The buccal segment has a substantial membranous lower lip.The uncini are shaped like combs with a vertical arrangement of 5 to 6 teeth, forming double rows at the posterior thorax. Well-defined ventral pads can be found on segments up to the 15th. Loimia medusa has an elongated body with eye-spots. Its tentacles are lengthy and often display purple bands. The first branchium is frequently larger than the other two. Seventeen segments have narrow-winged capillaries with smooth tips.