The small sinuous segmented body is enclosed, except for one small opening, in an enormous sac-like carapace, between the lamellae of which are protruded from the body the ovary and " liver," both large, bifurcate and ramified.
Frequently the margins of the carpels, which fold in to the centre, split there into two lamellae, each of which is curved outwards and projects into the FIG.
They may have rudimentary exopodites, and may or may not have branchial filaments or lamellae developed on their posterior faces.
On four feet (i, k,1, m) are the rudiments of the lamellae which subsequently form the brood-cavity.
This body appears to be the source of light, and has behind it a reflector formed of concentric lamellae, while, in front, in some cases, there is a refracting lens.