Eighteen sterols were identified in Botryllus schlosseri, stanols being the
main sterols. The sterol composition is in agreement with our recent paper
on taxonomic separation of tunicates into three groups. Again;we found in
invertebrates of the Black Sea sterols with a (22Z)-double bond. This confi
rms the presence of such sterols in nature. The composition of the phosphol
ipids appeared to be complex, and twelve groups of them were identified in
Botryllus schlosseri. The main representatives of phospholipids appeared to
be phosphatidylcholine and phosphatidylethanolamine. Only four volatile co
mpounds were identified, which is unusual for marine invertebrates.