Aeolosoma variegatum, Oildrop worm, head and tail of one single individual. Aelosoma is a nearly cosmopolitan genus (the type of the family Aeolosomatidae) comprising minute aquatic oligochaete worms with large prostomia and usually with bright-colored oil globules in the integument. Microscopic contrast technique : Differential interference contrast.Magnification 180x when printed 10 centimetres wide.