For taxonomic aims the 70% alcohol fixation is the best. During field works 4% solution of formalin with seawater is suitable, but later in a laboratory formalin must be replaced with alcohol to avoid dissolution of brachial skeleton and spicules in soft tissues. In fixed specimens lophophoral tentacles curl and filtering wall dissociates. Spicules in lophophore, in anterior body-wall and in mantle lobes are seen well under binocular microscope but for deeper investigation and for photo it is necessary to cut out the spicules together with a piece of soft tissue in order to make preparation in glycerin. The simplest way to study brachial skeletons is to examine them in empty shells of dead specimens. All details of skeleton are usually kept well in closed shell full of mud, and it is necessary only to wash it carefully under thin water jet in Petri dish. If there are no dead empty shells in the sample, an average living specimen has to be chosen in order to boil it during 15 minutes in thin solution of KOH or NaOH. Then soft tissues decompose and all details of skeleton become well seen, but when we wash and desiccate the preparation, it will unfortunately crumble very soon, because all skeleton elements composed of separate fibers are consolidated with organic matrix, which we crush in alkali together with lophophore.

The main literature: Hatai, 1940; Konzhukova, 1957; Zezina, 1979, 1985, 1997.