10a. Ventral cirri long (Figure 30-46a); composite spinigerous setae 



and capillary superior simple setae absent 



Streptosyllis, p. 30-52 



10b. Ventral cirri short; composite spinigerous setae (Figure 30-48f) 



and capillary superior simple setae (Figure 30-48e) present. . . . 



S t reptospinigera, p. 30-54 



11a. One pair of tentacular cirri Parapionosyllis, p. 30-55 



lib. Two pairs of tentacular cirri 12 



12a. Pharynx with a single middorsal tooth (Figure 30-56a) 13 



12b. Pharynx with a series of large teeth (Figure 30-76g) 16 



13a. Middorsal pharyngeal tooth located posteriorly (Figure 30-56a) . . 



Op is thodonta, p. 30-62 



13b. Middorsal pharyngeal tooth located anteriorly (Figure 30-60a). . . 



14 



14a. Anterior margin of pharynx smooth Pionosyllis, p. 30-65 



14b. Anterior margin of pharynx denticulate 15 



15a. Parapodia long; palps long and linguiform (Figure 30-72a) 



Dioplosyllis, p. 30-77 



15b. Parapodia short; palps maximally as long as prostomiura, not lin- 

 guiform (Figure 30-74a) Eusyllis, p. 30-79 



16a. Pharynx with anterior trepan of polycuspid teeth; nuchal organs as 



cylindrical, projecting epaulettes; occipital flap absent 



Amblyosyllis* 



16b. Pharynx with medial ventral series of teeth (Figure 30-76g); 

 nuchal organs as ciliated ridges along posterior border of prosto- 



raium; occipital flap present (Figure 30-76a) 



Odontosyllis, p. 30-80 



17a. Pharynx with trepan of ten teeth (Figure 30-82h), with or without 

 additional middorsal tooth, or unarmed; body dorsoventrally flat- 

 tened 18 



17b. Pharynx with single middorsal tooth and/or denticulate margin; 

 body usually cylindrical, sometimes flattened 21 



18a. Dorsal cirri articled (Figure 30-82a) 19 



18b. Dorsal cirri globular (Figure 30-96a) 20 



19a. Dorsum smooth; pharynx with trepan .... Trypanosyllis, p. 30-86 



19b. Dorsum with transverse rows of short ridges; pharynx unarmed. . . 



Xenosyllis, p. 30-95 



20a. Dorsum with rows of globular tubercles (Figure 30-94a) 



Eurysyllis, p. 30-97 



20b. Dorsum smooth or with irregular ridges (Figure 30-96a) 



Plakosyllis, p. 30-99 



21a. Middorsal tooth located medially or posteriorly in pharynx (Figure 

 30-98a) Opisthosyllis, p. 30-103 



30-7 



