Pteropoda
Preservation and collections

Net samples should be sorted before fixation. Naked species are best preserved in formalin, preferably after narcotization (Heyman, 1981). Alcohol is also adequate, and is especially recommended for shelled species in museum collections. Specimens should be handled carefully with small forceps (e.g. entomological aluminium forceps) as the bodies and shells are fragile. A dissecting microscope suffices for observation of most characters, although a compound microscope is required for the buccal organs.

Alcohol-preserved, formalin-preserved, and even dry collections should be kept in the dark. Specimens should not come in contact with wood or cardboard (Moolenbeek, 1994). Glass tubes and jars can be used but, especially for dry collections, glass should be avoided as it affects the shells through a process of recrystalization. All shelled specimens should be properly cleaned with fresh water before storage. Cotton wool is used to cap tubes in dry collections and alcohol-filled bottles, but such stoppers should be wrapped in soft or rice-paper in order to prevent the tiny organisms from becoming entangled in the cotton wool. Whenever possible labels should not be placed in the jar together with the animals, as even a paper label may crush the shells. Dry shells can be handled with a wet brush to which the specimens adhere upon contact, or with fine forceps.

Dissection of the radula, sometimes needed for identification, is achieved by making a cross cut in the ventral side of the neck region and picking out the esophagus at the level of the ganglia. This section of the mouth parts is placed on a slide, the tissues are dissolved with KOH so that the chitinous plates become visible under the microscope. Almost any medium can be used for mounting. Hooks and buccal cones can be accessed by making a cut in the hood over the buccal mass, and the organs can be mounted on microscopic slides as described above for the radula.