Lophogastrids: Lophogastrida

Lophogastrids (loh-foh-GAS-trids) are long, shrimplike, and usually measure 0.39 to 3.15 inches (10 to 80 millimeters) in length, but one species reaches 13.78 inches (350 millimeters). Both pairs of antennae are branched, or biramous (BY-ray-mus). The outer branches of the second pair of antennae, or exopods, are short and flaplike. The compound eyes are set on stalks. Each eye has multiple individual lenses. The first pair of jaws, or mandibles, is biramous. The larger branch is used to crush food. The smaller branch is used for handling food and for cleaning. The second pair of branched jaws is called the maxillae (mack-SIH-lee). They are bristly and used to filter particles of food from the water.

A shieldlike carapace covers the head and segmented thorax. The carapace is loosely attached to the body and extends forward out over the head in a beaklike projection. It also covers the sides of the body down to the bases of the thoracic limbs. The thoracic limbs, or pereopods (PAIR-ee-oh-pawds), are biramous. Special plates form the marsupium (mar-SOUP-ee-uhm), a special brood pouch for carrying eggs.

Both males and females have well-developed biramous limbs, or pleopods (PLEE-oh-pawds), on the underside of the abdomen. The tip of the abdomen has a pair of long appendages called uropods (YUR-oh-pawds). The uropods are found on either side of a long, pointed tail-segment, or telson. The uropods and telson of this species are distinct and do not form a fanlike tail.