It could be genus Chloeia?

Collecting data would be useful for species, or even genus, id. It looks like an Eurythoe species due to the cushion-shaped structure on the head of the worm, namely caruncle. A related genus, Hermodice, has a thicker and striated caruncle, looking like a peach seed, but it is barely noticeable in the photos. Good luck!

Hello, does not detail about the location where he took the pictures. However in our opinion it seems to be of the genus Hermodice. By the external morphology it seems to be Hermodice carunculata.

You need look the chaetae and take best photos of the anterior end to see the caruncle as well as the type of branchs.

Because of the dorsal pattern color and the shape of the caruncle, I would say that it belong to Euryhtoe. Just take a closer look to the anterior region, the caruncle will be helpful to distinguish among those closely related genera: Hermodice and Eurythoe. See the following links with the images of each caruncle; the former is for Hermodice-like species and the latter for Eurythoe-like ones. All the best!

Hermodice:

http://scienceblogs.com/photosynthesis/2009/08/26/bearded-fireworm-a-macro-study/

Eurythoe:

http://annelida.myspecies.info/sites/annelida.myspecies.info/files/E_complanataPB110102ed.jpg

http://annelida.myspecies.info/sites/annelida.myspecies.info/files/DSCN0711b_0_0.jpg

Hi: seem me isn't Chloeia neither other genus of amphinomids with body shape oval and acute. You need look in that segments begin the branchiae, shape of branchiae, aspect of caruncle and chaetae morphology along body. For me could be a species of Eurythoe. However, need observe arrangemerts and types of chaetae.