1 Blades of some compound chaetae provided with long, basal spurs on margin (Fig. 89B)...................................................................................................................... 2

—— Without basal spurs on blades of compound chaetae (Fig. 88D).................................................. 4

2 Longest blades of compound chaetae lacking basal spurs, only present on medium-length blades.................................................................................. S. spinosus

—— Longest blades of compound chaetae with basal spurs................................................................. 3

3 Dorsal simple chaetae distally rounded, with distal hood (several rows of minute spines, under SEM)............................................................................. S. tam n.sp.

—— Dorsal simple chaetae pointed, without hood............................................................. S. japonicus

4 Dorsal simple chaetae distally rounded, with distal hood (several rows of minute spines, under SEM). Proventricle long, through 4 segments.......................................................................................................................... S. pumilus

—— Dorsal simple chaetae distally bifid, without hood. Proventricle short, through 2 segments............................................................................................. Syllides sp.