http://www.amazon.com/Field-Guide-Corals-Radiates-Galapagos/dp/0966493249/ref=sr_1_1?ie=UTF8&s=books&qid=1215156745&sr=8-1
A new guidebook on corals and other cnidarians of the Galapagos has been published. The author, Cleveland Hickman Jr., invited JDR in 2007 on a cruise to the islands. Included in the guidebook are several pages on zoanthids. Overall, the guide is very well done. Take a look at JDR's copy or order one yourself!
