Polychaeta
Methods

Mero- and holoplanktonic species of polychaetes are common in plankton communities, and they are collected by commonly used methods, such as standard and horizontal hauls with open or opening-closing nets of different mesh sizes (0.2-0.5 mm). Many species of pelagic polychaetes are very fragile and are often damaged during collection. Nets with large volume: mouth ratios, large cod ends and slow towing speeds improve the condition of the fragile species. Samples are best preserved immediately in 4-5% formalin in filtered seawater neutralized with a borax-saturated solution. Although, long-term preservation in an ethanol solution is not recommended for gelatinous worms, "working specimens" may be kept in a 70% ethanol solution. The glands in the parapodia of the tomopterid polychaetes can be seen with the naked eye, but this requires care and some practice. The chromophil glands stain deeply with haematoxylin which helps to observe these structures.