The Bathyal Holothurians of the New Zealand Region
[Introduction]
Diagnosis: Body elongate, more or less cylindrical. Ventrolateral radii each with large well developed pedicels, distributed throughout the radius. Midventral radius naked, or with some small pedicels. Dorsal processes elongate, flexible, distributed throughout the radii. Calcareous deposits include wheels in large numbers. Gonads branched. Mesenteries as continuous membranes. (After Mortensen, 1927; Deichmann, 1930.)
This family is well defined on the basis of the presence of numerous wheels in all genera. Representatives are found in all depths, and the family is cosmopolitan.
The family Laetmogonidae contains eight genera, of which those known from New Zealand may be distinguished as follows: