Diagnosis: Calcareous deposits include two-armed anchors associated with single perforated anchor plates of varying shapes, which usually have three marginal projections. No rosettes of racquet-shaped plates; no fusiform rods. Phosphatic bodies present, at least in adult specimens.

Type Species: Ankyroderma marenzelleri Theel.

Remarks: This genus was erected (Pawson, 1963) to accommodate those molpadiids with peculiar triradiate anchor plates, and two species, the type species and Ankyroderma tridens Sluiter, were included.

Heteromolpadia marenzelleri (Theel)

For synonymy, see Pawson (1963, p. 11).

Material Examined: Marine Dept., Stn. 2, 2 specimens; Stn. 3, 6 specimens; Stn. 5, 5 specimens; Stn. 16, 2 specimens.

Remarks: Typical specimens, ranging in length from 19mm to 45mm. Colour in alcohol grey, body-wall thin and prickly to the touch. Characteristic anchors, anchor-plates and tables are abundant, and phosphatic deposits are consequently rare.

Distribution: From New Zealand waters in depths ranging between 25 and 720 metres.

Heteromolpadia pikei Pawson

Heteromolpadia pikei Pawson, 1965b, p. 79, Text-fig. 1, figs. 4–6.

Material Examined: Marine Dept. Stn. 2, 1 specimen; Stn. 21, 1 specimen; Stn. 25, 2 specimens.