POLYCHAETE WORMS, PART 1 113 



Key to the New England Genera of SylHdae 



1. Body exceedingly tiny, linear, threadlike. Antennae, tentacular and dorsal 



cirri short, fusiform or subulate. Tentacular cirri 1-2 pairs. Reproduction 

 direct (epigamy), forming sexual epitokes with swimming setae at ma- 

 turity; with large yolky eggs and developing young attached to body of 



female (gestation) 2 



Body larger. Antennae, tentacular and dorsal cirri longer, filiform or clavate. 

 Tentacular cirri 2 pairs 5 



2. Tentacular cirri 2 pairs, similar to antennae and dorsal cirri (fig. 356). 



Brania (p. 133) 

 Tentacular cirri 1 pair (fig. Z5,a,d,e) 3 



3. Tentacular cirri rudimentary, smaller than dorsal cirri (fig. 35d). Antennae 



and dorsal cirri clavate to cylindrical, not inflated basally . Exogone (p. 129) 



Tentacular cirri similar to dorsal cirri. Antennae and dorsal cirri wider 



basally, tapering to slender tips 4 



4. Palps fused on basal third (fig. 35e). Body smooth, without surface papillae. 



Parapionosyllis (p. 132) 



Palps fused for nearly their entire length (fig. 35a). Body covered with 



adhesive papillae, often incrusted with mud . . . Sphaerosyllis (p. 135) 



5. Without vental cirri (fig. 38c). Prostomium with palps poorly developed 



or wanting, fused, turned ventrally (fig. 385). Antennae and dorsal cirri 

 smooth. Reproduction by sexually dimorphic stolons, produced singly 



(fig. 38a) or in chains (fig. 40a) Autolytus (p. 137) 



With ventral cirri (fig. 326) 6 



6. Body short, flattened, with segments few (about 15). With a pair of ciliated 



nuchal epaulettes (fig. 34e) Amblyosyllis (p. 128) 



Body subcylindrical, with segments more numerous. Without nuchal 

 epaulettes 7 



7. Ventral cirri elongate, slender, extending beyond parapodial lobes (fig. 31 A;). 



Antennae and at least some of dorsal cirri clavate, inflated distally ... 8 



Ventral cirri not extending beyond setal lobes. Antennae and dorsal cirri 



filiform 9 



8. With enlarged knobbed acicula in certain number of anterior segments (fig. 



31/b) Streptosyllis (p. 126) 



Without enlarged knobbed acicula Syllides (p. 124) 



9. With a semicircular nuchal hood on tentacular segment, covering posterior 



part of prostomium (fig. 35c). Proboscis with a circlet of large recurved 



teeth Odontosyllis (p. 122) 



Without a semicircular nuchal hood (it may be low and crescent-shaped, 

 fig. 31n). Proboscis with a single large dorsal tooth 10 



10. Antennae and dorsal cirri distinctly moniliform (fig. 32, a, b). Reproduction 



usually by stolons (chaetosyllis stage). Proboscis with smooth chitinous 



rim Syllis (p. 113) 



Antennae and dorsal cirri smooth or indistinctly articled. Reproduction 

 direct (epigamy), forming sexual epitokes with swimming setae at maturity. 

 Proboscis with finely denticled chitinous rim (fig. Sip) . Eusyllis (p. 118) 



Genus Syllis (Savigny, MS.) Lamarck, 1818 



Type (monotypy): Syllis momlaris (Savigny, ms.) Lamarck, 1818. 



The 3 species represented have the body elongate, slender, with 



numerous segments, flattened ventrally, arched dorsally, tapering 



