'' Fuxianhuiids reached a size of up to . The fuxianhuiid exoskeleton was unmineralised, and the number of
tergites (plates on the back associated with body segments) ranged from 15 to over 40. The
cephalon (head section) was covered by a heart-shaped head shield, and contained stalked eyes connected by the
anterior sclerite (a plate-like structure attached to the head), a pair of
antennae, and a butterfly shaped
hypostome (a plate-like structure), which covered the posterior-facing mouth. Fuxianhuiids possessed specialized appendages near the front of the body posterior to the antennae with serrated edges used for food processing, with chengjiangocardids having
gnathobases (basal segments of the limbs close to where they connect with the body with sturdy, thick spines), used for processing food. To the underside of the body were attached numerous pairs of two-branched (
biramous) limbs, with the lower branches (the
endopods), which served as walking legs, having at least 10 segments (
podomeres) and were generally short and similar in appearance to each other along the length of the body, with the frontmost legs of chenjiangocaridids ending in pronounced claws, while the upper branches (the
exopods) of fuxianhuiids were flap-shaped. Fuxianhuiids had a straight
gut tract that ran along the length of the body, with the sides of the gut tract of
Fuxianhuia having pairs of lobe-shaped pockets (diverticulae) associated with each body segment. The
ventral nerve cord, which in arthropods functions analogously to the vertebrate
spinal cord, has reported to have been found preserved in a specimen of
Chengjiangocaris, though the degree of certainty of this identification was later questioned. The brains of fuxianhuiids, based on an exceptionally preserved specimen of
Fuxianhuia are suggested to have been composed of three parts (tri-partite) and to have been relatively complex. == Paleobiology ==