Bathynellaceans: Bathynellacea - Physical Characteristics

Bathynellaceans (bath-ee-nel-AYS-see-ans) range in length from 0.02 to 0.14 inches (0.5 to 3.5 millimeters). They do not have eyes and lack any body coloration. The body is divided into a head, thorax, and abdomen. The head may or may not have a beaklike projection, or rostrum. The first pair of antennae, called antennules, is uniramous, or unbranched. The segmented thorax has seven or eight pairs of simple biramous, or branched, legs. There are no leglike thoracic limbs associated with the mouthparts. The six-segmented abdomen may or may not have one or two pairs of small limbs. Bathynellaceans do have a pair of limbs on the end of the body called uropods. The uropods are found on either side of a central projection, or telson.