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