Nais variabilis Piguet

Recognition

One or 2 dorsal hair chaetae are present and sometimes very long. The 1 to 2 dorsal needle chaetae are bifid and straighter than the ventral chaetae, but the teeth may be small. The ventral chaetae on 2 to 5 have elongate upper teeth and they are longer and abruptly dissimilar to those on segment 6. Ventral chaetae from 6 with teeth about equal. The eyes may be present or absent. The stomach widens suddenly.

Summary

A highly variable species. The length is 3 to 10 mm. It swims with spiral movements.

Distribution

It is widespread and common worldwide.

26 MAY 1996 D.L. Gustafson
AIM home page
dlg@rivers.oscs.montana.edu