postnatatory setigers; nuchal epaulettes somewhat triangular, 

 extending on first setiger; pigmented pattern as in stem form, trans- 

 verse reddish brown dorsal bands every 1 to 4 segments, with dark 

 spots on the ventral sides of the parapodia; eggs carried in 3-lobed 

 egg sac; eggs whitish, bright blue or purplish. Male stolon (fig. 37, 

 a, h) with 6 prenatatory, 21-29 natatory, 13-53 postnatatory setigers; 

 body light to dark reddish brown banded, as in stem form. 



Biology. — Found at low water under stones, on pilings, among 

 algae, hydroids, bryozoa. Dredged up to 18 fathoms on gravelly 

 bottom, in sponges, on shells, among bryozoan nodules. Stem form, 

 with sexual buds forming, may be found at any time of year but are 

 especially abundant in June through August (Massachusetts) ; sexual 



mAn 



Figure 38. — Syllidae, Autolyius fasciatus, stem form with bud: a, dorsal view anterior end 

 with head of sexual bud forming between setigers 13 and 14; b, dorsal view anterior end, 

 with bases of antennae and cirri only shown; c, parapodium; d, neuroseta, simple 

 bayonette; e, neuroseta, compound bidentate falciger. 



