Longitudinal muscles form a continuous layer inside the body wall, not split up into bands.
Source: Knight-Jones and Ryland, 1990.
The following taxa of this order occur in the region:
Family Golfingiidae
Genus Golfingia
Genus Nephasoma
Genus Thysanocardia
Family Phascolionidae
Genus Onchnesoma
Genus Phascolion
Golfingia elongata
Golfingia margaritacea
Golfingia vulgaris
Nephasoma minutum
Onchnesoma squamatum
Onchnesoma steenstrupi
Phascolion strombus
Thysanocardia procera