Hydroides gracilislive in white tubes and possess a pale yellow to light brown colored body (Bush, 1905). Often times, poking out from these tubes are their branchial crown composed of a left and right lobe with approximately 14 radioles on each lobe (Bastida-Zavala and ten Hove, 2003; Bush and Bush, 1910). In conjunction, they maintain a peduncle and pseudoperculum (Bush, 1905). Their operculum has a funnel with pointed tips and verticil spines that curve inwards without internal, external, or lateral spinules. In addition, they have collar chaetae with two teeth (blunt-elongate, rounded-short, or pointed-short) and capillary chaetae.Their thorax have well-developed membranes with two different sized hooded chaetae (Bastida-Zavala and ten Hove, 2003).
Hydroides gracilislive in fragmentary white tubes with walls that varies in thickness.
Found off the rocky shallow water (0-5 m) coasts of Central to Baja California
