Description
English: A sandcastle worm (Phragmatopoma californica) in the laboratory of Russell Stewart, University of Utah, making a tube out of sand (yellow) and beads of zirconium oxide (white).
Date November 2008
Source University of Utah http://www.unews.utah.edu/p/?r=111008-1&showAllPhotos=true
Author Fred Hayes for the University of Utah
Source: https://commons.wikimedia.org/wiki/File:Sandcastle_worm_in_laboratory_closeup.jpg

The sandcastle worm (Phragmatopoma californica), also called the honeycomb worm or honeycomb tube worm, is a reef-forming marine polychaete worm belonging to the family Sabellarididae. It is dark brown in color with a crown of lavender tentacles and has a length of up to about 7.5 centimeters (3.0 in). The worm inhabits the Californian coast, from Sonoma County to northern Baja California. Order: Canalipalpata, Suborder: Sabellida, Family: Sabellarididae.