Cystophora moniliformis

Very similar to farnesylacetone, the following com-potmd, which is also isolated from Cystophora moniliformis, has its ketone function engaged in a cyclic hemiketal. 

Reddy, P. and Urban, S. (2008) Linear and cyclic Cjg terpenoids from the Southern Australian marine brown alga Cystophora moniliformis. J. Nat. Prod., 71,1441-1446. 

Van Altena, LA. (1988) Terpenoids from the brown alga Cystophora moniliformis. Aust.J. Chem., 41,49-56. 

---